Dynamic non-uniform phase shift measurement via Doppler frequency shift in vortex interferometer.

A vortex beam interferometer based on Doppler frequency shift is proposed to retrieve the dynamic non-uniform phase shift from the petal-like fringes produced by the coaxial superposition of high-order conjugated Laguerre-Gaussian modes. Unlike the uniform phase shift measurement in which the petal-like fringes rotate as a whole, the fringes due to the dynamic non-uniform phase shift rotate at different angles at different radii, resulting in highly twisted and stretched petals; this hinders rotation angle identification and phase retrieval via image morphological operation. To address the problem, a rotating chopper combined with a collecting lens and a point photodetector are placed at the exit of the vortex interferometer to introduce a carrier frequency in the absence of the phase shift. Once the phase starts to shift non-uniformly, the petals at different radii generate different Doppler frequency shifts, owing to their different rotation velocities. Thus, identification of spectral peaks near the carrier frequency immediately indicates the rotation velocities of the petals and the phase shifts at those radii. The results verified a relative error of phase shift measurement to be within 2.2% at the surface deformation velocities of 1, 0.5, and 0.2 µm/s. The method manifests itself to have potential in exploiting mechanical and thermophysical dynamics from the nanometer to micrometer scale.

Identification of a novel distal regulatory element of the human Neuroglobin gene by the chromosome conformation capture approach.

Neuroglobin (NGB) is predominantly expressed in the brain and retina. Studies suggest that NGB exerts protective effects to neuronal cells and is implicated in reducing the severity of stroke and Alzheimer's disease. However, little is known about the mechanisms which regulate the cell type-specific expression of the gene. In this study, we hypothesized that distal regulatory elements (DREs) are involved in optimal expression of the NGB gene. By chromosome conformation capture we identified two novel DREs located -70 kb upstream and +100 kb downstream from the NGB gene. ENCODE database showed the presence of DNaseI hypersensitive and transcription factors binding sites in these regions. Further analyses using luciferase reporters and chromatin immunoprecipitation suggested that the -70 kb region upstream of the NGB gene contained a neuronal-specific enhancer and GATA transcription factor binding sites. Knockdown of GATA-2 caused NGB expression to drop dramatically, indicating GATA-2 as an essential transcription factor for the activation of NGB expression. The crucial role of the DRE in NGB expression activation was further confirmed by the drop in NGB level after CRISPR-mediated deletion of the DRE. Taken together, we show that the NGB gene is regulated by a cell type-specific loop formed between its promoter and the novel DRE.

Simple interrogator for optical fiber-based white light Fabry-Perot interferometers.

In this Letter, we present the design of a simple signal interrogator for optical fiber-based white light Fabry-Perot (F-P) interferometers. With the hardware being composed of only a flat fused silica wafer and a CCD camera, this interrogator translates the spectral interference into a spatial interference pattern, and then demodulates the F-P cavity length with the use of a relatively simple demodulation algorithm. The concept is demonstrated experimentally in a fiber optic sensor with a sapphire wafer as the F-P cavity.

Sourceless optical fiber high temperature sensor.

A sourceless sapphire fiber extrinsic Fabry-Perot interferometer for ultrahigh temperature sensing is developed. A sapphire wafer is mounted on the tip of a sapphire fiber as the Fabry-Perot cavity. The interference signal is generated by the thermal radiation that transmits through the wafer and is guided to a spectrometer by a sapphire and then a silica fiber. The entire sensor system is compact and low cost. The sensor was experimentally tested up to 1593°C, and a resolution around 1°C was achieved.

Temperature dependence of sapphire fiber Raman scattering.

Anti-Stokes Raman scattering in sapphire fiber has been observed for the first time. Temperature dependence of Raman peaks' intensity, frequency shift, and linewidth were also measured. Three anti-Stokes Raman peaks were observed at temperatures higher than 300°C in a 0.72-m-long sapphire fiber excited by a second-harmonic Nd YAG laser. The intensity of anti-Stokes peaks are comparable to that of Stokes peaks when the temperature increases to 1033°C. We foresee the combination of sapphire fiber Stokes and anti-Stokes measurement in use as a mechanism for ultrahigh temperature sensing.

Methanol Steam Reforming for Hydrogen Production over Ni-Based Catalysts: State-Of-The-Art Review and Future Prospects.

With increasing global emphasis on environmental sustainability, the reliance on traditional energy sources such as coal, natural gas, and oil are encountering significant challenges. H2, known for its high energy content and pollution-free usage, emerges as a promising alternative. However, despite the great potential of H2, approximately 95 % of hydrogen production still depends on non-renewable resources. Hence, the shift towards producing H2 from renewable sources, particularly through methods like steam reforming of methanol - a renewable resource - represents a beacon of hope for advancing sustainable energy practices. This review comprehensively examines recent advancements in efficient H2 production using Ni-based catalysts in methanol steam reforming (MSR) and proposes the future prospects. Firstly, the fundamental principles of MSR technology and the significance in clean energy generation are elucidated. Subsequently, the design, synthesis techniques, and optimization strategies for enhancing the catalytic performance of Ni-based catalysts are discussed. Through the analysis of various catalyst compositions, structural adjustments, surface active sites, and modification methods, the review uncovers effective approaches for boosting the activity and durability of MSR reactions. Moreover, the review investigates the causes of deactivation in Ni-based catalysts during MSR reactions and proposes strategies for extending catalyst lifespan through fine design and optimization of operation parameters. Lastly, this review outlines the current research challenges and anticipates the future trends and potential applications of Ni-based catalysts in MSR hydrogen production. By offering a comprehensive critical analysis, this review serves as a valuable reference to enhance MSR hydrogen production efficiency and catalyst performance.

Carrier optical vortex interferometer using segmentation demodulation method for dynamic measurement of axisymmetric surface deformation.

The dynamic measurement of surface deformation with an axisymmetric profile at nanometer- to micrometer-scale is of great interest in understanding micromechanical and thermophysical dynamics. We propose a carrier optical vortex interferometer (COVI) to measure such surface deformation dynamically by segmentation demodulation of the petal-like interferogram that is produced by the coaxial superposition of conjugated p-radial order Laguerre-Gaussian beams. Specifically, a rotating chopper placed at the exit of the interferometer introduces a carrier frequency in the absence of surface deformation. A camera placed behind the chopper uses a multi-ring segmentation detection scheme to produce a Doppler shift relative to the carrier frequency at the radius of each ring in the presence of axisymmetric surface deformation. Locating the Doppler shifts gives the surface deformation velocities at those radii. Thus, the dynamic surface deformation profile can be obtained by integrating the velocities over time. We reveal the basic principles of the carrier frequency and the Doppler shifts in the COVI theoretically. As a proof-of-concept, an external force-induced axisymmetric mechanical surface deformation is measured dynamically to demonstrate the validity of the COVI. The results show that the measurement error of the surface deformation velocity is within (-2.1, 1.1 nm/s) for the velocity ranging from 20 to 86 nm/s. The lower limit of the measurable velocity can reach 20 nm/s. The measurement error of the surface deformation profile is less than 2.5 nm for the amplitude of the surface deformation of 500 nm.

Functional and sequence analysis of human neuroglobin gene promoter region.

Neuroglobin (Ngb), a recently found oxygen-binding protein belonging to the vertebrate globin family, is mainly expressed in neurons of brains and eyes. Current studies have revealed diverse potential functions of Ngb and it was found to be able to reduce the severity of stroke and Alzheimer's disease, implying its importance in brains. However, the mechanism of Ngb regulation of transcription has not been elucidated yet. In this study, we analyzed the 5'-flanking region of human neuroglobin gene (NGB) and identified a transcription start site (TSS) located at -306bp relative to the translation start site ATG. We characterized the proximal promoter of NGB and found two GC-boxes located at -16 and +30bp relative to the TSS which are bound by transcription factor Sp1 and Sp3. Mutation of either GC-box led to a significant reduction in NGB promoter activity, while overexpression of Sp1 and Sp3 resulted in activation of the promoter. However, two putative NRSE sites (-359 and -127bp relative to the TSS) apparently showed no influence on NGB tissue-specific expression. Treatment of two non-neuronal cell lines HeLa and BEAS-2B with 5-aza-2'-deoxycytidine remarkably induced NGB expression, suggesting a potential role of DNA methylation in regulating NGB tissue-specific expression.

Functional results of modified Mason-Allen suture versus horizontal mattress suture in the arthroscopic Broström-Gould procedure for chronic ankle instability.

BACKGROUND: The arthroscopic Broström-Gould procedure (ABG) gained particular attention among clinicians and researchers due to its high rate of satisfactory results. There is a lack of evidence regarding the differences in clinical outcomes for the various suture techniques. The purpose of this study was to compare the differences in clinical effect in patients treated with one-anchor modified Mason-Allen suture or two-anchor horizontal mattress suture for chronic ankle instability (CAI). METHODS: This retrospective cohort study examined CAI patients who underwent either one-anchor modified Mason-Allen suture or two-anchor horizontal mattress suture ABG between January 2018 and January 2020. Patients were divided into two groups based on the suture knot type used and the associated number of anchors. The operative time, surgical cost, Visual Analog Scale (VAS), American Orthopedic Foot & Ankle Society (AOFAS) Score, Karlsson Ankle Functional Score (KAFS), the rate of return to sports, complications, and measured biomechanical strength using standardized equipment were compared between groups. RESULTS: Sixty-four CAI patients were included (one-anchor modified Mason-Allen suture group n = 30, two-anchor horizontal mattress suture group n = 34). Compared to the two-anchor horizontal mattress suture group, the one-anchor modified Mason-Allen suture group had significantly shorter operative time (p < .001) and lower surgical cost (p < .001). There were no postoperative complications in the two groups, and no significant differences in the VAS, AOFAS, KAFS, and rate of return to sports in postoperative follow-up between the two groups at 1 and 2 years after surgery. There was no statistically significant difference in biomechanical strength anterior drawer test displacement (p > .05) between the one-anchor modified Mason-Allen suture and two-anchor horizontal mattress suture at 2 years after surgery. CONCLUSION: ABG using a one-anchor modified Mason-Allen suture showed comparable clinical results to a two-anchor horizontal mattress suture in the treatment of CAI at intermediate-term follow-up time. However, one-anchor modified Mason-Allen suture may be a faster, simpler, cost-effective substitute technology. LEVEL OF EVIDENCE: Level III, comparative study.

Development of a confocal line-scan laser scattering probe for dark-field surface defects detection of transmissive optics.

Dark-field detection has long been used to identify micron/submicron-sized surface defects benefiting from the broadening effect of the actual defect size caused by light scattering. However, the back-side scattering of a transmissive optical slab is inevitably confused with the front-side scattering phenomenon, resulting in deterioration of the signal-to-noise ratio (SNR) of the scattering signal and false alarms for real defect detection. To this end, a confocal line-scan laser scattering probe equipped with optical sectioning ability is proposed to separate the back-side scattering from the front-side scattering. The optical sectioning ability is realized through a confocal light scattering collector, which overcomes the restriction imposed on the numerical aperture (NA) and the field of view (FOV), reaching an FOV length of 90 mm and NA of 0.69. The line-scan principle of the probe protects itself from crosstalk because it produces only a laser spot on the tested surface in an instant. Experimental results verified that the probe has a line-scan length of 90 mm with a uniformity better than 98%, an rms electronic noise of 3.4 mV, and an rms background noise of 6.4 mV with laser on. The probe can reject the false back-side scattering light for a 2 mm thick fused silica slab at 17.1 dB SNR and operate at a high imaging efficiency of 720 mm2/s with a minimum detectability limit of 1.4 µm at 12 dB SNR. This work put forward an effective method with great application value for submicron-sized defect detection in transmissive optics.

Novel patterns by focused ion beam guided anodization.

Focused ion beam patterning is a powerful technique for guiding the growth of ordered hexagonal porous anodic alumina. This study shows that, with the guidance of the focused ion beam patterning, hexagonal porous anodic alumina with interpore distances from 200 to 425 nm can be fabricated at 140 V in 0.3 M phosphoric acid. When the interpore distance is increased to 500 nm, alternating diameter nanopore arrays are synthesized with the creation and growth of new small pores at the junctions of three large neighboring pores. Moreover, alternating diameter nanopore arrays in hexagonal arrangement are fabricated by focused ion beam patterning guided anodization. Interpore distance is an important parameter affecting the arrangement of alternating diameter nanopore arrays. Different types of novel patterns are obtained by designing different focused ion beam concave arrays. The fundamental understanding of the process is discussed.

Robust Hydrogen Production via Pickering Interfacial Catalytic Photoreforming of n-Octanol-Water Biphasic System.

Pickering emulsion offers a promising platform for conducting interfacial reactions between immiscible reagents; it is particularly suitable for hydrogen production by photoreforming of non-water soluble biomass liquid and water. Herein, Pt-promoted (001)-facet-dominated anatase TiO2 nanosheets were synthesized by a hydrothermal route associated with microfluidic technology for high activity and metal dispersion, and selective surface modification was carried out for preparing Janus particles. Photoreforming hydrogen production through n-octanol and water that formed O/W microemulsion with an average diameter of 540 µm was achieved to obtain amphiphilic catalyst. The as-prepared 2D Janus-type catalysts exhibited remarkably stable emulsification performance as well as photocatalytic activity. This finding indicates that triethoxyfluorosilane had negligible impact on the catalytic performance, yet provided a remarkable benefit to large specific surface area at microemulsion interface, thereby enhancing the H2 yield up to 2003 µmol/g. The cyclic experiments indicate that the decrease in cyclic performance was more likely to be caused by the coalescence of the microemulsion rather than the decrease in catalytic activity, and the microemulsion could be easily recovered by simply hand shaking to more than 96% of the initial performance.

SIAH-1 interacts with mammalian polyhomeotic homologues HPH2 and affects its stability via the ubiquitin-proteasome pathway.

Polycomb Group (PcG) genes encode proteins that form large multimeric and chromatin-associated complexes implicated in the stable repression of developmentally essential genes. HPH2, the Homo sapiens polyhomeotic homologue 2, functions as one of the subunits of PcG complex 1. In our study, SIAH-1, an E3 ligase, could directly associate with HPH2 both in vitro and in vivo. Both the cysteine-rich region of SIAH-1 and the PxVxAxP motif of HPH2 were essential for the interaction. HPH2 was co-localized with SIAH-1 in nuclei. Furthermore, SIAH-1 was able to facilitate the ubiquitination and degradation of HPH2 via ubiquitin-proteasome pathway in vivo. The ubiquitination activity was severely impaired in the SIAH-1 mutant that either lost E3 ligase activity or had weakened binding ability with HPH2, strongly suggesting that SIAH-1 was the direct E3 ligase of HPH2. Thus, our results propose a novel role of SIAH-1 in regulating the expression level of HPH2 through the ubiquitin-proteasome pathway.

Unique nanopore pattern formation by focused ion beam guided anodization.

The fabrication of ordered porous templates in large areas with sophisticated patterns beyond mono-sized pores in hexagonal packing remains a great technical challenge. Conventional anodization cannot overcome this limitation and a new approach needs to be sought. This study is focused on designing pore patterns in square and hexagonal arrangements via focused ion beam lithography with varying interpore distances in order to form organized pore arrays with more sophisticated patterns. The results demonstrate that the small pores from the anodization can be meshed with the larger pores from the focused ion beam lithography and unique, complicated nanopore patterns can be created. Large pore patterns that cross the grain boundaries are also made possible with the guidance of the pores from focused ion beam lithography. A fundamental pore pattern formation mechanism is proposed.

Effective electron collection in highly (110)-oriented ZnO porous nanosheet framework photoanode.

A highly (110)-oriented ZnO porous nanosheet framework is designed as the photoanode in photoelectrochemical systems, by virtue of its anisotropic electronic properties. It can be facilely prepared in large scale via a hydrothermal method. X-ray diffraction (XRD) analyses show that the orientation index of the (110) diffraction plane is 3.54, indicating the films possess (110) preferred orientation. Field-emission scanning electron microscope (FE-SEM) images exhibit that most of the nanosheets stand nearly perpendicularly on the substrate. The {002} lattice planes work just like conducting wires and induce the electrons to transport to the substrate. Chronoamperometry measurement demonstrates an effective electron collection. When the nanostructured photoanode is introduced to dye-sensitized solar cells, a conversion efficiency of 3.7% is obtained. The photoanode also has potential application in the other photoelectrochemical systems, such as photocatalytical splitting of water.

Effects of ondansetron on apamin-sensitive small conductance calcium-activated potassium currents in pacing-induced failing rabbit hearts.

BACKGROUND: Ondansetron, a widely prescribed antiemetic, has been implicated in drug-induced long QT syndrome. Recent patch clamp experiments have shown that ondansetron inhibits the apamin-sensitive small conductance calcium-activated potassium current (IKAS). OBJECTIVE: The purpose of this study was to determine whether ondansetron causes action potential duration (APD) prolongation by IKAS inhibition. METHODS: Optical mapping was performed in rabbit hearts with pacing-induced heart failure (HF) and in normal hearts before and after ondansetron (100 nM) infusion. APD at 80% repolarization (APD80) and arrhythmia inducibility were determined. Additional studies with ondansetron were performed in normal hearts perfused with hypokalemic Tyrode's (2.4 mM) solution before or after apamin administration. RESULTS: The corrected QT interval in HF was 326 ms (95% confidence interval [CI] 306-347 ms) at baseline and 364 ms (95% CI 351-378 ms) after ondansetron infusion (P < .001). Ondansetron significantly prolonged APD80 in the HF group and promoted early afterdepolarizations, steepened the APD restitution curve, and increased ventricular vulnerability. Ventricular fibrillation was not inducible in HF ventricles at baseline, but after ondansetron infusion, ventricular fibrillation was induced in 5 of the 7 ventricles (P = .021). In hypokalemia, apamin prolonged APD80 from 163 ms (95% CI 146-180 ms) to 180 ms (95% CI 156-204 ms) (P = .018). Subsequent administration of ondansetron failed to further prolong APD80 (180 ms [95% CI 156-204 ms] vs 179 ms [95% CI 165-194 ms]; P = .789). The results were similar when ondansetron was administered first, followed by apamin. CONCLUSION: Ondansetron is a specific IKAS blocker at therapeutic concentrations. Ondansetron may prolong the QT interval in HF by inhibiting small conductance calcium-activated potassium channels, which increases the vulnerability to ventricular arrhythmias.

Satisfaction, preference and error occurrence of three dry powder inhalers as assessed by a cohort naïve to inhaler operation.

Background: Inhaled medication is central to the treatment of COPD. Various types of inhaler devices, which directly deliver medication to the lung, have been developed. However, patients often exhibit incorrect techniques of inhaler usage. Effectiveness of therapy may be affected by the ease of device usage, size, convenience of use, durability, clarity of instructions and device preferences of patients. This study compares the satisfaction and preference, as well as error occurrence, with the use of Genuair®, Ellipta™ and Breezhaler™ by healthy subjects in Hong Kong. Subjects and methods: One hundred and thirty healthy Hong Kong Chinese subjects aged ≥40 years without a previous diagnosis of COPD and asthma and with no experience of using dry powder inhalers (DPIs) were recruited. Subjects learned to use the three DPIs by initially reading the instructions and then observing a demonstration with verbal explanation. The number of errors committed was evaluated. Subjects also completed a questionnaire to indicate their satisfaction and preference. Results: The satisfaction score of comfort for Breezhaler was significantly higher than that for Ellipta (p≤0.05), while the satisfaction score on confidence to have inhaled the entire dose was highest for Genuair compared with Ellipta (p≤0.0001) or Breezhaler (p≤0.05). The overall satisfaction score was significantly higher for Genuair than Ellipta (p≤0.05) or Breezhaler (p≤0.01). After reading the instructions, the highest number of subjects committing one or more critical errors was with Breezhaler (97) followed by Genuair (70) and then Ellipta (33). Demonstration reduced the number of critical errors made by subjects for each DPI to one third or lower. Conclusion: Breezhaler seemed to be more comfortable and easy to carry, but users made less critical errors when using Ellipta after reading the instructions only. Genuair provided the clearest indication of correct dose preparation and inhalation.

Whole Genome Sequencing of Hulunbuir Short-Tailed Sheep for Identifying Candidate Genes Related to the Short-Tail Phenotype.

The Hulunbuir short-tailed sheep (Ovis aries) is a breed native to China, in which the short-tail phenotype is the result of artificial and natural selection favoring a specific set of genetic mutations. Here, we analyzed the genetic differences between short-tail and normal-tail phenotypes at the genomic level. Selection signals were identified in genome-wide sequences. From 16 sheep, we identified 72,101,346 single nucleotide polymorphisms. Selection signals were detected based on the fixation index and heterozygosity. Seven genomic regions under putative selection were identified, and these regions contained nine genes. Among these genes, T was the strongest candidate as T is related to vertebral development. In T, a nonsynonymous mutation at c.G334T resulted in p.G112W substitution. We inferred that the c.G334T mutation in T leads to functional changes in Brachyury-encoded by this gene-resulting in the short-tail phenotype. Our findings provide a valuable insight into the development of the short-tail phenotype in sheep and other short-tailed animals.

Antiarrhythmic effects of stimulating the left dorsal branch of the thoracic nerve in a canine model of paroxysmal atrial tachyarrhythmias.

BACKGROUND: Stellate ganglion nerve activity (SGNA) precedes paroxysmal atrial tachyarrhythmia (PAT) episodes in dogs with intermittent rapid left atrial (LA) pacing. The left dorsal branch of the thoracic nerve (LDTN) contains sympathetic nerves originating from the stellate ganglia. OBJECTIVE: The purpose of this study was to test the hypothesis that high-frequency electrical stimulation of the LDTN can cause stellate ganglia damage and suppress PATs. METHODS: We performed long-term LDTN stimulation in 6 dogs with and 2 dogs without intermittent rapid LA pacing while monitoring SGNA. RESULTS: LDTN stimulation reduced average SGNA from 4.36 µV (95% confidence interval [CI] 4.10-4.62 µV) at baseline to 3.22 µV (95% CI 3.04-3.40 µV) after 2 weeks (P = .028) and completely suppressed all PAT episodes in all dogs studied. Tyrosine hydroxylase staining showed large damaged regions in both stellate ganglia, with increased percentages of tyrosine hydroxylase-negative cells. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that 23.36% (95% CI 18.74%-27.98%) of ganglion cells in the left stellate ganglia and 11.15% (95% CI 9.34%-12.96%) ganglion cells in the right stellate ganglia were positive, indicating extensive cell death. A reduction of both SGNA and heart rate was also observed in dogs with LDTN stimulation but without rapid LA pacing. Histological studies in the 2 dogs without intermittent rapid LA pacing confirmed the presence of extensive stellate ganglia damage, along with a high percentage of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells. CONCLUSION: LDTN stimulation damages both left and right stellate ganglia, reduces left SGNA, and is antiarrhythmic in this canine model of PAT.

Role of apamin-sensitive small conductance calcium-activated potassium currents in long-term cardiac memory in rabbits.

BACKGROUND: Apamin-sensitive small conductance calcium-activated K current (IKAS) is up-regulated during ventricular pacing and masks short-term cardiac memory (CM). OBJECTIVE: The purpose of this study was to determine the role of IKAS in long-term CM. METHODS: CM was created with 3-5 weeks of ventricular pacing and defined by a flat or inverted T wave off pacing. Epicardial optical mapping was performed in both paced and normal ventricles. Action potential duration (APD80) was determined during right atrial pacing. Ventricular stability was tested before and after IKAS blockade. Four paced hearts and 4 normal hearts were used for western blotting and histology. RESULTS: There were no significant differences in either echocardiographic parameters or fibrosis levels between groups. Apamin induced more APD80 prolongation in CM than in normal ventricles (mean [95% confidence interval]: 9.6% [8.8%-10.5%] vs 3.1% [1.9%-4.3%]; P <.001). Apamin significantly lengthened APD80 in the CM model at late activation sites, indicating significant IKAS up-regulation at those sites. The CM model also had altered Ca2+ handling, with the 50% Ca2+ transient duration and amplitude increased at distal sites compared to a proximal site (near the pacing site). After apamin, the CM model had increased ventricular fibrillation (VF) inducibility (paced vs control: 33/40 (82.5%) vs 7/20 (35%); P <.001) and longer VF durations (124 vs 26 seconds; P <.001). CONCLUSION: Chronic ventricular pacing increases Ca2+ transients at late activation sites, which activates IKAS to maintain repolarization reserve. IKAS blockade increases VF vulnerability in chronically paced rabbit ventricles.