High-speed k-linear swept laser using acousto-optic deflectors with Doppler shift compensation for optical coherence tomography.

Swept laser based on the acousto-optic deflector (AOD) is a promising swept source in optical coherence tomography (OCT) applications for its high wavenumber linear sweep without mechanical motion. However, the poor coherence length and the elongated cavity of the laser imposed limitations on the acquisition of high-quality images with adequate imaging depth and high imaging speed. In this Letter, we demonstrate a compact high-speed wavenumber linear swept laser based on AOD using Doppler shift compensation, achieving a high linearity of Pearson's R of 0.999991, a duty cycle of ∼100%, an extended coherence length of 5.7 mm, an output power of 18 mW, and excellent phase stability at a sweep speed of 500 kHz. OCT structural images with a system sensitivity of 103.2 dB and OCT angiography (OCTA) of human palm in vivo have been successfully performed, serving as a compelling demonstration of the excellent performance of this swept laser. We believe that the proposed laser will be of high potential in various clinical and industrial applications in the future.

Extension of a biotic ligand model for predicting the toxicity of neodymium to wheat: The effects of pH, Ca2+ and Mg2.

The damage excessive neodymium (Nd) causes to animals and plants should not be underestimated. However, there is little research on the impact of pH and associated ions on the toxicity of Nd. Here, a biotic ligand model (BLM) was expanded to predict the effects of pH and chief anions on the toxic impact of Nd on wheat root elongation in a simulated soil solution. The results suggested that Nd3+ and NdOH2+ were the major ions causing phytotoxicity to wheat roots at pH values of 4.5-7.0. The Nd toxicity decreased as the activities of H+, Ca2+, and Mg2+ increased but not when the activities of K+ and Na+ increased. The results indicated that H+, Ca2+, and Mg2+ competed with Nd for binding sites. An extended BLM was developed to consider the effects of pH, H+, Ca2+, and Mg2+, and the following stability constants were obtained: logKNdBL = 2.51, logKNdOHBL = 3.90, logKHBL = 4.01, logKCaBL = 2.43, and logKMgBL = 2.70. The results demonstrated that the BLM could predict the Nd toxicity well while considering the competition of H+, Ca2+, Mg2+ and the toxic species Nd3+ and NdOH2+ for binding sites.

Atomically Precise Nanometer-Sized Pt Catalysts with an Additional Photothermy Functionality.

Atomically precise ~1-nm Pt nanoparticles (nanoclusters, NCs) with ambient stability are important in fundamental research and exhibit diverse practical applications (catalysis, biomedicine, etc.). However, synthesizing such materials is challenging. Herein, by employing the mixture ligand protecting strategy, we successfully synthesized the largest organic-ligand-protected (~1-nm) Pt23 NCs precisely characterized with mass spectrometry and single-crystal X-ray diffraction analyses. Interestingly, natural population analysis and Bader charge calculation indicate an alternate, varying charge -layer distribution in the sandwich-like Pt23 NC kernel. Pt23 NCs can catalyze the oxygen reduction reaction under acidic conditions without requiring calcination and other treatments, and the resulting specific and mass activities without further treatment are sevenfold and eightfold higher than those observed for commercial Pt/C catalysts, respectively. Density functional theory and d-band center calculations interpret the high activity. Furthermore, Pt23 NCs exhibit a photothermal conversion efficiency of 68.4 % under 532-nm laser irradiation and can be used at least for six cycles, thus demonstrating great potential for practical applications.

Mesophilic Argonaute-Based Single Polystyrene Sphere Aptamer Fluorescence Platform for the Multiplexed and Ultrasensitive Detection of Non-Nucleic Acid Targets.

The rapid, simultaneous, and accurate identification of multiple non-nucleic acid targets in clinical or food samples at room temperature is essential for public health. Argonautes (Agos) are guided, programmable, target-activated, next-generation nucleic acid endonucleases that could realize one-pot and multiplexed detection using a single enzyme, which cannot be achieved with CRISPR/Cas. However, currently reported thermophilic Ago-based multi-detection sensors are mainly employed in the detection of nucleic acids. Herein, this work proposes a Mesophilic Argonaute Report-based single millimeter Polystyrene Sphere (MARPS) multiplex detection platform for the simultaneous analysis of non-nucleic acid targets. The aptamer is utilized as the recognition element, and a single millimeter-sized polystyrene sphere (PSmm ) with a large concentration of guide DNA on the surface served as the microreactor. These are combined with precise Clostridium butyricum Ago (CbAgo) cleavage and exonuclease I (Exo I) signal amplification to achieve the efficient and sensitive recognition of non-nucleic acid targets, such as mycotoxins (<60 pg mL-1 ) and pathogenic bacteria (<102 cfu mL-1 ). The novel MARPS platform is the first to use mesophilic Agos for the multiplex detection of non-nucleic acid targets, overcoming the limitations of CRISPR/Cas in this regard and representing a major advancement in non-nucleic acid target detection using a gene-editing-based system.

Polarization-isolated stretched-pulse mode-locked swept laser for 10.3-MHz A-line rate optical coherence tomography.

Stretched-pulse mode-locked (SPML) lasing based on a chirped fiber Bragg grating (CFBG) has proven to be a powerful method to generate wavelength-swept lasers at speeds of tens of megahertz. However, light transmitted through the CFBG may lead to undesirable laser oscillation that disrupts the mechanism of the laser active mode locking in the theta ring cavity. In this Letter, we demonstrate a simple and low-cost approach to suppress the transmitted light and achieve an effective duty cycle of ∼100% with only one CFBG and no need for intra-cavity semiconductor optical amplifier (SOA) modulation, extra-cavity optical buffering, and post amplification. By utilizing polarization isolation of the bi-directional CFBG, a swept laser centered at 1305 nm, with repetition rate of 10.3 MHz, optical power of 84 mW, and 3 dB bandwidth of 109 nm, is demonstrated. Ultrahigh speed 3D optical coherence tomography (OCT) structural imaging of a human palm in vivo using this swept laser is also demonstrated. We believe that this ultrahigh speed swept laser will greatly promote the OCT technique for industrial and biomedical applications.

Clinical application of single-layer annular vaginal flap in transvaginal repair for vesicovaginal fistula.

PURPOSE: To compare the first-time success rate and prognosis of repairing vesicovaginal fistula (VVF) by transvaginal and transvesical approaches, and to highlight a modified transvaginal repair technique which only require single layer closure of an annular vaginal flap. METHODS: Retrospective analysis of 57 consecutive patients who underwent VVF repair between 2007 and 2021. Fistula characteristics, operative factors, post-surgical complications and outcomes were analyzed. RESULTS: A total of 57 women with a median age of 50.4 (27-75) years were included. The history ranged from 7 days to 8 years, with an average of 20 months. 56 cases (98.2%) of VVFs were caused by pelvic surgery, and only one resulted from difficult labour. 11 cases (19.3%) had a history of surgical repair failure. All 57 cases of surgery were smoothly completed. Among them, 17 patients underwent transvaginal repair, whereas 40 (70.2%) women had transvesical repair. Transvaginal approach had a significantly shorter operative time, less intraoperative blood loss, reduced postoperative hospital stay, less hospitalization cost and lower minor complication rates than transvesical group (p < 0.05). No serious complications occurred in the two groups. No cystostomy was performed in the transvaginal group, but 12 cases (30%) in the transvesical group. The average follow-up time was 18.5 (3-48) months. The first-time success rates of transvaginal and transvesical techniques were 82.3 and 75%, respectively. CONCLUSION: VVF repair with single layer closure of an annular vaginal flap is a technically feasible, simple and successful approach with significantly better operative parameters and lower complications rates.

Recent advances in the chemistry of aryltriazene.

Triazene is one of the most versatile building blocks in organic synthesis. Generally, it is viewed as a safe equivalent of diazonium salt, thus immediately finding numerous applications in preparative chemistry and medicinal chemistry. Besides, it can be used as a removable directing group in C-H functionalization or play a smart role as a precursor for aryl cation/radical generation. In this review, we will highlight recent noteworthy developments in this field.

siRNA targeting Atp5a1 gene encoding ATPase α, the ligand of Peg fimbriae, reduced Salmonella Enteritidis adhesion.

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a zoonotic pathogen that can infect both humans and animals. Among the 13 types of fimbrial operons in S. Enteritidis, the highly conserved Peg fimbriae play a crucial role in the adhesion and invasion of S. Enteritidis into host cells but are not well studied. In this study, we identified the ATP synthase subunit alpha (ATPase α) as a ligand of Peg fimbriae using ligand blotting and mass spectrometry techniques. We confirmed the in vitro binding of ATPase α to the purified adhesion protein (PegD). Furthermore, we used siRNA to suppress the expression of ATPase α gene Atp5a1 in Leghorn male hepatoma (LMH) cells, which resulted in a significant reduction in the adhesion rate of S. Enteritidis to the cells (P < 0.05). The findings in this study provide insight into the mechanism of S. Enteritidis infection through Peg fimbriae and highlight the importance of ATPase α in the adhesion process.RESEARCH HIGHLIGHTS Ligand blotting was performed to screen the ligand of S. Enteritidis Peg fimbriae.Binding assay confirmed that ATPase α is the ligand of the Peg fimbriae.siRNA targeting ATPase α gene (Atp5a1) significantly reduced S. Enteritidis adhesion.

Antimicrobial-Resistant Escherichia coli, Enterobacter cloacae, Enterococcus faecium, and Salmonella Kentucky Harboring Aminoglycoside and Beta-Lactam Resistance Genes in Raw Meat-Based Dog Diets, USA.

The practice of feeding raw meat-based diets to dogs has grown in popularity worldwide in recent years. However, there are public health risks in handling and feeding raw meat-based dog diets (RMDDs) to dogs since there are no pathogen reduction steps to reduce the microbial load, which may include antimicrobial-resistant pathogenic bacteria. A total of 100 RMDDs from 63 suppliers were sampled, and selective media were used to isolate bacteria from the diets. Bacterial identification, antimicrobial susceptibility testing, and whole-genome sequencing (WGS) were conducted to identify antimicrobial resistance (AMR). The primary meat sources for RMDDs included in this study were poultry (37%) and beef (24%). Frozen-dry was the main method of product production (68%). In total, 52 true and opportunistic pathogens, including Enterobacterales (mainly Escherichia coli, Enterobacter cloacae) and Enterococcus faecium, were obtained from 30 RMDDs. Resistance was identified to 19 of 28 antimicrobials tested, including amoxicillin/clavulanic acid (23/52, 44%), ampicillin (19/52, 37%), cephalexin (16/52, 31%), tetracycline (7/52, 13%), marbofloxacin (7/52, 13%), and cefazolin (6/52, 12%). All 19 bacterial isolates submitted for WGS harbored at least one type of AMR gene. The identified AMR genes were found to mediate resistance to aminoglycoside (gentamicin, streptomycin, amikacin/kanamycin, gentamicin/kanamycin/tobramycin), macrolide, beta-lactam (carbapenem, cephalosporin), tetracycline, fosfomycin, quinolone, phenicol/quinolone, and sulfonamide. In conclusion, the results of this study suggest that feeding and handling RMDDs may pose a significant public health risk due to the presence of antimicrobial-resistant pathogens, and further research and intervention may be necessary to minimize these risks.

Lattice Compression Revealed at the ≈1†nm Scale.

Lattice tuning at the ≈1 nm scale is fascinating and challenging; for instance, lattice compression at such a minuscule scale has not been observed. The lattice compression might also bring about some unusual properties, which waits to be verified. Through ligand induction, we herein achieve the lattice compression in a ≈1 nm gold nanocluster for the first time, as detected by the single-crystal X-ray crystallography. In a freshly synthesized Au52 (CHT)28 (CHT=S-c-C6 H11 ) nanocluster, the lattice distance of the (110) facet is found to be compressed from 4.51 to 3.58 Šat the near end. However, the lattice distances of the (111) and (100) facets show no change in different positions. The lattice-compressed nanocluster exhibits superior electrocatalytic activity for the CO2 reduction reaction (CO2 RR) compared to that exhibited by the same-sized Au52 (TBBT)32 (TBBT=4-tert-butyl-benzenethiolate) nanocluster and larger Au nanocrystals without lattice variation, indicating that lattice tuning is an efficient method for tailoring the properties of metal nanoclusters. Further theoretical calculations explain the high CO2 RR performance of the lattice-compressed Au52 (CHT)28 and provide a correlation between its structure and catalytic activity.

Recent advancements in iodide/phosphine-mediated photoredox radical reactions.

Photoredox catalysis plays a crucial role in contemporary synthetic organic chemistry. Since the groundbreaking work of Shang and Fu on photocatalytic decarboxylative alkylations in 2019, a wide range of organic transformations, such as alkylation, alkenylation, cyclization, amination, iodination, and monofluoromethylation, have been progressively achieved using a combination of iodide and PPh3. In this review, we primarily focus on summarizing the recent advancements in inexpensive and readily available iodide/phosphine-mediated photoredox radical transformations.

Atomic Interface-Exciting Catalysis on Cobalt Nitride-Oxide for Accelerating Hydrogen Generation.

The rational design of the interface structure between nitride and oxide using the same metallic element and correlating the interfacial active center with a determined catalytic mechanism remain challenging. Herein, a Co4 N-Co3 O4 interface structure is designed to determine the effect of interfacial active centers on hydrogen generation from ammonia borane. An unparalleled catalytic activity toward H2 production with a turnover frequency up to 79 min-1 is achieved on Co4 N-Co3 O4 @C catalyst for ten recycles. Experimental analyses and theoretical simulation suggest that the atomic interface-exciting effect (AieE) is responsible for the high catalytic activity. The Co4 N-Co3 O4 interface facilitates the targeted adsorption and activation of NH3 BH3 and H2 O molecules to generate H* and H2 . The two active centers of Co(N)* and Co(O)* at the Co4 N-Co3 O4 interface activate NH3 BH3 and H2 O, respectively. This proof-of-concept research on AieE provides important insights regarding the design of heterogeneous catalysts and promotes the development of the nature and regulation of energy chemical conversion.

Transition-Metal- and Light-Free Generation of an Iminyl Radical: Facile Approach to Oxindoles and Isoquinolinediones with a Quaternary Carbon Center via Cyanoalkylarylation.

We have developed an efficient and non-toxic method for the environmental-friendly generation of an iminyl radical from cyclobutanone oxime ester via direct thermolysis in the absence of light, transition metals, "tin", and other activators. This redox-neutral cyanoalkylarylation protocol enjoys a wide substrate scope and a good functional group tolerance, providing facile access to oxindoles and isoquinolinediones with a quaternary carbon center that are difficult to prepare by traditional methods.

Rationale and Design of the ADIDAS Study: Association Between Dapagliflozin-Induced Improvement and Anemia in Heart Failure Patients.

BACKGROUND: Heart failure (HF) is one of the most serious health concerns worldwide. Anemia is a highly prevalent comorbidity and outcome predictor in HF patients. Sodium glucose co-transport 2 (SGLT2) inhibitors have been demonstrated to reduce the risk of cardiovascular death and HF hospitalization in HF patients. PURPOSE: This investigator-initiated, interventional, prospective, double-blind, multicenter study is designed to investigate whether anemia correction is one of the prerequisites and determinants related to the beneficial effects of dapagliflozin in HF patients. METHODS AND RESULTS: Up to 2030 HF participants receiving standard care will be randomly assigned to either oral dapagliflozin 10 mg once daily or placebo 10 mg once daily for 12 months. The primary outcome is the composite incidence of hospital admission for HF and all-cause death. Secondary outcomes include change in the Kansas City Cardiomyopathy Questionnaire (KCCQ) score and change in 6-min walk distance and hemoglobin level. Patients will be followed for 12 months after randomization. CONCLUSIONS: The ADIDAS trial offers an opportunity to assess the hemoglobin change and association between hemoglobin change and readmissions due to heart failure and all-cause death in patients with heart failure treated with dapagliflozin or placebo. This study could highlight if dynamic hemoglobin change is related to the outcome for HF patients. TRIAL REGISTRATION: ClinicalTrials.gov ; NCT04707261. Registration date, 2020/12/01, "retrospectively registered".

A successful case of electrical storm rescue after acute myocardial infarction.

BACKGROUND: Electrical storm (ES) is a heterogeneous clinical emergency that can present with malignant ventricular arrhythmias such as ventricular fibrillation (VF), ventricular tachycardia (VT), requiring the need for cardiac defibrillation. ES is a life-threatening condition with a high mortality rate. Successfully managing ES in the setting of acute myocardial infarction (MI) is expected to be known by physicians on call to reduce in-hospital mortality. CASE PRESENTATION: A 57-year-old man presenting with acute onset chest pain was found to have an infero-posterior ST-segment elevation myocardial infarction (STEMI) complicated by acute right ventricular MI secondary to total occlusion of the proximal right coronary artery (RCA). The patient developed ES in the form of recurrent VF that was managed successfully with electrical defibrillation, antiarrhythmic therapy with amiodarone and esmolol, endotracheal intubation, sedation, electrolyte replacement, volume resuscitation, comfort care, psychological intervention, and percutaneous coronary intervention (PCI) of the occluded epicardial artery. With these interventions used in quick succession and with the aspiration of a massive RCA thrombus, the patient was reversed to hemodynamic stability, did not have further episodes of VF, and survived the index hospitalization. CONCLUSION: ES is a rare but fatal complication of acute MI. Residents on night shifts should be better prepared and equipped to deal with this rare condition. We hope our successful experience can benefit physicians on call who take care of acute MI patients that deteriorate with ES.

Experimental Study on Magnetic Coupling Piezoelectric-Electromagnetic Composite Galloping Energy Harvester.

In order to solve the demand for low-power microcomputers and micro-electro-mechanical system components for continuous energy supply, a magnetic coupling piezoelectric-electromagnetic composite galloping energy harvester (MPEGEH) is proposed. It is composed of a piezoelectric energy harvester (PEH) and an electromagnetic energy harvester (EEH) coupled by magnetic force. The bistable nonlinear magnetic coupling structure improves the output power of the MPEGEH. The advantages and output performance of the MPEGEH are analyzed. The prototype of the energy harvester is made, and the nonlinear output characteristics under different load resistances are analyzed. Through the experiment on the key parameters of the composite energy harvester, it is found that the higher the coupling degree of the two parts of the MPEGEH, the stronger the nonlinear characteristics and the better the output characteristics. The results show that the onset wind velocity and output power of the MPEGEH are better than the classic galloping piezoelectric energy harvester (CGPEH). At the same wind speed, with the increase in the distance d0 between magnets A and B, the output power of both the PEH and the EEH decreases. When d0 is 37 mm, the output power of the EEH is the largest. The distance s0 between magnets B and C has little influence on the output power of the PEH but has a great influence on the EEH. When s0 is 23 mm, the EEH has the best output characteristics. Compared with the CGPEH, the onset wind velocity is reduced by 28%, and the output power is increased by 136% when the wind speed is 11 m/s.

Selective CO2 Photoreduction into C2 Product Enabled by Charge-Polarized Metal Pair Sites.

Selective CO2 photoreduction into a high-energy-density C2 product is still challenging. Here, charge-polarized metal pair sites are designed to trigger C-C coupling through manipulating asymmetric charge distribution on the reduction intermediates. Taking the synthetic partially reduced Co3O4 nanosheets as an example, theoretical calculations unveil the asymmetric charge distribution on surface cobalt sites. The formed charge-polarized cobalt pair sites not only donate electrons to CO2 molecules but also accelerate the coupling of asymmetric COOH* intermediates through lowering the energy barrier from 0.680 to 0.240 eV, affirmed by quasi in situ X-ray photoelectron spectroscopy and Gibbs free energy calculations. Also, the electron-rich cobalt sites strengthen their interaction with O of the HOOC-CH2O* intermediate, which favors the C-O bond cleavage and hence facilitates the rate-limiting CH3COOH desorption process. The partially reduced Co3O4 nanosheets achieve 92.5% selectivity of CH3COOH in simulated air, while the CO2-to-CH3COOH conversion ratio is 2.75%, obviously higher than that in pure CO2.

Advances and Prospects in Metal-Organic Frameworks as Key Nexus for Chemocatalytic Hydrogen Production.

Hydrogen is a clean and sustainable energy carrier, which is considered a promising alternative for fossil fuels to solve the global energy crisis and respond to climate change. Social concerns on its safe storage promote continuous exploration of alternatives to traditional storage methods. In this case, chemical hydrogen storage materials initiate plentiful research with special attention to the design of heterogeneous catalysts that can enhance efficient and highly selective hydrogen production. Metal-organic frameworks (MOFs), a kind of unique crystalline porous materials featuring highly ordered porosities and tailorable structures, can provide various active sites (i.e., metal nodes, functional linkers, and defects) for heterogeneous catalysis. Furthermore, the easy construction of active sites in highly ordered MOFs, which can work as plate for the delicate active site engineering, make them ideal candidates for a variety of heterogeneous catalysts including chemocatalytic hydrogen production. This review concentrates on the application of MOFs as heterogeneous catalysts or catalyst supports in chemocatalytic hydrogen production. Recent progresses of MOFs as catalysts for chemocatalytic hydrogen production are comprehensively summarized. The research methods, mechanism analyses, and prospects of MOFs in this field are discussed. The challenges in future industrial applications of MOFs as catalysts for hydrogen production are proposed.

High-resolution melting curve FRET-PCR rapidly identifies SARS-CoV-2 mutations.

Reverse transcription fluorescence resonance energy transfer-polymerase chain reaction (FRET-PCRs) were designed against the two most common mutations in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) (A23403G in the spike protein; C14408T in the RNA-dependent RNA polymerase). Based on high-resolution melting curve analysis, the reverse transcription (RT) FRET-PCRs identified the mutations in american type culture collection control viruses, and feline and human clinical samples. All major makes of PCR machines can perform melting curve analysis and thus further specifically designed FRET-PCRs could enable active surveillance for mutations and variants in countries where genome sequencing is not readily available.

High-speed all-optical processing for spectrum.

Data-processing techniques in spectroscopy are fundamental and powerful analytical tools for lots of practical applications. In the age of big data, high-speed data-processing in spectroscopy is in urgent need, especially for the real-time analysis/feedback of data stream of spectroscopy or the capture of non-repetitive/rare phenomena in fast dynamic process. So far, intensive researches focus on high-speed processing of light signal in time/spatial domain but few people find a way to do it in spectral domain. Here, we report an optical computing technology for high-speed optical spectrum processing with features of real time, multiple functions, all-fiber configuration and immunity to electromagnetic interference. The software-controlled system could perform as, but not limited to, the first-order (or arbitrary fractional-order) differentiator/integrator/Hilbert transformer and tunable band-pass filter, respectively, to handle spectral data rapidly. High-speed processing of optical spectrum at a rate of 10,000,000 times per second is demonstrated.