The Girl I Love I Cannot Call My Own

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Study of the stability of 1alkyl-3-methylimidazolium hexafluoroantimonate(V) based ionic liquids using xray photoelectron spectroscopy

A series of highly pure 1-alkyl-3-methylimidazolium hexafluoroantimonate (V) ionic liquids was firstly investigated by XPS. Reliable binding energy values for all elements within the samples were obtained by applying a C 1s fitting model previously employed for other imidazolium ionic liquids, based on setting the C 1s aliphatic component to 285.0 eV when alkyl chains are longer than 8 carbons. We also observed a straightforward X-ray-mediated photoreduction of Sb (V) to Sb (III) species, i.e. reduction of [SbF6]- anion to volatile SbF3. Thus, binding energies values observed at 542.5 eV and 533.1 eV were attributed to Sb 3d3/2 (V) and Sb 3d5/2 (V), respectively, whereas values at 541.0 eV and 531.7 eV were found for Sb 3d3/2 (III) and Sb 3d5/2 (III), respectively. The SbF3 being formed can be lost either by evaporation and/or redistribution to the bulk. Providing the sample is cooled to freezing temperatures, the SbF3 is prevented from escaping the ionic liquid and it accumulated on the surface of cooled [C4C1Im][SbF6] and [C8C1Im][SbF6]. Particularly in the case of prolonged X-ray exposure of a cooled [C4C1Im][SbF6], an unprecedented further reduction of Sb (III) to Sb (0) was noticed. This study provides fundamental knowledge on the XPS data for antimony compounds as well as providing a step towards the surface analysis of materials composed by antimony species, notably the hexafluoroantimonate (V) anion

Formation routes and structural details of the CaF1 layer on Si(111) from high-resolution noncontact atomic force microscopy data

We investigate the CaF1/Si(111) interface using a combination of high-resolution scanning tunnelling and noncontact atomic force microscopy operated at cryogenic temperature as well as x-ray photoelectron spectroscopy. Submonolayer CaF1 films grown at substrate temperatures between 550 and 600 ◦C on Si(111) surfaces reveal the existence of two island types that are distinguished by their edge topology, nucleation position, measured height, and inner defect structure. Our data suggest a growth model where the two island types are the result of two reaction pathways during CaF1 interface formation. A key difference between these two pathways is identified to arise from the excess species during the growth process, which can be either fluorine or silicon. Structural details as a result of this difference are identified by means of high-resolution noncontact atomic force microscopy and add insights into the growth mode of this heteroepitaxial insulator-on-semiconductor system

Variation in Flight Morphology in a Damselfly with Female-Limited Polymorphism

Background: Female-limited colour polymorphisms occur in many species of dragonflies and damselflies. Often one female morph appears male-like in coloration (androchromes) whereas one or more others are distinct from males (gynochromes). These androchromes are hypothesized to be male-mimics, thereby avoiding the harassment of excessive male mating attempts. Organism: The damselfly Ischnura ramburii, Rambur’s forktail, is a widespread New World species with androchrome and gynochrome females. It was introduced to the Hawaiian Islands in the mid-1970s and females were thought to be exclusively gynochromatic there. Questions: How do males and females differ in their flight apparatus? Do females with different colour morphologies also differ in flight morphology? Hypothesis: Because male-like coloration is sometimes associated with male-like flight behaviours, androchrome females should have more male-like wings than gynochrome females. Methods: We caught individuals of I. ramburii in the field from seven populations on three of the Hawaiian Islands and three populations in Texas (part of its native range). Using digitized wing and body images, we compared body size, wing size, and wing shape between sexes, between female morphs, and among geographic regions. Results: Male I. ramburii are smaller than females and have smaller, more slender wings. Although androchromes are absent from the Big Island of Hawaii, both androchrome and gynochrome females are common on Oahu and Kauai. Androchrome females are indistinguishable from gynochrome females in all aspects of their flight apparatus except for forewing size, which is smaller than that of gynochromes and thus more-male like. Wing shape and size vary geographically. Body- and wing-size differences between males and females are consistent across regions, although the degree and direction of sexual dimorphism in wing shape are not

An antimicrobial impregnated urinary catheter that reduces mineral encrustation and prevents colonisation by multi-drug resistant organisms for up to 12 weeks

Two major complications of indwelling urinary catheterisation include infection and mineral encrustation of the catheter. Our antimicrobial urinary catheter (AUC) impregnated with rifampicin, triclosan, and sparfloxacin has demonstrated long-term protective activity against major uropathogens. This study aimed to firstly assess the ability of the AUC to resist mineral encrustation in the presence and absence of bacteria. Secondly, it aimed to investigate the AUC’s anti-biofilm activity against multi-drug resistant organisms. There was no difference in surface roughness between AUC and control segments. In a static and a perfusion model, phosphate deposition was significantly reduced on AUCs challenged with P. mirabilis. Furthermore, none of the AUCs blocked during the 28 day test period, unlike controls. The AUC prevented colonisation by methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, extended-spectrum beta-lactamase producing E. coli, and carbapenemase-producing E. coli for 12 consecutive weekly challenges. All three drugs impregnated into the catheter continued to exert protective activity throughout 12 weeks of constant perfusion. The drugs appear to migrate into the crystalline biofilm to continually protect against bacteria not it direct contact with the catheter surface. In conclusion, the AUC reduces mineral encrustation and may increase time to blockage in the presence of P. mirabilis, and does not predispose to mineral deposition under other conditions. It also offers 12 weeks of protection against multi-drug resistant bacteria

Links between Anr and Quorum Sensing in Pseudomonas aeruginosa Biofilms

In Pseudomonas aeruginosa, the transcription factor Anr controls the cellular response to low oxygen or anoxia. Anr activity is high in oxygen-limited environments, including biofilms and populations associated with chronic infections, and Anr is necessary for persistence in a model of pulmonary infection. In this study, we characterized the Anr regulon in biofilm-grown cells at 1% oxygen in the laboratory strain PAO1 and in a quorum sensing (QS)-deficient clinical isolate, J215. As expected, transcripts related to denitrification, arginine fermentation, high-affinity cytochrome oxidases, and CupA fimbriae were lower in the Δanr derivatives. In addition, we observed that transcripts associated with quorum sensing regulation, iron acquisition and storage, type VI secretion, and the catabolism of aromatic compounds were also differentially expressed in the Δanr strains. Prior reports have shown that quorum sensing-defective mutants have higher levels of denitrification, and we found that multiple Anr-regulated processes, including denitrification, were strongly inversely proportional to quorum sensing in both transcriptional and protein-based assays. We also found that in LasR-defective strains but not their LasR-intact counterparts, Anr regulated the production of the 4-hydroxy-2-alkylquinolines, which play roles in quorum sensing and interspecies interactions. These data show that Anr was required for the expression of important metabolic pathways in low-oxygen biofilms, and they reveal an expanded and compensatory role for Anr in the regulation of virulence-related genes in quorum sensing mutants, such as those commonly isolated from infections

Duplex DNA from Sites of Helicase-Polymerase Uncoupling Links Non-B DNA Structure Formation to Replicative Stress

BACKGROUND: Replication impediments can produce helicase-polymerase uncoupling allowing lagging strand synthesis to continue for as much as 6 kb from the site of the impediment. MATERIALS AND METHODS: We developed a cloning procedure designed to recover fragments from lagging strand near the helicase halt site. RESULTS: A total of 62% of clones from a p53-deficient tumor cell line (PC3) and 33% of the clones from a primary cell line (HPS-19I) were within 5 kb of a G-quadruplex forming sequence. Analyses of a RACK7 gene sequence, that was cloned multiple times from the PC3 line, revealed multiple deletions in region about 1 kb from the cloned region that was present in a non-B conformation. Sequences from the region formed G-quadruplex and i-motif structures under physiological conditions. CONCLUSION: Defects in components of non-B structure suppression systems (e.g. p53 helicase targeting) promote replication-linked damage selectively targeted to sequences prone to G-quadruplex and i-motif formation

The Oldest Mineralized Bryozoan? A Possible Palaeostomate in the Lower Cambrian of Nevada, USA

All skeletal marine invertebrate phyla appeared during the Cambrian explosion, except for Bryozoa with mineralized skeletons, which first appear in the Early Ordovician. However, the skeletal diversity of Early Ordovician bryozoans suggests a preceding interval of diversification. We report a possible earliest occurrence of palaeostomate bryozoans in limestones of the Cambrian Age 4 Harkless Formation, western United States. Following recent interpretations of the early Cambrian Protomelission as a soft-bodied bryozoan, our findings add to the evidence of early Cambrian roots for the Bryozoa. The Harkless fossils resemble some esthonioporate and cystoporate bryozoans, showing a radiating pattern of densely packed tubes of the same diameter and cross-sectional shape. Further, they show partitioning of new individuals from parent tubes through the formation of a separate wall, a characteristic of interzooecial budding in bryozoans. If confirmed as bryozoans, these fossils would push back the appearance of mineralized skeletons in this phylum by ~30 million years and impact interpretations of their evolution

Teaching Musculoskeletal Physical Diagnosis Using A Web-based Tutorial and Pathophysiology-Focused Cases

ObjectiveTo assess the effectiveness of an experimental curriculum on teaching first-year medical students the musculoskeletal exam as compared to a traditional curriculum.BackgroundMusculoskeletal complaints are common in the primary care setting. Practitioners are often deficient in examination skills and knowledge regarding musculoskeletal diseases. There is a lack of uniformity regarding how to teach the musculoskeletal examination among sub-specialists. We propose a novel web-based approach to teaching the musculoskeletal exam that is enhanced by peer practice with pathophysiology-focused cases. We sought to assess the effectiveness of an innovative musculoskeletal curriculum on the knowledge and skills of first-year medical students related to musculoskeletal physical diagnosis as compared to a traditional curriculum. The secondary purpose of this study was to assess satisfaction of students and preceptors exposed to this teaching method.MethodsThis quasi-experimental study was conducted at a single LCME-accredited medical school and included a convenience sample from 2 consecutive classes of medical students during the musculoskeletal portion of their physical diagnosis class. We conducted a needs assessment of the traditional curriculum used to teach musculoskeletal examination. The needs assessment informed the development of an experimental curriculum. One class (control group) received the traditional curriculum while the second class (experimental group) received the experimental curriculum, consisting of a web-based musculoskeletal tutorial, pathophysiology-focused cases, and facilitator preparation. We used multiple-choice questions and musculoskeletal OSCE scores to assess differences between knowledge and skills in the 2 groups.ResultsThe sample consisted of 140 students in each medical school class. There were no statistically significant differences between the 2 groups. One hundred seven students from the control group and 120 students from the experimental group took the multiple-choice examination. The average score was 66% (95% CI= 59.7-72.3) for the control group and 66% (95% CI = 60.5-71.5) for the experimental group. There was no difference between the median musculoskeletal OSCE scores between the 2 groups. The experimental group was satisfied with the new teaching method and gained the additional benefit of a persistent resource.ConclusionsThis web-based experimental curriculum was as effective as the traditional curriculum for teaching the musculoskeletal exam. Additionally, users were satisfied with the web-based training and benefited from a persistent resource

Optimal iron content in ready-to-use therapeutic foods for the treatment of severe acute malnutrition in the community settings: A protocol for the systematic review and meta-analysis

Introduction: The current standard of care for children with severe acute malnutrition (SAM) involves using ready-to-use therapeutic food (RUTF) to promote growth; however, the precise formulation to achieve optimal recovery remains unclear. Emerging research suggests that alternative RUTF formulations may be more effective in correcting SAM-related complications such as anaemia and iron deficiency. This systematic review commissioned by the WHO aims to synthesise the most recent research on the iron content in RUTF and related products in the community-based treatment of uncomplicated severe malnutrition in children aged 6 months and older. Methods and analysis: We will search multiple electronic databases. We will include randomised controlled trials and non-randomised studies with a control arm. The intervention group will be infants who received RUTF treatments other than the current recommended guidelines set forth by the WHO. The comparison group is children receiving RUTF containing iron at the current WHO-recommended level of 1.9 mg/100 kcal (10-14 mg/100 g). The primary outcomes of interest include blood haemoglobin concentration, any anaemia, severe anaemia, iron-deficiency anaemia, recovery from SAM and any adverse outcomes. We will use meta-analysis to pool findings if sufficient homogeneity exists among included studies. The risk of bias in studies will be evaluated using the Cochrane risk of bias-2. We will use the Grading of Recommendations Assessment, Development, and Evaluation(GRADE) approach to examine the overall certainty of evidence. Ethics and dissemination: This is a systematic review and will not involve direct contact with human subjects. The findings of this review will be published in a peer-reviewed journal and will guide the WHO\u27s recommendation on the optimal iron content in RUTFs for the treatment of SAM in children aged 6-59 month