Brain activation associated with low- and high-intensity concentric versus eccentric isokinetic contractions of the biceps brachii: An fNIRS study.

Studies have shown that neural responses following concentric (CON) and eccentric (ECC) muscle contractions are different, which suggests differences in motor control associated with CON and ECC contractions. This study aims to determine brain activation of the left primary motor cortex (M1) and left and right dorsolateral prefrontal cortices (DLPFCs) during ECC and CON of the right bicep brachii (BB) muscle at low- and high-contraction intensities. Eighteen young adults (13M/5F, 21-35 years) were recruited to participate in one familiarization and two testing sessions in a randomized crossover design. During each testing session, participants performed either ECC or CON contractions of the BB (3 sets × 8 reps) at low- (25% of maximum ECC/CON, 45°/s) and high-intensity (75% of maximum ECC/CON, 45°/s) on an isokinetic dynamometer. Eleven-channel functional near-infrared spectroscopy was used to measure changes in oxyhemoglobin (O2 Hb) from the left M1, and left and right DLPFC during ECC and CON contractions. Maximum torque for ECC was higher than CON (43.3 ± 14.1 vs. 46.2 ± 15.7 N m, p = 0.025); however, no differences in O2 Hb were observed between contraction types at low or high intensities in measured brain regions. High-intensity ECC and CON contractions resulted in greater increases in O2 Hb of M1 and bilateral DLPFC compared to low-intensity ECC and CON contractions (p = 0.014). Our findings suggest no differences in O2 Hb responses between contraction types at high and low intensities. High-contraction intensities resulted in greater brain activation of the M1 and bilateral DLPFC, which may have implications for neurorehabilitation to increase central adaptations from exercise.

Scaled-Model Radar Cross-Section Measurement: The Influence of the Scattered Field under Gaussian Beam Illumination-A Theoretical Analysis.

At microwave frequencies, radar cross-section (RCS) measurements are usually performed by placing the target in the far-field region of the antenna. The wavefront of the radiating field from the antenna can be approximated as planar, ensuring that the incident field and the power interact with the target independently of the antenna. However, for electrically large targets, the required distance becomes significant, posing challenges for implementation. Scaled-model RCS measurements offer an alternative solution. RCS measurements at terahertz and optical frequencies typically require a collimated beam as the source, where the intercepted power and RCS become dependent on the excitation. To address this dependency, researchers have proposed modifying the RCS definition to account for the intercepted power and to analytically formulate the scattering problem. However, such modifications require prior knowledge of the target's geometry and material properties, which are often not readily available in practice. This also limits the study to only canonical targets. In this paper, we propose an alternative approach for modelling the intercepted power. The Gaussian beam is decomposed into a number of plane waves travelling to different directions using the theory of plane wave spectrum. The scattering problem is solved using the full-wave method of moment. Through theoretical proofs and numerical examples involving spheres and a non-canonical target, with a scaled-model aircraft, we demonstrate that the original RCS definition can serve as a good approximation for scaled measurements, provided that the beam waist is approximately four times the target's dimensions. These findings provide valuable guidelines for radar engineers when performing scaled measurements using collimated beams. The results, which match those obtained from full-model measurements, enable us to predict the RCS of full-scale targets. This capability facilitates various target-related applications, such as target characterization, classification, detection, and even recognition.

Distance-Based Detection of Cough, Wheeze, and Breath Sounds on Wearable Devices.

Smart wearable sensors are essential for continuous health-monitoring applications and detection accuracy of symptoms and energy efficiency of processing algorithms are key challenges for such devices. While several machine-learning-based algorithms for the detection of abnormal breath sounds are reported in literature, they are either too computationally expensive to implement into a wearable device or inaccurate in multi-class detection. In this paper, a kernel-like minimum distance classifier (K-MDC) for acoustic signal processing in wearable devices was proposed. The proposed algorithm was tested with data acquired from open-source databases, participants, and hospitals. It was observed that the proposed K-MDC classifier achieves accurate detection in up to 91.23% of cases, and it reaches various detection accuracies with a fewer number of features compared with other classifiers. The proposed algorithm's low computational complexity and classification effectiveness translate to great potential for implementation in health-monitoring wearable devices.

iTRAQ quantitative clinical proteomics revealed role of Na(+)K(+)-ATPase and its correlation with deamidation in vascular dementia.

Dementia is a major public health burden characterized by impaired cognition and loss of function. There are limited treatment options due to inadequate understanding of its pathophysiology and underlying causative mechanisms. Discovery-driven iTRAQ-based quantitative proteomics techniques were applied on frozen brain samples to profile the proteome from vascular dementia (VaD) and age-matched nondementia controls to elucidate the perturbed pathways contributing to pathophysiology of VaD. The iTRAQ quantitative data revealed significant up-regulation of protein-l-isoaspartate O-methyltransferase and sodium-potassium transporting ATPase, while post-translational modification analysis suggested deamidation of catalytic and regulatory subunits of sodium-potassium transporting ATPase. Spontaneous protein deamidation of labile asparagines, generating abnormal l-isoaspartyl residues, is associated with cell aging and dementia due to Alzheimer's disease and may be a cause of neurodegeneration. As ion channel proteins play important roles in cellular signaling processes, alterations in their function by deamidation may lead to perturbations in membrane excitability and neuronal function. Structural modeling of sodium-potassium transporting ATPase revealed the close proximity of these deamidated residues to the catalytic site during E2P confirmation. The deamidated residues may disrupt electrostatic interaction during E1 phosphorylation, which may affect ion transport and signal transduction. Our findings suggest impaired regulation and compromised activity of ion channel proteins contribute to the pathophysiology of VaD.

Illegal synthetic dyes in spices: a Singapore case study.

Some synthetic dyes are fraudulently added into spices to appeal visually to consumers. Food regulations in several countries, including the United States, Australia, Japan and the European Union, strictly prohibit the use of unauthorised synthetic dyes in food. Nevertheless, illegal practices persist, where spices contaminated with potentially carcinogenic dyes have been documented, posing potential health risks to consumers. In the present study, 14 synthetic dyes were investigated through liquid chromatography/tandem mass spectrometry in 252 commercially available spices in the Singapore market. In 18 out of these (7.1%) at least 1 illegal dye was detected at concentrations ranging from 0.010 to 114 mg/kg. Besides potential health risks, presence of these adulterants also reflects the economic motivations behind their fraudulent use. Findings in the present study further emphasise the need for increased public awareness, stricter enforcement, and continuous monitoring of illegal synthetic dyes in spices to ensure Singapore's food safety.

Evaluating TESLA-G, a gamified, telegram-delivered, quizzing platform for surgical education in medical students: protocol for a pilot randomised controlled trial.

INTRODUCTION: Online multiple-choice question (MCQ) quizzes are popular in medical education due to their ease of access and ability for test-enhanced learning. However, a general lack of motivation among students often results in decreasing usage over time. We aim to address this limitation by developing Telegram Education for Surgical Learning and Application Gamified (TESLA-G), an online platform for surgical education that incorporates game elements into conventional MCQ quizzes. METHODS AND ANALYSIS: This online, pilot randomised control trial will be conducted over 2 weeks. Fifty full-time undergraduate medical students from a medical school in Singapore will be recruited and randomised into an intervention group (TESLA-G) and an active control group (non-gamified quizzing platform) with a 1:1 allocation ratio, stratified by year of study.We will evaluate TESLA-G in the area of endocrine surgery education. Our platform is designed based on Bloom's taxonomy of learning domains: questions are created in blocks of five questions per endocrine surgery topic, with each question corresponding to one level on Bloom's taxonomy. This structure promotes mastery while boosting student engagement and motivation. All questions are created by two board-certified general surgeons and one endocrinologist, and validated by the research team. The feasibility of this pilot study will be determined quantitatively by participant enrolment, participant retention and degree of completion of the quizzes. The acceptability of the intervention will be assessed quantitatively by a postintervention learner satisfaction survey consisting of a system satisfaction questionnaire and a content satisfaction questionnaire. The improvement of surgical knowledge will be assessed by comparing the scores of preintervention and postintervention knowledge tests, which consist of separately created questions on endocrine surgery. Retention of surgical knowledge will be measured using a follow-up knowledge test administered 2 weeks postintervention. Finally, qualitative feedback from participants regarding their experience will be obtained and thematically analysed. ETHICS AND DISSEMINATION: This research is approved by Singapore Nanyang Technological University (NTU) Institutional Review Boards (Reference Number: IRB-2021-732). All participants will be expected to read and sign a letter of informed consent before they are considered as recruited into the study. This study poses minimal risk to participants. Study results will be published in peer-reviewed open-access journals and presented in conference presentations. TRIAL REGISTRATION NUMBER: NCT05520671.

Diagnosis of an extremely rare case of malignant adenomyoepithelioma in pleomorphic adenoma: A case report.

BACKGROUND: Pleomorphic adenoma (PA) is the most common type of salivary gland tumor, and its common sites are parotid gland, sinus, nasal septum and cleft palate. PA is an uncommon benign type of tumor occurring in the breast, and there are few reports of cases in Asia. CASE SUMMARY: An 84-year-old woman found a mass in the upper outer quadrant of the right breast > 1 year ago. The patient underwent a right breast lumpectomy and sentinel lymph node biopsy. The pathological diagnosis was PA in the upper outer quadrant of the right breast, and the malignant component was malignant adenomyoepithelioma. The postoperative course was uneventful, and no chemotherapy was administered. At 18 mo of follow-up, the patient is alive and well, with no evidence of recurrent disease. CONCLUSION: Patients with breast PA should first undergo extended excision of breast masses followed by pathological examination. If malignancy is confirmed or the surgical margin is positive, modified radical mastectomy should be performed.

Association of genetic polymorphisms with acute kidney injury after cardiac surgery in a Southeast Asian population.

INTRODUCTION: Genetic polymorphisms are important in explaining the wide interpatient variability that exists in the development of acute kidney injury (AKI) post cardiac surgery. We hypothesised that polymorphisms in 4 candidate genes, namely angiotensin-converting enzyme (ACE), apolipoprotein-E (ApoE), interleukin-6 (IL-6), and tumour necrosis factor-alpha (TNF-α) are associated with AKI. METHODS: 870 patients who underwent cardiac surgery in Singapore were analysed. All patients who fulfilled stage 1 KDIGO criteria and above were considered to have AKI. This was investigated against various demographic, clinical and genetic factors. RESULTS: Increased age, history of hypertension, anaemia and renal impairment remained important preoperative risk factors for AKI. Intraoperatively, longer cardiopulmonary bypass (CPB) time and the use of intra-aortic balloon pump (IABP) were shown to be associated with AKI. Among the genetic factors, ACE-D allele was associated with an increased risk of AKI while IL6-572C allele was associated with a decreased risk of AKI. CONCLUSION: ACE-D allele was associated with the development of AKI similar to other studies. On the other hand, IL6-572C was shown to have a protective role against the development of AKI, contradictory to studies done in the Caucasian population. This contradictory effect of IL6-572C is a result of a complex interplay between the gene and population specific modulating factors. Our findings further underscored the necessity of taking into account population specific differences when developing prediction models for AKI.

Tailored chondroitin sulfate glycomimetics via a tunable multivalent scaffold for potentiating NGF/TrkA-induced neurogenesis.

The challenges inherent in the synthesis of large glycosaminoglycan (GAG) polysaccharides have made chemically accessible multivalent glycoligands a valuable tool in the field of GAG mimetics. However, the difficulty of positioning sulfated sugar motifs at desired sites has hindered efforts to precisely tailor their biofunctions. Here, we achieved precise orientation of sulfated disaccharide motifs by taking advantage of a structurally well-defined polyproline scaffold, and describe systematic explorations into the importance of the spatial arrangement of sulfated sugars along the scaffold backbone in designing multivalent glycoligands. Our protein binding studies demonstrate that the specific conformational display of pendant sugars is central to direct their multivalent interactions with NGF. By employing computational modeling and cellular studies, we have further applied this approach to engineer NGF-mediated signaling by regulating the NGF/TrkA complexation process, leading to enhanced neuronal differentiation and neurite outgrowth of PC12 cells. Our findings offer a promising strategy for the pinpoint engineering of GAG-mediated biological processes and a novel method of designing new therapeutic agents that are highly specific to GAG-associated disease.

Combinatorial bead-based peptide libraries improved for rapid and robust screenings.

In pursuit of utilizing combinatorial peptide libraries on beads, rapid and robust screening is one of the key steps for the success of high-throughput process. We have introduced improved structural features that greatly facilitate a MALDI-MS/MS-based sequencing, associated with easy and fast synthesis and analysis of such libraries. Whilst commonly used MS-based analysis involves in sophisticated procedures such as ladder synthesis, encoding tags are not required in our MS/MS-based sequencing platform. Fragment peaks in an acquired MS/MS should be outstanding in line with correct identification of parent mass in the preceding MS. To meet these requirements a one-bead-one-compound (OBOC) peptide library was designed by placing a positively charged arginine at C-terminus. As well as enhancing the overall ionization efficiency, arginine appended in all y-ion fragments generates a series of doublet peaks under MS/MS environments, which can speed up the sequencing process in conjunction with high accuracy. It is another strong benefit that the designed library significantly suppresses the adverse formation of sodium ion adducts, which seriously jeopardizes the sequencing, especially of peptides containing negatively charged amino acids. A peptide library constructed with D-amino acids was applied to screening against a clinically significant biomarker, C-reactive protein (CRP). Through the screening of focused libraries narrowed down from a comprehensive library, several hexamer peptide ligands were successfully identified and their binding affinity and specificity towards CRP were validated by surface plasmon resonance (SPR) and dot blot experiments.

Process automation toward ultra-high-throughput screening of combinatorial one-bead-one-compound (OBOC) peptide libraries.

With an aim to develop peptide-based protein capture agents that can replace antibodies for in vitro diagnosis, an ultra-high-throughput screening strategy has been investigated by automating labor-intensive, time-consuming processes that are the construction of peptide libraries, sorting of positive beads, and peptide sequencing through analysis of tandem mass spectrometry data. Although instruments for automation, such as peptide synthesizers and automatic bead sorters, have been used in some groups, the overall process has not been well optimized to minimize time, cost, and efforts, as well as to maximize product quality and performance. Herein we suggest and explore several solutions to the existing problems with the automation of the key processes. The overall process optimization has been done successfully in orchestration with the technologies such as rapid cleavage of peptides from beads and semiautomatic peptide sequencing that we have developed previously. This optimization allowed one-round screening, from peptide library construction to peptide sequencing, to be completed within 4 to 5 days. We also successfully identified a 6-mer ligand for carcinoembryonic antigen-cell adhesion molecule 5 (CEACAM 5) through three-round screenings, including one-round screening of a focused library.