Hot and dry deep crustal xenoliths from tibet

Anhydrous metasedimentary and mafic xenoliths entrained in 3-million-year-old shoshonitic lavas of the central Tibetan Plateau record a thermal gradient reaching about 800 degrees to 1000 degrees C at a depth of 30 to 50 kilometers; just before extraction, these same xenoliths were heated as much as 200 degrees C. Although these rocks show that the central Tibetan crust is hot enough to cause even dehydration melting of mica, the absence of hydrous minerals, and the match of our calculated P-wave speeds and Poisson's ratios with seismological observations, argue against the presence of widespread crustal melting.     

Melting of tin teliuride at high pressures

The melting curve of tintelluride (Sn(0.496)Te(0.504) was determined by differential thermal analysis at pressures between 5 and 40 kilobars. Near 844 degrees +/-4 degrees C and 12.0+/-1.0 kb, the liquid and two solid polymorphscoexist.     

Serum C'3 lytic system in patients with glomerulonephritis

The serums of patients with hypocomplementemic glomerulonephritis contain a substance that combines with a normal serum cofactor in the presence of magnesium ion to specifically cleave the third component of complement. This lysis of C'3 is 80 to 90 percent complete in 20 minutes at 37 degrees C and pH 7. Neither the nephritic factor nor its cofactor is identifiable with the complement system.     

Production of hemadsorption-negative areas by serums containing Australia antigen

Exposure of human Wi-38 cells to human serums containing Australia antigen, and presumably serum hepatitis virus, renders the cells refractory to infection by Newcastle disease virus as detected by the hemadsorption-negative plaque test for intrinsic interference. Induction of the Newcastle disease virus refractory state could be passed in cell culture with up to a 1 : 100,000 dilution of material obtained from cells "infected" with serums containing Australia antigen after filtration (0.45-microm pores) and heating to 60 degrees C for 1 hour. Human antiserums to the Australia antigen prevented induction of the Newcastle disease virus refractory state.     

Phase Transformation at High Temperatures in Hafnia and Zirconia

Phase transformation curves for HfO(2) and ZrO(2) have been made. Transformation hysteresis is discussed. The transformation of monoclinic to tetragonal as temperature increases occurs over the range 1000 degrees to 1200 degrees C in ZrO(2), and 1500 degrees to 1600 degrees C in HfO(2). With decreasing temperature the transition back to monoclinic occurs from 970 degrees to 750 degrees C in ZrO(2) and 1550 degrees to 1450 degrees C in HfO(2). These transformations have been visually observed in ZrO(2), but not in HfO(2).     

Rapid bottom melting widespread near Antarctic Ice Sheet grounding lines

As continental ice from Antarctica reaches the grounding line and begins to float, its underside melts into the ocean. Results obtained with satellite radar interferometry reveal that bottom melt rates experienced by large outlet glaciers near their grounding lines are far higher than generally assumed. The melting rate is positively correlated with thermal forcing, increasing by 1 meter per year for each 0.1 degrees C rise in ocean temperature. Where deep water has direct access to grounding lines, glaciers and ice shelves are vulnerable to ongoing increases in ocean temperature.     

Not so hot "hot spots" in the oceanic mantle

Excess volcanism and crustal swelling associated with hot spots are generally attributed to thermal plumes upwelling from the mantle. This concept has been tested in the portion of the Mid-Atlantic Ridge between 34 degrees and 45 degrees (Azores hot spot). Peridotite and basalt data indicate that the upper mantle in the hot spot has undergone a high degree of melting relative to the mantle elsewhere in the North Atlantic. However, application of various geothermometers suggests that the temperature of equilibration of peridotites in the mantle was lower, or at least not higher, in the hot spot than elsewhere. The presence of H(2)O-rich metasomatized mantle domains, inferred from peridotite and basalt data, would lower the melting temperature of the hot spot mantle and thereby reconcile its high degree ofmelting with the lack of a mantle temperature anomaly. Thus, some so-called hot spots might be melting anomalies unrelated to abnormally high mantle temperature or thermal plumes.     

Energetics of hydrogen bond network rearrangements in liquid water

A strong temperature dependence of oxygen K-edge x-ray absorption fine structure features was observed for supercooled and normal liquid water droplets prepared from the breakup of a liquid microjet. Analysis of the data over the temperature range 251 to 288 kelvin (-22 degrees to +15 degrees C) yields a value of 1.5 +/- 0.5 kilocalories per mole for the average thermal energy required to effect an observable rearrangement between the fully coordinated ("ice-like") and distorted ("broken-donor") local hydrogen-bonding configurations responsible for the pre-edge and post-edge features, respectively. This energy equals the latent heat of melting of ice with hexagonal symmetry (ice Ih) and is consistent with the distribution of hydrogen bond strengths obtained for the "overstructured" ST2 model of water.     

Concanavalin A reaction with human normal immunoglobulin G and myeloma immunoglobulin G

Concanavalin A precipitated less than 5 percent of immunoglobulin G from human serum. It reacted with all of 42 myeloma serums of the immunoglobulin G type tested, but no more than approximately 50 percent of the total myeloma protein was ever precipitated. The fact that not all of the protein was precipitated and that the amounts precipitated varied from serum to serum may be interpreted as demonstrating heterogeneity of the carbohydrate in these myeloma proteins. Other glycoproteins precipitated by concanavalin A were identified, and subsequently separated from concanavalin A by chromatography.     

Chloroplast DNA from tobacco leaves

DNA from tobacco leaf chloroplasts was isolated as a single component with a buoyant density in CsCl of 1.702 compared to 1.697 for nuclear DNA. 5-Methylcytosine is present in nuclear DNA but absent in chloroplast DNA. Chloroplast DNA, with a guanine-cytosine content of 43 percent, has a melting temperature of 86 degrees C and renatures completely on slow cooling, whereas nuclear DNA ( melting temperature, 84 degrees C; guanine-cytosine content, 40 percent) does not renature. About 9 percent of the total DNA in tobacco leaves is chloroplast DNA representing about 4.7 xX 10-(15) gram of DNA per chloroplast with a molecular weight of approximately 4 xX 10(7).     

Sulfur Melting and Polymorphism under Pressure: Outlines of Fields for 12 Crystalline Phases

The polymorphism of sulfur has been investigated by static and dynamic methods up to 500 degrees C at 35 kilobars and up to 350 degrees C at 100 kilobars. The melting curve of sulfur to 31 kilobars and phase boundaries of the so-called "4.04-angstrom phase" have been determined. Evidence has been obtained for phase fields of nine new high-pressure forms of sulfur.     

Serpentine stability to mantle depths and subduction-related magmatism

Results of high-pressure experiments on samples of hydrated mantle rocks show that the serpentine mineral antigorite is stable to approximately 720 degrees C at 2 gigapascals, to approximately 690 degrees C at 3 gigapascals, and to approximately 620 degrees C at 5 gigapascals. The breakdown of antigorite to forsterite plus enstatite under these conditions produces 13 percent H(2)O by weight to depths of 150 to 200 kilometers in subduction zones. This H(2)O is in an ideal position for ascent into the hotter, overlying mantle where it can cause partial melting in the source region for calc-alkaline magmas at a depth of 100 to 130 kilometers and a temperature of approximately 1300 degrees C. The breakdown of antigorite in hydrated mantle produces an order of magnitude more H(2)O than does the dehydration of altered oceanic crust.     

Preparation of high-crystallinity polyethylene at low pressures

The preparation of highly crystalline polyethylene at low pressures is reported. With careful control of the substrate, the melting and crystallization schedule, and the physical state of the specimen (film thickness), it is possible to prepare polyethylene having a density in excess of 0.999 gram per cubic centimeter, a melting temperature of approximately 140 degrees C, and a heat of fusion in excess of 70 calories per gram. The approach appears to be general and should be applicable to a wide variety of polymers.     

The Seismic 8degrees Discontinuity and Partial Melting in Continental Mantle

Strong, scattered reflections beyond 8 degrees (8degrees) offset are characteristic features of all high-resolution seismic sections from the continents. The reflections identify a low-velocity zone below approximately 100 kilometers depth beneath generally stratified mantle. This zone may be caused by partial melting, globally initiated at equal depth in the continental mantle. Solid state is again attained at the Lehmann discontinuity in cold, stable areas, whereas the zone extends to near the 400-kilometer discontinuity in hot, tectonically active areas. Thus, the depth to the Lehmann discontinuity may be an indicator of the thermal state of the continental mantle.     

皖北甘薯主栽品种病毒病的检测

用国际马铃薯中心提供的可检测６种甘薯病毒病血清检测试剂盒,采用ＮＣＭ－ＥＬＩＳＡ方法,对皖北甘薯主栽品种及脱毒苗等１２４８个样进行了检测。结果表明：徐薯１８、皖薯１号、５５３、７－３、鲁薯７号、丰产１号、皖薯６号７个品种对６种病毒病血清均呈不同程度的阳性反应。其中以ＳＰＦＭＶ带毒率为３７．０２％,ＳＰＬＶ为１８．２７％、ＳＰＭＭＶ为８．６５％,Ｃ－２为１４．４２％,Ｃ－８为１３．４６％,Ｃ－６为１０．０１％。脱毒核心原原种苗不带毒,脱毒一二代苗及新品种皖薯６号只带ＳＰＦＭＶ病毒。巴西牵牛嫁接法与血清检测法结合应用可达到简单易行、规范化、标准化的目的。脱毒甘薯种植２～３ａ后必须更新。     

Late Bronze Age glass production at Qantir-Piramesses, Egypt

It has been uncertain whether the glass produced during the Late Bronze Age (LBA) originated in Egypt or Mesopotamia. Here we present evidence for the production of glass from its raw materials in the eastern Nile Delta during the LBA. Glass was made in workshops that were separate from where the production of objects took place. The initial melting of the raw materials to semi-finished glass was done at temperatures of 900 degrees to 950 degrees C, followed by coloration and ingot production at 1000 degrees to 1100 degrees C.     

Intermetallic compounds for high-temperature structural use

The next generation of efficient turbines and engines will require materials that can withstand operating temperatures approaching 2000 degrees C. Intermetallic compounds with high melting temperatures are candidates for this application, but the obstacle of their limited ductility must first be overcome. Because the available data on these materials is limited, a survey of the effects of chemistry and crystal structure must be performed. With the use of melting temperature and density as figures of merit, the most likely candidates have been identified for preliminary screening.     

Thermophilic ostracod: aquatic metazoan with the highest known temperature tolerance

The upper lethal temperature for an ostracod of the genus Potamocypris collected from a thermal stream ranged from 49 degrees C for incubation of more than 5 hours to 55.75 degrees C for 1-minute incubations. Field collections were held at 35 degrees C for less than 24 hours before experimental incubations. Calculated temperatues for 50 percent mortality for 60, 40, 20, 10, 5, and 1 minute of exposure were 50.44 degrees , 50.96 degrees , 51.43 degrees , 52.03 degrees , 52.77 degrees , and 55.12 degrees C, respectively.     

Melting of helium at room temperature and high pressure

Helium has been solidified at room temperature. The melting pressure at 24 degrees C is 115 kilobars, in complete agreement with the Simon equation. An original apparatus was developed for this experiment, which allows loading of the cell at room temperature. Applications to various areas of research are suggested.     

Thermal preference and tolerance of alvinellids

The highest oceanic temperatures are found at hydrothermal vents, where the polychaete Paralvinella sulfincola lives on vent sulfides within steep and dynamic thermal gradients. To determine P. sulfincola thermotolerance and preference, we developed a high-pressure aquarium that mimics in situ thermal gradients and permits P. sulfincola to move within the gradient. These polychaetes were thermotaxic, preferring temperatures of 40 degrees to 50 degrees C. Some individuals remained at 50 degrees C for 7 hours (the duration of the experiment), whereas others endured exposure to 55 degrees C for over 15 minutes, demonstrating that alvinellids prefer high temperatures and are among the most thermotolerant of marine organisms.