10 Fakta Mengenai Lead Element

1. THE ELEMENT LEAD IS EASY TO EXTRACT.

Salah satu sebab orang telah menggunakan plumbum untuk sekian lama adalah kerana ia sangat mudah diambil dari galena, atau sulfida utama. Terima kasih kepada titik lebur rendah 621.4 ° F (bandingkan dengan titik lebur besi, 2800 ° F), yang perlu anda lakukan untuk menciumnya adalah meletakkan batu-batu dalam api, kemudian mengeluarkan ekor dari abu sekali api terbakar.

Galena masih merupakan salah satu daripada sumber utama utama moden. Missouri, pengeluar utama utama di Amerika Syarikat (dan rumah kepada deposit plumbum terbesar di dunia), yang dianggap galena sebagai mineral negara rasmi pada tahun 1967. Galena juga merupakan mineral negara Wisconsin, di mana ia telah dilombong sejak sekurang-kurangnya abad ke-17. Beberapa bandar di seluruh A.S. dinamakan selepas mineral juga, terutamanya Galena, Illinois, salah satu pusat "Rush Lead" Amerika pada abad ke-19.

2. ORANG-ORANG TELAH MENGGUNAKAN LEAD SEPERTI PREHISTORY.

Objek utama sulaman tertua yang pernah ditemui telah ditemui di sebuah gua di Israel pada tahun 2012. Para penyelidik telah bertarikh alat berbentuk tongkat-berpotensi sebagai spindle whorl-hingga akhir 4000 SM, mengesan asal-usulnya untuk memimpin bijih di pergunungan Taurus sekarang Turki.

3. LEAD POISONING BOLEH BATAS.

Lead mempunyai struktur kimia yang sama dengan kalsium. Kedua-duanya mempunyai dua ion caj positif. Kerana itu, di dalam tubuh, logam toksik dapat mengikat protein yang sama sebagai mineral penting. Dari masa ke masa, keracunan plumbum berlaku kerana elemen mengumpul mineral yang diperlukan oleh tubuh anda, termasuk bukan sahaja kalsium, tetapi zat besi, zink, dan nutrien lain.

Kepalanya boleh bergerak melalui badan dengan cara yang sama bahawa mineral-mineral ini boleh, termasuk melalui penghalang darah-otak dan ke tulang. Akibatnya, pendedahan memimpin-sama ada menerusi cat, paip, tanah yang tercemar, atau apa-apa cara lain-boleh menjadi sangat berbahaya, terutamanya untuk kanak-kanak, yang menyebabkan keracunan menyebabkan kecacatan pembelajaran, kelewatan pertumbuhan, kerosakan otak, koma, dan kematian . Para saintis percaya tiada ambang selamat untuk pendedahan plumbum.

4. RAHSIA MAHU RAHSIA TERPAKAI LEAD.

Kegunaan utama mencapai tahap baru semasa Empayar Rom. Rom kuno digunakan untuk membuat alat memasak, paip air, kendi wain, duit syiling, dan sebagainya. Lead acetate juga digunakan sebagai pemanis, paling sering dalam wain. Hasil daripada meminum sedikit memimpin dengan setiap gigitan makanan dan air atau wain, penyelidik moden berpendapat bahawa dua pertiga daripada kaisar Romawi (dan juga banyak rakyat biasa) menunjukkan gejala keracunan plumbum. Pemeriksaan ke atas tubuh Paus Clement II abad ke-20, yang meninggal pada tahun 1047, menunjukkan bahawa keracunan plumbum menyebabkan kematian tiba-tiba pemimpin agama juga-walaupun terdapat beberapa spekulasi sama ada dia diracuni oleh musuh atau jika dia hanya minum terlalu banyak wain memimpin.

5. LEAD ATAU ELEMENT ELEMENT YANG SANGAT.

Pada atom fizik, bilangan 2, 8, 20, 28, 50, 82, dan 126 dianggap sebagai "sihir" kerana bilangan proton atau neutron sepenuhnya mengisi nukleus atom. Lead mempunyai 126 neutron dan 82 proton-dua nombor sihir. Akibatnya, isotop plumbum sangat stabil. Lead-208 adalah atom stabil terberat.

6. LEAD MADE KERETA KERETA SELESAI-DI KOS YANG TINGGI.

Tidak menghairankan bahawa kita tidak lagi menambah petunjuk kepada petrol (majalah TIME menyebutnya sebagai salah satu penemuan terburuk di dunia pada 2010). Tetapi mengapa ia pernah ada di tempat pertama?

Pada tahun 1921, seorang penyelidik General Motors mendapati bahawa penambahan tetraethyl membawa kepada petrol mengurangkan "mesin mengetuk" di dalam kereta, apabila poket udara dan bahan bakar meletup di tempat dan masa yang salah dalam enjin pembakaran. Selain menghasilkan bunyi yang kuat, ia juga merosakkan enjin. Walaupun terdapat bahan kimia lain seperti etanol dan tellurium yang sama-sama dapat memberikan rangsangan oktana untuk mengurangkan mengetuk, petrol yang dipimpin lebih mudah dan lebih murah untuk menghasilkan, dan tidak seperti tellurium, ia tidak reek bawang putih.

Malangnya, ia datang dengan kos yang tinggi untuk pekerja-pekerja kilang penapisan yang menghasilkan gasolin yang dipimpin (yang kebanyakan daripadanya sakit, dipandu gila, dan dibunuh oleh pendedahan mereka) dan alam sekitar secara keseluruhan.

Pada tahun 1960-an, ahli geokimia Clair Patterson cuba untuk mengukur umur sebenar bumi apabila dia menemui sejumlah pencemaran plumbum yang mengejutkan dalam makmalnya-dan semua yang dia uji, dari air kerannya menjadi habuk di udara ke kulit dan sampel kelemumurnya. Ketika dia terus bereksperimen, dia mendapati bahawa paras timbal di lautan air mula meningkat secara drastis sekitar waktu yang sama menjadi bahan tambah gas biasa. Setiap kereta di jalan raya mengetuk memimpin terus ke atmosfera.

Patterson kemudiannya menjadi penggerak dalam memaksa kerajaan A.S. melarang petrol yang diterajui. (Anda boleh membaca lebih lanjut mengenai dia dalam ciri kami, "Ahli Saintifik Paling Penting Anda Pernah Pernah Dengar.")

7. LEAD DIGUNAKAN DALAM ...

Dari segi sejarah, plumbum tidak hanya berharga kerana menjadi logam mudah dibentuk; ia juga dihargai untuk warna. Walaupun sebahagian besar daripada kita tahu bahawa plumbum digunakan secara sejarah dalam cat rumah (dan masih terus bersembunyi di dinding beberapa rumah hari ini), ia juga merupakan ramuan yang popular dalam seni halus selama ribuan tahun.

Diproduksi sejak zaman purba, plumbum putih (juga dikenali sebagai Cremnitz putih) merupakan pigmen cat kegemaran dari Old Master pada abad ke-17 dan ke-18, termasuk artis seperti Johannes Vermeer dan Rembrandt van Rijn.

"Selama dua millennia, karbonat utama membawa karbonat dan sulfat adalah satu-satunya pigmen putih yang dapat memberikan keputihan dan kecerahan yang cukup lama ke dalam dunia kasar dan warna bumi," kata ahli pigmen Juergen H. Braun dan John G. Dickinson. dalam edisi ketiga Sains Gunaan Polimer: Abad ke-21 pada tahun 2000. Seperti beberapa pigmen lain sebelum kedatangan cat sintetik, ketoksikannya adalah pengetahuan umum, tetapi bagi banyak pelukis, risiko itu berbaloi untuk mencapai warna yang mereka mahu Anda masih boleh membelinya hari ini, tetapi sebahagian besarnya telah diganti dengan putih titanium yang lebih selamat.

Memimpin putih bukanlah satu-satunya cat utama yang mengintai di banyak lukisan terkenal dari sejarah. Artis Belanda seperti Vermeer juga menyukai timah kuning kuning, yang dapat anda lihat dalam karya The Milkmaid.

8. ... DAN DALAM MAKEUP.

Pada abad ke-18, kedua-dua lelaki dan wanita menggunakan serbuk plumbum putih untuk mencapai kulit yang berwarna-warni, walaupun diketahui menjadi toksik. Mereka serbuk rambut mereka dengan serbuk plumbum putih juga. Trend berbahaya yang menyebabkan keradangan mata, reput gigi, kebotakan, dan akhirnya, kematian. Untuk mengatasinya, menggunakan serbuk plumbum membuat kulit menjadi gelap dari waktu ke waktu, jadi pemakai perlu menggunakan lebih banyak serbuk untuk mencapai penampilan yang dimaksudkan. Ratu Elizabeth I, yang kehilangan sebahagian besar gigi dan rambutnya pada akhir hidupnya, dilaporkan memakai setem plumbum penuh di wajahnya ketika dia meninggal dunia. Walaupun kematiannya tetap tidak jelas, satu teori popular berpendapat bahawa dia telah dibunuh oleh keracunan darah sejak pergantungannya lama kepada kosmetik yang dipimpinnya.

Penyelidik telah membuat hipotesis bahawa beberapa tokoh sejarah yang terkenal sama ada menderita atau mati akibat keracunan plumbum, termasuk pelukis seperti Vincent van Gogh dan Francisco Goya. Dalam beberapa kes, pengubahsuaian telah membuktikan ini: Analisis 2010 tentang apa yang dianggap sebagai tulang Caravaggio menunjukkan tahap yang sangat tinggi memimpin (cukup untuk memandu dia gila, jika tidak membunuh dia secara langsung) mungkin dari pendedahannya memimpin cat sepanjang hidupnya. Potongan rambut dan tengkorak yang dipercayai milik Ludwig van Beethoven juga menunjukkan paras timbal yang sangat tinggi, berpotensi dari wain yang diminumnya.

9. LEAD IS A SUPERCONDUCTOR.

Yang bermaksud jika ia disejukkan di bawah suhu tertentu, ia akan kehilangan semua rintangan elektrik. Jika anda menjalankan arus melalui dawai plumbum yang mempunyai suhu di bawah 7.2K (-446.71 ° F), ia akan menjalankan arus yang sempurna tanpa kehilangan apa-apa tenaga untuk memanaskan. Semasa berjalan melalui cincin plumbum boleh terus mengalir selama-lamanya tanpa sumber tenaga di luar.

Seperti superkonduktor lain, plumbum diamagnetic-ia ditolak oleh medan magnet.

10. PADA VENUS, IT SNOWS LEAD.

Venus adalah planet terpanas dalam sistem suria, dengan suhu permukaan rata-rata 867 ° F. Itu jauh di atas paras lebur 621.4 ° F. Pada tahun 1995, saintis menemui apa yang kelihatan seperti "salji" logam di pergunungan Venus-sebuah planet terlalu panas untuk mempunyai ais air. Pada tahun 2004, para penyelidik di Universiti Washington di St. Louis mendapati bahawa "salji" Venusian mungkin campuran sulfida plumbum dan bismut sulfida.

Ini "salji" bentuk kerana suhu tinggi Venus menguap mineral di permukaan planet, mewujudkan jenis kabut logam yang, apabila ia mencapai ketinggian yang relatif sejuk, condenser ke dalam fros metalik yang jatuh di puncak tertinggi di planet ini.

sumber

Bagaimana Para Ilmuwan Digunakan 1906 Gambar untuk Cari Pusat Gempa yang paling terkenal di San Francisco

Para penyelidik menggunakan gambar kasar dari sebuah kereta terobosan yang digabungkan dengan akaun saksi untuk menganalisis gempa bumi yang mematikan yang melanda San Francisco lebih 110 tahun yang lalu.

Pada tahun 1906, magnitud 7.9 gempa melanda San Francisco, memusnahkan banyak bandar dan membunuh sebanyak 3,000 orang, menjadikannya salah satu gempa bumi paling dahsyat dalam sejarah. Tetapi ia juga melahirkan sains gempa Amerika moden. Sekarang, penyelidik cuba memahami gempa menggunakan teknik canggih-dan beberapa dokumen lama.

"Penting untuk memahami bagaimana gempa yang lebih besar ini berlaku supaya kami dapat membina bangunan yang lebih selamat," jelas Swetha Veeraraghavan, pensyarah penyelidikan postdoctoral dalam sains pengkomputeran struktur di Makmal Nasional Idaho. "Saya fikir ini jenis saksi mata benar-benar membantu dengan ini. Itulah sebabnya saya mendapati masalah itu sangat keren. "

Para saintis telah cuba menganalisis imej-imej lama dan data saksi mata sebelum untuk memahami lebih baik gempa bumi tahun 1906. Simulasi gempa bumi yang lebih baru berdasarkan data yang lebih banyak dan daya pengkomputeran yang lebih baik mengilhami para penyelidik untuk melihat lagi pada gambar terkenal sebuah lokomotif wap yang duduk di sisinya, yang diambil tak lama setelah gempa itu. Mereka juga memeriksa keterangan konduktor kejadian itu. Akaun 1907 berbunyi:

Di Stesen Point Reyes di kepala Tomales Bay, tren 5:15 untuk San Francisco baru sahaja siap. Konduktor itu baru sahaja mengayunkan diri ketika kereta api itu melanda di timur, diikuti oleh yang lain di barat, yang melemparkan seluruh kereta api di sisinya. Konduktor yang mengejutkan itu turun ketika ia berlalu, dan pada pandangan cerobong jatuh dan memecah tingkap stesen, dia memahami bahawa ia adalah Temblor. Ahli bomba beralih untuk melompat dari enjin ke barat ketika kejutan kembali datang. Dia kemudian melompat ke arah timur dan meminjam kodak dia mengambil gambar kereta api di sini.

Ini mungkin terdengar seperti maklumat yang kurang penting untuk membina semula gempa bumi, tetapi ia menyediakan lebih banyak data daripada yang anda fikirkan. Gempa itu mesti cukup kuat untuk menyebabkan guncangan dan tip keretanya. Pasukan ini memudahkan pengukuran kereta api menjadi prisma segi empat panjang yang panjang, dan mempermudahkan gempa ke gerakan gelombang atas dan bawah tanah. Mereka kemudian menggunakan persamaan yang digambarkan untuk menggambarkan blok segi empat goyang sebagai tindak balas kepada gerak tanah untuk mengira betapa besar gelombang itu mesti dilakukan untuk mengarahkan kereta api.

Analisis mereka mendedahkan bahawa pecutan minimum tanah yang diperlukan untuk membatalkan kereta api itu telah 4 meter sesaat kuasa dua (sedikit kurang daripada separuh percepatan sesuatu yang jatuh ke bumi dalam vakum), manakala halaju minimum adalah 0.5 meter sesaat, atau sekitar 1.6 kaki sesaat.

Di samping analisis mereka mengenai keratan keretapi, penyelidik dapat menganggarkan lokasi gempa bumi gempa bumi - kawasan di mana ia sebenarnya berlaku di Bumi di bawah pusat gempa di permukaan berdasarkan lokasi dan tingkah laku kereta api. Walaupun model terdahulu telah mencadangkan tiga lokasi untuk hypocenter, hasil ini mendedahkan bahawa hanya hypocenter di selatan Point Reyes, California, akan menciptakan semula arah timur, kemudian ke arah barat kereta api, menurut kertas yang diterbitkan dalam Surat Penyelidikan Seismologi. Ini meninggalkan luar pesisir hypocenter dari San Francisco atau berhampiran bandar San Juan Bautista California, mengesahkan anggaran sebelumnya.

Kertas ini datang dengan ketidakpastian-contohnya, penyelidik tidak tahu berapa kereta api ditimbang, dan menggunakan model mudah untuk memahami apa yang berlaku.

Namun, ia mengesahkan satu badan penyelidikan mencipta gempa yang penting ini. Dan ia menunjukkan lebih umum bahawa walaupun tanpa data, petunjuk konteks, akaun saksi, dan gambar dapat membuktikan penting untuk memahami gempa bumi. Veeraraghavan berkata: "Orang-orang bahkan menggunakan batu nisan atau patung-patung yang digulingkan untuk menganggarkan gerakan tanah."

sumber 

100,000 tahun lebih awal daripada disangka.

Dengan galeri utama yang penuh cahaya dan pemandangan Pergunungan Altai di selatan Rusia, Gua Denisova adalah versi zaman Batu dari penthouse Manhattan. Menghadap Sungai Anui, di mana ternakan haiwan yang diminum, ia menawarkan pemandangan yang tidak dapat dilihat untuk mengesan permainan dan manusia lain, serta perlindungan dari ribut Siberia. Generasi Neanderthal, sepupu Denisovan mereka, dan manusia moden menikmati pemandangan.

Tetapi bilakah setiap kumpulan menetap di sana? Waktu itu boleh memberi gambaran tentang bagaimana manusia-manusia yang beragam ini berinteraksi dan menumpahkan cahaya baru kepada yang paling misterius dari tiga, yang Denisovans, yang hanya diketahui oleh DNA dan fosil-fosil yang mengalir dari gua ini. Fosil dan artifak manusia Denisova telah menjadi sangat sukar untuk dikemas kini kerana lapisan lapisan sedimen yang kompleks di dalam tiga biliknya. Sekarang, dua pasukan telah menggabungkan kaedah temu janji yang canggih untuk membuat garis masa penghuni gua.

Bagi Denisovans, hasil yang dilaporkan dalam Alam minggu ini melukis potret ketahanan. Mereka pertama kali berpindah pada 287,000 tahun yang lalu, lebih dari 100,000 tahun lebih awal daripada yang difikirkan, dan kemudian menduduki gua itu dan melalui peralihan iklim hingga 55,000 tahun yang lalu, satu masa ketika Neanderthal juga datang dan pergi. "Gambaran umum sekarang jelas," kata arkeolog Robin Dennell dari University of Sheffield di United Kingdom, yang bukan ahli pasukan dari penyelidikan itu.

sumber

Scientists Have Detected an Enormous Cavity Growing Beneath Antarctica

Antarctica is not in a good place. In the space of only decades, the continent has lost trillions of tonnes of ice at alarming rates we can't keep up with, even in places we once thought were safe.

Now, a stunning new void has been revealed amidst this massive vanishing act, and it's a big one: a gigantic cavity growing under West Antarctica that scientists say covers two-thirds the footprint of Manhattan and stands almost 300 metres (984 ft) tall.

This huge opening at the bottom of the Thwaites Glacier – a mass infamously dubbed the "most dangerous glacier in the world" – is so big it represents an overt chunk of the estimated 252 billion tonnes of ice Antarctica loses every year.

Researchers say the cavity would once have been large enough to hold some 14 billion tonnes of ice. Even more disturbing, the researchers say it lost most of this ice volume over the last three years alone.

"We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it," says glaciologist Eric Rignot from the University of California, Irvine, and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

"Thanks to a new generation of satellites, we can finally see the detail."

Rignot and fellow researchers discovered the cavity using ice-penetrating radar as part of NASA's Operation IceBridge, with additional data supplied by German and French scientists.

According to the readings, the hidden void is but one ice casualty among a "complex pattern of retreat and ice melt" that's taking place at Thwaites Glacier, sectors of which are retreating by as much as 800 metres (2,625 ft) every year.

The complex pattern the new readings reveal – which don't fit with current ice sheet or ocean models – suggest scientists have more to learn about how water and ice interact with one another in the frigid but warming Antarctic environment.

"We are discovering different mechanisms of retreat," first author of the new paper, JPL radar scientist Pietro Milillo explains.

While researchers are still learning new things about the complex ways ice melts at the Thwaite Glacier, at its most basic, the giant cavity represents a simple (if unfortunate) scientific actuality.

"[The size of] a cavity under a glacier plays an important role in melting," Milillo says.

"As more heat and water get under the glacier, it melts faster."

That's important to know, since Thwaites currently accounts for about 4 percent of global sea level rise.

If it were to disappear entirely, the ice held in the glacier could lift the ocean by an estimated 65 centimetres (about 2 ft). But that's not even the worst-case scenario.

The Thwaites Glacier actually holds in neighbouring glaciers and ice masses further inland. If its buttressing force disappeared, the consequences could be unthinkable, which is why it's considered such a pivotal natural structure in the Antarctic landscape.

Just how long it will stay, nobody knows – which is why scientists are right now embarking on a major expedition to learn more about Thwaites.

What they'll find remains to be seen, but it's inarguably among the most important scientific research being conducted in the world right now.

As New York University geoscientist David Holland, who wasn't involved in the current study, told The Washington Post last year: "For global sea-level change in the next century, this Thwaites glacier is almost the entire story."

resource

Israeli Scientists Claim They're On The Path To A Cure For Cancer

It doesn't seem possible. But they say it's true. A small team of Israeli scientists is telling the world they will have the first “complete cure” for cancer within a year, The Jerusalem Post reported on Monday. And not only that, but they claim it will be brief, cheap and effective and will have no or minimal side-effects.

“We believe we will offer in a year’s time a complete cure for cancer,” said Dan Aridor, chairman of the board of Accelerated Evolution Biotechnologies Ltd. (AEBi), a company founded in 2000 in the ITEK incubator in the Kiryat Weizmann Science Park in Ness Ziona, Israel, just north of the Weizmann Institute of Science in Rehovot, Israel. A development-stage biopharmaceutical company engaged in discovery and development of therapeutic peptides, AEBi developed the SoAP platform, a combinatorial biology screening platform technology, which provides functional leads—agonist, antagonist, inhibitor, etc.—to very difficult targets.

Still skepticism was high among those in the know. Weighing in on behalf of the American Cancer Society (ACS) on his blog, “A Cure For Cancer? Not So Fast,” Len Lichtenfeld, MD, ACS chief medical officer cautioned: “…it goes without saying, we all share the aspirational hope that they are correct. Unfortunately, we must be aware that this is far from proven as an effective treatment for people with cancer, let alone a cure."

list several key points that he says must be kept in mind no matter what media reports say:

This is a news report based on limited information provided by researchers and a company working on this technology. It apparently has not been published in the scientific literature where it would be subject to review, support and/or criticism from knowledgeable peers.

My colleagues here at American Cancer Society tell me phage or peptide display techniques, while very powerful research tools for selecting high affinity binders, have had a difficult road as potential drugs. If this group is just beginning clinical trials, they may well have some difficult experiments ahead.

This is based on a mouse experiment which is described as “exploratory.” It appears at this point there is not a well-established program of experiments which could better define how this works—and may not work—as it moves from the laboratory bench to the clinic.

We all have hope that a cure for cancer can be found and found quickly. It is certainly possible this approach may be work. However, as experience has taught us so many times, the gap from a successful mouse experiment to effective, beneficial application of exciting laboratory concepts to helping cancer patients at the bedside is in fact a long and treacherous journey, filled with unforeseen and unanticipated obstacles.

It will likely take some time to prove the benefit of this new approach to the treatment of cancer. And unfortunately–based on other similar claims of breakthrough technologies for the treatment of cancer–the odds are that it won’t be successful.

“Our hopes are always on the side of new breakthroughs in the diagnosis and treatment of cancer. We are living in an era where many exciting advances are impacting the care of patients with cancer,” Lichtenfeld went on. “We hope that this approach also bears fruit and is successful. At the same time, we must always offer a note of caution that the process to get this treatment from mouse to man is not always a simple and uncomplicated journey.”

Called MuTaTo (multi-target toxin), researchers said the drug is essentially "on the scale of a cancer antibiotic–a disruption technology of the highest order."

Aridor told The Jerusalem Post: “Our cancer cure will be effective from day one, will last a duration of a few weeks and will have no or minimal side-effects at a much lower cost than most other treatments on the market. Our solution will be both generic and personal.”

Currently in development by AEBi under the leadership of CEO Dr. Ilan Morad, the potential game-changer in the world-wide fight against cancer will use a combination of cancer-targeting peptides and a toxin that will specifically kill cancer cells.

The Jerusalem Post reported that the anti-cancer drug is based on AEBi's so-called SoAP technology, which belongs to the phage display group of technologies. With it, “scientists introduce DNA coding for a protein, such as an antibody, into a bacteriophage – a virus that infects bacteria. The protein is then displayed on the surface of the phage. Researchers can use these protein-displaying phages to screen for interactions with other proteins, DNA sequences and small molecules.”

A team of scientists won the Nobel Prize last year for their work on phage display in the directed evolution of new proteins – in particular, for the production of antibody therapeutics, The Jerusalem Post reported. “AEBi is doing something similar but with peptides, compounds of two or more amino acids linked in a chain.” According to Morad, peptides have several advantages over antibodies, including that they are smaller, cheaper, and easier to produce and regulate.

According to an article in Elsevier’s Science Direct, peptide therapeutics have played a notable role in medicine since the advent of insulin therapy in the 1920s. “Over 60 peptide drugs are approved in the United States and other major markets, and peptides continue to enter clinical development at a steady pace,” the article states.

The International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) estimates the  global cancer burden to have risen to 18.1 million new cases and 9.6 million deaths in 2018. The IARC reports 1 in 5 men and 1 in 6 women worldwide develop cancer during their lifetime, and 1 in 8 men and 1 in 11 women die from the disease. In addition, every sixth death in the world is due to cancer, making it the second leading cause of death, second only to cardiovascular disease.

Morad said in its infancy, AEBi was essentially “doing what everyone else was doing, trying to discover individual novel peptides for specific cancers.”

But then Morad and his colleague, Dr. Hanan Itzhaki, began attempting to identify why other cancer-killing drugs and treatments didn’t work or eventually failed. And they say they’ve found a way to counter that effect.

Morad said most anti-cancer drugs attack a specific target on or in the cancer cell. “Inhibiting the target usually affects a physiological pathway that promotes cancer. Mutations in the targets – or downstream in their physiological pathways – could make the targets not relevant to the cancer nature of the cell, and hence the drug attacking it is rendered ineffective,” he told The Jerusalem Post.

“In contrast, MuTaTo is using a combination of several cancer-targeting peptides for each cancer cell at the same time, combined with a strong peptide toxin that would kill cancer cells specifically,” Morad said. “By using at least three targeting peptides on the same structure with a strong toxin, we made sure that the treatment will not be affected by mutations; cancer cells can mutate in such a way that targeted receptors are dropped by the cancer.”

“The probability of having multiple mutations that would modify all targeted receptors simultaneously decreases dramatically with the number of targets used,” Morad continued. “Instead of attacking receptors one at a time, we attack receptors three at a time – not even cancer can mutate three receptors at the same time.”

According to Morad, many cancer cells activate detoxification mechanisms when in stress from drugs and the cells pump out the drugs or modify them to be non-functional. Morad told The Jerusalem Post that detoxification takes time, and he’s banking on a strong toxin that will have a high probability of killing the cancer cell before that detoxification occurs.

“Many cytotoxic anticancer treatments aim at fast-growing cells. But cancer stem cells are not fast growing, and they can escape these treatments. Then, when the treatment is over, they can generate cancer again,” The Jerusalem Post reported.

“If it does not completely annihilate the cancer, the remaining cells can start to get mutations again, and then the cancer comes back, but this time it is drug resistant,” Morad said.

Because cancer cells are born out of mutations that occur in cancer stem cells, most of the over-expressed proteins which are targeted on the cancer cell exist in the cancer stem cells. “MuTaTo’s multiple-target attack ensures that they will be destroyed as well,” he said.

Finally, some cancer tumors can erect shields which prohibit large molecules from accessing them. “MuTaTo acts like an octopus or a piece of spaghetti and can sneak into places where other large molecules cannot reach,” Morad said. “The peptide parts of MuTaTo are very small (12 amino acids long) and lack a rigid structure. This should make the whole molecule non-immunogenic in most cases and would enable repeated administration of the drug.”

Morad said AEBi's discovery could also decrease the sickening side-effects of most cancer treatments dramatically, which are the result of drug treatments interacting with the wrong or additional targets, or the correct targets but on non-cancerous cells. “He said MuTaTo’s having a combination of several highly specific cancer-targeting peptides on one scaffold for each type of cancer cell would increase the specificity to the cancer cell due to the avidity effect. In addition, in most cases, the non-cancer cells that have a protein in common with the cancer cells do not over-express it.”

Morad equated the concept of MuTaTo to the triple drug cocktail that has helped change AIDS “from being an automatic death sentence to a chronic – but often manageable – disease.” Today people with AIDS and HIV are carriers of the disease, but they are not sick anymore. And the reason is the combination of drugs they are given.

“Today, AIDS patients take protease inhibitors in combination with two other drugs called reverse transcriptase inhibitors,” The Jerusalem Post reported. “The drug combination disrupts HIV at different stages in its replication, restrains an enzyme crucial to an early stage of HIV duplication and holds back another enzyme that functions near the end of the HIV replication process.”

“We used to give AIDS patients several drugs, but we would administer them one at a time,” Morad explained. “During the course of treatment, the virus mutated, and the AIDS started attacking again. Only when patients started using a cocktail, were they able to stop the disease.”

According to Morad, the MuTaTo cancer treatment will eventually be designed specifically for each person. A piece of each patient’s biopsy will be given to the lab, which will then analyze it to know which receptors are over-expressed, he said. “The individual would then be administered exactly the molecule cocktail needed to cure his disease.”

But unlike with HIV and AIDS, where patients must take the cocktail for the rest their lives, with MuTaTo, the cells would be killed, and the patient could likely stop treatment after only a few weeks.

Aridor said AEBi is in the process of writing patents on specific peptides, which will be a large bank of targeting toxin peptides wholly owned and hard to break.

The company has finished exploratory mice experiments, which “inhibited human cancer cell growth and had no effect at all on healthy mice cells, in addition to several in-vitro trials,” The Jerusalem Post reported.

Next, AEBi will begin a round of clinical trials which could be completed within a few years and would make the treatment available in specific cases.

Resource

Zionis guna dadah hapuskan pemuda Palestin

BUKAN saja dikenakan pelbagai sekatan dan tekanan, rejim Zionis juga menggunakan bahan khayal untuk melemahkan generasi muda Palestin di Baitulmaqdis bagi 'menghapuskan' mereka secara senyap.

Tidak cukup dengan itu, mereka juga diberikan wang untuk membeli bekalan dadah jika kehabisan stok dan taktik itu sudah digunakan sejak beberapa tahun lalu.

Mendedahkan perkara itu, aktivis Ummet Vakfi Turkey Dr Sameer Saed al-Quds berkata, menyasarkan golongan remaja dan pemuda, ia menjadi senjata paling berkesan dalam memastikan generasi muda tidak mampu melawan dan menemui maut secara perlahan-lahan.

"Tindakan ini dilakukan secara senyap, tidak perlu bertempur, baling batu atau bertindak kasar, hanya menggunakan dadah, remaja Palestin akhirnya akan tunduk kepada tentera tanpa paksaan.

"Sehingga kini puluhan ribu remaja di sekitar Kompleks al-Aqsa dan Palestin terbabit dengan penyalahgunaan dadah yang dirancang rapi tanpa disedari banyak pihak.

sumber metro

Penumpang van sekolah haram tiada insurans

AKIBAT menyalahgunakan Lesen Kenderaan Motor (LKM), lapan pengusaha van sekolah haram bakal berdepan hukuman mahkamah apabila kegiatan mereka berjaya dihidu anggota Jabatan Pengangkutan Jalan (JPJ).

Tangkapan terhadap lapan pengusaha berusia 30 hingga 50 tahun dilakukan dalam operasi yang diadakan selama lima hari bermula 20 hingga 24 Januari lalu di sekitar bandar Chukai, Kemaman.

Pengarah JPJ Terengganu, Zulkarnain Mat Yasin berkata, pihaknya memandang serius kesalahan itu kerana penumpang tidak dilindungi insurans sekiranya van berkenaan terbabit dalam kemalangan.

sumber metro

20 anggota JPJ menyamar penumpang bas

SERAMAI 20 anggota dan pegawai Jabatan Pengangkutan Jalan (JPJ) Terengganu menyamar sebagai penumpang bas ekspres bagi mengesan kesalahan dilakukan pemandu sempena Tahun Baru Cina 2019.

Kaedah penyamaran itu dilakukan setiap hari di semua destinasi sepanjang Op Tahun Baru Cina (TBC) 2019 yang diadakan selama dua minggu bermula 29 Januari hingga 12 Februari ini.

Pengarah JPJ Terengganu Zulkarnain Mat Yasin berkata, kaedah penyamaran memberi kesan besar terhadap penguatkuasaan jalan raya dan ia terbukti apabila tidak ada rekod kesalahan yang dikesan dalam Ops TBC 2018 dilakukan pemandu bas ekspres.

“Dalam Op TBC 2018, anggota kita melakukan penyamaran dalam 52 bas manakala pada tahun ini, penyamaran sudah dibuat terhadap 10 bas dan angka itu akan meningkat sehingga tamat operasi.

“Tujuan penyamaran adalah bagi mengesan kesalahan pandu melebihi had, menghisap rokok dan menggunakan telefon bimbit ketika memandu. Setiap kesalahan itu akan dirakam dan saman dikeluarkan kepada pemandu sebaik bas berkenaan tiba di lokasi terakhir.

“Hasil penyamaran mendapati sehingga hari ini kita belum lagi mengeluarkan sebarang saman terhadap pemandu bas ekspres,” katanya pada sidang media sempena pelancaran Ops TBC 2019 bagi Terengganu di Kompleks Hentian Bas Majlis Bandaraya Kuala Terengganu, malam tadi.

Katanya, bagi memastikan setiap bas yang beroperasi di musim perayaan selamat digunakan, JPJ menjalankan pemeriksaan terhadap 68 bas ekspres di lima depot untuk memastikan ia mematuhi aspek keselamatan fizikal ditetapkan seperti brek, tayar dan lampu berfungsi dengan baik.

Zulkarnain berkata, selain penyamaran, pihaknya juga menggunakan beberapa kaedah lain bagi mengesan kesalahan dilakukan pengguna jalan raya antaranya menerusi rakaman video daripada penguat kuasa, rondaan serta aduan orang ramai.

“Op TBC 2019 ini membabitkan seramai 72 pegawai dan anggota dengan menyasarkan penurunan kes kemalangan motosikal kepada 60 peratus sepanjang operasi.

“Motosikal adalah penyumbang utama peningkatan kes kemalangan jalan raya setiap kali musim perayaan,” katanya.

Beliau berkata, dalam pada itu, pihaknya akan memfokuskan tujuh kesalahan utama iaitu gagal mematuhi lampu isyarat, memotong di garisan berkembar, memandu di lorong kecemasan, menggunakan telefon bimbit ketika memandu, tidak memakai tali pinggang keledar, memotong barisan serta memandu di lorong kanan secara berterusan bagi bas dan kenderaan perdagangan bagi mengurangkan kadar kemalangan maut di jalan raya.

“Tindakan tegas akan diambil terhadap mereka yang gagal mematuhi undang-undang ini, yang mana pesalah akan didakwa di mahkamah dan dikenakan denda maksimum RM2,000,”

sumber metro

JPNP gagalkan cubaan curi balak

CUBAAN satu sindiket mencuri lebih 200 batang balak pelbagai spesies dianggarkan bernilai RM200,000 dipatahkan pihak berkuasa di hutan tanah kerajaan di Kampung Batu 21 Jalan Kuantan-Sungai Lembing, Kuantan, malam tadi.

Serbuan Op Tanglung berakhir kira-kira jam 8.30 malam oleh tujuh anggota Seksyen Penguatkuasaan Pahang Timur Jabatan Perhutanan Negeri Pahang (JPNP) itu menemui dua longgok kayu pelbagai spesies dalam hutan dan matau berhampiran sebuah kilang papan.

Difahamkan, anggota penguat kuasa terpaksa berjalan lebih 400 meter melalui jalan balak dan menggunakan lampu ketika membuat pemeriksaan dalam kawasan hutan.

Ketua Penolong Pengarah Penguat Kuasa JPNP, Mohd Rahim Ramli berkata, harga tinggi mendorong sindiket berkenaan cuba mencuri spesies balak seperti meranti damar laut, keruing dan damar hitam.

“Ini kes pertama cubaan memindahkan balak dalam kawasan hutan kerajaan yang terkenal dengan pelbagai spesies pokok balak berkualiti tinggi terutama membabitkan pokok meranti damar laut yang semakin sukar ditemui.

“Kita percaya pokok balak terbabit ditebang beberapa minggu lalu oleh beberapa individu sebelum dipindahkan,” katanya di sini, hari ini.

Mohd Rahim berkata, kejayaan mengesan cubaan memindahkan balak tanpa permit adalah hasil Ops Tanglung 2019 yang dilancarkan Pengarah Jabatan Perhutanan Negeri Pahang, Datuk Dr Mohd Hizamri Mohd Yasin kelmarin.

Katanya, kegiatan menceroboh dan memindahkan balak serta hasil hutan lain dijangka aktif berlaku ketika cuti Tahun Baru Cina dan pihaknya akan membuat pemantauan berterusan.

“Beberapa kawasan hutan yang sebelum ini menjadi tumpuan pencuri balak akan dipantau siang dan malam, saya percaya pihak tidak bertanggungjawab cuba mengambil kesempatan pada musim cuti perayaan ini.

“Permintaan tinggi dan harga balak yang mahal mendorong aktiviti mencuri balak semakin aktif berlaku, kita akan terus menyekat kegiatan terbabit,” katanya yang akan terus melakukan intipan dengan pelbagai cara sebelum membuat serbuan.

sumber metro

Beg 'asli' tipu

KEMENTERIAN Perdagangan Dalam Negeri dan Hal Ehwal Pengguna (KPDNHEP) Kuala Selangor menyerbu dua premis di Sungai Besar yang dipercayai menjual barangan tiruan.

Dalam serbuan jam 11 pagi hingga 2 petang semalam, operasi yang disertai tujuh anggota serta pegawai penguat kuasa KPDNHEP bersama wakil cap dagang merampas pelbagai barangan tiruan bernilai RM2,500.

Ketua Pegawai Penguat kuasa KPDNHEP Kuala Selangor, K Ramesh berkata, operasi itu dijalankan selepas menerima aduan wakil cap dagang yang mendakwa terdapat jualan beg dan dompet tiruan milik syarikatnya di dua premis itu.

“Pemeriksaan di premis berkenaan mendapati kedua-dua premis itu menjual beg galas, beg tangan, topi dan selipar yang menggunakan perihal dagangan palsu jenama terkenal.

“Antara jenama terkenal tiruan yang didapati dalam premis terbabit termasuk Puma, Tommy Hilfiger, Burberry dan Michael Kors yang dijual pada harga murah.

“Kami merampas 96 unit barangan yang disyaki tiruan dengan nilai rampasan dianggarkan berjumlah RM2,500,” katanya.

Beliau berkata, pihaknya juga sudah mengambil keterangan dua lelaki dipercayai pemilik kedua-dua premis berusia lingkungan 40 dan 50 tahun bagi membantu siasatan.

“Kedua-dua kes itu disiasat mengikut Seksyen 8 (2)(b) Akta Perihal Dagangan 201 kerana menawarkan jualan barangan tiruan di premis.

“Sabit kesalahan, kedua-dua peniaga boleh didenda tidak melebihi RM10,000 bagi setiap barangan atau dipenjara tidak melebihi tiga tahun,”

sumber metro

Ganti setiap 4 tahun

KUALA TERENGGANU: Jabatan Bomba dan Penyelamat Malaysia (JBPM) negeri menafikan dakwaan gagal menggantikan kasut keselamatan untuk pegawai dan anggotanya sejak tujuh tahun lalu.

Pengarah JBPM negeri Azlimin Mat Noor berkata, semua pegawai dan anggota bomba sudah diarahkan membuat pertukaran kasut keselamatan yang mengalami kerosakan.

Beliau berkata, proses pertukaran kasut keselamatan yang rosak dilakukan secara berperingkat.

“Semakan dilakukan mendapati penggunaan kasut keselamatan oleh pegawai dan anggota bomba di semua balai di negeri ini hanya dalam tempoh tiga dan empat tahun.

“JBPM negeri baru sahaja menyelesaikan pertukaran kasut keselamatan yang rosak dan koyak di peringkat pertama,” katanya ditemui di pejabatnya semalam.

Azlimin mengulas dakwaan ada antara pegawai dan anggota bomba di negeri ini terpaksa memakai kasut keselamatan rosak serta koyak ketika menyertai operasi terutama operasi memadam kebakaran.

Berdasarkan dakwaan yang tular di laman sosial sejak bulan lalu, pegawai dan anggota bomba terpaksa memakai kasut keselamatan koyak dan rosak ketika menyertai pelbagai operasi.

Azlimin tidak menolak kemungkinan dakwaan itu disebarkan pemilik laman sosial susulan pendedahan baju kalis api yang kini sedang disiasat oleh Suruhanjaya Pencegahan Rasuah Malaysia (SPRM).

Beliau berkata, proses penukaran kasut keselamatan yang rosak dan koyak kini memasuki peringkat kedua.

“Selain untuk pegawai dan anggota bomba bertaraf tetap, JBPM negeri turut membekalkan kasut keselamatan kepada pegawai serta anggota bantuan.

“Dakwaan seperti yang tular di laman sosial mengatakan tiada pengagihan kasut keselamatan baharu sejak tujuh tahun lalu tidak tepat,".

sumber metro

Global Honeybee Deaths Have Been Blamed on the Wrong Culprit All Along

The bees are dying at an alarming rate. Along with pesticides, parasites, and poor nutrition, scientists blame the colony collapse phenomenon on disease. However, one of the most dangerous diseases has just been shown to be quite innocent, revealing the actual threat.

For a long time, scientists blamed the Varroa destructor mite for transmitting deformed wing virus, a disease that does exactly what its name says. They even suspected that these mites make DWV even more deadly to the bees. But in a paper published Tuesday in the journal Proceedings of the Royal Society B, University of Sydney researchers show that it isn’t the virus that’s the problem — it’s the mites.

clip video

Viruses like DWV are normally found in bee populations, experiencing seasonal spikes as they’re transmitted through feces. But despite what was once believed about DWV’s danger, the team hypothesized that it isn’t the virus itself that’s super-deadly — it’s the mite. The mite, they thought, actually supercharged transmission rates among members of a bee colony as the mites bit different bees and passed the disease around.

To test this idea, the researchers extracted biological material from bee pupae and then injected it into others, over and over, simulating a mite biting many individuals in succession. Then, they introduced DWV to the colony and observed its spread, as well as the spread of even more deadly viruses transmitted by varroa mites, called Sacbrood virus (SBV) and Black queen cell virus (BQCV).

Like they hypothesized, DWV rapidly spread through the colony when they simulated the mite bites with the repeated injections, helping to explain how V. destructor mites and DWV seem to go hand-in-hand. More importantly, however, they showed that the mites have been the more destructive force all along. For a virus to spread, its hosts must survive: Dead hosts mean dead ends for a virus, so it actually pays off for a virus to not immediately kill its host. As the very fatal viruses SBV and BQCV spread in the colony, many of the pupae they infected died — which meant that SBV and BQCV levels spiked in the experimental colony then quickly dropped off. But DWV, a much less deadly virus, persisted in the population because it didn’t kill its hosts.

“The arrival of V. destructor quickly selects for an increase in the prevalence of the most virulent viruses until they become so virulent their transmission grinds to a halt due to the death of the brood and thus the mites,” write the authors. “Now more benign viruses such as DWV can make their appearance. Hence, instead of V. destructor directly causing a change in virulence of DWV, DWV is simply more favourable to the mite’s lifecycle and therefore given the upper hand after more virulent species have been selected against.”

In short, varroa mites spread DWV as well as other viruses, but the more virulent infections subsist quickly, giving way to what has always appeared as steady rates of DWV.

Resource

The Midwest is facing record-breaking cold. Blame the polar vortex.

It’s going to get very, very, very cold for millions of people across the Midwestern United States this week.

Fargo, North Dakota, for example, is expected to hit an overnight low of minus 33 degrees Fahrenheit on Wednesday. At that temperature, vodka freezes solid. The daytime high is forecast to be a frigid -18°F. Chicago, which is home to 2.7 million people, might hit a low of -22°F on Wednesday as well.

The windchill — a measure of frostbite risk that combines wind speed and air temperature — is expected to drop even lower across the region, into the negative 60s. At that windchill, frostbite sets in on exposed skin in just five minutes. It’s a dangerous situation; cold temperatures can be deadly.

“Dangerous, potentially life-threatening extreme cold and wind chills are expected,” the Des Moines office of the National Weather Service warns. “This is the coldest air many of us will have ever experienced.”

The forecast continues: “This is not a case of ‘meh, it`s Iowa during winter and this cold happens.’ These are record-breaking cold air temperatures, with wind chill values not seen in the 21st century in Iowa.”

The coldest air is expected to push through the region from Tuesday to Thursday, and it is likely to break records across the region. Overall, the Washington Post reports, the cold outbreak will hit 87 million Americans over the next few days.

Resource

37 Illustrations Prove Living Alone Can Be Awesome

#1 Enjoying Some Peace And Quiet

#2 Playing With Your Pup

#3 Escaping Reality

#4 Working Whenever You Feel Like It

#5 Enjoying A Cup Of Tea While Watching The Rain

#6 Binge Eating All You Want

#7 Dancing Like No One Is Watching (Cause No One Is)

#8 Doing Nothing All Day

#9 Cuddling With Your Best Friend

#10 Being A Little Clumsy

#11 Enjoying The Little Things

#12 Bathing As Long As You Want

#13 Having A Party With Yourself

#14 Snacking Whenever You Feel Like It Without Anyone Judging You

#15 Meditating Without Distractions

#16 Having A Carefree Sort Of Walk

#17 Working The Way You Like

#18 Enjoying A Morning To Yourself

#19 Treating Yourself To A Whole Batch Of Cookies

#20 Enjoying Some Quality Me Time

#21 Dreaming On A Rainy Day

#22 Having Your Puppy Around All The Time

#23 Stretching In The Morning With The Room To Yourself

#24 Taking Your Time In The Mornings

#25 Cleaning However You Like

#26 Creating Your Own “Fine Dining” Rules

#27 Waking Up With Your Pup

#28 Melting Away Your Troubles

#29 Trying On All Your Clothes

#30 Marking Your Territory

#31 Taking It All In On Your Morning Walk

#32 Making A Mess

#33 Working On Your Flexibility

#34 Doing Laundry Wherever You Want

#35 Being By Your Pups Side

#36 Releasing Your Inner Artist

#37 Leaving Your Hair Everywhere Because You Can

Seeking Superpowers in the Axolotl Genome

The axolotl, sometimes called the Mexican walking fish, is a cheerful tube sock with four legs, a crown of feathery gills and a long, tapered tail fin. It can be pale pink, golden, gray or black, speckled or not, with a countenance resembling the “slightly smiling face” emoji. Unusual among amphibians for not undergoing metamorphosis, it reaches sexual maturity and spends its life as a giant tadpole baby.


According to Aztec legend, the first of these smiling salamanders was a god who transformed himself to avoid sacrifice. Today, wild axolotls face an uncertain future. Threatened by habitat degradation and imported fish, they can only be found in the canals of Lake Xochimilco, in the far south of Mexico City.

Captive axolotls, however, are thriving in labs around the world. In a paper published Thursday in Genome Research, a team of researchers has reported the most complete assembly of DNA yet for the striking amphibians. Their work paves the way for advances in human regenerative medicine Many animals can perform some degree of regeneration, but axolotls seem almost limitless in their capabilities.

As long as you don’t cut off their heads, they can “grow back a nearly perfect replica” of just about any body part, including up to half of their brain, said Jeramiah Smith, an associate professor of biology at the University of Kentucky and an author of the paper.

To understand how they evolved these healing superpowers, Dr. Smith and his colleagues looked to the axolotl’s DNA. At 10 times the size of the human genome, the axolotl genome was no small beast to tackle. “This thing’s huge,” said Melissa Keinath, a postdoctoral fellow at the Carnegie Institution for Science in Baltimore and an author of the paper. Building off a previous study, Dr. Keinath and her colleagues mapped more than 100,000 pieces of DNA onto chromosomes, the structures that package DNA in the nucleus of each cell.

Their axolotl genome is the largest genome to be assembled at this level. The scientists used an approach called linkage mapping, which relies on the fact that DNA sequences that are physically close together on a chromosome tend to be inherited together. To identify axolotl-specific DNA, the researchers juxtaposed axolotls with tiger salamanders, which are close relatives.

Specifically, they crossed axolotls and tiger salamanders, then back-crossed these first-generation hybrids with pure axolotls. Tracking patterns of gene inheritance across 48 of these second-generation hybrids, the researchers were able to infer which sequences of DNA belonged to axolotls and where they physically sat along the amphibian’s 14 chromosomes (humans have a greater number of chromosomes, but the axolotl’s are much larger).

It was like “putting together 14 linear puzzles,” said Randal Voss, a professor of neuroscience at the University of Kentucky and an author of the study. In the process of validating their results, they identified a gene mutation that causes a commonly studied heart defect in axolotls, demonstrating that their research will speed up the process of scanning the axolotl genome for mutations in the future. Ultimately, knowing how DNA is positioned along chromosomes “allows you to start thinking about functions and how genes are regulated,” Dr. Voss said.

For instance, much of the genome consists of noncoding DNA sequences that turn genes on and off. Often, these noncoding sequences occur on the same chromosome as the genes they interact with. “Once these relationships are known, then we can ask questions about whether the same kind of controls happen in other animals, like humans,” said Jessica Whited, a professor and limb regeneration expert at Harvard Medical School who was not involved in the study.

Over all, she added, that will help scientists understand whether there are predictable ways to “render humans more like axolotls,” fantastic regenerators of the animal kingdom.




Resource