Preparation of High Vibrational States in the Entire Molecular Beam.

Preparing highly excited molecules is of great interest in chemistry, but it has long been a challenge due to the high laser power required within the narrow line width to excite a weak transition. We present a cavity-enhanced infrared excitation scheme using a milliwatt laser. As a demonstration, about 35% of CO molecules in a ground-state rotational level were excited to the highly excited v = 3 state in the entire pulsed supersonic beam, as confirmed by the depletion of molecules in the ground state. The method was also applied to excite HD molecules to the v = 2 state with a continuous-wave diode laser. This work provides a universal approach to prepare molecules in a specific quantum state, paving the way to study the chemical reaction dynamics of highly excited molecules.

Mid-infrared Doppler-free saturation absorption spectroscopy of the Q branch of CH4ν3 = 1 band using a rapid-scanning continuous-wave optical parametric oscillator.

We have developed a mid-infrared Doppler-free saturation absorption spectroscopy apparatus that employs a commercial continuous-wave optical parametric oscillator (CW OPO), complemented by a home-built automation and wavelength scanning system. Here, we report a comprehensive spectral scan of the Q branch transitions of the ν3 = 1 band of methane (CH4) with an average linewidth (FWHM) of 4.5 MHz. The absolute frequency calibration was achieved using previously reported transition frequencies determined using optical frequency combs, while a Fabry-Perot etalon was used for the relative frequency calibration. We report 15 transitions with improved accuracies of 1.13 MHz (3.76 × 10-5 cm-1).

The public's perception of the nursing profession: Validity and reliability of the Chinese version of the nursing image scale in Taiwan.

The public's perception of the nursing image deeply influences nurses' work and professional development. However, the Taiwanese public's perception of nursing remains unclear. This study aimed to determine the validity and reliability of a Chinese version of the Nursing Image Scale (NIS) in Taiwan. This was a psychometric study using a cross-sectional survey. Participants were recruited via the snowball sampling method through the online community software LINE from August 1 to 13, 2019. After data collection, the construction and validation of the NIS to measure public opinion were assessed, including content validity, corrected item-total correlation, exploratory factor analysis (EFA), and reliability. A total of 1331 valid responses were included in the analysis. After EFA analysis, the 20 scale items were divided across the four domains of prudence and care, innovation and cooperation, efficiency and division, and professionalism and respect. The NIS (Chinese version) was valid and reliable for measuring public opinion and may be used to examine changes in public perceptions of nursing.

Development and Validation of the Interprofessional Collaboration Practice Competency Scale (IPCPCS) for Clinical Nurses.

Interprofessional collaborative practice is a core competency and is the key to strengthening health practice systems in order to deliver safe and high-quality nursing practice. However, there is no Interprofessional Collaboration Practice Competency Scale (IPCPCS) for clinical nurses in Taiwan. Therefore, the purposes of this study were to develop an IPCPCS and to verify its reliability and validity. This was a psychometric study with a cross-sectional survey using convenience sampling to recruit nurses from the seven hospitals of a medical foundation. A self-designed structured IPCPCS was rolled out via a Google survey. The data were analyzed using descriptive statistics, principal-axis factoring (PAF) with Promax rotation, Pearson correlation, reliability analysis, and one-way ANOVA. PAF analysis found that three factors could explain 77.76% of cumulative variance. These were collaborative leadership and interprofessional conflict resolution, interprofessional communication and team functioning, and role clarification and client-centered care. The internal consistency of the three factors (Cronbach's α) was between 0.970 to 0.978, and the Pearson correlation coefficients were between 0.814 to 0.883. Significant differences were presented in the IPCPCS score by age, education level, total years of work experience, position on the nursing clinical ladder, and participation in interprofessional education. In conclusion, the three factors used in the IPCPCS have good reliability and construct validity. This scale can be used as an evaluation tool of in-service interprofessional education courses for clinical nurses.

High Barrier Properties of Butyl Rubber Composites Containing Liquid Rubber and Graphene Oxide.

The high elasticity and excellent gas barrier properties of rubber composites make them irreplaceable in the field of sealing. Constructing a complicated barrier network to reduce free volume is crucial to improving gas barrier properties. In this research, liquid acrylonitrile-butadiene rubber/γ-Methacryloxypropyl trimethoxy silane (KH570) modified graphene oxide/butyl rubber composites (LNBR/KGO/IIR) were fabricated. A KGO lamellar network was constructed to resist gas diffusion in the IIR matrix. Meanwhile, LNBR macromolecules further occupied the free volume inside the IIR composites, thereby maximizing the retardation of the path of small molecule gas permeation. The modification of GO by KH570 was successfully demonstrated through FTIR and XRD. The grafting rate of KH570 was calculated to be approximately 71.4%. KGO was well dispersed in IIR due to emulsion compounding and the formation of lamellar networks. The 300% modulus, tensile strength and tear strength of KGO/IIR were improved by 43.5%, 39.1% and 14.8%, respectively, compared to those of the IIR composite. In addition, the introduction of LNBR resulted in a 44.2% improvement in the gas barrier performance of nitrogen permeability relative to the original IIR composite.

Mid-infrared-near-infrared double-resonance spectroscopy of molecules with kilohertz accuracy.

Precision measurements of molecular transitions to highly excited states are needed in potential energy surface modeling, state-resolved chemical dynamics studies, and astrophysical spectra analysis. Selective pumping and probing of molecules are often challenging due to the high state density and weak transition moments. We present a mid-infrared and near-infrared double-resonance spectroscopy method for precision measurements. As a demonstration, Doppler-free stepwise two-photon absorption spectra of 13CO2 were recorded by pumping the fundamental transition of R14 (00011)-(00001) and probing the P15 (00041)-(00011) transition enhanced by a high-finesse optical cavity, and the transition frequencies were determined with an accuracy of a few kilohertz.

Rovibrational Energies of 13C16O2 Determined with Kilohertz Accuracy.

Accurate spectroscopic data of carbon dioxide are widely used in many important applications, such as carbon monitoring missions. Here, we present comb-locked cavity ring-down saturation spectroscopy of the second most abundant isotopologue of CO2, 13C16O2. We determined the positions of 88 lines in three vibrational bands in the 1.6 µm region, 30011e/30012e/30013e-00001e, with an accuracy of a few kHz. Based on the analysis of combination differences, we obtained for the first time the ground-state rotational energies with kHz accuracy. We also provide a set of hybrid line positions for 150 13C16O2 transitions. The rotational energies (J < 50) in the 30013e vibrational state can be fitted by a set of rotational and centrifugal constants with deviations within a few kHz, indicating that the 30013e state is free of perturbations. These precise isotopic line positions will be utilized to improve the Hamiltonian model and quantitative remote sensing of carbon dioxide. Moreover, they will help to track changes in the carbon source and sink through isotopic analysis.

Ultralow-content Pt nanodots/Ni3Fe nanoparticles: interlayer nanoconfinement synthesis and overall water splitting.

Minimizing precious metal loading into electrocatalysts for water splitting is vital to promoting hydrogen energy technology toward practical applications. Low-content loading of precious-metal electrocatalysts is achieved by decorating precious metal nanostructures on co-electrocatalysts typically via surface confinement. Here, an electrocatalyst of ultralow-content Pt nanodots (0.71 wt%)/Ni3Fe nanoparticles on reduced oxidation graphene (Pt/Ni3Fe/rGO) is constructed for overall water splitting by pyrolyzing a single-source precursor PtCl63- guest-intercalated MgNiFe-layered double hydroxide (MgNiFe-LDH) host via a distinctive interlayer confinement. Consequently, Pt/Ni3Fe/rGO demonstrates attractive overpotentials of 240 and 76 mV at 10 mA cm-2 for the oxygen and hydrogen evolution reactions (OER and HER), respectively, outperforming those of its /Ni3Fe/rGO counterpart. Moreover, the Pt/Ni3Fe/rGO∥Pt/Ni3Fe/rGO electrolyzer generates a current density of 10 mA cm-2 at 1.55 V, with a retention of 92.4% after 50 h. Furthermore, the measured specific activity and low transfer resistance, as well as the density functional theory (DFT) calculations, indicate that the active Pt/Ni3Fe in Pt/Ni3Fe/rGO can optimize the adsorption/desorption of reaction intermediates and thus boost OER/HER kinetics, all of which lead to enhanced performance. The results demonstrate that such an interlayer confinement-based synthesis strategy can allow for the design of cost-effective precious nanodots as potential electrocatalysts.

Iron accumulation induced by hepcidin1 knockout accelerates the progression of aging osteoporosis.

OBJECTIVE: Iron accumulation is associated with osteoporosis. This study aims to explore the effect of chronic iron accumulation induced by hepcidin1 deficiency on aging osteoporosis. METHODS: Iron accumulation in hepcidin1 knockout aging mice was assessed by atomic absorption spectroscopy and Perl's staining. Bone microarchitecture was observed using Micro-CT. Hepcidin, ferritin, oxidative stress, and markers of bone turnover in serum were detected by enzyme-linked immunosorbent assay. Bone formation and resorption markers were measured by real-time quantitative PCR. Cell aging was induced by D-galactose treatment. CCK-8, flow cytometry, EdU assays, and Alizarin red staining were performed to reveal the role of hepcidin1 knockout in cell model. Iron Colorimetric Assay Kit and western blot were applied to detect iron and ferritin levels in cells, respectively. RESULTS: In hepcidin1-knockout mice, the ferritin and iron contents in liver and tibia were significantly increased. Iron accumulation induced by hepcidin1 knockout caused a phenotype of low bone mass and deteriorated bone microarchitecture. Osteogenic marker was decreased and osteoclast marker was increased in mice, accompanied by increased oxidative stress level. The mRNA expression levels of osteoclast differentiation markers (RANKL, Mmp9, OPG, Trap, and CTSK) were up-regulated, while bone formation markers (OCN, ALP, Runx2, SP7, and Col-1) were down-regulated in model group, compared to wild type mice. In vitro, hepcidin1 knockdown inhibited proliferation and osteogenic differentiation, while promoted apoptosis, with increased levels of iron and ferritin. CONCLUSION: Iron accumulation induced by hepcidin1 deficiency aggravates the progression of aging osteoporosis via inhibiting osteogenesis and promoting osteoclast genesis.

Precision spectroscopy of molecular hydrogen.

Precision measurements on the hydrogen molecule are of fundamental importance in understanding molecular theory. Comparison of accurate experimental data and theoretical results are used to test the quantum electrodynamics theory and determine physical constants used in the calculation. We review recent advances and perspectives in the precision spectroscopy of molecular hydrogen, representing state-of-the-art molecular spectroscopy methods and cutting-edge high-precision calculations.

Endogenous hydrogen sulfide inhibition suppresses tumor growth by promoting apoptosis and pyroptosis in esophageal cancer cells.

BACKGROUND: Hydrogen sulfide (H2S) has been identified as the third gaseous signaling molecule. Endogenous H2S plays a key role in the progression of various types of cancer. However, the effect of endogenous H2S on the growth of esophageal cancer (EC) remains unknown. METHODS: In this study, three kinds of H2S-producing enzymes inhibitors, DL-propargylglycine (PAG, inhibitor of cystathionine-γ-lyase), aminooxyacetic acid (AOAA, inhibitor of cystathionine-ß-synthase), and L-aspartic acid (L-Asp, inhibitor of 3-mercaptopyruvate sulfurtransferase) were used to determine the role of endogenous H2S in the growth of EC9706 and K450 human EC cells. RESULTS: The results indicated that the combination (PAG+AOAA+L-Asp) group showed higher inhibitory effects on the viability, proliferation, migration, and invasion of EC cells than PAG, AOAA, and L-Asp group. Inhibition of endogenous H2S promoted apoptosis via activation of mitogen-activated protein kinase pathway in EC cells. Endogenous H2S suppression triggered pyroptosis of EC cells by activating reactive oxygen species-mediated nuclear factor-κB signaling pathway. In addition, the combine group showed its more powerful growth-inhibitory effect on the growth of human EC xenograft tumors in nude mice without obvious toxicity. CONCLUSION: Our results indicate that inhibition of endogenous H2S production can significantly inhibit human EC cell growth via promotion of apoptosis and pyroptosis. Endogenous H2S may be a promising therapeutic target in EC cells. Novel inhibitors for H2S-producing enzymes can be designed and developed for EC treatment.

Multiple Gas Detection by Cavity-Enhanced Raman Spectroscopy with Sub-ppm Sensitivity.

Accurate and sensitive detection of multicomponent trace gases below the parts-per-million (ppm) level is needed in a variety of medical, industrial, and environmental applications. Raman spectroscopy can identify multiple molecules in the sample simultaneously and has excellent potential for fast diagnosis of various samples, but applications are often limited by its sensitivity. In this contribution, we report the development of a cavity-enhanced Raman spectroscopy instrument using a narrow-line width 532 nm laser locked with a high-finesse cavity through a Pound-Drever-Hall locking servo, which allows continuous measurement in a broad spectral range. An intracavity laser power of up to 1 kW was achieved with an incident laser power of about 240 mW, resulting in a significant enhancement of the Raman signal in the range of 200-5000 cm-1 and a sub-ppm sensitivity for various molecules. The technique is applied in the detection of different samples, including ambient air, natural gas, and reference gas of sulfur hexafluoride, demonstrating its capability for the quantitative measurement of various trace components.

kHz-precision wavemeter based on reconfigurable microsoliton.

The mode-locked microcomb offers a unique and compact solution for photonics applications, ranging from the optical communications, the optical clock, optical ranging, the precision spectroscopy, novel quantum light source, to photonic artificial intelligence. However, the photonic micro-structures are suffering from the perturbations arising from environment thermal noises and also laser-induced nonlinear effects, leading to the frequency instability of the generated comb. Here, a universal mechanism for fully stabilizing the microcomb is proposed and experimentally verified. By incorporating two global tuning approaches and the autonomous thermal locking mechanism, the pump laser frequency and repetition rate of the microcomb can be controlled independently in real-time without interrupting the microcomb generation. The high stability and controllability of the microcomb frequency enables its application in wavelength measurement with a precision of about 1 kHz. The approach for the full control of comb frequency could be applied in various microcomb platforms, and improve their performances in timing, spectroscopy, and sensing.

Visualization of Polymer-Surfactant Interaction by Dual-Emissive Gold Nanocluster Labeling.

Polymer-surfactant interaction decides the performance of corresponding complexes, making its rapid and intuitionistic visualization important for enhancing the performance of products and/or processing in related fields. In this study, the fluorescence visualization of the interaction between cationic hyperbranched polyethyleneimine and anionic sodium dodecyl sulfonate surfactant was realized by dual-emissive gold nanocluster labeling. The sensing mechanism was due to the interaction-induced polymer conformation change, which regulated the molecular structure and subsequent photoradiation process of the gold nanoclusters. All three inflection points of the interactions between the polymers and the surfactants were obtained by the change in fluorescence emission ratio of the designed dual-emissive gold nanoclusters. Moreover, these inflection points are verified by the hydrodynamic diameter and zeta potential measurements.

Effects of montmorillonite (MMT) on the crystallization behavior of poly(L-lactic acid) (PLLA) by variable-temperature FTIR coupled with difference spectrometry, PCMW2D and 2DCOS analyses.

Effects of montmorillonite (MMT) on the crystallization behavior of poly(L-lactic acid) (PLLA) were investigated by variable-temperature FTIR spectroscopy. The variations of carbonyl band (1800-1720 cm-1) of different PLLA/MMT nanocomposites were focused due to its strong intensity and the involved abundant structure information. Difference spectrometry was used to evaluate the structural variations of PLLA after introducing MMT, and perturbation correlation moving window two-dimensional analysis (PCMW2D) split the temperature range into two sub-regions, i.e., 32-116 ℃ and 116-152 ℃, on the basis of the spectral variation. Two-dimensional correlation spectroscopy (2DCOS) was further applied to such sub-regions in order to find the change order between varied PLLA polymorphs. The results showed that less addition of MMT (≤3%) would lead to a well-exfoliated structure, which not only had no nucleation effect for PLLA, but also delayed the cold crystallization to a higher temperature compared with the one of pure PLLA. However, a higher addition of MMT (≥5%) would lead to an intercalated structure, which acted as a nucleating agent and thus advanced the cold crystallization to a lower temperature. Nevertheless, the introduction of MMT cannot affect the phase transition order between the amorphous, the intermediate, the α'- and the α'-PLLAs based on 2DCOS results.

Fast atom-trap analysis of 39Ar with isotope pre-enrichment.

We demonstrate fast analysis of 39Ar/Ar at the 10-16 level using a mass spectrometer for isotope pre-enrichment and an atom trap for counting. An argon gas sample first passes through a dipole mass separator that reduces the dominant isotope 40Ar by two orders of magnitude while preserving both the rare tracer isotope 39Ar and a minor stable isotope 38Ar for control purposes. Measurements of both natural and enriched samples with atom trap trace analysis demonstrate that the 39Ar/38Ar ratios change less than 10%, while the overall count rates of 39Ar are increased by one order of magnitude. By overcoming the analysis-speed bottleneck, this advance will benefit large-scale applications of 39Ar dating in the earth sciences, particularly for mapping ocean circulation.

Molecular dynamics simulation of the formation mechanism of the thermal conductive filler network of polymer nanocomposites.

In this work, the thermal transfer capabilities of spherical and laminar/spherical filled polymer nanocomposites (PNCs) were systematically investigated by using molecular dynamics (MD) simulation. The effects of various factors such as physical interfacial interaction, filler size and filler shape on the thermal conductivity were explored. The relationship between thermal conductivity and its corresponding microstructure was examined. The thermal transfer ability of the PNCs was characterized using two approaches, including thermal conductivity (TC) and the filler conductive network. Our results showed that the increase in the filling fraction and the matrix-filler physical interfacial interaction were both conducive to the formation of the thermally conductive network. The non-linear effect of the filler size on the TC results from a competition between the filler overlapped structure and the physical interfacial interaction. Besides, the introduction of spherical nanoparticles (NPs) into laminar-filled PNCs and increasing the NP-polymer physical interfacial strength could remarkably promote the formation of a hybrid overlapping filler network and also a thermal conduction pathway. Moreover, the oscillatory shear could significantly increase the thermal conductivity of laminar/spherical filled PNCs by enhancing the overlapped structure between spherical fillers. This study provides some insights on understanding the relationship between the microstructures and the thermal conductivity of laminar/spherical NP filled PNCs at the molecular level.

Fabrication of a High-Performance and Reusable Planar Face Mask in Response to the COVID-19 Pandemic.

The coronavirus disease 2019 (COVID-19) pandemic has caused a surge in demand for face masks, with the massive consumption of masks leading to an increase in resource-related and environmental concerns. In this work, we fabricated meltblown polypropylene (mb-PP)-based high-performance planar face masks and investigated the effects of six commonly used disinfection methods and various mask-wearing periods on the reusability of these masks. The results show that, after three cycles of treatment using hot water at 70 °C for 30 min, which is one of the most scalable, user-friendly methods for viral disinfection, the particle filtration efficiency (PFE) of the mask remained almost unchanged. After mask wearing for 24 h and subsequent disinfection using the same treatment procedures, the PFE decreased to 91.3%; the average number of bacterial and fungal colonies was assessed to be 9.2 and 51.6 colony-forming units per gram (CFU∙g- 1), respectively; and coliform and pyogenic bacteria were not detected. Both the PFE and the microbial indicators are well above the standard for reusable masks after disinfection. Schlieren photography was then used to assess the capabilities of used and disinfected masks during use; it showed that the masks exhibit a high performance in suppressing the spread of breathed air.

The effect of in-package cold plasma on the formation of polycyclic aromatic hydrocarbons in charcoal-grilled beef steak with different oils or fats.

In-package cold plasma (ICP) pretreatment is an emerging non-thermal food processing methods. In the current study, ICP on the formation of polycyclic aromatic hydrocarbons (PAHs) in grilled beef steaks with different oils and fats was evaluated, the influence of prolonged storage periods (1 d, 2 d) of raw meat after ICP pretreatment on the PAH inhibitory effect was investigated. The results showed that sunflower seed oil had an inhibitory effect on PAH formation; the groups with ICP pretreatment showed a significant decrease in PAH content (p < 0.05) according to the UHPLC results, inhibitory rates were dependent on the original contents in each group without ICP pretreatment, ranging from 35% to 96%. The optimal condition was grilling immediately after ICP pretreatment, and the results indicated that the nonpolar radical scavenging activity (RSA) of ungrilled meat was negatively correlated with PAH8 contents according the DPPH assay, while ICP pretreatment enhanced the RSAoil of raw meat.

Irreversible Electroporation Treatment With Intraoperative Biliary Stenting for Unresectable Perihilar Cholangiocarcinoma: A Pilot Study.

BACKGROUND: Treating perihilar cholangiocarcinoma (PHCC) is particularly difficult due to the fact that it is usually in an advanced stage at the time of diagnosis. Irreversible electroporation treatment (IRE) involves the local administration of a high-voltage electric current to target lesions without causing damage to surrounding structures. This study investigated the safety and efficacy of using IRE in conjunction with intraoperative biliary stent placement in cases of unresectable PHCC. METHODS: This study enrolled 17 patients with unresectable Bismuth type III/IV PHCC who underwent IRE in conjunction with intraoperative biliary stent placement (laparotomic) in two medical centers in Asia between June 2015 and July 2018. Analysis focused on the perioperative clinical course, the efficacy of biliary decompression, and outcomes (survival). RESULTS: Mean total serum bilirubin levels (mg/dL) on postoperative day (POD) 7, POD30, and POD90 were significantly lower than before IRE (respectively 3.46 vs 4.54, p=0.007; 1.21 vs 4.54, p<0.001; 1.99 vs 4.54, p<0.001). Mean serum carbohydrate antigen 19-9 (CA19-9, U/ml) levels were significantly higher on POD3 than before the operation (518.8 vs 372.4, p=0.001) and significantly lower on POD30 and POD90 (respectively 113.7 vs 372.4, p<0.001; 63.9 vs 372.4, p<0.001). No cases of Clavien-Dindo grade III/IV adverse events or mortality occurred within 90 days post-op. The median progression-free survival was 21.5 months, and the median overall survival was 27.9 months. All individuals who survived for at least one year did so without the need to carry percutaneous biliary drainage (PTBD) tubes. CONCLUSIONS: It appears that IRE treatment in conjunction with intraoperative biliary stent placement is a safe and effective approach to treating unresectable PHCC. The decompression of biliary obstruction without the need for PTBD tubes is also expected to improve the quality of life of patients.