DDX5 inhibits inflammation by modulating m6A levels of TLR2/4 transcripts during bacterial infection.

DExD/H-box helicases are crucial regulators of RNA metabolism and antiviral innate immune responses; however, their role in bacteria-induced inflammation remains unclear. Here, we report that DDX5 interacts with METTL3 and METTL14 to form an m6A writing complex, which adds N6-methyladenosine to transcripts of toll-like receptor (TLR) 2 and TLR4, promoting their decay via YTHDF2-mediated RNA degradation, resulting in reduced expression of TLR2/4. Upon bacterial infection, DDX5 is recruited to Hrd1 at the endoplasmic reticulum in an MyD88-dependent manner and is degraded by the ubiquitin-proteasome pathway. This process disrupts the DDX5 m6A writing complex and halts m6A modification as well as degradation of TLR2/4 mRNAs, thereby promoting the expression of TLR2 and TLR4 and downstream NF-κB activation. The role of DDX5 in regulating inflammation is also validated in vivo, as DDX5- and METTL3-KO mice exhibit enhanced expression of inflammatory cytokines. Our findings show that DDX5 acts as a molecular switch to regulate inflammation during bacterial infection and shed light on mechanisms of quiescent inflammation during homeostasis.

A Proof-of-Concept Sandwich Enzyme-Linked Immunoassay Development for Small Molecules.

A sandwich immunoassay theoretically exhibits higher sensitivity and specificity compared to a competitive counterpart; however, it is extremely difficult to obtain a pair of antibodies that can bind to a small molecule simultaneously, which is always thought to be a single epitope. In the present study, abamectin (ABM) was selected to prove the effect of hapten design and antibody recognition properties on the development of a sandwich immunoassay for small molecules. First, the epitopes of ABM were roughly located, and epitope distances were determined. Then, two haptens were designed by introducing spacer arms at the C4″-OH and C5-OH of ABM, respectively, aiming to provide the longest epitope distances. A total of seven rabbit polyclonal antibodies (pAbs) and 21 mouse monoclonal antibodies (mAbs) with various recognition properties were obtained. Extensive combinatorial associations of antibody pairs for simultaneously binding to ABM were performed, and only two mAb-mAb pairs were observed to achieve a sandwich immunoassay for ABM with a total success rate of 0.27%. The best mAb pair for sandwich immunoassay was confirmed by surface plasmon resonance, used to develop a sandwich immunoassay, and then evaluated by cross-reactivities and molecular docking with structurally similar analogues and abamectin. Altogether, the study provided a theoretical foundation as well as practical experience and demonstrated the importance of careful hapten design and extensive antibody screening to successfully establish the sandwich immunoassay for small molecules.

Noninvasive prediction of node-positive breast cancer response to presurgical neoadjuvant chemotherapy therapy based on machine learning of axillary lymph node ultrasound.

OBJECTIVES: To explore an optimal model to predict the response of patients with axillary lymph node (ALN) positive breast cancer to neoadjuvant chemotherapy (NAC) with machine learning using clinical and ultrasound-based radiomic features. METHODS: In this study, 1014 patients with ALN-positive breast cancer confirmed by histological examination and received preoperative NAC in the Affiliated Hospital of Qingdao University (QUH) and Qingdao Municipal Hospital (QMH) were included. Finally, 444 participants from QUH were divided into the training cohort (n = 310) and validation cohort (n = 134) based on the date of ultrasound examination. 81 participants from QMH were used to evaluate the external generalizability of our prediction models. A total of 1032 radiomic features of each ALN ultrasound image were extracted and used to establish the prediction models. The clinical model, radiomics model, and radiomics nomogram with clinical factors (RNWCF) were built. The performance of the models was assessed with respect to discrimination and clinical usefulness. RESULTS: Although the radiomics model did not show better predictive efficacy than the clinical model, the RNWCF showed favorable predictive efficacy in the training cohort (AUC, 0.855; 95% CI 0.817-0.893), the validation cohort (AUC, 0.882; 95% CI 0.834-0.928), and the external test cohort (AUC, 0.858; 95% CI 0.782-0.921) compared with the clinical factor model and radiomics model. CONCLUSIONS: The RNWCF, a noninvasive, preoperative prediction tool that incorporates a combination of clinical and radiomics features, showed favorable predictive efficacy for the response of node-positive breast cancer to NAC. Therefore, the RNWCF could serve as a potential noninvasive approach to assist personalized treatment strategies, guide ALN management, avoiding unnecessary ALND.

Minimum Distance Between Two Epitopes in Sandwich Immunoassays for Small Molecules.

The pursuit of the limit between dimensionalities is a scientific goal with high applicability. Sandwich immunoassay, usually based on two antibodies binding two epitopes, is one of the most popular mainstay tools in both academic and industrial fields. Herein, we determined and evaluated the minimum distance of two epitopes in sandwich immunoassays for small molecules. Briefly, nine model analytes comprising two hapten epitopes, that is, melamine (MEL) and p-nitroaniline (NIA), were designed by increasing the linear chain linkers brick by brick. Two groups of monoclonal antibodies (mAbs) were produced with different recognition properties toward MEL and NIA using 12 new haptens with different spacer arms. The results indicated that two epitopes of the analyte with a distance of only 2.4 Å could be simultaneously bound by two mAbs, which is the known limit of epitope distance in sandwich immunoassays thus far. We further found that an epitope distance of below 8.8 Å for the analyte generally induces noticeable steric hindrance of antibodies, preventing a sandwich immunoassay with high probability. These observations were investigated and evaluated by molecular docking, molecular dynamics, and surface plasmon resonance and using model and real analytes. Altogether, we determined the minimum distance of two epitopes and explored the molecular mechanism of the antibody-analyte-antibody ternary complex in sandwich immunoassays, providing a theoretical basis for hapten design, antibody discovery and development, and sandwich immunoassay establishment for small molecules.

Breast cancer subtypes affect the ultrasound performance for axillary lymph node status evaluation after neoadjuvant chemotherapy: a retrospective analysis.

PURPOSE: The aim of our study was to investigate the effect of breast cancer subtypes on the diagnostic value of axillary ultrasound for node status evaluation after neoadjuvant chemotherapy. PATIENTS AND METHODS: Pathologic node-positive breast cancer patients underwent axillary ultrasound imaging after neoadjuvant chemotherapy were retrospectively reviewed. The enrolled patients were classified into four subtypes: Luminal A, Luminal B, human epidermal growth factor receptor 2-enriched and triple-negative. Ultrasound images of axillary nodes were reviewed and were evaluated as normal or abnormal and were associated with final pathologic results. Diagnostic value of axillary ultrasound was assessed in four subtypes based on sensitivity, specificity, positive predictive value and negative predictive value. The diagnostic value of axillary ultrasound as well as clinical and pathological characteristics was compared between four breast cancer subtypes using chi-square test or fisher's exact test. RESULT: Luminal A subtype had highest positive predictive value (92.1%), lowest sensitivity (43.8%) and lowest negative predictive value (11.8%). Triple-negative subtype had lowest positive predictive value (73.2%), highest sensitivity (76.9%) and highest negative predictive value (59.1%) (P < 0.05). Luminal B and human epidermal growth factor receptor 2-enriched subtypes had medium sensitivity, positive predictive value and negative predictive value. CONCLUSION: The diagnostic value of axillary ultrasound for node residue disease assessment after neoadjuvant chemotherapy is different between four breast cancer subtypes.

[Clinical Characteristics of Aldosterone Producing Adenoma and Idiopathic Hyperaldosteronism with Obstructive Sleep Apnea Hypopnea Syndrome].

OBJECTIVE: To investigate the clinical characteristics of aldosterone producing adenoma (APA) and idiopathic hyperaldosteronism (IHA) complicated with obstructive sleep apnea hypopnea syndrome (OSAHS) and the effect of OSAHS on renin-angiotensin-aldosterone system (RAAS) in APA and IHA patients. METHODS: The clinical data of 127 patients with primary aldosteronism (PA) diagnosed from May 2010 to Aug. 2019 were retrospectively analyzed. There were 70 cases of APA, 53 cases of IHA. Another 4 cases were primary adrenal hyperplasia (PAH), so not included into further analysis. According to the results of polysomnography, the 123 patients of APA or IHA were divided into OSAHS group (96 cases) and non-OSAHS group (27 cases ). The patients with OSAHS were divided into mild, moderate and severe subgroups based on apnea hypopnea index (AHI).The clinical characteristics, biochemical parameters, plasma renin activity, aldosterone levels, and the ratio of aldosterone to renin activity (ARR) in the patients of APA and IHA complicated with OSAHS were compared with those of the patients without OSAHS. RESULTS: There were 49 OSAHS cases (49/70, 70.0%) in APA patients. and 47 OSAHS cases (47/53, 88.7%) in IHA patients. The age, male ratio, body mass index (BMI), waist circumference, triglyceride, blood uric acid, and blood creatinine in APA patients with OSAHS were higher than those in APA patients without OSAHS ( P<0.05), while high-density lipoprotein and estimated glomerular filtration rate (eGFR) were lower ( P<0.05). Compared to the patients without OSAHS, IHA-OSAHS patients had higher BMI and waist circumference ( P<0.05). Moderate/severe OSAHS-APA patients exhibited higher plasma renin activity levels and lower ARR values than the APA patients with no/mild OSAHS ( P<0.05). There were no significant differences in plasma renin activity, aldosterone levels, and ARR values between moderate/severe OSAHS-IHA group and no/mild OSAHS-IHA group. CONCLUSION: The prevalence of OSAHS is significantly higher in the patients with PA than normal population, and OSAHS may aggravate glycose, lipid and uric acid metabolism in PA patients. Moderate/severe OSAHS can increase renin levels and decrease ARR values in APA patients, but has no significant effect on RAAS in IHA patients.

Resolution of the Ongoing Challenge of Estimating Nonpoint Source Neonicotinoid Pollution in the Yangtze River Basin Using a Modified Mass Balance Approach.

Neonicotinoid insecticides have been widely consumed worldwide, particularly in China. There is a growing interest in the environmental research community about the occurrence, fates, sources, and risks of neonicotinoids. Nine neonicotinoids in river/lake water were measured at 12 sites along the Yangtze River Basin during the dry and wet seasons in 2016, and nonpoint sources were also identified based on a modified mass balance method. A significantly higher concentration of neonicotinoids was found during the dry season probably due to the dilution effect and insecticide consumption. The high pollution levels are due to posing high ecological risks compared with the recommended thresholds. In 2016, 1190 (95% confidence interval (CI) = 822-1690) tons of neonicotinoids were transferred into the adjacent sea. Nonpoint source pollution (1700 (CI = 1200-2370) tons) was the major contributor (91.3%) to the total input of neonicotinoids into the system. Composition profiles identifying specific neonicotinoid sources indicated some changes in usage patterns from old to new types of neonicotinoids. This spatial and seasonal field study and source identification is expected to fill the data gap regarding the limited information on neonicotinoid use patterns and to inform further effective policy-making and intervention programs in China that should be urgently promoted in the near future.

Serum WFA+ -M2BP levels for evaluation of early stages of liver fibrosis in patients with chronic hepatitis B virus infection.

BACKGROUND & AIMS: Accurate evaluation of liver fibrosis is crucial for predicting progression of chronic hepatitis B virus (HBV) infection. We assessed the utility of a novel fibrosis glycobiomarker Wisteria floribunda agglutinin-positive Mac-2-binding protein (WFA+ -M2BP) for evaluating liver fibrosis and disease progression in patients with chronic HBV infection. METHODS: We enrolled 774 patients with chronic HBV infection, with or without fibrosis, diagnosed by liver biopsy/FibroScan. Patients who underwent liver biopsy (n = 297) were divided into training (n = 221) and validation (n = 76) groups. Serum WFA+ -M2BP values were measured and compared with FIB-4 index, aspartate aminotransferase (AST)-to-platelet ratio (APRI) and AST-to-alanine aminotransferase ratio (AAR) using receiver-operating characteristic (ROC) analysis. RESULTS: Serum WFA+ -M2BP levels increased significantly with fibrosis progression (P < 0.0001). Area under the ROC curve of WFA+ -M2BP for diagnosing significant fibrosis was higher than that of FIB-4 (P = 0.198), APRI (P = 0.017) and AAR (P < 0.001), with sensitivity and specificity in the training set of 60.5% and 79.8% and validation set of 59.5% and 82.1%, respectively. Serum WFA+ -M2BP levels were significantly correlated with FibroScan values (P < 0.0001) and improved the accuracy of FibroScan in assessing significant fibrosis. Changes in WFA+ -M2BP levels were parallel with those in FibroScan values during nucleot(s)ide analogues therapy in patients with chronic HBV infection. CONCLUSIONS: WFA+ -M2BP is an accurate serum indicator for assessing early stages of liver fibrosis and may monitor regression of fibrosis during the treatment of chronic HBV infection. WFA+ -M2BP provides a simple and reliable alternative or complementary method to liver biopsy and FibroScan.

Digital Breast Tomosynthesis: A New Diagnostic Method for Mass-Like Lesions in Dense Breasts.

To compare the rates and accuracy of digital breast tomosynthesis (DBT) and 2D digital mammography (DM) for detecting and diagnosing mass-like lesions in dense breasts. Mediolateral and craniocaudal images taken with DBT (affected breast) and DM (both breasts) of the dense breasts of 631 women were assessed independently using Breast Imaging Reporting and Data System (BI-RADS) scores. Images were compared for detection and diagnostic accuracy for masses; sensitivity and specificity of diagnosis; false-negative and recall rates; and clarity of display, particularly of margins and spicules. Histopathology was conducted via surgical biopsies of all patients. The detection and diagnostic accuracy rates of DBT images (84.3% and 82.3%, respectively) were significantly higher than that of DM (77.3% and 73.4%; p < 0.01, both). The sensitivity and specificity of DBT (68.1% and 95.2%) were higher than that of DM (58.8% and 86.7%), whereas the recall rate of DBT was lower (3.6% cf. 9.8%). The number of cases of benign circumscribed masses and malignant spiculated masses detected by DBT (172 and 182) was significantly higher than the number detected through DM (75 and 115; p < 0.01, both). Radiologists assigned higher BI-RADS scores for probability of malignancy to DBT images than DM, to lesions proved malignant (p = 0.025); for benign cases, the methods were comparable (p = 0.065). Compared with DM, DBT yielded significantly higher rates of detection and diagnostic accuracy for benign and malignant masses, with greater sensitivity and specificity and lower recall rates. In addition, DBT images facilitated analysis of margins, and the rate of accuracy for judgments of malignancy probability was higher, as proved on biopsy.

Remote Construction of Chiral Vicinal Tertiary and Quaternary Centers by Catalytic Asymmetric 1,6-Conjugate Addition of Prochiral Carbon Nucleophiles to Cyclic Dienones.

An unprecedented remote construction of chiral vicinal tertiary and quaternary centers by a catalytic asymmetric 1,6-conjugate addition of prochiral carbon nucleophiles to cyclic dienones has been developed. Both 5H-oxazol-4-ones and 2-oxindoles were found to be very efficient carbon nucleophiles in this reaction at a remote position, giving products with excellent enantio- and diastereoselectivities (up to 99% ee and >19:1 d.r. for 5H-oxazol-4-ones and up to 97% ee and >19:1 d.r. for 2-oxindoles).

Direct Catalytic Asymmetric Doubly Vinylogous Michael Addition of α,ß-Unsaturated γ-Butyrolactams to Dienones.

An asymmetric doubly vinylogous Michael addition (DVMA) of α,ß-unsaturated γ-butyrolactams to sterically congested ß-substituted cyclic dienones with high site-, diastereo-, and enantioselectivity has been achieved. An unprecedented DVMA/vinylogous Michael addition/isomerization cascade reaction affords chiral fused tricyclic γ-lactams with four newly formed stereocenters.

A two-center study of a combined nomogram based on mammography and MRI to predict ALN metastasis in breast cancer.

OBJECTIVES: To develop and validate a predictive method for axillary lymph node (ALN) metastasis of breast cancer by using radiomics based on mammography and MRI. MATERIALS AND METHODS: A retrospective analysis of 492 women from center 1 (The affiliated Hospital of Qingdao University) and center 2 (Yantai Yuhuangding Hospital) with primary breast cancer from August 2013 to May 2021 was carried out. The radscore was calculated using the features screened based on preoperative mammography and MRI from the training cohort of Center 1 (n = 231), then tested in the validation cohort (n = 99), an internal test cohort (n = 90) from Center 1, and an external test cohort (n = 72) from Center 2. Univariate and multivariate analyses were used to screen for the clinical and radiological characteristics most associated with ALN metastasis. A combined nomogram was established in combination with radscore that predicted the clinicopathological and radiological characteristics. Calibration curves were used to test the effectiveness of the combined nomogram. The receiver operating characteristic (ROC) curve was used to evaluate the performance of the combined nomogram and then compare with the clinical and radiomic models. The decision curve analysis (DCA) value was used to evaluate the combined nomogram for clinical applications. RESULTS: The constructed combined nomogram incorporating the radscore and MRI-reported ALN metastasis status exhibited good calibration and outperformed the radiomics signatures in predicting ALN metastasis (area under the curve [AUC]: 0.886 vs. 0.846 in the training cohort; 0.826 vs. 0.762 in the validation cohort; 0.925 vs. 0.899 in the internal test cohort; and 0.902 vs. 0.793 in the external test cohort). The combination nomogram achieved a higher AUC in the training cohort (0.886 vs. 0.786) and the internal test cohort (0.925 vs. 0.780) and similar AUCs in the validation (0.826 vs. 0.811) and external test (0.902 vs. 0.837) cohorts than the clinical model. CONCLUSION: A combined nomogram based on mammography and MRI can be used for preoperative prediction of ALN metastasis in primary breast cancer.

Prediction of Disease-Free Survival in Breast Cancer using Deep Learning with Ultrasound and Mammography: A Multicenter Study.

BACKGROUND: Breast cancer is a leading cause of cancer morbility and mortality in women. The possibility of overtreatment or inappropriate treatment exists, and methods for evaluating prognosis need to be improved. MATERIALS AND METHODS: Patients (from January 2013 to December 2018) were recruited and divided into a training group and a testing group. All patients were followed for more than 3 years. Patients were divided into a disease-free group and a recurrence group based on follow up results at 3 years. Ultrasound (US) and mammography (MG) images were collected to establish deep learning models (DLMs) using ResNet50. Clinical data, MG, and US characteristics were collected to select independent prognostic factors using a cox proportional hazards model to establish a clinical model. DLM and independent prognostic factors were combined to establish a combined model. RESULTS: In total, 1242 patients were included. Independent prognostic factors included age, neoadjuvant chemotherapy, HER2, orientation, blood flow, dubious calcification, and size. We established 5 models: the US DLM, MG DLM, US + MG DLM, clinical and combined model. The combined model using US images, MG images, and pathological, clinical, and radiographic characteristics had the highest predictive performance (AUC = 0.882 in the training group, AUC = 0.739 in the testing group). CONCLUSION: DLMs based on the combination of US, MG, and clinical data have potential as predictive tools for breast cancer prognosis.

The Application of Three-Dimensional-Printed Hydrogels in Bone Tissue Engineering.

Bone defects are a prevalent clinical issue that presents a serious medical challenge. Bone tissue engineering (BTE) has emerged as an effective approach for treating large bone defects. Hydrogels, as hydrophilic three-dimensional polymers, are recognized as suitable material for BTE due to their excellent biocompatibility and degradability. However, the submicron and nanoporous structure of hydrogels limits the survival of osteoblasts, hindering bone tissue regeneration. In recent years, 3D printing technology has attracted appreciable attention. The use of hydrogels as 3D-printed ink facilitates the printing of hydrogels in any desired shape, enabling personalized or more complex requirements. This article provides a systematic review of the latest applications of 3D-printed hydrogels in BTE. These hydrogels serve as a multifunctional platform for the next generation technology in treating bone defects. The advantages and limitations of 3D-printed hydrogels in BTE are discussed, and future research directions are explored. This review can form the basis for future hydrogel design.

Investigation of Antibody Tolerance in Methanol for Analytical Purposes: Methanol Effect Patterns and Molecular Mechanisms.

The extraction of targets from biological samples for immunoassays using organic solvents, such as methanol, is often necessary. However, high concentrations of organic solvents in extracts invariably lead to instability of the employed antibody, resulting in poor performance of the immunoassay. Evaluating the tolerance ability and exploring the molecular mechanisms of antibody tolerance in organic solvents are essential for the development of robust immunoassays. In this work, 25 monoclonal antibodies and methanol are utilized as models to address these questions. A novel protocol is initially established to precisely and rapidly determine antibody tolerance in methanol, identifying two distinct methanol effect patterns. Through a detailed investigation of the structural basis, a novel hypothesis regarding methanol effect patterns is proposed, termed "folding-aggregation," which is subsequently validated through molecular dynamics simulations. Furthermore, the investigation of sequence basis reveals significant differences in residue types within the complementarity-determining regions and ligand-binding residues, distinguishing the two antibody methanol effect patterns. Moreover, the methanol effect patterns of the antibodies are defined by germline antibodies. This work represents the first exploration of antibody methanol effect patterns and associated molecular mechanisms, with potential implications for the discovery and engineering of tolerant antibodies for the development of robust immunoassays.

Characterization of TRIP6-dependent nasopharyngeal cancer cell migration.

Nasopharyngeal carcinoma (NPC) is a leading malignancy most often reported in endemic areas such as in Southeast Asia and the Mediterranean area. NPC remains as a major challenge for clinical management largely due to its high propensity for cancer invasion, metastasis, and recurrence. Therefore, control of NPC cell motility stands as a major obstacle for successful NPC management. The current study sought to identify a new regulator for NPC cell motility in light of previous data showing a similar role of thyroid receptor interactor protein 6 (TRIP6) in other cancer cell types. Results showed that TRIP6 is up-regulated in NPC cells as compared to normal nasopharyngeal epithelial cells. Moreover, TRIP6 overexpression/knockdown results in significant enhancement/inhibition of NPC cell migration, respectively. Interestingly, data also suggested that TRIP6 Y55E (tyrosine 55 to glutamic acid) mutant can promote cell migration more efficiently than wild type does, while Y55A (tyrosine 55 to alanine) mutant has no effects on cell migration as demonstrated with different methodology. Consistently, we also found that c-Src physically interacts with TRIP6, which suggests its potential role as a TRIP6 kinase. Taken together, these data suggested that TRIP6 is involved in the regulation of NPC cell motility, and phosphorylation of tyrosine 55 residue plays an important regulatory role for this event. These data highlight the importance of TRIP6 as a novel regulator of NPC cell motility, which warrants a good basis for further investigation on the underlying mechanism by which TRIP6 exerts this effect and the pathophysiological role TRIP6 plays in vivo.

A gas-selective Zn-MOF exhibits selective sensing of Fe3+ ions by doping with Tb3.

Here, a new Zn2+ metal organic framework, {[Me2NH2][Zn2(L)(DTZ)]·2DMF·3H2O}n (Zn-MOF), has been synthesized with low-symmetric carboxylic acid ligand 2,6 bis(2',5'-dicarboxyphenyl)pyridine (H4L) as the main ligand and 3,5-diamino-1,2,4-riazole (DTZ) containing an electron-rich N atom as an auxiliary ligand. Because of its high structural stability and adsorption properties, it can be used to efficiently separate CO2/CH4 and C2H2/CH4. In addition, Tb@Zn-MOF was obtained by doping with Tb3+ to partially replace Zn2+. A study of its luminescence sensing performance demonstrated that Tb@Zn-MOF showed intense luminescence properties and can be used for the directional detection of Fe3+ in aqueous solution. Furthermore, PXRD analysis, UV-vis spectroscopy and X-ray photoelectron spectroscopy (XPS) were also used to study possible luminescence sensing mechanisms. The recognition mechanism for Fe3+ ions is believed to be caused by electron transfer.

Enhanced selectivity of transcutaneous spinal cord stimulation by multielectrode configuration.

Objective: Transcutaneous spinal cord stimulation (tSCS) has been gaining momentum as a non-invasive rehabilitation approach to restore movement to paralyzed muscles after spinal cord injury (SCI). However, its low selectivity limits the types of movements that can be enabled and, thus, its potential applications in rehabilitation. Approach: In this cross-over study design, we investigated whether muscle recruitment selectivity of individual muscles could be enhanced by multielectrode configurations of tSCS in 16 neurologically intact individuals. We hypothesized that due to the segmental innervation of lower limb muscles, we could identify muscle-specific optimal stimulation locations that would enable improved recruitment selectivity over conventional tSCS. We elicited leg muscle responses by delivering biphasic pulses of electrical stimulation to the lumbosacral enlargement using conventional and multielectrode tSCS. Results: Analysis of recruitment curve responses confirmed that multielectrode configurations could improve the rostrocaudal and lateral selectivity of tSCS. To investigate whether motor responses elicited by spatially selective tSCS were mediated by posterior root-muscle reflexes, each stimulation event was a paired pulse with a conditioning-test interval of 33.3 ms. Muscle responses to the second stimulation pulse were significantly suppressed, a characteristic of post-activation depression suggesting that spatially selective tSCS recruits proprioceptive fibers that reflexively activate muscle-specific motor neurons in the spinal cord. Moreover, the combination of leg muscle recruitment probability and segmental innervation maps revealed a stereotypical spinal activation map in congruence with each electrode's position. Significance: Improvements in muscle recruitment selectivity could be essential for the effective translation into stimulation protocols that selectively enhance single-joint movements in neurorehabilitation.

Enhanced selectivity of transcutaneous spinal cord stimulation by multielectrode configuration.

Objective.Transcutaneous spinal cord stimulation (tSCS) has been gaining momentum as a non-invasive rehabilitation approach to restore movement to paralyzed muscles after spinal cord injury (SCI). However, its low selectivity limits the types of movements that can be enabled and, thus, its potential applications in rehabilitation.Approach.In this cross-over study design, we investigated whether muscle recruitment selectivity of individual muscles could be enhanced by multielectrode configurations of tSCS in 16 neurologically intact individuals. We hypothesized that due to the segmental innervation of lower limb muscles, we could identify muscle-specific optimal stimulation locations that would enable improved recruitment selectivity over conventional tSCS. We elicited leg muscle responses by delivering biphasic pulses of electrical stimulation to the lumbosacral enlargement using conventional and multielectrode tSCS.Results.Analysis of recruitment curve responses confirmed that multielectrode configurations could improve the rostrocaudal and lateral selectivity of tSCS. To investigate whether motor responses elicited by spatially selective tSCS were mediated by posterior root-muscle reflexes, each stimulation event was a paired pulse with a conditioning-test interval of 33.3 ms. Muscle responses to the second stimulation pulse were significantly suppressed, a characteristic of post-activation depression suggesting that spatially selective tSCS recruits proprioceptive fibers that reflexively activate muscle-specific motor neurons in the spinal cord. Moreover, the combination of leg muscle recruitment probability and segmental innervation maps revealed a stereotypical spinal activation map in congruence with each electrode's position.Significance. Improvements in muscle recruitment selectivity could be essential for the effective translation into stimulation protocols that selectively enhance single-joint movements in neurorehabilitation.

Diet composition and selection of Père David's deer in Hubei Shishou Milu National Nature Reserve, China.

Hubei Shishou Milu National Nature Reserve is an ideal place to restore the wild population of Père David's deer (Elaphurus davidianus). Understanding foraging ecology and diet composition is essential for assessing population development or establishing long-term effective conservation measures for endangered species. However, little is known about the diet composition of Père David's deer and its diet selection mechanism. In this study, we used stable isotope technology to investigate the diet composition of Père David's deer according to various tissues (i.e., fur, muscle, liver, heart, and feces) and seasons, and evaluated the correlation between the nutrient composition of plants and diet composition. Bayesian isotope analysis showed that the autumn and winter diet estimated by fur and fecal samples indicated a diet dominated by C3 grasses (42.7%-57.2%, mean), while the summer diet estimated by muscle and liver samples was dominated by C3 forbs (30.9%-41.6%, mean). The Pearson correlation test indicated that the contribution of winter diet composition reflected by fur and fecal samples was associated with correlations with crude protein (r = .666, p < .01) and soluble sugars (r = .695, p < .01). The results indicated that crude protein and soluble sugars were important factors influencing the winter diet selection of Père David's deer. In the context of the current reintroduction facing many challenges, such as habitat fragmentation, wetland degradation, and human disturbance, comprehensively evaluating the diet selection mechanism of Père David's deer under different resource specificities and temporal changes should be considered in the future.