Characterization of the broad-spectrum antibacterial activity of bacteriocin-like inhibitory substance-producing probiotics isolated from fermented foods.

Antimicrobial peptides, such as bacteriocin, produced by probiotics have become a promising novel class of therapeutic agents for treating infectious diseases. Selected lactic acid bacteria (LAB) isolated from fermented foods with probiotic potential were evaluated for various tests, including exopolysaccharide production, antibiotic susceptibility, acid and bile tolerance, antibacterial activity, and cell adhesion and cytotoxicity to gastric cell lines. Six selected LAB strains maintained their high viability under gastrointestinal conditions, produced high exopolysaccharides, showed no or less cytotoxicity, and adhered successfully to gastric cells. Furthermore, three strains, Weissella confusa CYLB30, Lactiplantibacillus plantarum CYLB47, and Limosilactobacillus fermentum CYLB55, demonstrated a strong antibacterial effect against drug-resistant Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica serovar Choleraesuis, Enterococcus faecium, and Staphylococcus aureus. Whole genome sequencing was performed on these three strains using the Nanopore platform; then, the results showed that all three strains did not harbor genes related to toxins, superantigens, and acquired antimicrobial resistance, in their genome. The bacteriocin gene cluster was found in CYLB47 genome, but not in CYLB30 and CYLB55 genomes. In SDS-PAGE, the extract of CYLB30 and CYLB47 bacteriocin-like inhibitory substance (BLIS) yielded a single band with a size of less than 10 kDa. These BLIS inhibited the growth and biofilm formation of drug-resistant P. aeruginosa and methicillin-resistant S. aureus (MRSA), causing membrane disruption and inhibiting adhesion ability to human skin HaCaT cells. Moreover, CYLB30 and CYLB47 BLIS rescued the larvae after being infected with P. aeruginosa and MRSA infections. In conclusion, CYLB30 and CYLB47 BLIS may be potential alternative treatment for multidrug-resistant bacteria infections.

Perspectives of nurse preceptors on a web-based clinical pedagogy program and clinical teaching: A descriptive qualitative study.

Nurse preceptors are key stakeholders in providing quality clinical education. This study aimed to explore the perspectives of nurse preceptors on a web-based clinical pedagogy program and clinical teaching. A descriptive qualitative design was adopted. The program was made accessible to the nurse preceptors who were assigned nursing students from July 2019 to June 2020. Upon completion of clinical teaching, a total of 19 nurse preceptors participated in four focus group discussions. The discussions were audio recorded and transcribed verbatim, and thematic analysis was conducted. Five themes, with 11 subthemes, emerged: (i) Undergoing the process of self-awareness and development; (ii) Mastering newly acquired skills to refine own teaching approach; (iii) Implementing consistent evaluation and constructive feedback; (iv) Dual roles and responsibilities of preceptor; and (v) Benefits and barriers of the program. This study highlighted the knowledge and skills preceptors gained through the program which gave them newfound confidence and facilitated their clinical teaching and evaluation. As the shift towards online learning progresses, web-based learning can be a useful platform for professional development of nurse preceptors.

A Clinical Teaching Blended Learning Program to Enhance Registered Nurse Preceptors' Teaching Competencies: Pretest and Posttest Study.

BACKGROUND: Clinical nursing education provides opportunities for students to learn in multiple patient care settings, receive appropriate guidance, and foster the development of clinical competence and professionalism. Nurse preceptors guide students to integrate theory into practice, teach clinical skills, assess clinical competencies, and enhance problem-solving and critical thinking skills. Previous research has indicated that the teaching competencies of nurse preceptors can be transferred to students' clinical learning to enhance their clinical competencies. OBJECTIVE: This study aimed to develop a clinical teaching blended learning (CTBL) program with the aid of web-based clinical pedagogy (WCP) and case-based learning for nurse preceptors and to examine the effectiveness of the CTBL program on nurse preceptors' clinical teaching competencies, self-efficacies, attitudes toward web-based learning, and blended learning outcomes. METHODS: A quasi-experimental single-group pretest and posttest design was adopted. A total of 150 nurse preceptors participated in the CTBL program, which was conducted from September 2019 to December 2019. A set of questionnaires, including the clinical teaching competence inventory, preceptor self-efficacy questionnaire, attitudes toward web-based continuing learning survey, and e-learning experience questionnaire, was used to assess the outcomes before and after the CTBL program. RESULTS: Compared with the baseline, the participants had significantly higher total mean scores and subdomain scores for clinical teaching competence (mean 129.95, SD 16.38; P<.001), self-efficacy (mean 70.40, SD 9.35; P<.001), attitudes toward web-based continuing learning (mean 84.68, SD 14.76; P<.001), and blended learning outcomes (mean 122.13, SD 14.86; P<.001) after the CTBL program. CONCLUSIONS: The CTBL program provides a comprehensive coverage of clinical teaching pedagogy and assessment strategies. The combination of the WCP and case-based approach provides a variety of learning modes to fit into the diverse learning needs of the preceptors. The CTBL program allows the preceptors to receive direct feedback from the facilitators during face-to-face sessions. Preceptors also gave feedback that the web-based workload is manageable. This study provides evidence that the CTBL program increases the clinical teaching competencies and self-efficacies of the preceptors and promotes positive attitudes toward web-based learning and better blended learning outcomes. The health care organization can consider the integration of flexible learning and intellect platforms for preceptorship education.

Synthesis of 3-(2-Olefinbenzyl)-4H-chromen-4-one through Cyclobenzylation and Catalytic C-H Bond Functionalization Using Palladium(II).

An efficient strategy for synthesizing 3-(2-olefinbenzyl)-4H-chromen-4-one in two steps was developed. The first step is a cyclobenzylation reaction between (E)-3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one and benzyl bromide to produce homoisoflavonoid. The second step involves intermolecular Pd-catalyzed π-chelating-assisted C-H bond olefination. Using the C-2/C-3 double bond of chromone, palladium-catalyzed aryl C-H bond activation can be functionalized to generate ortho-olefination derivatives in moderate to high yields.

Au Nanoparticles Decorated TiO2 Nanotube Arrays as a Recyclable Sensor for Photoenhanced Electrochemical Detection of Bisphenol A.

A photorefreshable and photoenhanced electrochemical sensing platform for bisphenol A (BPA) detection based on Au nanoparticles (NPs) decorated carbon doped TiO2 nanotube arrays (TiO2/Au NTAs) is described. The TiO2/Au NTAs were prepared by quick annealing of anodized nanotubes in argon, followed by controllable electrodeposition of Au NPs. The decoration of Au NPs not only improved photoelectrochemical behavior but also enhanced electrocatalytic activities of the resulted hybrid NTAs. Meanwhile, the high photocatalytic activity of the NTAs allowed the electrode to be readily renewed without damaging the microstructures and surface states after a short UV treatment. The electrochemical detection of BPA on TiO2/Au NTAs electrode was significantly improved under UV irradiation as the electrode could provide fresh reaction surface continuously and the further increased photocurrent resulting from the improved separation efficiency of the photogenerated electron-hole pairs derived from the consumption of holes by BPA. The results showed that the refreshable TiO2/Au NTAs electrode is a promising sensor for long-term BPA monitoring with the detection limit (S/N = 3) of 6.2 nM and the sensitivity of 2.8 µA·µM(-1)·cm(-2).

Saponins from Chinese Medicines as Anticancer Agents.

Saponins are glycosides with triterpenoid or spirostane aglycones that demonstrate various pharmacological effects against mammalian diseases. To promote the research and development of anticancer agents from saponins, this review focuses on the anticancer properties of several typical naturally derived triterpenoid saponins (ginsenosides and saikosaponins) and steroid saponins (dioscin, polyphyllin, and timosaponin) isolated from Chinese medicines. These saponins exhibit in vitro and in vivo anticancer effects, such as anti-proliferation, anti-metastasis, anti-angiogenesis, anti-multidrug resistance, and autophagy regulation actions. In addition, related signaling pathways and target proteins involved in the anticancer effects of saponins are also summarized in this work.

Chemical proteomics identifies heterogeneous nuclear ribonucleoprotein (hnRNP) A1 as the molecular target of quercetin in its anti-cancer effects in PC-3 cells.

Quercetin, a flavonoid abundantly present in plants, is widely used as a phytotherapy in prostatitis and prostate cancer. Although quercetin has been reported to have a number of therapeutic effects, the cellular target(s) responsible for its anti-cancer action has not yet been clearly elucidated. Here, employing affinity chromatography and mass spectrometry, we identified heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) as a direct target of quercetin. A specific interaction between quercetin and hnRNPA1 was validated by immunoblotting and in vitro binding experiments. We found that quercetin bound the C-terminal region of hnRNPA1, impairing the ability of hnRNPA1 to shuttle between the nucleus and cytoplasm and ultimately resulting in its cytoplasmic retention. In addition, hnRNPA1 was recruited to stress granules after treatment of cells with quercetin for up to 48 h, and the levels of cIAP1 (cellular inhibitor of apoptosis), an internal ribosome entry site translation-dependent protein, were reduced by hnRNPA1 regulation. This is the first report that anti-cancer effects of quercetin are mediated, in part, by impairing functions of hnRNPA1, insights that were obtained using a chemical proteomics strategy.

Microfluidic Platform for Studying Chemotaxis of Adhesive Cells Revealed a Gradient-Dependent Migration and Acceleration of Cancer Stem Cells.

Recent studies reveal that solid tumors consist of heterogeneous cells with distinct phenotypes and functions. However, it is unclear how different subtypes of cancer cells migrate under chemotaxis. Here, we developed a microfluidic device capable of generating multiple stable gradients, culturing cells on-chip, and monitoring single cell migratory behavior. The microfluidic platform was used to study gradient-induced chemotaxis of lung cancer stem cell (LCSC) and differentiated LCSC (dLCSC) in real time. Our results showed the dynamic and differential response of both LCSC and dLCSC to chemotaxis, which was regulated by the ß-catenin dependent Wnt signaling pathway. The microfluidic analysis showed that LCSC and dLCSC from the same origin behaved differently in the same external stimuli, suggesting the importance of cancer cell heterogeneity. We also observed for the first time the acceleration of both LCSC and dLCSC during chemotaxis caused by increasing local concentration in different gradients, which could only be realized through the microfluidic approach. The capability to analyze single cell chemotaxis under spatially controlled conditions provides a novel analytical platform for the study of cellular microenvironments and cancer cell metastasis.

Activation of multiple signaling pathways during the differentiation of mesenchymal stem cells cultured in a silicon nanowire microenvironment.

Mesenchymal stem cells (MSC) offer an optimal source for bone tissue engineering due to their capability of undergoing multilineage differentiation, where the mechanical properties of the microenvironment of MSCs are vital for osteochondral formation. However, the mechanisms of how mechanical and microenvironmental cues control osteogenesis and chondrogenesis are yet to be elucidated. In this study, we investigated the effects of vertically aligned silicon nanowire (SiNW) array on the differentiation of MSCs and the associated molecular mechanisms involved in osteogenesis and chandrogenesis. The results showed that the microenvironment of SiNW array activated a number of mechanosensitive pathways (including Integrin, TGF-ß/BMP, Akt, MAPK, Insulin, and Wnt pathways) in MSCs, which converged to stimulate the osteogenesis and chondrogenesis via the Ras-Raf-MEK-ERK cascade. FROM THE CLINICAL EDITOR: This study reports on the mechanisms and microenvironmental influence of osteogenesis and chondrogenesis by mesenchymal stem cells interacting with vertically aligned silicon nanowire scaffolds.

Langer-Giedion syndrome: the evolving imaging features in hands and beyond.

Trichorhinophalangeal syndrome (TRP) is a group of rare genetic disorders with characteristic clinical and radiological features. In this case report we discuss the evolution of imaging features in hands in a Chinese boy diagnosed with TRP II (Langer-Giedion syndrome, LGS). This article ramifies the diagnostic value of serial hand radiograph in clinically suspected cases of TRP.

An integrated and multi-functional droplet-based microfluidic platform for digital DNA amplification.

Digital DNA amplification is a powerful method for detecting and quantifying rare nucleic acids. In this study, we developed a multi-functional droplet-based platform that integrates the traditional digital DNA amplification workflow into a one-step device. This platform enables efficient droplet generation, transition, and signal detection within a 5-min timeframe, distributing the sample into a uniform array of 4 × 104 droplets (variation <2%) within a chamber. Subsequent in-situ DNA amplification, fluorescence detection, and signal analysis were carried out. To assess the platform's performance, we quantitatively detected the human epidermal growth factor receptor (EGFR) mutation and human papillomavirus (HPV) mutation using digital polymerase chain reaction (dPCR) and digital loop-mediated isothermal amplification (dLAMP), respectively. The fluorescence results exhibited a positive, linear, and statistically significant correlation with target DNA concentrations ranging from 101 to 105 copies/µL, demonstrating the capability and feasibility of the integrated device for dPCR and dLAMP. This platform offers high-throughput droplet generation, eliminates droplet fusion and transition, is user-friendly, reduces costs compared to current methods, and holds potential for thermocycling and isothermal nucleic acid quantification with high sensitivity and accuracy.

Quantitative accuracy of lung function measurement using parametric response mapping: A virtual imaging study.

Parametric response mapping (PRM) is a voxel-based quantitative CT imaging biomarker that measures the severity of chronic obstructive pulmonary disease (COPD) by analyzing both inspiratory and expiratory CT scans. Although PRM-derived measurements have been shown to predict disease severity and phenotyping, their quantitative accuracy is impacted by the variability of scanner settings and patient conditions. The aim of this study was to evaluate the variability of PRM-based measurements due to the changes in the scanner types and configurations. We developed 10 human chest models with emphysema and air-trapping at end-inspiration and end-expiration states. These models were virtually imaged using a scanner-specific CT simulator (DukeSim) to create CT images at different acquisition settings for energy-integrating and photon-counting CT systems. The CT images were used to estimate PRM maps. The quantified measurements were compared with ground truth values to evaluate the deviations in the measurements. Results showed that PRM measurements varied with scanner type and configurations. The emphysema volume was overestimated by 3 ± 9.5 % (mean ± standard deviation) of the lung volume, and the functional small airway disease (fSAD) volume was underestimated by 7.5±19 % of the lung volume. PRM measurements were more accurate and precise when the acquired settings were photon-counting CT, higher dose, smoother kernel, and larger pixel size. This study demonstrates the development and utility of virtual imaging tools for systematic assessment of a quantitative biomarker accuracy.

Development and Application of a Virtual Imaging Trial Framework for Longitudinal Quantification of Emphysema in CT.

Pulmonary emphysema is a progressive lung disease that requires accurate evaluation for optimal management. This task, possible using quantitative CT, is particularly challenging as scanner and patient attributes change over time, negatively impacting the CT-derived quantitative measures. Efforts to minimize such variations have been limited by the absence of ground truth in clinical data, thus necessitating reliance on clinical surrogates, which may not have one-to-one correspondence to CT-based findings. This study aimed to develop the first suite of human models with emphysema at multiple time points, enabling longitudinal assessment of disease progression with access to ground truth. A total of 14 virtual subjects were modeled across three time points. Each human model was virtually imaged using a validated imaging simulator (DukeSim), modeling an energy-integrating CT scanner. The models were scanned at two dose levels and reconstructed with two reconstruction kernels, slice thicknesses, and pixel sizes. The developed longitudinal models were further utilized to demonstrate utility in algorithm testing and development. Two previously developed image processing algorithms (CT-HARMONICA, EmphysemaSeg) were evaluated. The results demonstrated the efficacy of both algorithms in improving the accuracy and precision of longitudinal quantifications, from 6.1±6.3% to 1.1±1.1% and 1.6±2.2% across years 0-5. Further investigation in EmphysemaSeg identified that baseline emphysema severity, defined as >5% emphysema at year 0, contributed to its reduced performance. This finding highlights the value of virtual imaging trials in enhancing the explainability of algorithms. Overall, the developed longitudinal human models enabled ground-truth based assessment of image processing algorithms for lung quantifications.

VLST: Virtual Lung Screening Trial for Lung Cancer Detection Using Virtual Imaging Trial.

Importance: The efficacy of lung cancer screening can be significantly impacted by the imaging modality used. This Virtual Lung Screening Trial (VLST) addresses the critical need for precision in lung cancer diagnostics and the potential for reducing unnecessary radiation exposure in clinical settings. Objectives: To establish a virtual imaging trial (VIT) platform that accurately simulates real-world lung screening trials (LSTs) to assess the diagnostic accuracy of CT and CXR modalities. Design Setting and Participants: Utilizing computational models and machine learning algorithms, we created a diverse virtual patient population. The cohort, designed to mirror real-world demographics, was assessed using virtual imaging techniques that reflect historical imaging technologies. Main Outcomes and Measures: The primary outcome was the difference in the Area Under the Curve (AUC) for CT and CXR modalities across lesion types and sizes. Results: The study analyzed 298 CT and 313 CXR simulated images from 313 virtual patients, with a lesion-level AUC of 0.81 (95% CI: 0.78-0.84) for CT and 0.55 (95% CI: 0.53-0.56) for CXR. At the patient level, CT demonstrated an AUC of 0.85 (95% CI: 0.80-0.89), compared to 0.53 (95% CI: 0.47-0.60) for CXR. Subgroup analyses indicated CT's superior performance in detecting homogeneous lesions (AUC of 0.97 for lesion-level) and heterogeneous lesions (AUC of 0.71 for lesion-level) as well as in identifying larger nodules (AUC of 0.98 for nodules > 8 mm). Conclusion and Relevance: The VIT platform validated the superior diagnostic accuracy of CT over CXR, especially for smaller nodules, underscoring its potential to replicate real clinical imaging trials. These findings advocate for the integration of virtual trials in the evaluation and improvement of imaging-based diagnostic tools.

A cross-sectional study of the beliefs and attitudes towards menstruation of Chinese undergraduate males and females in Hong Kong.

AIMS AND OBJECTIVES: To explore the beliefs and attitudes towards menstruation of Chinese undergraduates in Hong Kong and to compare those of (1) male and female undergraduates with those of (2) undergraduates studying health-related vs. nonhealth-related programmes. BACKGROUND: Menstruation is typically viewed as a forbidden topic or a troublesome experience. These negative beliefs and attitudes result from existing myths and taboos associated with cultural factors and health education levels. DESIGN: A cross-sectional survey was conducted in all universities in Hong Kong. Undergraduates were invited through convenience sampling to complete a questionnaire assessing their attitudes and beliefs towards menstruation. METHODS: A questionnaire on 'beliefs about and attitudes towards menstruation' was adopted. Questionnaires were self-administered by the respondents. RESULTS: A total of 450 questionnaires were distributed, and a response rate of 96.6% was obtained; 416 completed questionnaires were collected and analysed. Many Chinese undergraduates agreed that menstruation is annoying, causes disability, involves prescription and proscription and is not pleasant. When comparing the beliefs and attitudes towards menstruation of Chinese male undergraduates with those of female undergraduates, females tended to disagree that menstruation should be maintained secret, but tended to agree that it was annoying. When comparing the beliefs and attitudes towards menstruation of Chinese undergraduates studying health-related programmes with those under nonhealth-related programmes, the latter group exhibited a higher level of belief in prescription and proscription for menstruation than the former group. CONCLUSION: Chinese undergraduates in Hong Kong were influenced by the traditional Chinese culture and social environment, resulting in negative attitudes towards menstruation. This study recommends that sex education, especially reproductive health education, be extended to tertiary education. RELEVANCE TO CLINICAL PRACTICE: This study provides relevant information on planning the content of sex education or reproductive health education for Chinese undergraduates.

Development and Application of a Virtual Imaging Trial framework for Airway Quantifications via CT.

Chronic obstructive pulmonary disease (COPD) is one of the top three causes of death worldwide, characterized by emphysema and bronchitis. Airway measurements reflect the severity of bronchitis and other airway-related diseases. Airway structures can be objectively evaluated with quantitative computed tomography (CT). The accuracy of such quantifications is limited by the spatial resolution and image noise characteristics of the imaging system and can be potentially improved with the emerging photon-counting CT (PCCT) technology. This study evaluated the quantitative performance of PCCT against energy-integrating CT (EICT) systems for airway measurements, and further identified optimum CT imaging parameters for such quantifications. The study was performed using a novel virtual imaging framework by developing the first library of virtual patients with bronchitis. These virtual patients were developed based on CT images of confirmed COPD patients with varied bronchitis severity. The human models were virtually imaged at 6.3 and 12.6 mGy dose levels using a scanner-specific simulator (DukeSim), synthesizing clinical PCCT and EICT scanners (NAEOTOM Alpha, FLASH, Siemens). The projections were reconstructed with two algorithms and kernels at different matrix sizes and slice thicknesses. The CT images were used to quantify clinically relevant airway measurements ("Pi10" and "WA%") and compared against their ground truth values. Compared to EICT, PCCT provided more accurate Pi10 and WA% measurements by 63.1% and 68.2%, respectively. For both technologies, sharper kernels and larger matrix sizes led to more reliable bronchitis quantifications. This study highlights the potential advantages of PCCT against EICT in characterizing bronchitis utilizing a virtual imaging platform.

A web-based clinical pedagogy program to promote professional development for nurse preceptors: A quasi-experimental study.

OBJECTIVE: To examine the effectiveness of a web-based clinical pedagogy program on nurse preceptors' clinical teaching competency, self-efficacy, and attitudes toward web-based learning in comparison to face-to-face course. BACKGROUND: Preceptorship is a dynamic educational process that requires designing, and implementing various teaching strategies, evaluation, assessment and feedback. Web-based learning has been recognized as an effective learning approach for nursing professional development. DESIGN: A prospective quasi-experimental approach with two-group pre-test and post-test repeated measures was adopted. METHODS: The web-based clinical pedagogy program was provided to the preceptors in the experimental group, while control group received the face-to-face preceptorship course. Clinical Teaching Competence Inventory (CTCI), Preceptor Self-efficacy Assessment Instrument (PSEQ), and Attitudes toward Web-based Continuing Learning Survey (AWCLS) were used to evaluate preceptors' learning outcomes. Data were collected at three time points - before, immediately after the learning program, and after 6 months of the clinical teaching experience. RESULTS: A total of 150 nurses (75 participants/group) were recruited from a tertiary hospital in Singapore from July 2018 to June 2020. The results from the repeated measures analysis of covariance showed that there was a significant interaction effect (group x time) on the overall CTCI score after adjusting for covariate (F = 5.390, p = 0.005). However, there were no significant interaction effect (group x time) on PSEQ (F = 2.693, p = 0.070) and overall AWCLS score (F = 1.341, p = 0.264) between the two groups across the three time points. CONCLUSION: The web-based clinical pedagogy program produced outcomes comparable to the face-to-face program in terms of preceptors' clinical teaching competence and self-efficacy. The innovative and cost-effective web-based clinical pedagogy program provided professional development and the flexibility to accommodate preceptors' busy work schedules. Online learning has become increasingly popular during the COVID-19 pandemic and the web-based clinical pedagogy program was implemented when face-to-face workshop was not feasible.

Characterization of 5-HT transporter and receptor system in HeLaS3 cells by [(3)H]8-OH-DPAT and other serotonergic ligands.

[(3)H]8-OH-DPAT is a selective ligand for labeling 5-HT(1A) receptor sites. In competition binding experiments, we found that classic biogenic amine transporter inhibitors displaced [(3)H]8-OH-DPAT binding at its high-affinity binding sites in HeLaS3 cells. [(125)I]RTI-55 and [(3)H]paroxetine are known to specifically label amine transporter sites, and this was observed in our cells. Displacement studies showed that 8-OH-DPAT displayed affinity in a dose-dependent manner for the labeled amine transporter sites. These data suggest that [(3)H]8-OH-DPAT binds to amine uptake sites in HeLaS3 cells. A variety of drugs targeting different classes of receptors did not significantly affect [(3)H]8-OH-DPAT binding. Moreover, we determined the specific binding effects of various serotonergic ligands (i.e. [(125)I]cyanopindolol, [(3)H]ketanserin/[(3)H]mesulergine, [(3)H]GR-65630, [(3)H]GR-113808 and [(3)H]LSD) that specifically labeled 5-HT(1), 5-HT(2), 5-HT(3), 5-HT(4) and 5-HT(5-7) receptors, respectively. It is suggested that HeLaS3 cells contain distinct types of the related to 5-HT receptor recognition binding sites. These observations could help elucidate the relevant characteristics of different types of 5-HT receptors and 5-HT membrane transporters in tumor cells and their role in tumorigenesis.

Superconductivity in the PbO-type structure alpha-FeSe.

The recent discovery of superconductivity with relatively high transition temperature (Tc) in the layered iron-based quaternary oxypnictides La[O(1-x)F(x)] FeAs by Kamihara et al. [Kamihara Y, Watanabe T, Hirano M, Hosono H (2008) Iron-based layered superconductor La[O1-xFx] FeAs (x = 0.05-0.12) with Tc = 26 K. J Am Chem Soc 130:3296-3297.] was a real surprise and has generated tremendous interest. Although superconductivity exists in alloy that contains the element Fe, LaOMPn (with M = Fe, Ni; and Pn = P and As) is the first system where Fe plays the key role to the occurrence of superconductivity. LaOMPn has a layered crystal structure with an Fe-based plane. It is quite natural to search whether there exists other Fe based planar compounds that exhibit superconductivity. Here, we report the observation of superconductivity with zero-resistance transition temperature at 8 K in the PbO-type alpha-FeSe compound. A key observation is that the clean superconducting phase exists only in those samples prepared with intentional Se deficiency. FeSe, compared with LaOFeAs, is less toxic and much easier to handle. What is truly striking is that this compound has the same, perhaps simpler, planar crystal sublattice as the layered oxypnictides. Therefore, this result provides an opportunity to better understand the underlying mechanism of superconductivity in this class of unconventional superconductors.

Singapore Basic Cardiac Life Support and Automated External Defibrillation Guidelines 2021.

Basic Cardiac Life Support and Automated External Defibrillation (BCLS+AED) refers to the skills required in resuscitating cardiac arrest casualties. On recognising cardiac arrest, the rescuer should call for '995' for Emergency Ambulance and immediately initiate chest compressions. Good-quality chest compressions are performed with arms extended, elbows locked, shoulders directly perpendicular over the casualty's chest, and the heel of the palm placed on the lower half of the sternum. The rescuer compresses hard and fast at 4-6 cm depth for adults at a compression rate of 100-120 per minute, with complete chest recoil after each compression. Two quick ventilations of 400-600 mL each can be delivered via a bag-valve-mask after every 30 chest compressions. Alternatively, a trained, able and willing rescuer can provide mouth-to-mouth ventilation. Cardiopulmonary resuscitation should be stopped only when the casualty wakes up, the emergency team takes over care, or when an automated external defibrillator prompts for heart rhythm analysis or delivery of a shock.