The continued value of disk diffusion for assessing antimicrobial susceptibility in clinical laboratories: Report from the Clinical and Laboratory Standards Institute Methods Development and Standardization Working Group

Expedited pathways to antimicrobial agent approval by the U.S. Food and Drug Administration (FDA) have led to increased delays between drug approval and the availability of FDA-cleared antimicrobial susceptibility testing (AST) devices.</jats:p

Novel bioanocatalysis for chromium (VI) remediation

Many industrial wastewater' s contain carcinogenic and mutagenic Cr (VI). Conversion to Cr(III) reduces toxicity. Desulfovibrio vulgaris NCIMB 8303 and Microbacterium sp. NCIMB 13776 immobilized in agar reduced Cr(VI) at initial rates of 127 and 15 nmol h$^{-1}$ mg dry cell wf$^{-1}$ in batch, and for 160 h in continuous-flow packed-bed columns. Similar columns containing agar-immobilized Bio-Pd(O) (Pd(II) was reduced to ceil-bound Pd(O) using growth decoupled cells of D. vulgaris) reduced Cr(VI) in excess of 1334 h. Bio-Pd(O) produced using Desulfovibrio species was catalytically superior to Bio-Pd(O) produced using Escherichia coli species. Application of enzyme kinetics to the immobilized Bio-Pd(O) system gave an apparent K$_{m}$ value of 650 μM for batch reduction, and 430 μM for continuous-flow. Magnetic Resonance Imaging (MRI) was used to demonstrate immobilization matrix integrity, homogeneity within agar beads, and to distinguish between columns containing Cr(III) and Cr(VI), suggesting it may be possible to study Cr(VI) reduction non-invasively in vivo using MRI. Biologically produced hydrogen was used in conjunction with resting and palladised cells of D. vulgaris for Cr(VI) reduction, and a system proposed for the concurrent treatment of industrial sugar wastes, precious metal scrap and Cr(VI)

Lévy flights in human behavior and cognition

Lévy flights represent the best strategy to randomly search for a target in an unknown environment, and have been widely observed in many animal species. Here, we inspect and discuss recent results concerning human behavior and cognition. Different studies have shown that human mobility can be described in terms of Lévy flights, while fresh evidence indicates that the same pattern accounts for human mental searches in online gambling sites. Thus, Lévy flights emerge as a unifying concept with broad cross-disciplinary implications. We argue that the ubiquity of such a pattern, both in behavior and cognition, suggests that the brain regions responsible for this behavior are likely to be evolutionarily old (i.e. no frontal cortex is involved), and that fMRI techniques might help to confirm this hypothesis

Terrestrial temperature evolution of southern Africa during the late Pleistocene and Holocene:Evidence from the Mfabeni Peatland

The scarcity of suitable high-resolution archives, such as ancient natural lakes, that span beyond the Holocene, hinders long-term late Quaternary temperature reconstructions in southern Africa. Here we target two cores from Mfabeni Peatland, one of the few long continuous terrestrial archives in South Africa that reaches into the Pleistocene, to generate a composite temperature record spanning the last ∼43 kyr. The Mfabeni Peatland has previously been proven suitable for temperature and hydrological reconstructions based on pollen and geochemical proxies. Here we use branched glycerol dialkyl glycerol tetraethers (brGDGTs) preserved in the Mfabeni peatland to derive a new quantitative air temperature record for south-east Africa. Our temperature record generally follows global trends in temperature and atmospheric CO2 concentrations, but is decoupled at times. Annual air temperatures during Marine Isotope Stage (MIS) 3 were moderately high (c. 20.5 °C), but dropped by c. 5 °C during the Last Glacial Maximum, reaching a minimum at c.16–15 ka. Asynchronous with local insolation, this cooling may have resulted from reduced sea surface temperatures linked to a northward shift in the Southern Hemisphere westerly winds. Concurrent with the southward retreat of the westerlies, and increasing sea surface temperatures offshore, warming from minimum temperatures (c. 15.0 °C) to average Holocene temperatures (c. 20.0 °C) occurred across the deglaciation. This warming was briefly but prominently interrupted by a millennial-scale cooling event of c. 3 °C at c. 2.4 ka, concurrent with a sudden change in hydrological conditions. The average Holocene temperatures of c. 20.0 °C were similar to those reconstructed for MIS 3, but after the 2.4 ka cooling period, air temperatures in the Mfabeni peat recovered and steadily increased towards the present. In summary, our record demonstrates that land temperature in eastern South Africa is highly sensitive to global drivers as well as nearby sea surface temperatures

The Salmonella enterica Serotype Typhimurium lpf, bcf, stb, stc, std, and sth Fimbrial Operons Are Required for Intestinal Persistence in Mice

Salmonella enterica serotype Typhimurium causes human infections that can frequently be traced back through the food chain to healthy livestock whose intestine is colonized by the pathogen. Little is known about the genes important for intestinal carriage of S. enterica serotype Typhimurium in vertebrate animals. Here we characterized the role of 10 fimbrial operons, agf, fim, lpf, pef, bcf, stb, stc, std, stf, and sth, using competitive infection experiments performed in genetically susceptible (BALB/c) and resistant (CBA) mice. Deletion of agfAB, fimAICDHF, lpfABCDE, pefABCDI, bcfABCDEFG, stbABCD, stcABCD, stdAB, stfACDEFG, or sthABCDE did not reduce the ability of S. enterica serotype Typhimurium to colonize the spleen and cecum of BALB/c mice 5 days after infection. Similarly, deletion of agfAB, fimAICDHF, pefABCDI, and stfACDEFG did not result in reduced recovery of S. enterica serotype Typhimurium from fecal samples collected from infected CBA mice over a 30-day time period. However, S. enterica serotype Typhimurium strains carrying deletions in lpfABCDE, bcfABCDEFG, stbABCD, stcABCD, stdAB, or sthABCDE were recovered at significantly reduced numbers from the feces of CBA mice. There was a good correlation (R(2) = 0.9626) between competitive indices in the cecum and fecal samples of CBA mice at 30 days after infection, suggesting that the recovery of S. enterica serotype Typhimurium from fecal samples closely reflected its ability to colonize the cecum. Collectively, these data show that six fimbrial operons (lpf, bcf, stb, stc, std, and sth) contribute to long-term intestinal carriage of S. enterica serotype Typhimurium in genetically resistant mice

A Custom, High-Channel-Count Data Acquisition System for Chemical Species Tomography of Aero-Jet Engine Exhaust Plumes

The fiber-laser imaging of gas turbine exhaust species project aims to provide a video-rate imaging (100 frames/s) diagnostic tool for application to the exhaust plumes of the largest civil aero-jet engines. This remit, enabled by chemical species tomography (CST) currently targeting carbon dioxide (CO 2 ), requires system design that facilitates expansion of multiple parameters. Scalability is needed in order to increase imaging speeds and spatial resolutions and extends the system toward other pertinent gases such as the oxides of nitrogen and sulfur and unburnt hydrocarbons. This paper presents a fully scalable, noninvasive instrument for installation in a commercial engine testing facility, technical challenges having been tackled iteratively through bespoke optical and mechanical design, and it specifically presents the high-speed data acquisition (DAQ) system required. Measurement of gas species concentration is implemented by tunable diode laser absorption with wavelength modulation spectroscopy (TDLAS-WMS) using a custom, high-speed 10-40-MS/s/channel 14-bit DAQ. For CO 2 tomography, the system uses six angular projections of 21 beams each. However, the presented DAQ has capacity for 192 fully parallel 10-Hz-3-MHz differential inputs, achieving a best-case signal-to-noise ratio (SNR) of 56.5 dB prior to filtering. A 12 Ethernet-connected digitization nodes based on field-programmable gate array technology with software control are distributed around a 7-m-diameter mounting “ring.” Hence, the high data rates of 8.96-Gb/s per printed circuit board and 107.52 Gb/s for the whole system can be reduced by using local digital lock-in amplifiers. We believe that this DAQ system is unique in both the TDLAS and CST literatures

Molecular and Phenotypic Analysis of the CS54 Island of Salmonella enterica Serotype Typhimurium: Identification of Intestinal Colonization and Persistence Determinants

The shdA gene is carried on a 25-kb genetic island at centisome 54 (CS54 island) of the Salmonella enterica serotype Typhimurium chromosome. In addition to shdA, the CS54 island of Salmonella serotype Typhimurium strain LT2 contains four open reading frames designated ratA, ratB, sivI, and sivH. DNA hybridization analysis revealed that the CS54 island is comprised of two regions with distinct phylogenetic distribution within the genus Salmonella. Homologues of shdA and ratB were detected only in serotypes of Salmonella enterica subsp. I. In contrast, sequences hybridizing with ratA, sivI, and sivH were present in S. enterica subsp. II and S. bongori in addition to S. enterica subsp. I. Deletion of the ratA and sivI genes did not alter the ability of Salmonella serotype Typhimurium to colonize the organs of mice. Insertional inactivation of the sivH gene resulted in defective colonization of the Peyer's patches of the terminal ileum but normal colonization of the cecum, mesenteric lymph nodes, and spleen. Deletion of the shdA gene resulted in decreased colonization of the cecum and Peyer's patches of the terminal ileum and colonization to a lesser degree in the mesenteric lymph nodes and spleen 5 days post-oral inoculation of mice. A strain containing a deletion in the ratB gene exhibited a defect for the colonization of the cecum but not of the Peyer's patches, mesenteric lymph nodes, and spleen. The shdA and ratB deletion strains exhibited a shedding defect in mice, whereas the sivH deletion strain was shed at numbers similar to the wild type. These data suggest that colonization of the murine cecum is required for efficient fecal shedding in mice

Coracoid Abnormalities and Their Relationship with Glenohumeral Deformities in Children with Obstetric Brachial Plexus Injury

<p>Abstract</p> <p>Background</p> <p>Patients with incomplete recovery from obstetric brachial plexus injury (OBPI) usually develop secondary muscle imbalances and bone deformities at the shoulder joint. Considerable efforts have been made to characterize and correct the glenohumeral deformities, and relatively less emphasis has been placed on the more subtle ones, such as those of the coracoid process. The purpose of this retrospective study is to determine the relationship between coracoid abnormalities and glenohumeral deformities in OBPI patients. We hypothesize that coracoscapular angles and distances, as well as coracohumeral distances, diminish with increasing glenohumeral deformity, whereas coracoid overlap will increase.</p> <p>Methods</p> <p>39 patients (age range: 2-13 years, average: 4.7 years), with deformities secondary to OBPI were included in this study. Parameters for quantifying coracoid abnormalities (coracoscapular angle, coracoid overlap, coracohumeral distance, and coracoscapular distance) and shoulder deformities (posterior subluxation and glenoid retroversion) were measured on CT images from these patients before any surgical intervention. Paired Student t-tests and Pearson correlations were used to analyze different parameters.</p> <p>Results</p> <p>Significant differences between affected and contralateral shoulders were found for all coracoid and shoulder deformity parameters. Percent of humeral head anterior to scapular line (PHHA), glenoid version, coracoscapular angles, and coracoscapular and coracohumeral distances were significantly lower for affected shoulders compared to contralateral ones. Coracoid overlap was significantly higher for affected sides compared to contralateral sides. Significant and positive correlations were found between coracoscapular distances and glenohumeral parameters (PHHA and version), as well as between coracoscapular angles and glenohumeral parameters, for affected shoulders. Moderate and positive correlations existed between coracoid overlap and glenohumeral parameters for affected shoulders. On the contrary, all correlations between the coracoid and glenohumeral parameters for contralateral shoulders were only moderate or relatively low.</p> <p>Conclusions</p> <p>These results indicate that the spatial orientation of the coracoid process differs significantly between affected and contralateral shoulders, and it is highly correlated with the glenohumeral deformity. With the progression of glenohumeral deformity, the coracoid process protrudes more caudally and follows the subluxation of the humeral head which may interfere with the success of repositioning the posteriorly subluxed humeral head anteriorly to articulate with the glenoid properly.</p