Structures of the essential efflux pump EfpA from Mycobacterium tuberculosis reveal the mechanisms of substrate transport and small-molecule inhibition.

As the first identified multidrug efflux pump in Mycobacterium tuberculosis (Mtb), EfpA is an essential protein and promising drug target. However, the functional and inhibitory mechanisms of EfpA are poorly understood. Herein we report cryo-EM structures of EfpA in outward-open conformation, either bound to three endogenous lipids or the inhibitor BRD-8000.3. Three lipids inside EfpA span from the inner leaflet to the outer leaflet of the membrane. BRD-8000.3 occupies one lipid site at the level of inner membrane leaflet, competitively inhibiting lipid binding. EfpA resembles the related lysophospholipid transporter MFSD2A in both overall structure and lipid binding sites, and may function as a lipid flippase. Combining AlphaFold-predicted EfpA structure, which is inward-open, we propose a complete conformational transition cycle for EfpA. Together, our results provide a structural and mechanistic foundation to comprehend EfpA function and develop EfpA-targeting anti-TB drugs.

Potent inhibitors targeting cyclin-dependent kinase 9 discovered via virtual high-throughput screening and absolute binding free energy calculations.

Due to the crucial regulatory mechanism of cyclin-dependent kinase 9 (CDK9) in mRNA transcription, the development of kinase inhibitors targeting CDK9 holds promise as a potential treatment strategy for cancer. A structure-based virtual screening approach has been employed for the discovery of potential novel CDK9 inhibitors. First, compounds with kinase inhibitor characteristics were identified from the ZINC15 database via virtual high-throughput screening. Next, the predicted binding modes were optimized by molecular dynamics simulations, followed by precise estimation of binding affinities using absolute binding free energy calculations based on the free energy perturbation scheme. The binding mode of molecule 006 underwent an inward-to-outward flipping, and the new binding mode exhibited binding affinity comparable to the small molecule T6Q in the crystal structure (PDB ID: 4BCF), highlighting the essential role of molecular dynamics simulation in capturing a plausible binding pose bridging docking and absolute binding free energy calculations. Finally, structural modifications based on these findings further enhanced the binding affinity with CDK9. The results revealed that enhancing the molecule's rigidity through ring formation, while maintaining the major interactions, reduced the entropy loss during the binding process and, thus, enhanced binding affinities.

Training machine learning potentials for reactive systems: A Colab tutorial on basic models.

In the last several years, there has been a surge in the development of machine learning potential (MLP) models for describing molecular systems. We are interested in a particular area of this field - the training of system-specific MLPs for reactive systems - with the goal of using these MLPs to accelerate free energy simulations of chemical and enzyme reactions. To help new members in our labs become familiar with the basic techniques, we have put together a self-guided Colab tutorial (https://cc-ats.github.io/mlp_tutorial/), which we expect to be also useful to other young researchers in the community. Our tutorial begins with the introduction of simple feedforward neural network (FNN) and kernel-based (using Gaussian process regression, GPR) models by fitting the two-dimensional Müller-Brown potential. Subsequently, two simple descriptors are presented for extracting features of molecular systems: symmetry functions (including the ANI variant) and embedding neural networks (such as DeepPot-SE). Lastly, these features will be fed into FNN and GPR models to reproduce the energies and forces for the molecular configurations in a Claisen rearrangement reaction.

Rivaroxaban for the treatment of heparin-induced thrombocytopenia with thrombosis in a patient undergoing artificial hip arthroplasty: A case report.

BACKGROUND: Anticoagulation treatment after lower limb surgery is one of the key methods to avoid thrombosis, and low-molecular-weight heparin is the treatment that is most frequently used in clinical practice. But one uncommon side effect of low-molecular-weight heparin is heparin-induced thrombocytopenia (HIT), which can develop into thrombosis if not caught early or managed incorrectly. CASE SUMMARY: We present a case of a patient who underwent hip arthroplasty and experienced thrombocytopenia due to HIT on the 9th d following the application of low-molecular-weight heparin anticoagulation. We did not diagnose HIT in time and applied 1 unit of platelets to the patient, which led to thrombosis. Luckily, the patient recovered following effective and timely surgery and treatment with rivaroxaban. CONCLUSION: Patients using low-molecular-weight heparin after lower limb surgery need to have their platelet counts regularly checked. If HIT develops, platelet treatment should be given with caution.

Tracking the Early Stage of Triplet-Induced Photodamage in a DNA Dimer and Oligomer Containing 5-Methylcytosine.

Methylation at the C5 position of cytosine, a naturally occurring epigenetic modification on DNA, shows a high correlation with mutational hotspots in disease such as skin cancer. Due to its essential biological relevance, numerous studies were devoted to confirming that the methylated sites favor the formation of the cyclobutane pyrimidine dimer (CPD), a well-known UV-induced lesion. However, photophysical and photochemical properties of dinucleotides and polynucleotides containing 5-methylcytosine (5mC) remain elusive. Herein, a charge transfer (CT) triplet state, generated via intersystem crossing (ISC) from a CT singlet state that enhanced after methylation on cytosine, is directly observed by using femtosecond transient absorption (TA) and time-resolved mid-infrared (TRIR) spectroscopy together with quantum chemical calculations for the first time in the T5mC dimer. Such an ISC process is quenched due to limitations of the ground-state geometries in 5mC-containing single-strand oligomer d(T5mC)9. This mechanistic information is important for understanding the early stage of triplet state-induced CPD formation in 5mC containing DNA.

Perspective: Reference-Potential Methods for the Study of Thermodynamic Properties in Chemical Processes: Theory, Applications, and Pitfalls.

In silico investigations of enzymatic reactions and chemical reactions in condensed phases often suffer from formidable computational costs due to a large number of degrees of freedom and enormous important volume in phase space. Usually, accuracy must be compromised to trade for efficiency by lowering the reliability of the Hamiltonians employed or reducing the sampling time. Reference-potential methods (RPMs) offer an alternative approach to reaching high accuracy of simulation without much loss of efficiency. In this Perspective, we summarize the idea of RPMs and showcase some recent applications. Most importantly, the pitfalls of these methods are also discussed, and remedies to these pitfalls are presented.

Machine learning based implicit solvent model for aqueous-solution alanine dipeptide molecular dynamics simulations.

Inspired by the recent work from Noé and coworkers on the development of machine learning based implicit solvent model for the simulation of solvated peptides [Chen et al., J. Chem. Phys., 2021, 155, 084101], here we report another investigation of the possibility of using machine learning (ML) techniques to "derive" an implicit solvent model directly from explicit solvent molecular dynamics (MD) simulations. For alanine dipeptide, a machine learning potential (MLP) based on the DeepPot-SE representation of the molecule was trained to capture its interactions with its average solvent environment configuration (ASEC). The predicted forces on the solute deviated only by an RMSD of 0.4 kcal mol-1 Å-1 from the reference values, and the MLP-based free energy surface differed from that obtained from explicit solvent MD simulations by an RMSD of less than 0.9 kcal mol-1. Our MLP training protocol could also accurately reproduce combined quantum mechanical molecular mechanical (QM/MM) forces on the quantum mechanical (QM) solute in ASEC environment, thus enabling the development of accurate ML-based implicit solvent models for ab initio-QM MD simulations. Such ML-based implicit solvent models for QM calculations are cost-effective in both the training stage, where the use of ASEC reduces the number of data points to be labelled, and the inference stage, where the MLP can be evaluated at a relatively small additional cost on top of the QM calculation of the solute.

Systemic lupus erythematosus with acquired hemophilia A: A case report and literature review / 中南大学学报(医学版)

Systemic lupus erythematosus (SLE) complicated with acquired hemophilia A (AHA) is a rare condition with frequently delayed diagnosis and a high mortality rate, so it is necessary to strengthen the understanding of this disease. In this study, the characteristics and treatment in 1 case of SLE complicated by AHA is reported and analyzed, and a literature review is conducted. The patient was a 29-year-old young female with a 10-year history of SLE, the main clinical manifestation was severe abdominal bleeding. Laboratory tests revealed that the activated partial thromboplastin time (APTT) was notably prolonged (118.20 s), and the coagulation factor VIII activity (FVIII꞉C) was extremely decreased (0.20%) with high-titer of factor VIII (FVIII) inhibitor (31.2 BU/mL). After treating with high-dose glucocorticoid, immunoglobulin, cyclophosphamide, rituximab, blood transfusion, and intravenous infusion of human coagulation FVIII, the coagulation function and coagulation FVIII꞉C were improved, and FVIII inhibitor was negative without serious adverse reactions. During the next 5-year follow-up, the patient's condition was stable and no bleeding occurred. In the case of coagulation dysfunction in SLE, especially with isolated APTT prolongation, AHA should be screened. When the therapeutic effects of glucocorticoid combined with immunosuppressants are not desirable, rituximab could be introduced.

Prenatal diagnosis and genetic analysis of a fetus with partial deletion of Yq and mosaicism of 45,X / 中华医学遗传学杂志

OBJECTIVE@#To carry out prenatal diagnosis and genetic analysis for a fetus with disorders of sex development (DSDs).@*METHODS@#A fetus with DSDs who was identified at the Shenzhen People's Hospital in September 2021 was selected as the study subject. Combined molecular genetic techniques including quantitative fluorescence PCR (QF-PCR), multiplex ligation-dependent probe amplification (MLPA), chromosomal microarray analysis (CMA), quantitative real-time PCR (qPCR), as well as cytogenetic techniques such as karyotyping analysis and fluorescence in situ hybridization (FISH) were applied. Ultrasonography was used to observe the phenotype of sex development.@*RESULTS@#Molecular genetic testing suggested that the fetus had mosaicism of Yq11.222qter deletion and X monosomy. Combined with the result of cytogenetic testing, its karyotype was determined as mos 45,X[34]/46,X,del(Y)(q11.222)[61]/47,X,del(Y)(q11.222),del(Y)(q11.222)[5]. Ultrasound examination suggested hypospadia, which was confirmed after elective abortion. Combined the results of genetic testing and phenotypic analysis, the fetus was ultimately diagnosed with DSDs.@*CONCLUSION@#This study has applied a variety of genetic techniques and ultrasonography to diagnose a fetus with DSDs with a complex karyotype.

Analysis on the risk factors and establishment of a prediction model for primary non-response to the treatment of anti-tumor necrosis factor-α monoclonal antibody in Crohn′s disease patients / 中华消化杂志

Objective:To investigate the risk factors and establish a prediction model of primary non-response (PNR) to anti-tumor necrosis factor-α(TNF-α) monoclonal antibody in Crohn′s disease (CD) patients.Methods:From December 1, 2018 to July 31, 2022, 103 patients with CD treated with the anti-TNF-α monoclonal antibody in Renmin Hospital of Wuhan University were enrolled (modeling group), and at the same time, 109 patients with CD treated with anti-TNF-α monoclonal antibody in Zhongnan Hospital of Wuhan University were selected (validation group). The baseline clinical data of all the patients before the first treatment of anti-TNF-α monoclonal antibody were collected, which included C-reactive protein (CRP), the simplified Crohn′s disease activity index (CDAI), and modified multiplier simple endoscopic score for Crohn′s disease (MM-SES-CD), etc. Multivariate logistic regression was used to screen the independent risk factors of PNR in patients with CD treated with the anti-TNF-α monoclonal antibody, and to establish the nomograms prediction model. The area under the curve (AUC) of the receiver operating characteristic curve (ROC), the net reclassification index (NRI), integrated discrimination improvement index (IDI), and decision curve analysis (DCA) were used to evaluate the predictive efficacy and clinical application value of the prediction model. DeLong test was used for statistical analysis.Results:The results of multivariate logistic regression analysis showed that high level of CRP ( OR=1.030, 95% confidence interval (95% CI) 1.002 to 1.059), simplified CDAI ( OR=1.399, 95% CI 1.023 to 1.913), and MM-SES-CD ( OR=1.100, 95% CI 1.025 to 1.181) in baseline were independent risk factors of PNR in patients with CD treated with the anti-TNF-α monoclonal antibody ( P=0.033, 0.036 and 0.008). The results of ROC analysis showed that the AUCs of CRP, simplified CDAI, MM-SES-CD, and the prediction model in the modeling group and the validation group were 0.697(95% CI 0.573 to 0.821), 0.772(95% CI 0.666 to 0.879), 0.819(95% CI 0.725 to 0.912), 0.869 (95% CI 0.786 to 0.951) and 0.856 (95% CI 0.756 to 0.955), respectively. The AUC of the prediction model in the modeling group was greater than those of CRP and simplified CDAI, and the differences were statistically significant ( Z=3.00 and 2.75, P=0.003 and 0.006), while compared with MM-SES-CD and the validation group, the differences were not statistically significant (both P>0.05). However, compared with MM-SES-CD, the NRI and IDI of the prediction model in the modeling group were 0.205(95% CI 0.002 to 0.409, P=0.048) and 0.098(95% CI 0.022 to 0.174, P=0.011), respectively, suggesting that the predictive ability of the prediction model was better than that of MM-SES-CD. The results of DCA indicated that the prediction model had significant clinical benefits in both the modeling group and the validation group. Conclusions:A prediction model was successfully constructed based on the independent risk factors for PNR in patients with CD treated with the anti-TNF-α monoclonal antibody. After verification, the prediction model has good prediction performance and significant clinical benefits.

Correlation of endoscopic evaluation with laboratory indices and clinical disease activity in Crohn disease patients with different intestinal involvement / 中华消化内镜杂志

Objective:To investigate the correlations of endoscopic evaluation results with laboratory indices and clinical disease activity in Crohn disease (CD) patients with different intestinal involvement.Methods:Data of 147 patients diagnosed as having CD who visited the Department of Gastroenterology, Zhongnan Hospital of Wuhan University from July 1, 2017 to June 30, 2022 were collected retrospectively. According to the involvement of intestinal segment, patients were divided into three groups: the group with isolated small intestinal involvement ( n=55), the group with both small intestinal and large intestinal involvement ( n=48), and the group with isolated large intestinal involvement ( n=44). Correlations of endoscopic evaluation (based on CDEIS) with laboratory indices and clinical disease activity (based on Harvey-Bradshaw index) were analyzed. Results:C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) could be used for the prediction of endoscopic disease activity. The areas under curve (AUC) of receiver operator characteristic (ROC) were 0.677 (0.506-0.849) and 0.744 (0.597-0.890), respectively. In terms of determing clinical disease activity, clinical Harvey-Bradshaw index was consistent with endoscopic CDEIS score in 65.3% (96/147) patients, showing a low positive correlation ( r=0.260, P<0.05). In subgroup analysis for patients with isolated small intestinal involvement, CRP showed no predictive value for clinical disease activity [AUC (95% CI): 0.617 (0.461-0.773), P=0.148], while for endoscopic activity neither CRP nor ESR showed predictive value [AUC (95% CI): 0.537 (0.146-0.929), P=0.829; AUC (95% CI): 0.571 (0.153-0.990), P=0.680]. Furthermore, for patients with isolated small intestinal involvement and both small intestinal and large intestinal involvement, no correlation was found between clinical Harvey-Bradshaw index and endoscopic CDEIS score ( r=0.222, P=0.092; r=0.142, P=0.322). Conclusion:For CD patients with small intestinal involvement, especially isolated small intestinal involvement, laboratory indices and clinical disease activity cannot accurately reflect endoscopic disease activity. Great importance should be attached to evaluation of the extent and activity of intestinal lesions by endoscopy, especially enteroscopy.

Epididymis cell atlas in a patient with a sex development disorder and a novel NR5A1 gene mutation / 亚洲男科学杂志(英文版)

This study aims to characterize the cell atlas of the epididymis derived from a 46,XY disorders of sex development (DSD) patient with a novel heterozygous mutation of the nuclear receptor subfamily 5 group A member 1 (NR5A1) gene. Next-generation sequencing found a heterozygous c.124C>G mutation in NR5A1 that resulted in a p.Q42E missense mutation in the conserved DNA-binding domain of NR5A1. The patient demonstrated feminization of external genitalia and Tanner stage 1 breast development. The surgical procedure revealed a morphologically normal epididymis and vas deferens but a dysplastic testis. Microfluidic-based single-cell RNA sequencing (scRNA-seq) analysis found that the fibroblast cells were significantly increased (approximately 46.5%), whereas the number of main epididymal epithelial cells (approximately 9.2%), such as principal cells and basal cells, was dramatically decreased. Bioinformatics analysis of cell-cell communications and gene regulatory networks at the single-cell level inferred that epididymal epithelial cell loss and fibroblast occupation are associated with the epithelial-to-mesenchymal transition (EMT) process. The present study provides a cell atlas of the epididymis of a patient with 46,XY DSD and serves as an important resource for understanding the pathophysiology of DSD.

Ursolic acid augments the chemosensitivity of drug-resistant breast cancer cells to doxorubicin by AMPK-mediated mitochondrial dysfunction.

Multidrug resistance remains the major obstacle to successful therapy for breast carcinoma. Ursolic acid (UA), a triterpenoid compound, has been regarded as a potential neoplasm chemopreventive drug in some preclinical studies since it exerts multiple biological activities. In this research, we investigated the role of UA in augmenting the chemosensitivity of drug-resistant breast carcinoma cells to doxorubicin (DOX), and we further explored the possible molecular mechanisms. Notably, we found that UA treatment led to inhibition of cellular proliferation and migration and cell cycle arrest in DOX-resistant breast cancers. Furthermore, combination treatment with UA and DOX showed a stronger inhibitory effect on cell viability, colony formation, and cell migration; induced more cell apoptosis in vitro; and generated a more potent inhibitory effect on the growth of the MCF-7/ADR xenograft tumor model than DOX alone. Mechanistically, UA effectively increased p-AMPK levels and concomitantly reduced p-mTOR and PGC-1α protein levels, resulting in impaired mitochondrial function, such as mitochondrial respiration inhibition, ATP depletion, and excessive reactive oxygen species (ROS) generation. In addition, UA induced a DNA damage response by increasing intracellular ROS production, thus causing cell cycle arrest at the G0/G1 phase. UA also suppressed aerobic glycolysis by prohibiting the expression and function of Glut1. Considered together, our data demonstrated that UA potentiated the susceptibility of DOX-resistant breast carcinoma cells to DOX by targeting energy metabolism through the AMPK/mTOR/PGC-1α signaling pathway, and it is a potential adjuvant chemotherapeutic candidate in MDR breast cancer.

Understanding of chiral site-dependent enantioselective identification on a plasmon-free semiconductor based SERS substrate.

Chiral differentiation is an important topic in diverse fields ranging from pharmaceutics to chiral synthesis. The improvement of sensitivity and the elucidation of the mechanism of chiral recognition are still the two main challenges. Herein, a plasmon-free semiconductive surface-enhanced Raman spectroscopy (SERS) substrate with sensitive chiral recognition ability is proposed for the discrimination of enantiomers. A homochiral environment is constructed by typical π-π stacking between l-tryptophan (l-Trp) and phenyl rings on well-aligned TiO2 nanotubes (TiO2 NTs). Using 3,4-dihydroxyphenylalanine (DOPA) enantiomers as the targets and the chelating interaction of Fe3+-DOPA for the onsite growth of Prussian blue (PB), the enantioselectivity difference between l-DOPA and d-DOPA on the homochiral substrate can be directly monitored from PB signals in the Raman-silent region. By combining the experimental results with molecular dynamic (MD) simulations, it is found that satisfactory enantioselective identification not only requires a homochiral surface but also largely depends on the chiral center environment-differentiated hydrogen-bond formation availability.

Hydrogen Abstraction by Alkoxyl Radicals: Computational Studies of Thermodynamic and Polarity Effects on Reactivities and Selectivities.

Density functional theory calculations (ωB97X-D) are reported for the reactions of methoxy, tert-butoxy, trichloroethoxy, and trifluoroethoxy radicals with a series of 26 C-H bonds in different environments characteristic of a variety of hydrocarbons and substituted derivatives. The variations in activation barriers are analyzed with modified Evans-Polanyi treatments to account for polarity and unsaturation effects. The treatments by Roberts and Steel and by Mayer have inspired the development of a simple treatment involving the thermodynamics of reactions, the difference between the reactant radical and product radical electronegativities, and the absence or presence of α-unsaturation. The three-parameter equation (ΔH⧧ = 0.52ΔHrxn(1 - d) - 0.35ΔχAB2 + 10.0, where d = 0.44 when there is α-unsaturation to the reacting C-H bond), correlates well with quantum mechanically computed barriers and shows the quantitative importance of the thermodynamics of reactions (dictated by the reactant and the product bond dissociation energies) and polar effects.

Near Infrared Light-Driven Photothermal Effect on Homochiral Au/TiO2 Nanotube Arrays for Enantioselective Desorption.

Chiral enantiomers have different effects on biological processes. Enantiomer separation is significant and necessary. Herein, a photothermal (PT) effect-derived enantioselective desorption strategy based on homochiral Au/TiO2 nanotubes (NTs) is developed. Using 3,4-dihydroxyphenylalanine (DOPA) as the model enantiomer, an obvious selective desorption of L/D-DOPA can be achieved by the NIR light-triggered local temperature enhancement. Molecular docking simulation further verifies that the distinct affinity precipitated by the different hydrogen bonds between homochiral sorbent and target enantiomers is the origin of enantioselective desorption. This desorption strategy provides a green and alternative approach for the selective separation of chiral molecules.

Differences between Chinese men and women with adult-onset non-radiographic axial spondyloarthritis / 中华风湿病学杂志

Objective:To explore the clinical characteristics of adult-onset non-radiographic axial spondyloarthritis (nr-axSpA) in different genders.Methods:A total of 662 patients with adult-onset nr-axSpA (age at disease onset ≥16 years) who visited the Rheumatology Department of the First Affiliated Hospital of Shantou University Medical College from 1999 to 2020 were included in the study. Comparisons of baseline demographic and clinical characteristics between different genders were performed.Results:Overall, the male-to-female ratio was 1.17∶1, and the prevalence of human leukocyte antigen-B27 (HLA-B27) positivity was 71.8%(475/662). The median baseline disease duration and age at diagnosis was 1.6 (0.5, 4.0) years and 25.0 (21.0, 33.0) years respectively. The males had a significantly earlier age at disease onset and diagnosis [21.0 (18.0, 28.0) vs 25.0 (21.0, 30.0), Z=5.63, P<0.001; 24.0 (19.0, 32.0) vs 27.0 (23.0, 34.5), Z=4.90, P<0.001, respectively] than females. HLA-B27 positivity was more frequent in males than in females [78.4% (280/357) vs 63.9%(195/305), χ2=17.06, P<0.001]. The prevalence of inflammatory back pain (IBP), morning stiffness, nocturnal pain, enthesitis, hip and groin pain were higher in males, whereas females showed a higher prevalence of small joint involvement of the hands. At baseline, males had higher median ankylosing spondylitis disease activity score (ASDAS)-C-reaction protein (CRP) [3.0(2.3, 3.8) vs 2.4(2.0, 3.0), Z=5.59, P<0.001] and a greater prevalence of high disease activity ASDAS-CRP>2.1 [81.9%(185/227) vs 67.9%(133/195), χ2=11.08, P=0.001] than females. The proportions of male patients with elevated CRP levels and erythrocyte sedimentation rate (ESR) were also higher than those of female patients [49.0%(175/357) vs 27.9%(85/305), χ2=30.85, P<0.001; 49.3%(176/357) vs 33.4%(102/305), χ2=16.98, P<0.001, respectively]. Conclusion:The adult-onset nr-axSpA in China is characterized by a comparable sex ratio. Males have an earlier age at disease onset and are higher HLA-B27 positivity with higher prevalence of IBP, enthesitis, hip and groin pain, as well as high disease activity.

Affordable Ab Initio Path Integral for Thermodynamic Properties via Molecular Dynamics Simulations Using Semiempirical Reference Potential.

Path integral molecular dynamics (PIMD) is becoming a routinely applied method for incorporating the nuclear quantum effect in computer simulations. However, direct PIMD simulations at an ab initio level of theory are formidably expensive. Using the protonated 1,8-bis(dimethylamino)naphthalene molecule as an example, we show in this work that the computational expense for the intramolecular proton transfer between the two nitrogen atoms can be remarkably reduced by implementing the idea of reference-potential methods. The simulation time can be easily extended to a scale of nanoseconds while maintaining the accuracy on an ab initio level of theory for thermodynamic properties. In addition, postprocessing can be carried out in parallel on massive computer nodes. A 545-fold reduction in the total CPU time can be achieved in this way as compared to a direct PIMD simulation at the same ab initio level of theory.

Potential effects of the nursing work environment on the work-family conflict in operating room nurses.

BACKGROUND: The nursing working environment is an important subsystem in the hospital environment. A good working environment could have a positive impact on nurses. However, the work-family conflict and unsatisfactory working environment could significantly reduce their working enthusiasm, efficacy as well as the overall quality of the nursing, increase their fatigue, and thereby compromise their career status. AIM: To explore the possible status quo and to analyze the correlation between work environment perception and the work-family conflict among nurses in the operating room. METHODS: A total of 312 operating room nurses from two first-class hospitals at Grade 2 and two first-class hospitals at Grade 3 in China from May to September 2017 were included in this research using the cluster sampling method. The data, including the general information questionnaire, the practice environment scale of the nursing work index (PES-NWI), and the work-family conflict scale, were systematically collected. Pearson correlation analysis was applied to analyze the correlation between the two scores, with influencing factors analyzed by hierarchical regression analysis. RESULTS: A total of 312 questionnaires were issued, and the response rate and effective questionnaire rate were both 96.15% (300/312). The total scores of the PES-NWI scale and the work-family conflict scale were 3.07 ± 0.43 (vs maximum up to 4 points) and 52.32 ± 8.79 (vs maximum up to 90 points), respectively. The scores of the PES-NWI scale were negatively correlated with that of work-family conflict scale (all P < 0.05). The perception of the nursing work environment and the number of night shifts per month were the major factors contributing to the work-family conflict (all P < 0.05). CONCLUSION: The nursing work environment and the work-family conflict among nurses in the operating room were both found at a medium level with a negative correlation between the two.

Phase-error-compensation-based surface recovery algorithm using spectrum selection for white light interferometry.

White light interferometry is a well-established surface recovery technique. In this paper, a white light signal processing algorithm based on phase error compensation using spectrum selection is proposed. The derived nonlinear phase distribution from the correlogram is modeled as the combination of random errors and systemic deviations. By developing a new, to the best of our knowledge, recovery algorithm, the phase noise can be separated from the linear map and significantly attenuated. Based on the proposed algorithm, the spectrum features of white light LEDs and halogen lamps are investigated in detail. The inner products defined by three selected points are employed to generate a coefficient to evaluate the linearity of an unwrapped phase map within a certain spectrum region. The optimal spectrum range corresponding to the best measurement performance can then be located where the coefficient approximates 1 and the spectrum energy stays relatively high. The simulations are carried out under different levels of SNR and scan step noises, which show that the new method can effectively reduce additional disturbance from the recovered topography. In experiments, the system with the proposed method is first calibrated by a step height standard (VLSI, 182.7±2.0nm) with the repeatability of 0.44 nm. A silicon wafer and three roughness standards are also tested to further verify the robustness of the new method.