Photonic-assisted wideband microwave frequency measurement based on optical heterodyne detection.

A photonic-assisted microwave frequency measurement (MFM) method based on optical heterodyne detection is proposed and experimentally demonstrated. In the proposed MFM system, a linearly chirped optical waveform (LCOW) from a three-electrode distributed Bragg reflector laser diode (DBR-LD) and a multi-wavelength signal from a Mach-Zehnder modulator (MZM), where the signal under test (SUT) is modulated on an optical carrier from a distributed feedback laser diode (DFB-LD), are heterodyne detected by the photodetector (PD). A bandpass filter then filters the detected signal, and the envelope is detected by an oscilloscope. Then, frequency-to-time mapping is realized, and the signal frequency is measured. Thanks to the fast tuning rate and large tuning range of the DBR-LD, the proposed MFM system has a high measurement speed and a broad instantaneous measurement bandwidth. In the experimental demonstration, a measurement error below 39.1 MHz is achieved at an instantaneous bandwidth of 20 GHz and a measurement speed of 1.12 GHz/µs. The MFM of a frequency-hopping signal is also experimentally demonstrated. The successful demonstration of the MFM system with a simple structure provides a new optical solution for realizing broadband and fast microwave frequency measurements.

No genetic causal association between circulating alpha-tocopherol levels and osteoarthritis, a two-sample Mendelian randomization analysis.

The causal association between vitamin E status and osteoarthritis (OA) remains controversial in previous epidemiological studies. We employed a Mendelian randomization (MR) analysis to explore the causal relationship between circulating alpha-tocopherol levels (main forms of vitamin E in our body) and OA. The instrumental variables (IVs) of circulating alpha-tocopherol levels were obtained from a Genome-wide association study (GWAS) dataset of 7781 individuals of European descent. The outcome of OA was derived from the UK biobank. Two-sample MR analysis was used to estimate the causal relationship between circulating alpha-tocopherol levels and OA. The inverse-variance weighted (IVW) method was the primary analysis in this analysis. We used the MR-Egger method to determine horizontal pleiotropic in this work. The heterogeneity effect of instrumental IVs was detected by MR-Egger and IVW analyses. Sensitivity analysis was performed by removing single nucleotide polymorphism (SNP) one by one. Three SNPs (rs964184, rs2108622, and rs11057830) (P < 5E-8) strongly associated with circulating alpha-tocopherol levels were used in this analysis. The IVW-random effect indicated no causal relationship between circulating alpha-tocopherol levels and clinically diagnosed OA (OR = 0.880, 95% CI 0.626, 1.236, P = 0.461). Similarly, IVW analysis showed no causal association between circulating alpha-tocopherol levels and self-reported OA (OR = 0.980, 95% CI 0.954, 1.006, P = 0.139). Other methods of MR analyses and sensitivity analyses revealed consistent findings. MR-Egger and IVW methods indicated no significant heterogeneity between IVs. The MR-Egger intercept showed no horizontal pleiotropic. The results of this linear Mendelian randomization study indicate no causal association between genetically predicted alpha-tocopherol levels and the progression of OA. Alpha-tocopherol may not provide beneficial and more favorable outcomes for the progression of OA. Further MR analysis based on updated GWASs with more IVs is required to verify the results of our study.

Strengthening Mechanism of Polyurea to Anti-Penetration Performance of Spherical Cell Porous Aluminum.

A composite structure containing a metallic skeleton and polyurea elastomer interpenetrating phase was fabricated, and its anti-penetration performance for low-velocity large mass fragments was experimentally studied. The protection capacity of three polyurea was compared based on the penetration resistance force measurement. Results show that the polyurea coating layer at the backside improves the performance of the polyurea-filled spherical cell porous aluminum (SCPA) plate due to its backside support effect and phase transition effect, which are accompanied by a large amount of energy absorption. The frontal-side-coated polyurea layer failed to shear and provided a very limited strengthening effect on the penetration resistance of the interpenetrating phase composite panel. The filling polyurea in SCPA increased the damage area and formed a compression cone for the backside coating layer, leading to a significant stress diffusion effect. The anti-penetration performance was synergistically improved by the plug block effect of the interpenetrating phase composite and the backside support effect of the PU coating layer. Compared with SCPA, the initial impact failure strength and the average resistance force of the composite plate were improved by 120-200% and 108-274%, respectively.

Atomistic Tuning of the GeoCas9 Recognition Lobe Modulates Allosteric Motions and Guide RNA Interactions.

The intuitive manipulation of specific amino acids to alter the activity or specificity of CRISPR-Cas9 has been a topic of great interest. As a large multi-domain RNA-guided endonuclease, the intricate molecular crosstalk within the Cas9 protein hinges on its conformational dynamics, but a comprehensive understanding of the extent and timescale of the motions that drive its allosteric function and association with nucleic acids remains elusive. Here, we investigated the structure and multi-timescale molecular motions of the recognition (Rec) lobe of GeoCas9, a thermophilic Cas9 from Geobacillus stearothermophilus. Our results provide new atomic details about the GeoRec subdomains (GeoRec1, GeoRec2) and the full-length domain in solution. Two single-point mutants, K267E and R332A, enhanced and redistributed micro-millisecond flexibility throughout GeoRec, and NMR studies of the interaction between GeoRec and its guide RNA showed that mutations reduced this affinity and the stability of the ribonucleoprotein complex. Despite measured biophysical differences due to the mutations, DNA cleavage assays reveal only modest functional differences in on-target activity, and similar specificity. These data highlight how guide RNA interactions can be tuned in the absence of major functional losses, but also raise questions about the underlying mechanism of GeoCas9, since analogous single-point mutations have significantly impacted on- and off-target DNA editing in mesophilic S. pyogenes Cas9. A K267E/R332A double mutant did modestly enhance GeoCas9 specificity, highlighting the robust evolutionary tolerance of Cas9 and species-dependent complexity. Ultimately, this work provides an avenue by which to modulate the structure, motion, and nucleic acid interactions at the level of the Rec lobe of GeoCas9, setting the stage for future studies of GeoCas9 variants and their effect on its allosteric mechanism.

Cooperative production of monophenolic chemicals and carbon adsorption materials from cascade pyrolysis of acid hydrolysis lignin.

A novel cascade pyrolysis upgrading process for acid hydrolysis lignin (AHL), consisting of pyrolysis, catalytic upgrading of pyrolysis vapors, and pyrolysis char, was developed to improve the yield of value-added products (monophenolic chemicals and carbon materials). Pyrolysis of AHL at 450 °C and subsequent catalytic upgrading of pyrolysis vapors over Ni/H-ZSM-5 boosted the concentration of monophenolic chemicals in pyrolysis liquids by 58%. The carbon material prepared from pyrolysis char using KOH as activating agent exhibited a large specific surface area of 2902.5 m2/g and a large total pore volume of 1.45 cm3/g, thus affording good adsorption capacity for methylene blue (824.87 mg/g) and iodine (2333.17 mg/g). Moreover, the cascade pyrolysis upgrading of AHL achieved a yield of 68.52% desired products, which was much higher than the reported results (single production of monophenols and pyrolysis char). In summary, this work provides a potential reference for efficient utilization of lignin in large-scale applications.

Theoretical and experimental study on stable oscillation of dual-frequency signals in an optoelectronic oscillator.

Due to the gain competition effect, it is hard to simultaneously maintain oscillation at two frequencies in an optoelectronic oscillator (OEO) loop. In this paper, a study of the gain competition effect in a dual-frequency OEO is theoretically and experimentally demonstrated. The steady-state conditions in the dual-frequency OEO are theoretically analyzed by deriving dynamic equations. A nonlinear time-varying model, as well as its calculation methods, is carried out to design and study the dynamic process of the dual-frequency OEO. Thanks to this model, the waveform, spectrum, and amplitude evaluation of generated signals, as well as the gain variation in the OEO loop, are numerically simulated. Based on the theoretical analysis and numerical simulation results, three schemes that can suppress the gain competition effect are proposed, and the one based on wavelength division multiplexing (WDM) technology is experimentally realized. The experimental results show that the novel independently tunable dual-frequency OEO, to the best of our knowledge, can generate two-tone RF signals in a range from 1.8 to 18.6 and 1.5 to 18.3 GHz, respectively.

Effect of O-arm on reduction quality and functional recovery of acetabular dome impaction fractures: a retrospective clinical study.

BACKGROUND: Acetabular dome impaction fractures (ADIF) are difficult to reduce and have a high failure rate. Consistency between the acetabulum and the femoral head is usually assessed using intraoperative X-ray fluoroscopy to evaluate the quality of fracture reduction. This study examines the effects of intraoperative mobile 2D/3DX imaging system (O-arm) on the reduction quality and functional recovery of ADIF. METHODS: We retrospectively analysed the data of 48 patients with ADIF treated at Honghui Hospital between October 2018 and October 2021.The patients were divided into the X-ray and O-arm groups. The residual step-off and gap displacements in the acetabular dome region were measured, and fracture reduction quality was evaluated. Hip function was evaluated using the modified Merle d'Aubigné and Postel scoring systems. RESULTS: There were no significant intergroup differences in the preoperative general data (p > 0.05). The mean residual average step displacement in the acetabular dome region was 3.48 ± 2.43 mm and 1.61 ± 1.16 mm (p < 0.05), while the mean gap displacement was 6.72 ± 3.69 mm and 3.83 ± 1.67 mm (p < 0.05) in the X-ray and the O-arm groups, respectively. In the X-ray group, according to the fracture reduction criteria described by Verbeek and Moed et al., one case was excellent, 13 cases were good, 11 cases were poor; 56% were excellent or good. In the O-arm group, seven cases were excellent, 12 cases were good, and four cases were poor; overall in this group, 82.6% were excellent or good (p < 0.05). A total of 46 patients achieved fracture healing at the last follow-up. In the X-ray group, according to the modified Merle d'Aubigné and Postel function score, three cases were excellent,12 cases were good, six cases were middle, three cases were poor; 62.5% were excellent or good, In the O-arm group, 15 cases were excellent, four cases were good, two cases were middle, one case was poor; 86.4% were excellent or good (p < 0.05). CONCLUSIONS: The application of O-arm in ADIF can improve fracture reduction quality and functional recovery.

Collagen-EGCG Combination Synergistically Prevents UVB-Induced Skin Photoaging in Nude Mice.

Ultraviolet (UV) radiation is a major cause of skin photoaging through generating excessive oxidative stress and inflammation. One of the strategies is to use photo-chemoprotectors, such as natural products with antioxidant and anti-inflammatory properties, to protect the skin from photo damage. The present study investigates the photoprotective potentials of topical administration of unhydrolyzed collagen, epigallocatechin gallate (EGCG), and their combination against ultraviolet B (UVB)-induced photoaging in nude mice. It is found that both the solo and combined pretreatments could recover UVB-induced depletion of antioxidative enzymes, including superoxide dismutase and glutathione peroxidase (GSH-Px), as well as an increase of lipid peroxide malondialdehyde and inflammatory tumor necrosis factor-α. Meanwhile, the UVB-stimulated skin collagen degradation is attenuated significantly with drug treatments, which is evidenced by expression analysis of matrix metalloproteinase-1 and hydroxyproline. Additionally, the mouse skin histology shows that the drug-pretreated groups possess decreased epidermis thickness and normal collagen fiber structure of the dermis layer. These results demonstrate that both EGCG and collagen can protect the skin against UVB-induced skin photoaging. Synergistically, the combination of them shows the maximum prevention to skin damage, showing its potential in the application of anti-photoaging formulation products.

Fast reconstruction algorithm based on HMC sampling.

In Noisy Intermediate-Scale Quantum (NISQ) era, the scarcity of qubit resources has prevented many quantum algorithms from being implemented on quantum devices. Circuit cutting technology has greatly alleviated this problem, which allows us to run larger quantum circuits on real quantum machines with currently limited qubit resources at the cost of additional classical overhead. However, the classical overhead of circuit cutting grows exponentially with the number of cuts and qubits, and the excessive postprocessing overhead makes it difficult to apply circuit cutting to large scale circuits. In this paper, we propose a fast reconstruction algorithm based on Hamiltonian Monte Carlo (HMC) sampling, which samples the high probability solutions by Hamiltonian dynamics from state space with dimension growing exponentially with qubit. Our algorithm avoids excessive computation when reconstructing the original circuit probability distribution, and greatly reduces the circuit cutting post-processing overhead. The improvement is crucial for expanding of circuit cutting to a larger scale on NISQ devices.

Regulating the orientation of a single coordinate bond by the synergistic action of mechanical forces and electric field.

The molecular binding orientation with respect to the electrode plays a pivotal role in determining the performance of molecular devices. However, accomplishing in situ modulation of single-molecule binding orientation remains a great challenge due to the lack of suitable testing systems and characterization approaches. To this end, by employing a developed STM-BJ technique, we demonstrate that the conductance of pyridine-anchored molecular junctions decreases as the applied voltage increases, which is determined by the repeated formation of thousands of gold-molecule-gold dynamic break junctions. In contrast, the static fixed molecular junctions (the distance between two electrodes is fixed) with identical molecules exhibit a reverse tendency as the bias voltage increases. Supported by flicker noise measurements and theoretical calculations, we provide compelling evidence that the orientation of nitrogen-gold bonds (a universal coordinate bond) in the pyridine-anchored molecular junctions can be manipulated to align with the electric field by the synergistic action of the mechanical stretching force and the electric fields, whereas either stimulus alone cannot achieve the same effect. Our study provides a framework for characterizing and regulating the orientation of a single coordinate bond, offering an approach to control electron transport through single molecular junctions.

Clinical Characteristics, Diagnosis, and Management of Aseptic Meningitis Induced by Trimethoprim-Sulfamethoxazole.

Objective: Trimethoprim sulfamethoxazole (TMP-SMX) is related to aseptic meningitis. However, a detailed description of its phenotype is lacking, which easily leads to misdiagnosis. The purpose of this article is to explore the clinical characteristics of TMP-SMX-induced aseptic meningitis (TSIAM). Methods: We collected literature related to TSIAM published before July 31, 2023, by searching Chinese and English databases. Data were extracted and analyzed descriptively. Results: The 55 patients were mostly female (60.0%), with a median age of 43 years (range: 2.5-90 years). The first onset time was from a few minutes to 3 months after administration, and the time of reonset was within 12 hours. Fever (98.2%), headache (78.2%), altered mental status (42.3%), nausea and vomiting (41.8%), and neck pain (34.5%) were the most common symptoms. In severe cases, patients presented with low blood pressure, seizures, unconsciousness, or coma. Typical cerebrospinal fluid analysis showed elevated white blood cell counts, with polymorphonuclear leukocytes predominating, elevated protein levels, and normal glucose levels. Brain imaging usually showed no abnormalities. Symptoms resolved rapidly after the discontinuation of TMP-SMX, within a median time of 2 days (range: 1, 60). Readministration of TMP-SMX led to another relapse of aseptic meningitis. Aseptic meningitis usually culminated in a full recovery, although one patient experienced permanent paraplegia. Conclusion: Clinicians should be aware that aseptic meningitis is a rare adverse effect of TMP-SMX. TMP-SMX should be discontinued in patients with TSIAM to reduce unnecessary testing and treatment, and readministration of TMP-SMX should be avoided.

Amoxicillin-induced aseptic meningitis: clinical features, diagnosis and management.

OBJECTIVES: The clinical features of aseptic meningitis associated with amoxicillin are unknown. The main objective of this study was to investigate the clinical characteristics of amoxicillin-induced aseptic meningitis (AIAM) and provide a reference for clinical diagnosis and treatment. METHODS: AIAM-related studies were collected by searching the relevant databases from inception to October 31, 2022. RESULTS: AIAM usually occurred 3 h to 7 days after amoxicillin administration in 13 males and 9 females. Twenty-one patients (95.5%) had recurrent AIAM with a total of 62 episodes. Fever (19 cases, 86.4%) and headache (18 cases, 81.8%) were the most common symptoms. Typical cerebrospinal fluid (CSF) findings were leukocytosis (100%) with lymphocytic predominance (14 cases, 63.6%), elevated protein (20 cases, 90.1%), normal glucose (21 cases, 95.5%) and negative culture (21 cases, 100%). Brain magnetic resonance imaging showed mild meningeal enhancement in one patient. The symptoms resolved mainly within 1-4 days after drug discontinuation in all patients. CONCLUSION: Clinical attention should be given to the adverse effects of AIAM. The medication history of patients with suspected meningitis should be investigated to avoid unnecessary examination and antibiotic treatment.

Causal association of NAFLD with osteoporosis, fracture and falling risk: a bidirectional Mendelian randomization study.

Introduction: The causal association between non-alcoholic fatty liver disease (NAFLD) and osteoporosis remains controversial in previous epidemiological studies. We employed a bidirectional two-sample Mendelian analysis to explore the causal relationship between NAFLD and osteoporosis. Method: The NAFLD instrumental variables (IVs) were obtained from a large Genome-wide association study (GWAS) meta-analysis dataset of European descent. Two-sample Mendelian randomization (MR) analyses were used to estimate the causal effect of NAFLD on osteoporosis, fracture, and fall. Reverse Mendelian randomization analysis was conducted to estimate the causal effect of osteoporosis on NAFLD. The inverse-variance weighted (IVW) method was the primary analysis in this analysis. We used the MR-Egger method to determine horizontal pleiotropic. The heterogeneity effect of IVs was detected by MR-Egger and IVW analyses. Results: Five SNPs (rs2980854, rs429358, rs1040196, rs738409, and rs5764430) were chosen as IVs for NAFLD. In forward MR analysis, the IVW-random effect indicated the causal effect of NAFLD on osteoporosis (OR= 1.0021, 95% CI: 1.0006-1.0037, P= 0.007) but not on fracture (OR= 1.0016, 95% CI: 0.998-1.0053, P= 0.389) and fall (OR= 0.9912, 95% CI: 0.9412-1.0440, P= 0.740). Furthermore, the reverse Mendelian randomization did not support a causal effect of osteoporosis on NAFLD (OR= 1.0002, 95% CI: 0.9997-1.0007, P= 0.231). No horizontal pleiotropic was detected in all MR analyses. Conclusions: The results of this study indicate a causal association between NAFLD and osteoporosis. NAFLD patients have a higher risk of osteoporosis but not fracture and falling risk. In addition, our results do not support a causal effect of osteoporosis on NAFLD.

4-hydroxylonchocarpin and corylifol A: The potential hepatotoxic components of Psoralea corylifolia L.

Psoralea corylifolia L. (P. corylifolia) has attracted increasing attention because of its potential hepatotoxicity. In this study, we used network analysis (toxic component and hepatotoxic target prediction, proteinprotein interaction, GO enrichment analysis, KEGG pathway analysis, and molecular docking) to predict the components and mechanism of P. corylifolia-induced hepatotoxicity and then selected 4-hydroxylonchocarpin and corylifol A for experimental verification. HepG2 cells were treated with low, medium, and high concentrations of 4-hydroxylonchocarpin or corylifol A. The activities of ALT, AST, and LDH in cell culture media and the MDA level, SOD activity, and GSH level in cell extracts were measured. Moreover, apoptosis, ROS levels, and mitochondrial membrane potential were evaluated. The results showed that the activities of ALT, AST, and LDH in the culture medium increased, and hepatocyte apoptosis increased. The level of MDA increased, and the activity of SOD and level of GSH decreased, and the ROS level increased with 4-hydroxylonchocarpin and corylifol A intervention. Furthermore, the mitochondrial membrane potential decreased in the 4-hydroxylonchocarpin and corylifol A groups. This study suggests that 4-hydroxylonchocarpin and corylifol A cause hepatocyte injury and apoptosis by inducing oxidative stress and mitochondrial dysfunction, suggesting that these compounds may be the potential hepatotoxic components of P. corylifolia.

Highly Enhanced Mechanical, Thermal, and Crystallization Performance of PLA/PBS Composite by Glass Fiber Coupling Agent Modification.

To improve the toughness and heat resistance of polylactic acid (PLA), polybutylene succinate (PBS) was sufficiently blended with PLA as the base matrix, and the glass fiber (GF) that was modified with 3-aminopropyltriethoxysilane (KF-GF) was added as the reinforcement. The results demonstrated a noteworthy boost in both mechanical and heat resistance properties when employing KH-GF, in comparison to pristine GF. When the content of KH-GF reached 20%, the tensile, flexural, and IZOD impact strength of the composites were 65.53 MPa, 83.43 MPa, and 7.45 kJ/m2, respectively, which were improved by 123%, 107%, and 189% compared to the base matrix, respectively. This enhancement was primarily attributed to the stronger interfacial adhesion between KH-GF and the PLA/PBS matrix. Furthermore, the Vicat softening temperature of the composites reached 128.7 °C, which was a result of increased crystallinity. In summary, the incorporation of KH-GF into PLA/PBS composites resulted in notable enhancements in their mechanical properties, crystallinity, and thermal characteristics. The high performance KH-GF-reinforced PLA/PBS composite showed a broad application potential in the field of biodegradable packaging, biodegradable textiles, and biodegradable plastic bags.

Anisotropic thermoelectric properties in hydrogenated nitrogen-doped porous graphene nanosheets.

By using density functional theory calculations combined with the nonequilibrium Green's function method and machine learning, we systematically studied the thermoelectric properties of four kinds of porous graphene nanosheets (PGNS) before and after nitrogen doping. The results show that the thermoelectric performance of porous graphene nanosheets along the armchair or zigzag chiral direction is improved due to the dramatically enhanced power factor caused by nitrogen doping. The calculated ZT values of nitrogen-doped porous graphene nanosheets are boosted by about one order of magnitude compared with those of undoped porous graphene nanosheets at room temperature. More importantly, an anisotropic thermoelectric transport is found in the nitrogen-doped porous graphene nanosheets. The results show that the ZT values of nitrogen-doped porous graphene nanosheets along the zigzag transport direction are nearly 11 times larger than those of them along the armchair transport direction. These results reveal that the thermoelectric properties of porous graphene nanosheets can be well regulated by nitrogen doping, and provide a good theoretical guidance for their application in thermoelectric devices.

Clinical characteristics, diagnosis and management of Sweet syndrome induced by azathioprine.

Sweet syndrome is a rare complication of azathioprine treatment with unelucidated clinical features. The purpose of this study was to investigate the clinical characteristics of azathioprine-induced Sweet syndrome (AISS) and provide a reference for diagnosis, treatment and prognosis. We collected relevant case reports of AISS by searching Chinese and English databases from 1960 to December 31, 2022, extracted the data and carried out a retrospective analysis. The median age of the 44 patients was 50 (range 9-89) years, and they included 32 males (72.7%). Fever (86.4%) and arthralgia (31.8%) were the most common clinical symptoms. The skin lesions were mainly pustules (54.5%), papules (40.9%), plaques (40.9%) and nodules (31.8%), which were mainly distributed on the extremities (54.5%), face (38.6%) and hands (36.4%). Laboratory examination revealed neutropenia (65.9%) as well as elevated C-reactive protein (63.6%) and erythrocyte sedimentation (40.9%) rates. Histopathology of the lesioned skin showed neutrophil infiltration (93.2%) and dermal edema (38.6%). Symptom relief was achieved at a median time of 7 days (range 2-28 days) after azathioprine discontinuation in all patients. Nine patients (20.5%) had skin lesions that recurred within 24 h after taking azathioprine again. Clinicians and pharmacists should grasp the regularity and characteristics of AISS and should not recommend the readministration of azathioprine, to avoid the recurrence of Sweet syndrome.

Association between caffeine consumption and bone mineral density in children and adolescent: Observational and Mendelian randomization study.

BACKGROUND: Coffee is the most commonly consumed beverage among children and adolescences. Caffeine was demonstrated to be associated with bone metabolism. However, the relationship between caffeine intake and BMD in children and adolescents remains unclear. This study aimed to identified relationship between caffeine consumption and bone mineral density (BMD) in children and adolescents. METHODS: Based on National Health and Nutrition Examination Survey (NHANES), we conducted an epidemiological cross-section study to measure the relationship between caffeine consumption and BMD in children and adolescents by multivariate linear regression models. Then, five methods of Mendelian randomization (MR) analyses were performed to estimate their causal relationship between coffee and caffeine intake and BMD in children and adolescents. MR-Egger and inverse-variance weighted (IVW) were used to evaluate the heterogeneity effect of instrumental variables (IVs). RESULTS: In epidemiological studies, individuals with the highest quartile of caffeine intake do not have a significant change in femur neck BMD (ß = 0.0016, 95% CI: -0.0096, 0.0129, P = 0.7747), total femur BMD (ß = 0.0019, P = 0.7552), and total spine BMD (ß = 0.0081, P = 0.1945) compared with the lowest quartile. In MR analysis, the IVW-random effect indicates no causal relationship between coffee consumption and TB- BMD (ß = 0.0034, P = 0.0910). Other methods of MR analyses and sensitivity analysis reveals consistent findings. Similarly, the fixed-effects IVW method shows no causal association between caffeine intake and TB-BMD in children and adolescents (ß = 0.0202, P = 0.7828). CONCLUSIONS: Our study does not support a causal relationship between caffeine consumption and BMD in children and adolescents. However, more studies are needed to verify our findings, such as its underlying molecular mechanisms and the long-term impact of early caffeine exposure at a younger age.

Prevalence of osteoporosis in spinal surgery patients older than 50 years: A systematic review and meta-analysis.

INTRODUCTION: In spine surgery, poor bone condition is associated with several complications like adjacent segment fractures, proximal junctional kyphosis, and screw loosening. Our study explored the prevalence of osteoporosis in spinal surgery patients older than 50 years through a systematic review and meta-analysis. METHODS: This systematic review and meta-analysis were conducted according to the PRISMA criteria. Three electronic databases, including PubMed, EMBASE, and Web of Science, were searched from inception to August 2022. We used the random-effects model to calculate the overall estimates, and the heterogeneity was measured using Cochran's Q and I2 tests. Meta-regression and subgroup analyses were used to determine the source of the heterogeneity. RESULTS: Based on the inclusion and criteria, we chose ten studies with 2958 individuals for our analysis. The prevalence of osteoporosis, osteopenia, and osteoporosis/osteopenia in the spinal surgery patients was 34.2% (95%CI: 24.5%-44.6%), 43.5% (95%CI: 39.8%-47.2%), and 78.7% (95%CI: 69.0%-87.0%), respectively. Regarding different diagnoses, the prevalence was highest in patients with lumbar scoliosis (55.8%; 95%CI: 46.8%-64.7%) and the lowest in patients with cervical disc herniation (12.9%; 95%CI: 8.1%-18.7%). In age groups 50-59, 50-69,70-79, the prevalence was 27.8%, 60.4%, 75.4% in females, and 18.9%, 17.4%, 26.1% in males. CONCLUSIONS: This study showed a high prevalence of osteoporosis in patients undergoing spine surgery, especially in females, people of older age, and patients who received degenerative scoliosis and compression fractures. Current osteoporosis screening standards for patients undergoing spine surgery may not be adequate. Orthopedic specialists should make more efforts regarding preoperative osteoporosis screening and treatment.

Chromatin Reprogramming of In Vitro Fertilized and Somatic Cell Nuclear Transfer Bovine Embryos During Embryonic Genome Activation.

Reprogramming of the gamete into a developmentally competent embryo identity is a fundamental aspect of preimplantation development. One of the most important processes of this reprogramming is the transcriptional awakening during embryonic genome activation (EGA), which robustly occurs in fertilized embryos but is defective in most somatic cell nuclear transfer (SCNT) embryos. However, little is known about the genome-wide underlying chromatin landscape during EGA in SCNT embryos and how it differs from a fertilized embryo. By profiling open chromatin genome-wide in both types of bovine embryos, we find that SCNT embryos fail to reprogram a subset of the EGA gene targets that are normally activated in fertilized embryos. Importantly, a small number of transcription factor (TF) motifs explain most chromatin regions that fail to open in SCNT embryos suggesting that over-expression of a limited number of TFs may provide more robust reprogramming. One such TF, the zygotically-expressed bovine gene DUXC which is a homologue of EGA factors DUX/DUX4 in mouse/human, is alone capable of activating ∻84% of all EGA transcripts that fail to activate normally in SCNT embryos. Additionally, single-cell chromatin profiling revealed low intra-embryo heterogeneity but high inter-embryo heterogeneity in SCNT embryos and an uncoupling of cell division and open chromatin reprogramming during EGA. Surprisingly, our data also indicate that transcriptional defects may arise downstream of promoter chromatin opening in SCNT embryos, suggesting additional mechanistic insights into how and why transcription at EGA is dysregulated. We anticipate that our work will lead to altered SCNT protocols to increase the developmental competency of bovine SCNT embryos.