concentrations 2 5

Tag: "concentrations" at biology news

Hormonal male contraception reversible after few months for all men

...igin, shorter treatment duration, and higher sperm concentrations at baseline. Although these factors modulated the speed of recovery, spermatogenesis recovered to levels compatible with fertility in all men. Dr Liu and colleagues comment: "Our data provide strong assurance that the previously described efficacy o...

Of mice, men, trees and the global carbon cycle

...if two plants were the same size but had different concentrations of nitrogen in their tissues, the one with the higher nitrogen concentration had a higher respiration rate. Conversely, a big plant and a small plant with the same total nitrogen content would put out equivalent amounts of carbon dioxide over the sam...

Pleasing plant shapes explained by new computer model

...ic scale, simulating cell division and showing how concentrations of the fundamental plant growth hormone auxin appear at regularly-spaced intervals. This creates the striking spiral patterns of seeds observed in sunflowers, daisies, and many other plants. Other patterns, such as branching at right angles observed...

Predicting success

...oncentration to one of low concentration until the concentrations become equal all around. However, in some cancers, even though the material "wants" to spread out evenly, fluids inside the tumor may be exerting pressure to prevent this. When the internal pressure created by these fluids rises above a certain level...

Anthrax spores may survive water treatment

... do not exist as spores," says Calomiris. Higher concentrations of chlorine were much more effective. At 5mg/L (a...ontamination protocols (such as exposure to higher concentrations of chlorine or an alternate disinfectant for an extended period of time) may be needed as regular tr...

Sweet 'water taste' paradoxically predicts sweet taste inhibitors

...ception switches back to sweetness when these high concentrations are rinsed from the mouth with water, resulting in...eparate study that saccharin ?commonly used at low concentrations as an artificial sweetener ?loses its initially sweet taste when tasted at high concentrations. Gal...

Pittsburgh researchers discover that certain chemicals in the blood may indicate brain injury

... and any leftover was frozen so that the biomarker concentrations could later be measured. The infants were then tracked until 1 year of age to determine whether any were subsequently diagnosed as being abused. Researchers were then able to determine how well the biomarkers established which children had SBS, which...

Cholesterol gets 'thumbs up' for role in digit development

... toe. At the site of its synthesis, Sonic hedgehog concentrations are high. It then diffuses out across the developing limb bud, and the declining concentrations (or gradient) of the protein dictate the identity of the other digits. "Questions have remained ab...

Curry and cauliflower could halt prostate cancer

...te cancer cells are barely responsive even to high concentrations of chemotherapeutic agents or radiotherapy. The authors noted that in contrast to the high incidence of prostate cancer in the United States, the incidence of this disease is very low in India. This has been attributed to the dietary consumption of ...

Alternatives to the use of nitrate as a fertiliser

...monium, this substance is not modified in moderate concentrations in the pea but it is so in spinach. Regarding the main metabolic modifications, these take place in the roots in the case of the pea and in the leaves in the case of spinach. Moreover, in the roots of the pea, morphological changes have been observed...

Extinctions linked to climate change

...y, and that the urgency of reducing greenhouse gas concentrations is now undeniable. ...

High resolution 'snapshots' detail dynamics of a cocaine antibody

...their binding ability is severely impaired by high concentrations of the drug. A catalytic monoclonal antibody such as 7A1, on the other hand, has the ability to regenerate after each new dose of the drug, making it far more effective than others in metabolizing cocaine. The study, which will be published in the F...

New test to detect rare proteins in blood

... the blood of breast-cancer patients. Higher blood concentrations of Her2/neu correlate with a lower response rate to chemotherapy and shorter survival time after relapse. The Greene lab developed mouse models that carry cancer cells overexpressing Her2/neu. When these cells are implanted into animals they form t...

Viral 'fitness' explains different resistance patterns to aids drugs

... only emerge, therefore, when challenged with high concentrations of drug. Overall, study findings showed that NNRTI resistance was found less often than PI resistance among patients who took the pills as directed. "We believe that when new drug classes are developed, more attention should be given in defining...

New study reveals promising osteoporosis treatment

...ium phosphate-based supplement that -- even at low concentrations -- significantly improves bone strength and thickness without the side effects of many current drug treatments. Dr. Racquel Z. LeGeros, a Professor of Biomaterials and Biomimetics and of Implant Dentistry, presented her research on the supplement at ...

Evolution follows few of the possible paths to antibiotic resistance

...herichia coli cells against treatment with various concentrations of antibiotic, the scientists found that only a very small fraction of these pathways confer ever-increasing resistance in pathogenic microbes, and are therefore relevant to natural selection. Resistance-granting mutations of beta-lactamase occur in...

Chemical signaling helps regulate sensory map formation in the brain

...discovered, with one receptor drawn toward certain concentrations of Wnt3 and the other driven away. "A repulsive Wnt-Ryk pathway competes with an attractive Wnt-Frizzled interaction," the authors write, "to titrate the response to Wnt3 protein at different concentrations." The net outcome of the competition, the...

New Research Shows Artificial Light at Night Stimulates Breast Cancer Growth in Laboratory Mice

...f the study co-authors. “This is because melatonin concentrations are not elevated during a person’s normal waking hours.?/p> “If the link between light exposure and cancer risk can be confirmed, it could have an immediate impact on the production and use of artificial lighting in this country,?said Richard Ste...

Contaminants linked to sturgeon decline in Columbia river

... the fish living in reservoirs behind the dams had concentrations of chemicals up to 20 times higher than the fish below Bonneville. The contamination was most significant in the reservoir behind the Bonneville Dam, the oldest dam on the river. "We believe that some contaminants are accumulating behind the dams b...

VCU Massey Cancer Center researchers identify a new class of anti-cancer drugs based on platinum

...Researchers compared the cytotoxicity and cellular concentrations of three anti-cancer drugs including the phase II clinical drug, BBR 3464, cisplatin and the new trinuclear platinum compound. In a laboratory model, human ovarian cancer cells were exposed to each drug. "In platinum antitumor chemistry our objecti...

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