Elastic Behavior of a Two-dimensional Crystal near Melting

Using positional data from video-microscopy we determine the elastic moduli of two-dimensional colloidal crystals as a function of temperature. The moduli are extracted from the wave-vector-dependent normal mode spring constants in the limit $q\to 0$ and are compared to the renormalized Young's modulus of the KTHNY theory. An essential element of this theory is the universal prediction that Young's modulus must approach $16 \pi$ at the melting temperature. This is indeed observed in our experiment.Comment: 4 pages, 3 figure

Bacillus anthracis diversity in Kruger National Park [South Africa]

The Kruger National Park (KNP), South Africa, has a recorded history of periodic anthrax epidemics causing widespread disease among wild animals. Bacillus anthracis is the causative agent of anthrax, a disease primarily affecting ungulate herbivores. Worldwide there is little diversity among B. anthracis isolates, but examination of variable-number tandem repeat (VNTR) loci has identified six major clones, with the most dissimilar types split into the A and B branches. Both the A and B types are found in southern Africa, giving this region the greatest genetic diversity of B. anthracis worldwide. Consequently, southern Africa has been hypothesized to be the geographic origin of B. anthracis. In this study, the genotypic types of 98 KNP B. anthracis isolates were identified using multiple-locus VNTR analysis. Two major types are evident, the A branch and the B branch. The spatial and temporal distribution of the different genotypes indicates that anthrax epidemic foci are independent, though correlated through environmental cues. Kruger B isolates were found on significantly higher-calcium and higher-pH soils than were Kruger type A. This relationship between genotype and soil chemistry may be due to adaptive differences among divergent anthrax strains. While this association may be simply fortuitous, adaptation of A types to diverse environmental conditions is consistent with their greater geographic dispersal and genetic dissimilarity

Anisotropic elasticity in confocal studies of colloidal crystals

We consider the theory of fluctuations of a colloidal solid observed in a confocal slice. For a cubic crystal we study the evolution of the projected elastic properties as a function of the anisotropy of the crystal using numerical methods based on the fast Fourier transform. In certain situations of high symmetry we find exact analytic results for the projected fluctuations.Comment: 6 pages, 7 figure

Tuning Pt characteristics on Pt/C catalyst for aqueous-phase reforming of biomass-derived oxygenates to bio-H-2

Pt/C catalysts with varied Pt sizes and distributions were investigated for aqueous-phase reforming (APR) of ethylene glycol (EG) to H2. APR experiments were performed on a continuous-flow fixed bed reactor with a catalyst loading of 1 g and EG feeding of 120 mL h−1 at 225 °C and 35 bar for 7 h. The fresh and used Pt/C catalysts were characterized by XRF, BET, CO chemisorption, TEM, XTEM, and XPS. Catalyst preparation protocols changed Pt characteristics on Pt/C catalysts, leading to a distinguishable H2 production. The rates for EG conversion and H2 production increased linearly with mean Pt size (3–11 nm), while having a volcano relationship with the mean size of agglomerated Pt particles (17–30 nm). Pt with concentrated Pt particles on surface of Pt/C catalysts was more preferable for APR of EG than the homogeneously distributed in catalysts. Optimal performance was obtained over a Pt/C-PR catalyst, which was prepared by precipitation method, showing a superb turnover frequency of 248 molH2 molPt−1 min−1 for H2 production from EG in APR. Besides, Pt/C catalysts also showed excellent stability. These results have shown the promise of Pt/C catalyst for APR of EG, which can be extended for bio-H2 production via APR of biomass-derived oxygenates in waste streams

Impact of the European Clinical Trials Directive on prospective academic clinical trials associated with BMT

The European Clinical Trials Directive (EU 2001; 2001/20/EC) was introduced to improve the efficiency of commercial and academic clinical trials. Concerns have been raised by interested organizations and institutions regarding the potential for negative impact of the Directive on non-commercial European clinical research. Interested researchers within the European Group for Blood and Marrow Transplantation (EBMT) were surveyed to determine whether researcher experiences confirmed this view. Following a pilot study, an internet-based questionnaire was distributed to individuals in key research positions in the European haemopoietic SCT community. Seventy-one usable questionnaires were returned from participants in different EU member states. The results indicate that the perceived impact of the European Clinical Trials Directive has been negative, at least in the research areas of interest to the EBMT

Characterization of MAS1-86 Activity in Malaria Parasites

In 2019, ~ 229 million malaria cases were reported globally, causing 409,000 deaths. Malaria is caused by the Plasmodium parasite with cyclical infection in human and Anopheles mosquito host. P. falciparum is the most common species, causing approximately 75% of malaria. Asexual, blood stage parasites cause malaria symptoms. The lifecycle begins with merozoites that invade red blood cells and they develop into rings, then trophozoite, and mature into schizonts. Artemisinin-based combination therapy (ACT) is the first-line treatment for uncomplicated falciparum malaria. Resistance to all artemisinin (ART) is a widespread problem, which is conferred by point mutations in Kelch 13. The K13C580Y mutation is the most abundant in SE Asia. P. falciparum’s apicoplast, an essential organelle that generates fatty acids, heme, and isoprenoid precursors, is a promising drug target since humans lack this organelle. The apicoplast’s primary function in asexual life stages is to produce isoprenoid precursor isopentenyl phosphate (IPP) via the methylerythritol phosphate (MEP) pathway. IPP supplementation has been shown to chemically rescue MEP inhibited cultures. Delayed death phenotype is defined as growth of treated parasite is unaffected, but growth arrest is observed in the progeny. This is seen when apicoplast biosynthesis and apicoplast metabolic pathways are inhibited. The apicoplast-located PfClpC/P complex degrades proteins and has chymotrypsinlike proteolytic activity. PfClpC is a chaperone to the PfClpP protease. P. falciparum 26S proteasome is a cytoplasmic protease with β1, β2, and β5 subunits that have caspase-like, trypsin-like and chymotrypsin-like activity, respectively. WLL, a proteasome inhibitor, targets the β2 and β5 subunits. An analog of MAS1-86 effectively inhibited multi-drug resistant Staphylococcus aureus ClpX, a homolog of PfClpC, in multi-drug resistant S. aureus. Analogs of MAS1-86 were then tested against P. falciparum and MAS1-86 was identified as the most potent inhibitor. We show that MAS1-86 selected parasites display a 6 - 23-fold increase in resistance to MAS1-86. IPP failed to rescue MAS1-86 parasite inhibition nor did MAS1-86 inhibition display a delayed death phenotype, defined as a 10-fold reduction in IC50 values at 120 hours compared to72 hours. We conclude that MAS1-86 does not target the MEP pathway. MAS1-86 inhibition caused a delay in late trophozoite stages through schizont stages, with fewer nuclei observed in schizonts. This observation is of interest since aberrant scizont morphology with fewer nuclei has been reported in auto-inhibited ClpC P. falciparum. There was no shift in the K13 mutant dose response curves, thus K13 haplotype does not influence parasite susceptibility to MAS1-86. MAS1-86-resistant parasites did not show cross-resistance to proteasome β2 and β5 subunit inhibitor, WLL, which has the same chymotrypsin-like activity as ClpP.https://digitalcommons.unmc.edu/surp2021/1052/thumbnail.jp

Alcohol Consumption is associated with Increased CEA Levels in Male Patients with Stage IV Colorectal Cancer- A Single-Institution Retrospective Analysis

Introduction: Alcohol use is an independent risk factor for liver metastasis, a major cause of morbidity and mortality in colorectal cancer (CRC) patients. Serum CEA level is an established prognostic indicator in CRC, yet the correlation with behavioral factors such as alcohol use remains to be defined. In a single-center review, we evaluated alcohol use, gender, and CEA levels in predicting advanced disease in CRC patients. Methods: Retrospective analysis of UNMC patients diagnosed with CRC as the primary cancer between 2012-2019, stages I-IV, and age \u3e19 with documentation of alcohol use. Univariable statistics were performed using Chi-Square and non-parametric tests. Associations between stage, gender, and alcohol use (some vs. none) and the log-transformed CEA outcome (either initial or rate of change) were assessed using linear regressions. Results: Alcohol use was found to be reported in 333 of 1243 CRC patients. The cohort was comprised of 192 male and 141 female subjects. Elevated CEA levels at CRC diagnosis were associated with increased all-cause mortality (33.0% for CEA \u3e 3.4ng/ml vs 10.4% for CEA \u3c 3.4ng/ml). Model analysis found that stage IV male alcohol users showed an increase in serial CEA levels compared to males who did not use alcohol, but this pattern was not observed among stage IV females. Conclusions: Males with a history of alcohol use may be at risk for advanced CRC disease suggesting the utility of serial serum CEA monitoring in these patients. A detailed alcohol use history should be obtained in all patients with CRC as it has prognostic value and may allow for early intervention. This analysis was limited by missing alcohol use data for the majority (73.2%) of CRC patients evaluated. A prospective study is warranted to define the implications of alcohol use and risk of CRC liver metastasis

Genome sequence of Burkholderia pseudomallei NCTC 13392

Here, we describe the draft genome sequence of Burkholderia pseudomallei NCTC 13392. This isolate has been distributed as K96243, but distinct genomic differences have been identified. The genomic sequence of this isolate will provide the genomic context for previously conducted functional studies

Francisella tularensis subsp. novicida isolated from a human in Arizona

<p>Abstract</p> <p>Background</p> <p><it>Francisella tularensis </it>is the etiologic agent of tularemia and is classified as a select agent by the Centers for Disease Control and Prevention. Currently four known subspecies of <it>F. tularensis </it>that differ in virulence and geographical distribution are recognized:<it>tularensis </it>(type A), <it>holarctica </it>(type B), <it>mediasiatica</it>, and <it>novicida</it>. Because of the Select Agent status and differences in virulence and geographical location, the molecular analysis of any clinical case of tularemia is of particular interest. We analyzed an unusual <it>Francisella </it>clinical isolate from a human infection in Arizona using multiple DNA-based approaches.</p> <p>Findings</p> <p>We report that the isolate is <it>F. tularensis </it>subsp. <it>novicida</it>, a subspecies that is rarely isolated.</p> <p>Conclusion</p> <p>The rarity of this <it>novicida </it>subspecies in clinical settings makes each case study important for our understanding of its role in disease and its genetic relationship with other <it>F. tularensis </it>subspecies.</p