Shift Changes Research Articles

Investigation of Chloride Anion Binding Properties of Glipizide Drug

This study addresses the anion binding property of Glipizide (GLP), an oral antidiabetic a second-generation drug member of the sulphonylurea (SU) family. GLP effectively interacts with Cl- anion according to 1H-NMR spectroscopic titrations of successive tetrabutylammonium chloride (TBACl) in deuterated chloroform (CDCl3) and dimethyl sulfoxide (d6-DMSO). Upon the addition of TBACl, the change in chemical shift was observed for both N-H protons of SU in CDCl3, whereas it causes a difference in the shift of only one of N-H proton in SU in d6-DMSO. In addition, the data obtained from 1H-NMR spectroscopic titrations was analyzed by DynaFit program to calculate the binding constant (Ka) value between GLP and Cl- anion. It was found that GLP binds Cl- anion in CDCl3 with higher affinity (Ka=77.37 M-1, Fitplot for N-Hh proton at δ=6.47 ppm) than in d6-DMSO (Ka=38.53 M-1, Fitplot for N-Hh proton at δ=6.32 ppm).

An automation of the detection processes of the strain characteristics of optical fibers, classification of their varieties and identification the influence factor according to Brillouin reflectograms

Research results into the automating the processing of measurement data obtained from the Brillouin optical reflectometer, light guides containing various types of optical fibers are presented in this paper. By analyzing the parameters of the Mandelstam–Brillouin scatter obtained from Brillouin reflectograms, we can classify optical fibers in the studied telecommunication optical cables. This makes it possible to evaluate the change of the Brillouin frequency shift and determine the longitudinal fiber tension. The initial values of the Brillouin frequency shift and the profile of the Mandelstam–Brillouin scatter spectrum are different for each fiber type. The programs for automated processing of Brillouin reflectogram data are discussed. Estimation of the level of the back-reflected signal allows you to identify the factor, that had a predominant effect on the parameters of the Mandelstam–Brillouin scatter signal in the studied sections of optical fibers, and to compensate for the influence of temperature changes in the longitudinal strain distribution graphs. After that, we can plot a graph of the distribution of longitudinal strain along the fiber, caused precisely by mechanical influences on optical fibers. Conclusions about the accuracy of the estimates obtained by various algorithms, based on the accumulated experience in working with the presented programs are drawn.

Risk Factors for Extubation Failure After Pediatric Cardiac Surgery and Impact on Outcomes: A Multicenter Analysis.

Extubation failure (EF) after pediatric cardiac surgery is associated with increased morbidity and mortality. We sought to describe the risk factors associated with early (< 48 hr) and late (48 hr ≤ 168 hr) EF after pediatric cardiac surgery and the clinical implications of these two types of EF. Retrospective cohort study using prospectively collected clinical data for the Pediatric Cardiac Critical Care Consortium (PC4) Registry. Pediatric patients undergoing Society of Thoracic Surgeons benchmark operation or heart transplant between 2013 and 2018 available in the PC4 Registry were included. We analyzed demographics and risk factors associated with EFs (primary outcome) including by type of surgery. We identified potentially modifiable risk factors. Clinical outcomes of mortality and length of stay (LOS) were reported. Overall 18,278 extubations were analyzed. Unplanned extubations were excluded from the analysis. The rate of early EF was 5.2% (948) and late EF was 2.5% (461). Cardiopulmonary bypass time, ventilator duration, airway anomaly, genetic abnormalities, pleural effusion, and diaphragm paralysis contributed to both early and late EF. Extubation during day remote from shift change and nasotracheal route of initial intubation was associated with decreased risk of early EF. Extubation in the operating room was associated with an increased risk of early EF but with decreased risk of late EF. Across all operations except arterial switch, EF portrayed an increased burden of LOS and mortality. Both early and late EF are associated with significant increase in LOS and mortality. Study provides potential benchmarking data by type of surgery. Modifiable risk factors such as route of intubation, time of extubation as well as treatment of potential contributors such as diaphragm paralysis or pleural effusion can serve as focus areas for reducing EFs.

Temperature dependent interaction of hydrogen with PdAg nanocomposite thin films revealed by in-situ synchrotron XRD

PdAg nanocomposite alloy thin films were synthesized using a DC magnetron sputtering process to study the structural changes that occur in the alloy film during the process of hydrogenation and dehydrogenation at different temperatures. The atomic composition of the nano-composite film is 88 at % Pd and 12% at Ag, as determined by the EDAX analysis. In-situ synchrotron X-ray diffraction (XRD) has been used to monitor the subtle structural changes that occurred throughout the hydrogenation and dehydrogenation cycles at an interval of 10 s. This aspect has not been addressed so far. In-situ XRD studies reveal that the XRD peak shifts towards a lower angle due to the lattice expansion in the alloy due to hydrogenation. The change in peak shift is found to be different for different temperatures. The present study also shows no hysteresis during the hydrogen absorption and desorption processes. In addition, the results show that (i) the phase segregation has been observed at 250 °C, (ii) the peak shift during the hydrogenation process at higher temperatures is not significant, whereas the peak shift throughout the process is more rapid and pronounced at ambient temperature.

19 F VT NMR: Novel Tm3+ and Ce3+ Complexes Provide New Insight into Temperature Measurement Using Molecular Sensors.

The front cover artwork is provided by Dr. Markus Plaumann's group at the Otto-von-Guericke University Magdeburg. The image shows the investigated 19 F labeled molecules, which can be used as temperature MR-sensors in different solvents. The direction of the chemical shift change is strongly solvent dependent. Read the full text of the Research Article at 10.1002/cphc.202300057.

Utilizing the Hofmeister Effect to Induce Hydrogelation of Nonionic Supramolecular Polymers into a Therapeutic Depot

AbstractNonionic hydrogels are of particular interest for long‐term therapeutic implantation due to their minimal immunogenicity relative to their charged counterparts. However, in situ formation of nonionic supramolecular hydrogels under physiological conditions has been a challenging task. In this context, we report on our discovery of salt‐triggered hydrogelation of nonionic supramolecular polymers (SPs) formed by self‐assembling prodrug hydrogelators (SAPHs) through the Hofmeister effect. The designed SAPHs consist of two SN‐38 units, which is an active metabolite of the anticancer drug irinotecan, and a short peptide grafted with two or four oligoethylene glycol (OEG) segments. Upon self‐assembly in water, the resultant nonionic SPs can be triggered to gel upon addition of phosphate salts. Our 1H NMR studies revealed that the added phosphates led to a change in the chemical shift of the methylene protons, suggestive of a disruption of the water‐ether hydrogen bonds and consequent reorganization of the hydration shell surrounding the SPs. This deshielding effect, commensurate with the amount of salt added, likely promoted associative interactions among the SAPH filaments to percolate into a 3D network. The formed hydrogels exhibited a sustained release profile of SN‐38 hydrogelator that acted potently against cancer cells.

Utilizing the Hofmeister Effect to Induce Hydrogelation of Nonionic Supramolecular Polymers into a Therapeutic Depot.

Nonionic hydrogels are of particular interest for long-term therapeutic implantation due to their minimal immunogenicity relative to their charged counterparts. However, in situ formation of nonionic supramolecular hydrogels under physiological conditions has been a challenging task. In this context, we report on our discovery of salt-triggered hydrogelation of nonionic supramolecular polymers (SPs) formed by self-assembling prodrug hydrogelators (SAPHs) through the Hofmeister effect. The designed SAPHs consist of two SN-38 units, which is an active metabolite of the anticancer drug irinotecan, and a short peptide grafted with two or four oligoethylene glycol (OEG) segments. Upon self-assembly in water, the resultant nonionic SPs can be triggered to gel upon addition of phosphate salts. Our 1 H NMR studies revealed that the added phosphates led to a change in the chemical shift of the methylene protons, suggestive of a disruption of the water-ether hydrogen bonds and consequent reorganization of the hydration shell surrounding the SPs. This deshielding effect, commensurate with the amount of salt added, likely promoted associative interactions among the SAPH filaments to percolate into a 3D network. The formed hydrogels exhibited a sustained release profile of SN-38 hydrogelator that acted potently against cancer cells.

Synthesis and Characterization of Dibenzothieno[a,f]pentalenes Enabling Large Antiaromaticity and Moderate Open-Shell Character through a Small Energy Barrier for Bond-Shift Valence Tautomerization.

Experimental and theoretical rationalization of bond-shift valence tautomerization, characterized by double-well potential surfaces, is one of the most challenging topics of study among the rich electronic properties of antiaromatic molecules. Although the pseudo-Jahn-Teller effect (PJTE) is an essential effect to provide attractive characteristics of 4nπ systems, an understanding of the structure-property relationship derived from the PJTE for planar 4nπ electron systems is still in its infancy. Herein, we describe the synthesis and characterization of two regioisomers of the thiophene-fused diareno[a,f]pentalenes 6 and 7. The magnetic and optoelectronic properties characterize these sulfur-doped diareno[a,f]pentalenes as open-shell antiaromatic molecules, in sharp contrast to the closed-shell antiaromatic systems of 3 and 5, in which these main cores consist of the same number of π electrons as 6 and 7. Notably, thiophene-fused 6b and 7b showed pronounced antiaromaticity, the strongest among the previous systems, as well as moderate open-shell characteristics. Our experimental and theoretical investigations concluded that these properties of 6b and 7b are derived from the small energy barrier Ea‡ for the bond-shift valence tautomerization. The energy profile of the single crystal of 6b showed the temperature-dependent structural variations assigned to the dynamic mutual exchange between the two Cs-symmetric structures, which was also supported by changes in the chemical shifts of variable-temperature 1H NMR spectra in the solution phase. Both experimental and computational results revealed the importance of introducing heteroaromatic rings into 4nπ systems for controlling the PJTE and manifesting the antiaromatic and open-shell natures originating from the high-symmetric structure. The findings of this study advance the understanding of antiaromaticity characterized by the PJTE by controlling the energy barrier for bond-shift valence tautomerizations, potentially leading to the rational design of optoelectronic devices based on novel antiaromatic molecules possessing the strong contributions of their high-symmetric geometries.

Analysis of the Structure, Thermal, and Molecular Dynamics of Organic-Inorganic Hybrid Crystal at Phases IV, III, II, and I: [NH2(CH3)2]2CdBr4.

A comprehensive understanding of the physicochemical properties of organic-inorganic hybrids is essential for their solid-state lighting applications. Therefore, a single crystal of [NH2(CH3)2]2CdBr4 was grown; the crystal structure was monoclinic, and the phase transition temperatures for the four phases IV, III, II, and I were 383 K (TC1), 417 K (TC2), and 427 K (TC3). Furthermore, the chemical shifts caused by the local field around 1H, 13C, 14N, and 113Cd changed continuously with temperature, especially near TC1, indicating that the local environment changes with temperature. Owing to the large change in 113Cd chemical shifts, the coordination geometry of Br around Cd in the CdBr4 tetrahedra changes near TC1. Therefore, it is proposed that Br plays a significant role in the N-H···Br hydrogen bond. Finally, the spin-lattice relaxation time T1ρ, representing the energy transfer around the 1H and 13C atoms of the cation, changed significantly with temperature. The activation energies obtained from the T1ρ results were two times larger at high temperatures than at low temperatures. This study provides an understanding of the fundamental properties of organic-inorganic hybrid compounds to broaden their applications.

Voluntary wheel exercise ameliorates cognitive impairment, hippocampal neurodegeneration and microglial abnormalities preceded by demyelination in a male mouse model of noise-induced hearing loss

Acquired peripheral hearing loss (APHL) in midlife has been identified as the greatest modifiable risk factor for dementia; however, the pathophysiological neural mechanisms linking APHL with an increased risk of dementia remain to be elucidated. Here, in an adult male mouse model of noise-induced hearing loss (NIHL), one of the most common forms of APHL, we demonstrated accelerated age-related cognitive decline and hippocampal neurodegeneration during a 6-month follow-up period, accompanied by progressive hippocampal microglial aberrations preceded by immediate-onset transient elevation in serum glucocorticoids and delayed-onset sustained myelin disruption in the hippocampus. Pretreatment with the glucocorticoid receptor antagonist RU486 before stressful noise exposure partially mitigated the early activation of hippocampal microglia, which were present at 7 days post noise exposure (7DPN), but had no impact on later microglial aberrations, hippocampal neurodegeneration, or cognitive decline exhibited at 1 month post noise exposure (1MPN). One month of voluntary wheel exercise following noise exposure barely affected either the hearing threshold shift or hippocampal myelin changes but effectively countered cognitive impairment and the decline in hippocampal neurogenesis in NIHL mice at 1MPN, paralleled by the normalization of microglial morphology, which coincided with a reduction in microglial myelin inclusions and a restoration of microglial hypoxia-inducible factor-1α (HIF1α) expression. Our results indicated that accelerated cognitive deterioration and hippocampal neuroplastic decline following NIHL are most likely driven by the maladaptive response of hippocampal microglia to myelin damage secondary to hearing loss, and we also demonstrated the potential of voluntary physical exercise as a promising and cost-effective strategy to alleviate the detrimental impact of APHL on cognitive function and thus curtail the high and continuously increasing global burden of dementia. Furthermore, the findings of the present study highlight the contribution of myelin debris overload to microglial malfunction and identify the microglial HIF1α-related pathway as an attractive candidate for future comprehensive investigation to obtain a more definitive picture of the underlying mechanisms linking APHL and dementia.

Evaluating Physician Stress During Patient Handoffs: Analysis of Physician Heart Rate Variability, Patient Handoff Characteristics, and ED Metrics

Patient handoffs represent a critical point in patient care, specifically in hospital Emergency Departments (EDs) where handoffs occur at every shift change. Previous studies have examined ED patient handoffs primarily by evaluating handoff communication methods and scheduling models that improve and reduce the prevalence of handoffs. In this study, we provided a quantitative analysis of physician stress by measuring the HRV of outgoing and oncoming physicians during patient handoffs. We recorded descriptive data of each observed patient handoff using the status of patient disposition as a measure of physician workload, and retrospectively gathered patient outcome and ED metric data for multivariate analysis. Results demonstrate that attending physicians experience increased HRV during handoff periods over non-handoff periods, with a significant increase observed in outgoing physicians (α = 0.05). This study creates a framework for future work that considers health care worker stress and evaluates ED handoffs via the stress and workload transferred between emergency physicians.

The Role of Apron Movement Control Unit Officers in Handling the Movement of Cargo Planes at the Tjilik Riwut Palangkaraya Airport Apron

The purpose of this study is to study; (1) What are the roles of AMC officers inhandling the movement of cargo aircraft on apron Bandar Udara Tjilik Riwut Palangkaraya? ; (2) What are the obstacles faced and solutions for AMC officers in handling the movement of cargo aircraft on apron Bandar Udara Tjilik Riwut Palangkaraya? . The research method used is a qualitative method with an interview and observation approach. The results showed that; (1) The role of AMC officers inhandling the movement of cargo aircraft on apron Bandar Udara Tjilik Riwut Palangkaraya as follows: (a) Regulate the movement and placement of aircraft so as not to collide with other aircraft. (b) Regulate the movement and placement of aircraft so that they do not collide or be obstructed by obstacles in the apron and its surroundings. (c) Regulate the placement of aircraft on the parking stand based on the type and size of the aircraft. (d) Regulate the entry and exit of aircraft from the apron (parking stand) to the manoeuvring area or vice versa. In this case, coordination must be carried out with the Aerodrome Control Tower unit in advance. (e) Ensure the safety and smooth movement of vehicles and the regularity of other activities on the apron. (2) Obstacles faced by AMC officers in handling the movement of cargo aircraft on the apron of Tjilik Riwut Airport Palangkaraya include; (a) Lack of personnel or human resources, (b) Lack of Quality and Quantity of CCTV compared to the apron area, (c) Does not have a remote area for all types of aircraft, (d) Parking stand Constraints for unscheduled flights, (e) Lack of Communication in AMC Officer Shift Changes. Solutions to the obstacles faced by AMC officers in handling the movement of cargo aircraft on apron Bandar Udara Tjilik Riwut Palangkaraya, including; (a) Addition of personnel or human resources, (b) Improvement of Quality and Quantity of CCTV in proportion to the area of ap ron, (c) Determination of remote areas for all types of aircraft, (d) Increase Officer Readiness in facing unscheduled flights, (e) Improve coordination and communication of AMC units.

649 Closed Loop Audit: Improving Surgical Handover in a Major Trauma Centre (RSCH)

Abstract Aim The goal of handover is the accurate reliable communication of task-relevant information across shift changes or between teams. Effective and safe transfer of clinical information is critical for patient safety. The aim of this study to assess Surgical handover in Royal Sussex County Hospital comparing it to the RCS guidelines as standard as well as improving the current practice. Method We undertook two cycles each cycle lasted for 6 weeks. These cycles aimed to assess the surgical handover and comparing them with RCS guidelines using checklists. A teaching session was conducted between the two cycles. In addition, RCS guidelines were handed over to all surgical doctors. Results we discussed a total of 2348 patients in morning surgical handover, over a period of 12 weeks (first cycle: 1203, second cycle:1145). Following conduction of teaching sessions and handing over guidelines, there was a significant improvement in documentation of patients age (from 73% to 97%), responsible consultant (from 92% to 98%), significant investigations (from 60% to 93%) and management plan (from 64% to 96%). Conclusions Education about proper handover was proven to be successful in improving the quality of surgical handover in a major trauma center.

Interaction study of 5- Fluorouracil with Bovine serum albumin by UV-Visible spectrophotometry

Introduction: 5-Fluorouracil (5-FU) is primary chemotherapeutic drug used for most colorectal, pancreatic and aggressive forms of breast cancers. Serum albumin is major carrier protein and its binding with drugs is important to examine the change in pharmacokinetic properties which directly influence the bio availability, sustained drug release and toxicity of drugs. Aim and objectives: The aim of the project is to perform a study on interaction of 5 - fluorouracil with bovine serum albumin employing the UV-Visible spectrophotometric method. Methods: Interaction of 5-FU with BSA has been studied systematically using UV spectroscopy by fixing the carbonate buffer of pH 7.4 as solvent and at a suitable wavelength 230 nm and 275 nm. To gain an insight into the interaction of 5-FU with BSA, the spectra of the 5-FU and BSA were examined in the absence and presence of various concentrations of the 5-FU and BSA respectively at zero minutes and repeated in 30 minutes, 60 minutes and 90 minutes time interval. The changes in peak intensity, absorbance and shift in peaks were observed. The detectable differences were recorded. This method can be used successfully for the interaction study of 5-FU with BSA. Results: Interaction study of 5-Fluorouracil with bovine serum albumin revealed that appreciable changes in absorbance, peak area and shifts in peak were observed which may be due to binding of drug with protein BSA.

Using 19F NMR to Investigate Cationic Carbon Dot Association with Per- and Polyfluoroalkyl Substances (PFAS).

There is much concern about per- and polyfluoroalkyl substances (PFAS) based on their environmental persistence and toxicity, resulting in an urgent need for remediation technologies. This study focused on determining if nanoscale polymeric carbon dots are a viable sorbent material for PFAS and developing fluorine nuclear magnetic resonance spectroscopy (19F NMR) methods to probe interactions between carbon dots and PFAS at the molecular scale. Positively charged carbon dots (PEI-CDs) were synthesized using branched polyethyleneimine to target anionic PFAS by promoting electrostatic interactions. PEI-CDs were exposed to perfluorooctanoic acid (PFOA) to assess their potential as a PFAS sorbent material. After exposure to PFOA, the average size of the PEI-CDs increased (1.6 ± 0.5 to 7.8 ± 1.8 nm) and the surface charge decreased (+38.6 ± 1.1 to +26.4 ± 0.8 mV), both of which are consistent with contaminant sorption. 19F NMR methods were developed to gain further insight into PEI-CD affinity toward PFAS without any complex sample preparation. Changes in PFOA peak intensity and chemical shift were monitored at various PEI-CD concentrations to establish binding curves and determine the chemical exchange regime. 19F NMR spectral analysis indicates slow-intermediate chemical exchange between PFOA and CDs, demonstrating a high-affinity interaction. The α-fluorine had the greatest change in chemical shift and highest affinity, suggesting electrostatic interactions are the dominant sorption mechanism. PEI-CDs demonstrated affinity for a wide range of analytes when exposed to a mixture of 24-PFAS, with a slight preference toward perfluoroalkyl sulfonates. Overall, this study shows that PEI-CDs are an effective PFAS sorbent material and establishes 19F NMR as a suitable method to screen for novel sorbent materials and elucidate interaction mechanisms.

MOF-composite sensors to eliminate the QCM positive frequency shift

In a quartz crystal microbalance (QCM) Sauerbrey equation can usually be applied in the ideal scenario and when the QCM frequency shift goes to the negative direction. In some cases, however, the requirements to achieve the ideal condition are not fulfilled and thus leading to QCM positive frequency shift phenomenon. Herein we have also observed that a porphyrin-based metal organic frameworks (MOF), namely MOF-525(Zn), QCM sensor also exhibits the positive frequency shift phenomenon when exposed to xylene isomers, which could be caused by the loose attachment of the MOF nanoparticles on the QCM surface. Therefore, in the presence of the analytes, the bonding between the MOF and the QCM surface is disturbed and higher analyte concentration also leads to the increase of the sensitive layer stiffness, resulting in higher positive frequency shift. However, such a phenomenon can be completely eliminated by simply adding polymer to MOF nanoparticle sensors to strengthen the bonding of MOF nanoparticles to the QCM surface. Through this study we have shown that adjusting the amount of polymer is very crucial to completely reverse the positive frequency response. Otherwise, it appears a critical analyte concentration of gas analytes where the QCM frequency shift changes its direction from negative to positive response. Lastly, the same strategy has also been used to other MOF-based QCM sensor systems where their sensitive layer is built from other MOFs, namely MOF-525 and NU-902, and ethanol is used as the analyte to prove the generalizability of this simple approach.

Spatial and temporal changes of charosphere hotspots with or without nitrogen additions

The charosphere is a thin soil one surrounding the biochar with highly active biochemical functions. Yet, little is known about the spatial and temporal distribution of charosphere hotspots. In this study, repacked soil cores were incubated with a central layer of biochar (pristine or acid-modified) with or without nitrogen (N) additions for 30 days and sliced at the millimeter scale for analyzing soil pH, mineral N, bacterial and fungal communities as well as the putative functions. We aimed to determine gradient distributions (in millimeter scale) of charosphere affected by biochar under different N additions. Our results showed narrower gradient changes (3 mm) of microbial community composition and wider shifts (6 mm) in pH and inorganic N contents in charosphere. The pristine biochar increased the soil pH up to 1.5 units in the charosphere, and subsequently boosted the relative abundance of Proteobacteria, Acidobacteria, and Zygomycota. With N addition, both the biochar site and charosphere were observed with decreased complexity of microbial networks, which might imply the limited microbial functionality of charosphere. These results will advance the understanding and prediction of biochar’s environmental impacts in soil.Graphical abstract

Obtaining Functional Proteomics Insights From Thermal Proteome Profiling Through Optimized Melt Shift Calculation and Statistical Analysis With InflectSSP

Thermal proteome profiling (TPP) is an invaluable tool for functional proteomics studies that has been shown to discover changes associated with protein–ligand, protein–protein, and protein–RNA interaction dynamics along with changes in protein stability resulting from cellular signaling. The increasing number of reports employing this assay has not been met concomitantly with new approaches leading to advancements in the quality and sensitivity of the corresponding data analysis. The gap between data acquisition and data analysis tools is important to fill as TPP findings have reported subtle melt shift changes related to signaling events such as protein posttranslational modifications. In this study, we have improved the Inflect data analysis pipeline (now referred to as InflectSSP, available at https://CRAN.R-project.org/package=InflectSSP) to increase the sensitivity of detection for both large and subtle changes in the proteome as measured by TPP. Specifically, InflectSSP now has integrated statistical and bioinformatic functions to improve objective functional proteomics findings from the quantitative results obtained from TPP studies through increasing both the sensitivity and specificity of the data analysis pipeline. InflectSSP incorporates calculation of a “melt coefficient” into the pipeline with production of average melt curves for biological replicate studies to aid in identification of proteins with significant melts. To benchmark InflectSSP, we have reanalyzed two previously reported datasets to demonstrate the performance of our publicly available R-based program for TPP data analysis. We report new findings following temporal treatment of human cells with the small molecule thapsigargin that induces the unfolded protein response as a consequence of inhibition of sarcoplasmic/endoplasmic reticulum calcium ATPase 2A. InflectSSP analysis of our unfolded protein response study revealed highly reproducible and statistically significant target engagement over a time course of treatment while simultaneously providing new insights into the possible mechanisms of action of the small molecule thapsigargin.

Lipid- and substrate-induced conformational and dynamic changes in a glycosyltransferase involved in E. coli LPS synthesis revealed by 19F and 31P NMR

WaaG is a glycosyltransferase (GT) involved in the synthesis of the bacterial cell wall, and in Escherichia coli it catalyzes the transfer of a glucose moiety from the donor substrate UDP-glucose onto the nascent lipopolysaccharide (LPS) molecule which when completed constitutes the major component of the bacterium's outermost defenses. Similar to other GTs of the GT-B fold, having two Rossman-like domains connected by a short linker, WaaG is believed to undergo complex inter-domain motions as part of its function to accommodate the nascent LPS and UDP-glucose in the catalytic site located in the cleft between the two domains. As the nascent LPS is bulky and membrane-bound, WaaG is a peripheral membrane protein, adding to the complexity of studying the enzyme in a biologically relevant environment. Using specific 5-fluoro-Trp labelling of native and inserted tryptophans and 19F NMR we herein studied the dynamic interactions of WaaG with lipids using bicelles, and with the donor substrate. Line-shape changes when bicelles are added to WaaG show that the dynamic behavior is altered when binding to the model membrane, while a chemical shift change indicates an altered environment around a tryptophan located in the C-terminal domain of WaaG upon interaction with UDP-glucose or UDP. A lipid-bound paramagnetic probe was used to confirm that the membrane interaction is mediated by a loop region located in the N-terminal domain. Furthermore, the hydrolysis of the donor substrate by WaaG was quantified by 31P NMR.

Work-schedule management in psychiatric hospitals and its associations with nurses' emotional exhaustion and intention to leave: A cross-sectional multicenter study

BackgroundManaging nurses' work schedules in hospitals is challenging because employer needs, like shift changes at short notice and overtime, may conflict with nurses' desires for a predictable and stable schedule. Nurses should have a certain degree of control over their work schedules, and their supervisors should support their needs in scheduling. How perceived control over work schedules, perceived support from supervisors in scheduling, shift changes at short notice, and overtime affect nurses' emotional exhaustion and intentions to leave has not been studied. ObjectivesThe aims are (1) to describe perceived control, perceived supervisor support, shift changes at short notice, and overtime among nurses in psychiatric hospitals; (2) to assess the variation of these four factors between units at psychiatric hospitals; and (3) to investigate the association between these factors with nurses' emotional exhaustion and intentions to leave. DesignCross-sectional survey study. Setting(s)Swiss psychiatric hospitals with 24-hour services. ParticipantsRegistered nurses (N = 994) from 114 adult-inpatient units. MethodsTo describe perceived control, perceived supervisor support, shift changes at short notice, and overtime among nurses, we calculated frequencies, percentages, means, and standard deviations of their responses to the survey. To assess the variation between units, we computed intraclass correlations for the four factors. We constructed random-effects models accounting for the clustering of nurses in units for emotional exhaustion and intentions to leave separately. ResultsPerception of work-schedule control was 3.32 (SD 1.39, range 0–5); perception of supervisor work-schedule support was 3.28 (SD 1.14, range 0–4). On average, 9 % of the nurses had to take over a shift at short notice at least three times per month, and 40 % worked at least 15 minute overtime on their most recent shift. Intraclass correlation for all four factors was higher than 0.05. Emotional exhaustion was significantly associated with supervisor support and overtime, and leaving intentions were significantly associated with perceived control, supervisor support and overtime. ConclusionPerceived control, perceived supervisor support, shift changes at short notice, and overtime are promising factors for interventions to prevent nurses' emotional exhaustion and allay their intentions to leave. Unit managers should provide nurses with increased predictability and influence on their work schedules. This could reduce early career endings and early retirement and counteract nurse shortages.