1,151 research outputs found
The Impact of the Economic Crisis upon Human Resource Development (HRD): Evidence from two Greek Banks
This study investigates the nature and changes of Human Resource Development (HRD) in two Greek banks under the challenging context of the economic crisis. It examines the latterâs impact upon HRD as it was perceived from different stakeholders and through a pre and ongoing-crisis assessment approach.
The study draws upon qualitative research data from two case study banking organisations in Greece, reporting on 76 semi-structured interviews with key stakeholders (HR staff, Bank Managers, employees) undertaken in 2014, six (6) years after the fall of Lehman Brothers.
The study contributes to academic knowledge as being the first empirical research offering a unique perspective through examining changes of HRD within a specific industry and national context (Greek banks) against a backdrop of an economic downturn. Its findings also raise important questions for HRD professionals, in both academia and practice in relation to claims and aspirations which prevail in respect of HRD and organisational change and business transformation
Resolved Spectroscopy of the T8.5 and Y0-0.5 Binary WISEPC J121756.91+162640.2AB
We present 0.9 - 2.5 um resolved spectra for the ultracool binary WISEPC
J121756.91+162640.2AB. The system consists of a pair of brown dwarfs that
straddles the currently defined T/Y spectral type boundary. We use synthetic
spectra generated by model atmospheres that include chloride and sulfide clouds
(Morley et al.), the distance to the system (Dupuy & Kraus), and the radius of
each component based on evolutionary models (Saumon & Marley) to determine a
probable range of physical properties for the binary. The effective temperature
of the T8.5 primary is 550 - 600 K, and that of the Y0 - Y0.5 secondary is 450
K. The atmospheres of both components are either free of clouds or have
extremely thin cloud layers. We find that the masses of the primary and
secondary are 30 and 22 M_Jup, respectively, and that the age of the system is
4 - 8 Gyr. This age is consistent with astrometric measurements (Dupuy & Kraus)
that show that the system has kinematics intermediate between those of the thin
and thick disks of the Galaxy. An older age is also consistent with an
indication by the H - K colors that the system is slightly metal-poor.Comment: 21 pages which include 6 Figures and 3 Tables. Accepted on November 8
2013 for publication in Ap
Periplasmic Phosphorylation of Lipid a Is Linked to the Synthesis of Undecaprenyl Phosphate
One-third of the lipid A found in the Escherichia coli outer membrane contains an unsubstituted diphosphate unit at position 1 (lipid A 1-diphosphate). We now report an inner membrane enzyme, LpxT (YeiU), which specifically transfers a phosphate group to lipid A, forming the 1-diphosphate species. 32P-labelled lipid A obtained from lpxT mutants do not produce lipid A 1-diphosphate. In vitro assays with Kdo2-[4â˛- 32P]lipid A as the acceptor shows that LpxT uses undecaprenyl pyrophosphate as the substrate donor. Inhibition of lipid A 1-diphosphate formation in wild-type bacteria was demonstrated by sequestering undecaprenyl pyrophosphate with the cyclic polypeptide antibiotic bacitracin, providing evidence that undecaprenyl pyrophosphate serves as the donor substrate within whole bacteria. LpxT-catalysed phosphorylation is dependent upon transport of lipid A across the inner membrane by MsbA, a lipid A flippase, indicating a periplasmic active site. In conclusion, we demonstrate a novel pathway in the periplasmic modification of lipid A that is directly linked to the synthesis of undecaprenyl phosphate, an essential carrier lipid required for the synthesis of various bacterial polymers, such as peptidoglycan
Simultaneous MQMAS NMR experiments for two half-integer quadrupolar nuclei
A procedure to acquire two Multiple-Quantum Magic Angle Spinning (MQMAS) NMR experiments with the same instrument time is presented. A triply tuned probe is utilized with multiple receivers to collect data with staggered acquisitions and thus more efficiently use the instrument time. The data for one nucleus is collected during the recovery delay of the other nucleus, and vice versa. The instrument time is reduced to 60-80% of the time needed for the single acquisition collection Specifically our approach is presented for recording triple-quantum (3Q) 17O and either 3Q or quintuple-quantum (5Q) 27Al MAS NMR spectra of a 1.18Na2Oâ˘5SiO2â˘Al2O3 glass gel
Pathophysiology, treatment, and animal and cellular models of human ischemic stroke
Stroke is the world's second leading cause of mortality, with a high incidence of severe morbidity in surviving victims. There are currently relatively few treatment options available to minimize tissue death following a stroke. As such, there is a pressing need to explore, at a molecular, cellular, tissue, and whole body level, the mechanisms leading to damage and death of CNS tissue following an ischemic brain event. This review explores the etiology and pathogenesis of ischemic stroke, and provides a general model of such. The pathophysiology of cerebral ischemic injury is explained, and experimental animal models of global and focal ischemic stroke, and in vitro cellular stroke models, are described in detail along with experimental strategies to analyze the injuries. In particular, the technical aspects of these stroke models are assessed and critically evaluated, along with detailed descriptions of the current best-practice murine models of ischemic stroke. Finally, we review preclinical studies using different strategies in experimental models, followed by an evaluation of results of recent, and failed attempts of neuroprotection in human clinical trials. We also explore new and emerging approaches for the prevention and treatment of stroke. In this regard, we note that single-target drug therapies for stroke therapy, have thus far universally failed in clinical trials. The need to investigate new targets for stroke treatments, which have pleiotropic therapeutic effects in the brain, is explored as an alternate strategy, and some such possible targets are elaborated. Developing therapeutic treatments for ischemic stroke is an intrinsically difficult endeavour. The heterogeneity of the causes, the anatomical complexity of the brain, and the practicalities of the victim receiving both timely and effective treatment, conspire against developing effective drug therapies. This should in no way be a disincentive to research, but instead, a clarion call to intensify efforts to ameliorate suffering and death from this common health catastrophe. This review aims to summarize both the present experimental and clinical state-of-the art, and to guide future research directions
Short cephalomedullary nail toggle: a closer examination
Objectives: In patients with wide femoral canals, an undersized short nail may not provide adequate stability, leading to toggling of the nail around the distal interlocking screw and subsequent loss of reduction. The purpose of this study was to identify risk factors associated with nail toggle and to examine whether increased nail toggle is associated with increased varus collapse.
Design: Retrospective cohort study.
Setting: Level 1 and level 3 trauma center.
Patients/Participants: Seventy-one patients with intertrochanteric femur fractures treated with short cephalomedullary nails (CMN) from October 2013 to December 2017.
Intervention: Short CMN.
Main Outcome Measurements: Nail toggle and varus collapse were measured on intraoperative and final follow-up radiographs. Risk factors for nail toggle including demographics, fracture classification, quality of reduction, Dorr type, nail/canal diameter ratio, lag screw engaging the lateral cortex, and tip-apex distance (TAD) were recorded.
Results: On multivariate regression analysis, shorter TAD (Pâ=â.005) and smaller nail/canal ratio (Pâ\u3câ.001) were associated with increased nail toggle. Seven patients (10%) sustained nail toggle \u3e4 degrees. They had a smaller nail/canal ratio (0.54 vs 0.74, Pâ\u3câ.001), more commonly Dorr C (57% vs 14%, Pâ=â.025), lower incidence of lag screw engaging the lateral cortex (29% vs 73%, Pâ=â.026), shorter TAD (13.4âmm vs 18.5âmm, Pâ=â.042), and greater varus collapse (6.2 degrees vs 1.3 degrees, Pâ\u3câ.001) compared to patients with nail toggleâ\u3câ4 degrees.
Conclusions: Lower percentage nail fill of the canal and shorter TAD are risk factors for increased nail toggle in short CMNs. Increased nail toggle is associated with increased varus collapse
BONCAT-FACS-Seq reveals the active fraction of a biocrust community undergoing a wet-up event
Determining which microorganisms are active within soil communities remains a major technical endeavor in microbial ecology research. One promising method to accomplish this is coupling bioorthogonal non-canonical amino acid tagging (BONCAT) with fluorescence activated cell sorting (FACS) which sorts cells based on whether or not they are producing new proteins. Combined with shotgun metagenomic sequencing (Seq), we apply this method to profile the diversity and potential functional capabilities of both active and inactive microorganisms in a biocrust community after being resuscitated by a simulated rain event. We find that BONCAT-FACS-Seq is capable of discerning the pools of active and inactive microorganisms, especially within hours of applying the BONCAT probe. The active and inactive components of the biocrust community differed in species richness and composition at both 4 and 21 h after the wetting event. The active fraction of the biocrust community is marked by taxa commonly observed in other biocrust communities, many of which play important roles in species interactions and nutrient transformations. Among these, 11 families within the Firmicutes are enriched in the active fraction, supporting previous reports indicating that the Firmicutes are key early responders to biocrust wetting. We highlight the apparent inactivity of many Actinobacteria and Proteobacteria through 21 h after wetting, and note that members of the Chitinophagaceae, enriched in the active fraction, may play important ecological roles following wetting. Based on the enrichment of COGs in the active fraction, predation by phage and other bacterial members, as well as scavenging and recycling of labile nutrients, appear to be important ecological processes soon after wetting. To our knowledge, this is the first time BONCAT-FACS-Seq has been applied to biocrust samples, and therefore we discuss the potential advantages and shortcomings of coupling metagenomics to BONCAT to intact soil communities such as biocrust. In all, by pairing BONCAT-FACS and metagenomics, we are capable of highlighting the taxa and potential functions that typifies the microbes actively responding to a rain event
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Non-Proteinogenic Amino Acids in Lacticin 481 Analogues Result in More Potent Inhibition of Peptidoglycan Transglycosylation
Lantibiotics are ribosomally synthesized and post-translationally modified peptide natural products that contain the thioether structures lanthionine and methyllanthionine and exert potent antimicrobial activity against Gram-positive bacteria. At present, detailed modes-of-action are only known for a small subset of family members. Lacticin 481, a tricyclic lantibiotic, contains a lipid II binding motif present in related compounds such as mersacidin and nukacin ISK-1. Here, we show that lacticin 481 inhibits PBP1b-catalyzed peptidoglycan formation. Furthermore, we show that changes in potency of analogues of lacticin 481 containing non-proteinogenic amino acids correlate positively with the potency of inhibition of the transglycosylase activity of PBP1b. Thus, lipid II is the likely target of lacticin 481, and use of non-proteinogenic amino acids resulted in stronger inhibition of the target. Additionally, we demonstrate that lacticin 481 does not form pores in the membranes of susceptible bacteria, a common mode-of-action of other lantibiotics.Chemistry and Chemical Biolog
A DedA Family Membrane Protein Is Required for Burkholderia thailandensis Colistin Resistance
Š Copyright Š 2019 Panta, Kumar, Stafford, Billiot, Douglass, Herrera, Trent and Doerrler. Colistin is a âlast resortâ antibiotic for treatment of infections caused by some multidrug resistant Gram-negative bacterial pathogens. Resistance to colistin varies between bacterial species. Some Gram-negative bacteria such as Burkholderia spp. are intrinsically resistant to very high levels of colistin with minimal inhibitory concentrations (MIC) often above 0.5 mg/ml. We have previously shown DedA family proteins YqjA and YghB are conserved membrane transporters required for alkaline tolerance and resistance to several classes of dyes and antibiotics in Escherichia coli. Here, we show that a DedA family protein in Burkholderia thailandensis (DbcA; DedA of Burkholderia required for colistin resistance) is a membrane transporter required for resistance to colistin. Mutation of dbcA results in \u3e100-fold greater sensitivity to colistin. Colistin resistance is often conferred via covalent modification of lipopolysaccharide (LPS) lipid A. Mass spectrometry of lipid A of ÎdbcA showed a sharp reduction of aminoarabinose in lipid A compared to wild type. Complementation of colistin sensitivity of B. thailandensis ÎdbcA was observed by expression of dbcA, E. coli yghB or E. coli yqjA. Many proton-dependent transporters possess charged amino acids in transmembrane domains that take part in the transport mechanism and are essential for function. Site directed mutagenesis of conserved and predicted membrane embedded charged amino acids suggest that DbcA functions as a proton-dependent transporter. Direct measurement of membrane potential shows that B. thailandensis ÎdbcA is partially depolarized suggesting that loss of protonmotive force can lead to alterations in LPS structure and severe colistin sensitivity in this species
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