Self-propulsion via slipping: Frictional swimming in multilegged locomotors.

Locomotion is typically studied either in continuous media where bodies and legs experience forces generated by the flowing medium or on solid substrates dominated by friction. In the former, centralized whole-body coordination is believed to facilitate appropriate slipping through the medium for propulsion. In the latter, slip is often assumed minimal and thus avoided via decentralized control schemes. We find in laboratory experiments that terrestrial locomotion of a meter-scale multisegmented/legged robophysical model resembles undulatory fluid swimming. Experiments varying waves of leg stepping and body bending reveal how these parameters result in effective terrestrial locomotion despite seemingly ineffective isotropic frictional contacts. Dissipation dominates over inertial effects in this macroscopic-scaled regime, resulting in essentially geometric locomotion on land akin to microscopic-scale swimming in fluids. Theoretical analysis demonstrates that the high-dimensional multisegmented/legged dynamics can be simplified to a centralized low-dimensional model, which reveals an effective resistive force theory with an acquired viscous drag anisotropy. We extend our low-dimensional, geometric analysis to illustrate how body undulation can aid performance in non-flat obstacle-rich terrains and also use the scheme to quantitatively model how body undulation affects performance of biological centipede locomotion (the desert centipede Scolopendra polymorpha) moving at relatively high speeds (∼0.5 body lengths/sec). Our results could facilitate control of multilegged robots in complex terradynamic scenarios.

Coherent Combining of Phase-Steerable High Power Microwaves Generated by Two X-Band Triaxial Klystron Amplifiers with Pulsed Magnetic Fields.

We report the first experimental demonstration of coherent combining of phase-steerable high power microwaves (HPMs) generated by X-band relativistic triaxial klystron amplifier modules under the guidance of pulsed magnetic fields. Electronically agile manipulation of the HPM phase is achieved with a mean discrepancy of 4° at the gain level of 110 dB, and the coherent combining efficiency has reached as high as 98.4%, leading to combined radiations with equivalent peak power of 4.3 GW and average pulse duration of 112 ns. The underlying phase-steering mechanism during the nonlinear beam-wave interaction process is furthermore explored by particle-in-cell simulation and theoretical analysis. This Letter paves the way for high power phase array in large scale and may stimulate new interest in research of phase-steerable high power masers.

Photoinduced Construction of a Benzothienopyridine-S,S-dioxide Framework Enabled by Polychloropyridyl Multifunctional Motifs.

Reported herein is a visible-light-induced, catalyst-free intramolecular cyclization of 4-phenylsulfonyl-2,3,5,6-tetrachloropyridine, leading to rapid assembly of a series of unprecedented benzo[4,5]thieno[3,2-c]pyridine 5,5-dioxide scaffolds under mild conditions. The rational introduction of a perchloropyridin-4-yl module significantly facilitated this photoinduced process and offers a versatile platform for broad structural variation. Mechanistic studies revealed that a newly identified charge-transfer complex with carbonate is crucial to this photoinduced process.

The toll-like receptor 4 antagonist transforming growth factor-ß-activated kinase(TAK)-242 attenuates taurocholate-induced oxidative stress through regulating mitochondrial function in mice pancreatic acinar cells.

BACKGROUND: Acute pancreatitis (AP) is a commonly occurring and potentially life-threatening disease. Recently, toll-like receptor 4 (TLR4) has been considered as a new clue for studying the pathogenesis of AP due to its important role in inflammatory response cascade. MATERIALS AND METHODS: The aim of this study was to investigate the potential protective effect of transforming growth factor-ß-activated kinase (TAK)-242, a novel TLR4 antagonist, in taurocholate-treated mice pancreatic acinar cells. The protective effects were measured by cell viability, lactate dehydrogenase release and apoptosis, and oxidative stress was assayed by lipid peroxidation and oxidative enzyme activities. To determine the potential underlying mechanisms, mitochondrial cytochrome c release, swelling, and calcium buffering capacity were measured in isolated mitochondria, and mitochondrial biogenesis and expression of mitochondrial dynamic proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: Treatment with 6-mM taurocholate significantly increased the expression of TLR4 at both mRNA and protein levels. TAK-242 markedly increased cell viability, decreased lactate dehydrogenase release, and inhibited apoptotic cell death as measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining in pancreatic acinar cells. These protective effects were accompanied by the suppressed lipid peroxidation and enhanced endogenous antioxidative enzyme activity. Using isolated and purified mitochondria from pancreatic acinar cells, we found that TAK-242 treatment also inhibited cytochrome c release into the cytoplasm, mitochondrial swelling, and decrease in mitochondrial Ca2+ buffering capacity after taurocholate exposure. In addition, TAK-242 significantly promoted mitochondrial biogenesis, as evidenced by increased mtDNA and upregulated mitochondrial transcription factors. The results of Western blot analysis showed that TAK-242 also differently regulated the expression of mitochondrial fusion and fission proteins. CONCLUSIONS: All these data strongly indicated that blocking TLR4 activity via TAK-242 exerts protective effects in an in vitro AP model, and it could be a possible strategy to improve clinical outcome in AP patients.

[Determination of indium in whole blood by graphite furnace atomic absorption spectrometry].

OBJECTIVE: To investigate the sensitization effect of different chemical modifiers in the determination of indium in whole blood by graphite furnace atomic absorption spectrometry, and to develop a new method for the determination of indium in whole blood. METHODS: A mixture of 0.3% HNO3 (V/V) + 0.1% Triton X-100 (V/V) was used as a diluent, and a solution of 1 000 µg/ml Pd (NO3)2 + 3 000 µg/ml Mg (NO3)2 was used as modifier. After being diluted five times, the concentration of indium of the blood was directly determined by graphite furnace atomic absorption spectrometry. RESULTS: The detection limit of the method was 0.33 µg/L, the linear range was 0.33~100.00 µg/L, the relative standard deviation was 1.43%~2.65%, and the recovery rate was 98.3%~105.3%. CONCLUSION: The method is simple and fast and has high recovery and precision, and it is suitable for the determination of indium in whole blood.

[Determination of ethylene glycol in workplace air by capillary column gas chromatography].

OBJECTIVE: To establish the method of capillary column gas chromatography for determination of ethylene glycol in workplace air. METHODS: Ethylene glycol in workplace air was collected with silicone tube, desorbed with methanol, separated with FFAP (nitroterephthalic acid-modified polyethylene glycol)capillary column, and measured with flame ionization detector. RESULTS: The detection limit of ethylene glycol was 0.41 mg/L, the lower limit of quantification was 1.4 mg/L, the range of measurement was 1.4~163.9 mg/L, and the minimum detectable concentration was 0.3 mg/m3 (1.5 L of air was collected as the sample). This method had a good repeatability, the relative standard deviation was 1.4%~5.2%, the average desorption efficiency was 94.4%~101.7%, and the sampling efficiency was 99.2%~100%. The penetrating capacity of 200 mg silicone was higher than 6.9 mg, and the samples could be preserved for 14 days at room temperature. CONCLUSION: The method has a low detection limit, high accuracy, and good precision, which is feasible for determination of ethylene glycol in workplace air.

[Risk analysis and assessment of occupational hazard fromindiumand its compounds in manufacture of liquid crystal display panel].

OBJECTIVE: To understand the exposed positions and levels of indium and its compounds in manufacture of liquid crystal displays, and to evaluate the degree of occupational hazard from indium and its compounds. METHODS: On-site investigation of occupational health, occupational hazard monitoring, and occupational health examination were used to evaluate the degree of occupational hazard from indium and its compounds in three manufacturers of liquid crystal display panel in Shenzhen, Guangdong, China. RESULTS: The time-weighted average (TWA) and short-term exposure limit (STEL) concentrations of indium and its compounds to which sputtering machine operating positions were exposed were less than 0.002~0.004 mg/m³ and 0.006~0.007 mg/m³, respectively, both of which complied with the National Hygienic Standard (PC-TWA = 0.1 mg/m³; PC-STEL = 0.3 mg/m³); the TWA and STEL concentrations of indium and its compounds to which grinding positions were exposed were 0.114~2.98 mg/m³ and 0.31~10.02 mg/m³, respectively, both of which exceeded the National Hygienic Standard with the highest concentration 33-fold higher than the standard. No significant health damages were found in exposed workers according to the results of occupational health examination. CONCLUSION: The grinding positions are the key to the control of occupational hazard from indium and its compounds in manufacture of liquid crystal display panel. The workers should be equipped with the anti-particulate full-face respirator, which is an effective way to prevent occupational hazard from indium and its compounds.

Evaluating ChatGPT-4.0's data analytic proficiency in epidemiological studies: A comparative analysis with SAS, SPSS, and R.

Background: OpenAI's Chat Generative Pre-trained Transformer 4.0 (ChatGPT-4), an emerging artificial intelligence (AI)-based large language model (LLM), has been receiving increasing attention from the medical research community for its innovative 'Data Analyst' feature. We aimed to compare the capabilities of ChatGPT-4 against traditional biostatistical software (i.e. SAS, SPSS, R) in statistically analysing epidemiological research data. Methods: We used a data set from the China Health and Nutrition Survey, comprising 9317 participants and 29 variables (e.g. gender, age, educational level, marital status, income, occupation, weekly working hours, survival status). Two researchers independently evaluated the data analysis capabilities of GPT-4's 'Data Analyst' feature against SAS, SPSS, and R across three commonly used epidemiological analysis methods: Descriptive statistics, intergroup analysis, and correlation analysis. We used an internally developed evaluation scale to assess and compare the consistency of results, analytical efficiency of coding or operations, user-friendliness, and overall performance between ChatGPT-4, SAS, SPSS, and R. Results: In descriptive statistics, ChatGPT-4 showed high consistency of results, greater analytical efficiency of code or operations, and more intuitive user-friendliness compared to SAS, SPSS, and R. In intergroup comparisons and correlational analyses, despite minor discrepancies in statistical outcomes for certain analysis tasks with SAS, SPSS, and R, ChatGPT-4 maintained high analytical efficiency and exceptional user-friendliness. Thus, employing ChatGPT-4 can significantly lower the operational threshold for conducting epidemiological data analysis while maintaining consistency with traditional biostatistical software's outcome, requiring only specific, clear analysis instructions without any additional operations or code writing. Conclusions: We found ChatGPT-4 to be a powerful auxiliary tool for statistical analysis in epidemiological research. However, it showed limitations in result consistency and in applying more advanced statistical methods. Therefore, we advocate for the use of ChatGPT-4 in supporting researchers with intermediate experience in data analysis. With AI technologies like LLMs advancing rapidly, their integration with data analysis platforms promises to lower operational barriers, thereby enabling researchers to dedicate greater focus to the nuanced interpretation of analysis results. This development is likely to significantly advance epidemiological and medical research.

Broadband Continuous Transverse Stub (CTS) Array Antenna for High-Power Applications.

A continuous transverse stub (CTS) array antenna with broad bandwidth and high-power handling capacity is proposed in this paper. The technologies of multi-step impedance matching and T-shaped electromagnetic band-gap (EBG) loading are utilized, which improved the antenna operating frequency bandwidth. An H-plane lens horn is used to feed the CTS array. As a result, a good bandwidth capability of more than 32% is achieved, with a gain variation less than 3.0 dB. The measured sidelobe level (SLL) is below -18 dB in the entire frequency range. Moreover, the power handling capacity of the antenna is more than 80 MW and can reach the GW level after arraying, which indicates that this antenna has application potential in the high-power microwave (HPM) field.

Multilegged matter transport: A framework for locomotion on noisy landscapes.

Whereas the transport of matter by wheeled vehicles or legged robots can be guaranteed in engineered landscapes such as roads or rails, locomotion prediction in complex environments such as collapsed buildings or crop fields remains challenging. Inspired by the principles of information transmission, which allow signals to be reliably transmitted over "noisy" channels, we developed a "matter-transport" framework that demonstrates that noninertial locomotion can be provably generated over noisy rugose landscapes (heterogeneities on the scale of locomotor dimensions). Experiments confirm that sufficient spatial redundancy in the form of serially connected legged robots leads to reliable transport on such terrain without requiring sensing and control. Further analogies from communication theory coupled with advances in gaits (coding) and sensor-based feedback control (error detection and correction) can lead to agile locomotion in complex terradynamic regimes.

Photocatalysed C-H amidation of indoles enabled by tert-butyl alkyl((perfluoropyridin-4-yl)oxy)carbamate.

Development of a new catalytic and straightforward strategy to construct C-N bonds is playing a pivotal role in synthetic chemistry. Here, we report a photocatalysed protocol to access direct C-H amidation of indoles, enabled by a rationally designed tert-butyl alkyl((perfluoropyridin-4-yl)oxy)carbamate. A series of biologically important aminoindoles were prepared under mild conditions with excellent regioselectivity and broad substrate scope.

N-Chlorosulfonyl carbamate-enabled, photoinduced amidation of quinoxalin-2(1H)-ones.

Reported herein is the design and development of a new photo-induced amidation protocol with the readily available N-chlorosulfonyl carbamate as an effective amidyl-radical precursor, which could be readily prepared from commercial low-cost chlorosulfonyl isocyanate (CSI) and alcohol feedstocks. The synthetic potency of this developed protocol was well demonstrated by direct amidation of various quinoxalin-2(1H)-ones. The protocol could be further streamlined by implementing a one-pot/two-step/three-component process of CSI, alcohol, and quinoxalin-2(1H)-one, with significantly improved reaction efficiency. This methodology offers an intriguing opportunity for rapid expansion of nitrogen-containing molecular complexity, thus inspiring comprehensive exploration of a new reaction mode of CSI reagent.

Visible-light-driven oxidation of organosilanes by a charge-transfer complex.

Direct oxidation of organosilanes is one of the most straightforward ways to access silanols. Herein, we describe a novel photo-induced strategy for oxidation of organosilanes to access silanols, promoted by a photoactive charge-transfer complex (CTC) between sodium benzenesulfinate and molecular O2. A streamlined sequence transformation of organosilanes to silyl ethers was also readily achieved. This developed protocol represents the first example of CTC-based oxidation of organosilanes, offering a facile approach to access a series of silanol and silyl ether products.

[Detecting the isoflurane in the air of workplaces with chromatographic method].

OBJECTIVE: To establish a solvent desorption Gas chromatographic method for detecting the isoflurane in air of workplaces. METHODS: This method is based on "Standardization of methods for determination of toxic substances in workplace air". RESULTS: This method presents the linear relation with the minimum detectable limit 1.0 µg/ml and the minimum detectable concentration 0.07 mg/m(3). The precision (RSD) was 0.5% ∼ 5.0%, the mean dsorption efficiencies were 96.7% ∼ 98.9%, the absorption efficiencies were 92.1% ∼ 100%, the breakthrough volume was 3.7 mg isoflurane/100 mg active carbon. Other volatile organic solvents (Sevoflurane, Enflurane and Ethyl Alcohol) did not interfere the detection. The sample could be stored in the active carbon tube at least for 10 days. CONCLUSION: This method is meet the requirement of GBZ/T 210.4-2008 "Guide for establishing occupational health standards-Part4: Determination methods of air chemicals in workplace" and is feasible for determining the isoflurane in the air of workplaces.

Inductively coupled plasma mass spectrometry based urine metallome to construct clinical decision models for autism spectrum disorder.

BACKGROUND: The global prevalence of autism spectrum disorder (ASD) is on the rise, and high levels of exposure to toxic heavy metals may be associated with this increase. Urine analysis is a noninvasive method for investigating the accumulation and excretion of heavy metals. The aim of this study was to identify ASD-associated urinary metal markers. METHODS: Overall, 70 children with ASD and 71 children with typical development (TD) were enrolled in this retrospective case-control study. In this metallomics investigation, inductively coupled plasma mass spectrometry was performed to obtain the urine profile of 27 metals. RESULTS: Children with ASD could be distinguished from children with TD based on the urine metal profile, with ASD children showing an increased urine metal Shannon diversity. A metallome-wide association analysis was used to identify seven ASD-related metals in urine, with cobalt, aluminum, selenium, and lithium significantly higher, and manganese, mercury, and titanium significantly lower in the urine of children with ASD than in children with TD. The least absolute shrinkage and selection operator (LASSO) machine learning method was used to rank the seven urine metals in terms of their effect on ASD. On the basis of these seven urine metals, we constructed a LASSO regression model for ASD classification and found an area under the receiver operating characteristic curve of 0.913. We also constructed a clinical prediction model for ASD based on the seven metals that were different in the urine of children with ASD and found that the model would be useful for the clinical prediction of ASD risk. CONCLUSIONS: The study findings suggest that altered urine metal concentrations may be an important risk factor for ASD, and we recommend further exploration of the mechanisms and clinical treatment measures for such alterations.

Photochemical Organocatalytic Aerobic Cleavage of C═C Bonds Enabled by Charge-Transfer Complex Formation.

A novel visible-light-driven organocatalytic protocol to access aerobic oxidative cleavage of olefins, promoted by sodium benzene sulfinate, is described herein. An array of alkenes smoothly delivered the corresponding aldehydes and ketones under transition-metal-free conditions. Notably, α-halo-substituted styrenes proceeded with photoinduced oxidation to finally afford α-halo-acetophenones with halogen migration. Crucial to this oxidation was the formation of charge-transfer complexes between sodium benzene sulfinate with molecular O2 to ultimately deliver the carbonyl products.

A novel Ka-band coaxial transit time oscillator with internal extraction.

In this paper, a Ka-band coaxial transit time oscillator (TTO) with internal extraction is proposed. Particle-in-cell simulation of this oscillator is performed to obtain results as follows: under the conditions of a diode voltage of 459 kV, current of 3.9 kA, and guiding magnetic field of 0.5 T, microwaves with an output power of 0.75 GW and a frequency of 31.4 GHz can be achieved with an efficiency of 42% and a saturation time of nearly 25 ns. Moreover, the asymmetric mode competition is suppressed in the preliminary experiments. The study of a Ka-band TTO aims to extend the working frequency of high power microwave sources to a higher level. Such a device has three merits. First, it implements high power and high efficiency. Second, the internal extraction of the microwave output decreases the over-mode ratio in the microwave extraction region. Third, the over-mode ratio of the internal extraction is smaller compared with the external extraction, which can effectively suppress asymmetric mode competition.

Plasma fibrinogen, D-dimer, and fibrin degradation product as biomarkers of rheumatoid arthritis.

This study aimed to assess the association of coagulation-related indicators such as plasma fibrinogen (FIB), D-dimer, and fibrin degradation product (FDP) in rheumatoid arthritis (RA) with the disease activity. Data from 105 RA patients and 102 age- and gender-matched healthy controls were collected in the retrospective study. Disease activity score in 28 joints based on C-reactive protein (DAS28-CRP) was used to divide RA patients into low activity group (DAS28-CRP ≤ 2.7) and active group (DAS28-CRP > 2.7). Receiver operating characteristic (ROC) curve was applied to determine area under the curve (AUC). The association between plasma FIB, D-dimer, and FDP and DAS28-CRP was evaluated by spearman correlation. Logistical regression analysis was used to identify the independent variables associated with RA disease activity. RA patients showed higher levels of plasma FIB, D-dimer, and FDP than the controls (P < 0.01). Plasma FIB, D-dimer, and FDP were also increased in active groups of RA patients than those in inactive groups (P < 0.001). ROC curve analyses revealed that the AUC of D-dimer was higher than erythrocyte sedimentation rate (ESR) and rheumatoid factor (RF), and that of FDP was higher than RF in RA patients. In addition, the optimal cut-off value of plasma FIB, D-dimer, and FDP for RA diagnosis was 286 mg/dL, 470 µg/L, and 1.45 mg/L, respectively. Spearman analysis showed that plasma FIB, D-dimer, and FDP were positively related with DAS28-CRP (P < 0.001) in RA patients. Logistical regression analysis showed that D-dimer (odds ratio 2.862, 95% confidence interval 1.851-5.426, P < 0.001) was an independent variable associated with RA disease activity. FIB, D-dimer, and FDP were increased in RA patients and positively correlated with the disease activity of RA. D-dimer may act as a novel inflammatory indice for indicating disease activity in RA patients.