Laser Scattering Tomography for the Study of Defects in Protein Crystals

The goal of this research is to explore the application of the non-destructive technique of Laser Scattering Tomography (LST) to study the defects in protein crystals and relate them to the x-ray diffraction performance of the crystals. LST has been used successfully for the study of defects in inorganic crystals and. in the case of lysozyme, for protein crystals

Facing the threat of influenza pandemic - roles of and implications to general practitioners

The 2009 pandemic of H1N1 influenza, compounded with seasonal influenza, posed a global challenge. Despite the announcement of post-pandemic period on 10 August 2010 by theWHO, H1N1 (2009) virus would continue to circulate as a seasonal virus for some years and national health authorities should remain vigilant due to unpredictable behaviour of the virus. Majority of the world population is living in countries with inadequate resources to purchase vaccines and stockpile antiviral drugs. Basic hygienic measures such as wearing face masks and the hygienic practice of hand washing could reduce the spread of the respiratory viruses. However, the imminent issue is translating these measures into day-to-day practice. The experience from Severe Acute Respiratory Syndrome (SARS) in Hong Kong has shown that general practitioners (GPs) were willing to discharge their duties despite risks of getting infected themselves. SARS event has highlighted the inadequate interface between primary and secondary care and valuable health care resources were thus inappropriately matched to community needs

In quest of a systematic framework for unifying and defining nanoscience

This article proposes a systematic framework for unifying and defining nanoscience based on historic first principles and step logic that led to a “central paradigm” (i.e., unifying framework) for traditional elemental/small-molecule chemistry. As such, a Nanomaterials classification roadmap is proposed, which divides all nanomatter into Category I: discrete, well-defined and Category II: statistical, undefined nanoparticles. We consider only Category I, well-defined nanoparticles which are >90% monodisperse as a function of Critical Nanoscale Design Parameters (CNDPs) defined according to: (a) size, (b) shape, (c) surface chemistry, (d) flexibility, and (e) elemental composition. Classified as either hard (H) (i.e., inorganic-based) or soft (S) (i.e., organic-based) categories, these nanoparticles were found to manifest pervasive atom mimicry features that included: (1) a dominance of zero-dimensional (0D) core–shell nanoarchitectures, (2) the ability to self-assemble or chemically bond as discrete, quantized nanounits, and (3) exhibited well-defined nanoscale valencies and stoichiometries reminiscent of atom-based elements. These discrete nanoparticle categories are referred to as hard or soft particle nanoelements. Many examples describing chemical bonding/assembly of these nanoelements have been reported in the literature. We refer to these hard:hard (H-n:H-n), soft:soft (S-n:S-n), or hard:soft (H-n:S-n) nanoelement combinations as nanocompounds. Due to their quantized features, many nanoelement and nanocompound categories are reported to exhibit well-defined nanoperiodic property patterns. These periodic property patterns are dependent on their quantized nanofeatures (CNDPs) and dramatically influence intrinsic physicochemical properties (i.e., melting points, reactivity/self-assembly, sterics, and nanoencapsulation), as well as important functional/performance properties (i.e., magnetic, photonic, electronic, and toxicologic properties). We propose this perspective as a modest first step toward more clearly defining synthetic nanochemistry as well as providing a systematic framework for unifying nanoscience. With further progress, one should anticipate the evolution of future nanoperiodic table(s) suitable for predicting important risk/benefit boundaries in the field of nanoscience

Growth of high {Tc} superconducting fibers using a miniaturized laser-heated float zone process. Progress report, November 6, 1990--December 31, 1991

This report summarizes the progress made on the project ``Growth of High {Tc} Superconducting Fibers Using a Miniaturized Laser-Heated Float Zone Process`` during the 14 month period from Nov. 6, 1990 to Dec. 31, 1991. The studies during this period focused primarily on phase diagram studies, phase relations in the calcium aluminate system and on Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (BSCCO). Some work was also done on the Advanced Fiber Growing Station. Because of the complicated phase relationships found in the incongruently melting BSCCO system, the incongruently melting CA{sub 3}Al{sub 2}O{sub 6} phase of the calcium oxide-aluminum oxide system was studied as a model material. The data obtained was in agreement with well known solidification theory. Fibers grown from calcium oxide rich sources contained calcium oxide nodules which transported from the melting source interface to the growth interface, while those grown from aluminum oxide rich sources contained continuous inclusions of a divorced eutectic. The melt compositions were also found to follow theoretical predictions. The agreement of this data with the phase diagram and solidification theory demonstrates that phase equilibrium information can be extracted from fiber growth experiments. BSCCO feed rods were made from 12 different compositions. Fibers were grown from these rods and the melts were abruptly quenched which preserves the as-grown 2212 fiber, a glassy frozen melt and the source. A future study of these sections will reveal the phase relationships that exist in the BSCCO system. Melt temperature gradients of 500--1,000 C/cm were measured near the interface in these experiments. During this reporting period, work continued on the mechanical components of the Advanced Fiber Growth Station

Retinoic acid receptors initiate induction of the cytomegalovirus enhancer in embryonal cells.

Reactivation of latent virus is believed to result from a signal transduction event that induces immediate-early (IE) gene transcription. Evidence is presented that the major IE promoter (MIEP) of human cytomegalovirus (hCMV) is activated by physiological levels of retinoic acid (RA) in human embryonal carcinoma cells. Mutagenesis experiments localized in the MIEP enhancer, a retinoic acid-responsive element composed of a direct repeat separated by five nucleotides. Protein-DNA binding experiments revealed that this element functions as a specific target site for the direct interaction of nuclear receptor proteins for RA. These findings implicate the biologically active derivative of vitamin A (RA) as a potential modulator of hCMV pathogenesis in infants and immunocompromised adults

Cranberry capsules to prevent nosocomial urinary tract bacteriuria after pelvic surgery: a randomised controlled trial

International audienceOBJECTIVE:To evaluate whether cranberries are able to prevent postoperative urinary bacteriuria in patients undergoing pelvic surgery and receiving transurethral catheterisation.DESIGN:Randomised, double-blind, placebo-controlled trial.SETTINGS:French tertiary Care centre, University Hospital.POPULATION:A total of 272 women undergoing pelvic surgery aged 18 or older.METHODS:Participants undergoing pelvic surgery were randomised to 36 mg cranberry (proanthocyanidins, PAC) or placebo once daily for 10 days. Statistical analysis was performed by a chi-square test.MAIN OUTCOME MEASURES:The primary and secondary outcomes were postoperative bacteriuria, defined by a positive urine culture, within the first 15 and 40 days, respectively.RESULTS:Two hundred and fifty-five participants received the intended treatment: 132 (51.8%) received PAC and 123 (48.2%) received placebo. There were no significant differences in baseline demographics, intra-operative characteristics or duration and type of catheterisation between the two groups. PAC prophylaxis did not reduce the risk of bacteriuria treatment within 15 days of surgery [27% bacteriuria with PAC compared with 25% bacteriuria with placebo: relative risk 1.05, 95% CI 0.78-1.4, P = 0.763). The same result was observed on day 40. Bacteriuria occurred more often in older women with increased length of catheterisation.CONCLUSION:Immediate postoperative prophylaxis with PAC does not reduce the risk of postoperative bacteriuria in patients receiving short-term transurethral catheterisation after pelvic surgery.TWEETABLE ABSTRACT:PAC prophylaxis does not reduce the risk of postoperative bacteriuria in patients undergoing pelvic surgery