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1.
Geriatrics (Basel) ; 9(2)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38667515

RESUMO

BACKGROUND: Viscosity is a common focus in the diet of patients with dysphagia. However, adhesiveness is an equally significant property that can affect swallowing function, even in semi-solid foods with similar levels of viscosity. The purpose of this study was to classify the adhesiveness of food into stages and determine whether these classifications are relevant to swallowing function. METHODS: This study included 30 healthy elderly adults aged 65 years. After categorizing adhesiveness into three levels based on the results of the sensory test, 30 participants were asked to swallow representative foods at each level. A videofluoroscopic swallowing study (VFSS) was performed to determine the presence or absence of pharyngeal residues based on the level of adhesiveness. The chi-square test was used to verify whether there was a difference in remnants according to the level of adhesiveness, and significance was judged with a p-value of less than 0.05. RESULTS: Adhesiveness was categorized into three distinct levels: level 1 (0-4 mJ), level 2 (4-18 mJ), and level 3 (>18 mJ). Upon examining the subjects presenting with residual material, we observed three cases of level 1 adhesiveness, 16 cases of level 2, and 25 cases of level 3. The chi-square test was used to assess the statistical significance between the levels, revealing a significant difference with a p-value < 0.0001. CONCLUSIONS: We presented the level of adhesiveness by dividing it into three stages and proved that it is meaningful in relation to the swallowing function. Selecting and recommending foods with an appropriate level of adhesiveness will help enhance swallowing safety in older adults.

2.
Clin Auton Res ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38652421

RESUMO

PURPOSE: The specific characteristics of autonomic involvement in patients with early Parkinson's disease (PD) are unclear. This study aimed to evaluate the characteristics of autonomic dysfunction in drug-naïve patients with early-stage PD without orthostatic hypotension (OH) by analyzing Valsalva maneuver (VM) parameters. METHODS: We retrospectively analyzed drug-naïve patients without orthostatic hypotension (n = 61) and controls (n = 20). The patients were subcategorized into early PD (n = 35) and mid-PD (n = 26) groups on the basis of the Hoehn and Yahr staging. VM parameters, including changes in systolic blood pressure at late phase 2 (∆SBPVM2), ∆HRVM3, Valsalva ratio (VR), pressure recovery time, adrenergic baroreflex sensitivity, and vagal baroreflex sensitivity, were assessed. RESULTS: In the early PD group, ∆SBPVM2, a marker of sympathetic function, was significantly lower compared with that in controls (risk ratio = 0.95, P = 0.027). Receiver operating characteristic (ROC) curve analysis showed an optimal cut-off value of -10 mmHg for ∆SBPVM2 [P = 0.002, area under the curve (AUC): 0.737]. VR exhibited an inverse relationship with Unified Parkinson's Disease Rating Scale Part 3 scores in the multivariable regression analysis (VR: P = 0.038, ß = -28.61), whereas age showed a positive relationship (age: P = 0.027, ß = 0.35). CONCLUSION: The ∆BPVM2 parameter of the VM may help detect autonomic nervous system involvement in early-PD without OH. Our results suggest that sympathetic dysfunction is an early manifestation of autonomic dysfunction in patients with PD.

3.
Nutrients ; 16(7)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38613064

RESUMO

Panax ginseng fruit is known to have various biological effects owing to its large amount of saponins such as ginsenosides. In the present study, ginseng berry juice was confirmed to be effective against acute inflammation. Ginseng berry juice was used for analysis of active constituents, antioxidant efficacy, and in vivo inflammation. A high-performance liquid chromatography method was used for analysis of ginsenosides. In an HCl/ethanol-induced acute gastric injury model, microscopic, immunofluorescent, and immunohistochemical techniques were used for analysis of inhibition of gastric injury and mechanism study. In a mouse model of acute gastritis induced with HCl/ethanol, ginseng berry juice (GBJ, 250 mg/kg) showed similar gastric injury inhibitory effects as cabbage water extract (CB, 500 mg/kg, P.O). GBJ dose-dependently modulated the pro-inflammatory cytokines such as Tumor Necrosis Factor-α (TNF-α), Interleukin-6 (IL-6), and Interleukin-13 (IL-13). GBJ inhibited the activation of Nuclear Factor kappa bB (NF-κB) and suppressed the expressions of cyclooxigenase-2 (COX-2) and prostaglandin 2 (PGE2). The anti-inflammatory effect of GBJ is attributed to ginsenosides which have anti-inflammatory effects. Productivity as an effective food source for acute gastritis was analyzed and showed that GBJ was superior to CB. In addition, as a functional food for suppressing acute ulcerative symptoms, it was thought that the efficacy of gastric protection products would be higher if GBJ were produced in the form of juice rather than through various extraction methods.


Assuntos
Gastrite , Ginsenosídeos , Panax , Animais , Camundongos , Frutas , Ginsenosídeos/farmacologia , Inflamação/tratamento farmacológico , Etanol , Anti-Inflamatórios/farmacologia
4.
J Oleo Sci ; 73(4): 437-444, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38556278

RESUMO

Polyhexamethylene guanidine (PHMG) is a guanidine-based chemical that has long been used as an antimicrobial agent. However, recently raised concerns regarding the pulmonary toxicity of PHMG in humans and aquatic organisms have led to research in this area. Along with PHMG, there are concerns about the safety of non-guanidine 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT) in human lungs; however, the safety of such chemicals can be affected by many factors, and it is difficult to rationalize their toxicity. In this study, we investigated the adsorption characteristics of CMIT/ MIT on a model pulmonary surfactant (lung surfactant, LS) using a Langmuir trough attached to a fluorescence microscope. Analysis of the π-A isotherms and lipid raft morphology revealed that CMIT/MIT exhibited minimal adsorption onto the LS monolayer deposited at the air/water interface. Meanwhile, PHMG showed clear signs of adsorption to LS, as manifested by the acceleration of the L o phase growth with increasing surface pressure. Consequently, in the presence of CMIT/MIT, the interfacial properties of the model LS monolayer exhibited significantly fewer changes than PHMG.


Assuntos
Anti-Infecciosos , Desinfetantes , Surfactantes Pulmonares , Humanos , Adsorção , Pulmão , Guanidinas/química , Guanidina
5.
Nano Lett ; 24(12): 3581-3589, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38471119

RESUMO

In this study, we demonstrate the implementation of programmable threshold logics using a 32 × 32 memristor crossbar array. Thanks to forming-free characteristics obtained by the annealing process, its accurate programming characteristics are presented by a 256-level grayscale image. By simultaneous subtraction between weighted sum and threshold values with a differential pair in an opposite way, 3-input and 4-input Boolean logics are implemented in the crossbar without additional reference bias. Also, we verify a full-adder circuit and analyze its fidelity, depending on the device programming accuracy. Lastly, we successfully implement a 4-bit ripple carry adder in the crossbar and achieve reliable operations by read-based logic operations. Compared to stateful logic driven by device switching, a 4-bit ripple carry adder on a memristor crossbar array can perform more reliably in fewer steps thanks to its read-based parallel logic operation.

6.
Heliyon ; 10(5): e26532, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38434311

RESUMO

The industrial manufacturing landscape is currently shifting toward the incorporation of technologies based on artificial intelligence (AI). This transition includes an evolution toward smart factory infrastructure, with a specific focus on AI-driven strategies in production and quality control. Specifically, AI-empowered computer vision has emerged as a potent tool that offers a departure from extant rule-based systems and provides enhanced operational efficiency at manufacturing sites. As the manufacturing sector embraces this new paradigm, the impetus to integrate AI-integrated manufacturing is evident. Within this framework, one salient application is AI deep learning-facilitated small-object detection, which is poised to have extensive implications for diverse industrial applications. This study describes an optimized iteration of the YOLOv5 model, which is known for its efficacious single-stage object-detection abilities underpinned by PyTorch. Our proposed "improved model" incorporates an additional layer to the model's canonical three-layer architecture, augmenting accuracy and computational expediency. Empirical evaluations using semiconductor X-ray imagery reveal the model's superior performance metrics. Given the intricate specifications of surface-mount technologies, which are characterized by a plethora of micro-scale components, our model makes a seminal contribution to real-time, in-line production assessments. Quantitative analyses show that our improved model attained a mean average precision of 0.622, surpassing YOLOv5's 0.349, and a marked accuracy enhancement of 0.865, which is a significant improvement on YOLOv5's 0.552. These findings bolster the model's robustness and potential applicability, particularly in discerning objects at reel granularities during real-time inferencing.

7.
Front Psychol ; 15: 1332464, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38348252

RESUMO

Introduction: Grit, a combination of enduring effort and persistent interest, is key to long-term goals. The training of preservice physical education (PE) teachers is vital for child development, emphasizing the need to assess their resilience and commitment. However, research is limited regarding how grit influences motivation and achievement goals in PE. The purpose of this study was to explore how the grit dimensions of preservice PE teachers impact their motivation and achievement goals, which may subsequently shape their future career intentions of becoming PE teachers. Methods: A total of 279 preservice physical education (PE) teachers (69.5% males; 26.9% PE graduate program) from five South Korean universities participated in the study. They completed validated questionnaires measuring grit, motivation, achievement goal orientations, and career intentions. Descriptive statistics, correlation analysis, and structural equation modeling (SEM) were used to examine variable relationships and test the hypothesis model. Results: Correlation analysis indicated a spectrum of relationships between facets of grit (perseverance of effort and consistency of interests), motivational parameters, and career intention, with both positive and negative correlations ranging from weak to moderate (r ranging from 0.119 to 0.425, p < 0.05-0.01). SEM confirmed the model's goodness-of-fit (χ2/df = 1.928, RMSEA = 0.058, IFI = 0.92, TLI = 0.91, CFI = 0.92). Path analysis showed that both perseverance of effort and consistency of interests significantly influenced motivational mechanisms (ß ranging from -0.34 to 0.57, p < 0.05-0.01), both directly and indirectly, which then notably impacted career intentions (ß = 0.10, p < 0.05). Notably, both grit dimensions significantly impacted mastery approach goals (ß ranging from 0.49 to 0.56, p < 0.01). Mastery approach goals, in turn, had a substantial impact on intrinsic motivation (ß = 0.27, p < 0.01), which subsequently significantly influenced career intentions (ß = 0.32, p < 0.01). Conclusion: The study illuminated the complex relationships between grit dimensions, motivation, achievement goals, and career intentions of future PE teachers. SEM validation confirmed grit's direct and indirect influence on goal orientations and motivation, underscoring the importance of incorporating grit-building strategies alongside mastery approach goals in preservice PE programs to enhance resilience, dedication, and long-term career commitment.

8.
J Plast Reconstr Aesthet Surg ; 91: 6-14, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38401279

RESUMO

PURPOSE: Sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND) can be performed either with a separate axillary incision or through the mastectomy incision. The authors hypothesized that after SLNB or ALND through a single incision, connection of the axilla with mastectomy pocket could increase drainage. This study investigated whether a separate incision decreases drainage amount and duration in implant-based breast reconstruction. METHODS: Medical records of breast cancer patients who underwent nipple-sparing or skin-sparing mastectomy with immediate breast reconstruction with prosthesis from March 2018 to February 2021 in a single tertiary center were reviewed. Demographic data, intraoperative details, and postoperative complications were reviewed. Breast drains were removed if the drain amount was less than 30cc for two consecutive days. Total breast drain amount, duration until removal, and prolonged drainage were compared with multivariate analysis. RESULTS: A total of 206 patients were included in the study, with separate incisions placed in 145 breasts and a single breast incision placed in 70 breasts. Mean duration and amount until drain removal were 12.8 ± 4.9 days and 817 ± 520 cc in the single incision group, respectively, and 9.9 ± 3.1 days and 434 ± 228 cc in the separate incision group, respectively Separate incision placement (p < 0.001), lower mastectomy weight (p < 0.001), and prepectoral plane of insertion (p < 0.001) were significantly associated with less drain amount and duration. None-separate incision placement (p = 0.01) and preoperative radiation therapy (p = 0.023) were significant factors for prolonged drainage. CONCLUSION: Placing a separate incision for axillary surgery during mastectomy and immediate implant-based reconstruction can decrease both drain amount and duration and reduce the risk of prolonged drainage.


Assuntos
Neoplasias da Mama , Mamoplastia , Humanos , Feminino , Mastectomia , Neoplasias da Mama/cirurgia , Neoplasias da Mama/patologia , Axila/cirurgia , Linfonodos/cirurgia , Excisão de Linfonodo , Drenagem , Biópsia de Linfonodo Sentinela , Próteses e Implantes
9.
Eur J Phys Rehabil Med ; 60(2): 233-244, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38332698

RESUMO

BACKGROUND: Appropriate evaluation and management of dysphagia are essential in neurological disorders. However, there is currently a lack of a simple yet reliable method for dysphagia evaluation. AIM: This study aimed to investigate the usefulness of new dynamic M-mode ultrasonography (US) parameters of suprahyoid muscle (SHM) to evaluate dysphagia. DESIGN: Prospective observational, cross-sectional study. SETTING: Inpatient setting at neurology department of tertiary medical center. POPULATION: A total of 89 patients with dysphagia and 175 healthy volunteers were enrolled in the study. Patients were subdivided into mild and severe dysphagia groups depending on the need for dietary changes and disease classification, which included amyotrophic lateral sclerosis, peripheral neuromuscular diseases, and stroke. METHODS: Dynamic M-mode US was performed during swallowing to obtain the SHM thickness (the baseline thickness of the SHM), SHM displacement (peak-to-peak amplitude of SHM movement), SHM difference (SHM displacement - SHM thickness), SHM ratio (SHM displacement/SHM thickness), peak-to-peak time, and total duration. A videofluoroscopic swallowing study (VFSS) was performed. RESULTS: Significant differences were found in SHM displacement and SHM difference according to dysphagia severity (P<0.001). The SHM ratio, total duration (P<0.001), and peak-to-peak time (P=0.001) differed significantly according to the patients' underlying diseases. The pharyngeal delay time and penetration-aspiration scale from the VFSS demonstrated significant negative correlations with SHM displacement and difference (P<0.001). By combining SHM difference and total duration, patients with dysphagia could be distinguished from healthy controls, with the highest negative predictive value of 95.6%. CONCLUSIONS: Dynamic M-mode US of the SHM provided added value in evaluating the severity of dysphagia and differentiating swallowing mechanics of dysphagia related to underlying neurological disorders. CLINICAL REHABILITATION IMPACT: Dynamic M-mode US of the SHM can serve as a supportive tool for rapid screening and repetitive follow-up of patients with dysphagia, which would contribute to dysphagia rehabilitation in patients with various neurological disorders.


Assuntos
Transtornos de Deglutição , Acidente Vascular Cerebral , Humanos , Transtornos de Deglutição/diagnóstico por imagem , Transtornos de Deglutição/etiologia , Estudos Transversais , Deglutição/fisiologia , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia , Músculos
11.
Sci Rep ; 14(1): 1144, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38212426

RESUMO

Water resources in lakes of the Korean Peninsula play a significant role in society and ecosystems in both South and North Korea. This study characterized spatiotemporal changes in the lake area during the dry season (March-May) in the Korean Peninsula over the last 40 years. The satellite images (Landsat 5-9) were used to derive annual areas of 975 lakes during the dry season from 1984 to 2023. Our analysis indicated that the MNDWI is the optimal remote sensing-based index for delineating lake areas in the Korean Peninsula, with an overall accuracy of 92.3%. Based on the selected index, the total lake areas of the dry seasons have increased from 1070.7 km2 in 1984 to 1659.3 km2 in 2023, mainly due to newly constructed dam reservoirs. While the detailed changes in lake area vary, we found divergent results based on their sizes. The large lakes (> 10 km2) showed their area increased by 0.0473 km2 (0.1%) every year and have more influences from climate change. On the contrary, the small lakes (≤ 10 km2) have area decreases by 0.0006-0.006 km2 (0.15-0.5%) every year and have less influence from climate change. This study shows that the spatiotemporal lake area changes are determined by either climate change or human activity.

12.
Nat Nanotechnol ; 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38228805

RESUMO

Perovskite light-emitting diodes (PeLEDs) have emerged as a promising new light source for displays. The development roadmap for commercializing PeLEDs should include a tandem device structure, specifically by stacking a thin nanocrystal PeLED unit and an organic light-emitting diode unit, which can achieve a vivid and efficient tandem display; however, simply combining light-emitting diodes with different characteristics does not guarantee both narrowband emission and high efficiency, as it may cause a broadened electroluminescence spectra and a charge imbalance. Here, by conducting optical simulations of the hybrid tandem (h-tandem) PeLED, we have discovered a crucial optical microcavity structure known as the h-tandem valley, which enables the h-tandem PeLED to emit light with a narrow bandwidth. Specifically, the centre structure of the h-tandem valley (we call it valley-centre tandem) demonstrates near-perfect charge balance and optimal microcavity effects. As a result, the h-tandem PeLED achieves a high external quantum efficiency of 37.0% and high colour purity with a narrow full-width at half-maximum of 27.3 nm (versus 64.5 nm in organic light-emitting diodes) along with a fast on-off response. These findings offer a new strategy to overcome the limitations of nanocrystal-based PeLEDs, providing valuable optical and electrical guidelines for integrating different types of light-emitting device into practical display applications.

13.
Materials (Basel) ; 17(2)2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38255518

RESUMO

This study presents an experimental approach to address sulfur-induced embrittlement in copper alloys. Building on recent theoretical insights, we identified specific solute elements, such as silicon and silver, known for their strong binding affinity with vacancies. Through experimental validation, we demonstrated the effectiveness of Si and Ag in preventing sulfur-induced embrittlement in copper, even though they are not typical sulfide formers such as zirconium. Additionally, our findings highlight the advantages of these elements over traditional solutes, such as their high solubility and propensity to accumulate along grain boundaries. This approach may have the potential to be applied to other metals prone to sulfur-induced embrittlement, including nickel, iron, and cobalt, offering broader implications for materials engineering strategies and alloy development.

14.
ACS Appl Mater Interfaces ; 16(1): 1054-1065, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38163259

RESUMO

We propose a hardware-friendly architecture of a convolutional neural network using a 32 × 32 memristor crossbar array having an overshoot suppression layer. The gradual switching characteristics in both set and reset operations enable the implementation of a 3-bit multilevel operation in a whole array that can be utilized as 16 kernels. Moreover, a binary activation function mapped to the read voltage and ground is introduced to evaluate the result of training with a boundary of 0.5 and its estimated gradient. Additionally, we adopt a fixed kernel method, where inputs are sequentially applied to a crossbar array with a differential memristor pair scheme, reducing unused cell waste. The binary activation has robust characteristics against device state variations, and a neuron circuit is experimentally demonstrated on a customized breadboard. Thanks to the analogue switching characteristics of the memristor device, the accurate vector-matrix multiplication (VMM) operations can be experimentally demonstrated by combining sequential inputs and the weights obtained through tuning operations in the crossbar array. In addition, the feature images extracted by VMM during the hardware inference operations on 100 test samples are classified, and the classification performance by off-chip training is compared with the software results. Finally, inference results depending on the tolerance are statistically verified through several tuning cycles.

15.
Anaesth Crit Care Pain Med ; 43(2): 101337, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38061682

RESUMO

BACKGROUND: General anaesthesia can immobile patients during interventional neuroradiology to improve image quality. Remimazolam, an ultrashort-acting benzodiazepine, is advantageous for haemodynamic stability. This study compared remimazolam and propofol anaesthesia during neuroradiology procedures regarding intraoperative hypotensive events and rapid recovery. METHODS: This single-masked randomised-controlled study included 76 participants who underwent elective endovascular embolisation in a single centre. Patients were randomised between a continuous remimazolam infusion (n = 38) or a target-controlled propofol infusion group (n = 38). In the remimazolam group, flumazenil (0.2 mg) was administered at the end of the procedure. Phenylephrine was titrated to maintain the mean arterial pressure within ± 20% of the baseline value. The primary outcome was the total phenylephrine dose during the procedure. RESULTS: The total phenylephrine dose was 0.0 [0.0-30.0] µg in the remimazolam group and 30.0 [0.0-205.0] µg in the propofol group (p = 0.001). Hypotensive events were observed in 11 (28.9%) patients in the remimazolam group and 23 (60.5%) patients in the propofol group (p = 0.001). Recovery times to spontaneous breathing, eye-opening, extubation, and orientation were shorter in the remimazolam group than in the propofol group (all p < 0.001). CONCLUSIONS: Remimazolam anaesthesia showed superior haemodynamic stability compared with propofol anaesthesia during neuroradiology procedures. Systematic use of flumazenil enabled rapid recovery from remimazolam anaesthesia. REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry; Registration number: UMIN000047384; URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000054046.

16.
Toxins (Basel) ; 15(12)2023 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-38133195

RESUMO

This study was designed to compare the effects of various doses of botulinum neurotoxin A (BoNT/A) on nerve regeneration. Sixty-five six-week-old rats with sciatic nerve injury were randomly allocated to three experimental groups, a control group, and a sham group. The experimental groups received a single session of intraneural BoNT/A (3.5, 7.0, or 14 U/kg) injection immediately after nerve-crushing injury. The control group received normal intraneural saline injections after sciatic nerve injury. At three, six, and nine weeks after nerve damage, immunofluorescence staining, an ELISA, and toluidine blue staining was used to evaluate the regenerated nerves. Serial sciatic functional index analyses and electrophysiological tests were performed every week for nine weeks. A higher expression of GFAP, S100ß, GAP43, NF200, BDNF, and NGF was seen in the 3.5 U/kg and 7.0 U/kg BoNT/A groups. The average area and myelin thickness were significantly greater in the 3.5 U/kg and 7.0 U/kg BoNT/A groups. The sciatic functional index and compound muscle action potential amplitudes exhibited similar trends. These findings indicate that the 3.5 U/kg and 7.0 U/kg BoNT/A groups exhibited better nerve regeneration than the 14 U/kg BoNT/A and control group. As the 3.5 U/kg and the 7.0 U/kg BoNT/A groups exhibited no statistical difference, we recommend using 3.5 U/kg BoNT/A for its cost-effectiveness.


Assuntos
Toxinas Botulínicas Tipo A , Traumatismos dos Nervos Periféricos , Neuropatia Ciática , Ratos , Animais , Toxinas Botulínicas Tipo A/farmacologia , Traumatismos dos Nervos Periféricos/tratamento farmacológico , Traumatismos dos Nervos Periféricos/metabolismo , Regeneração Nervosa , Nervo Isquiático/lesões
17.
ACS Omega ; 8(44): 41548-41557, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37969985

RESUMO

We report on the covalent binding of acetonitrile (CH3CN) on Si{111}-(7 × 7) at ∼300 K studied by scanning tunneling microscopy, thermal desorption spectroscopy, and first-principles theoretical calculations. The site-specific study makes it possible to unravel the site-by-site and step-by-step kinetics. A polarized CH3CN prefers to adsorb on the faulted half more frequently compared to on the unfaulted half. Moreover, a molecular CH3CN adsorbs four-times more preferably on the center adatom-rest atom (CEA-REA) pair than on the corner adatom-rest atom (COA-REA) pair. Such site selectivity, the number ratio of reacted-CEA/reacted-COA, depends on the number of reacted adatoms in the half-unit cell. The site selectivity and the resulting reacted-adatom patterns are understood well by considering a simple model. In this simple model, the molecular adsorption probability changes step-by-step and site-by-site with increasing reacted adatoms. Furthermore, our theoretical calculations are overall consistent with the experimental results. The site-selectivity of the adsorption of CH3CN on Si{111}-(7 × 7) is explained well by the chemical reactivity depending on the local conformation, the local density of states, and the interaction between polarized adsorbates.

18.
ACS Macro Lett ; 12(11): 1558-1563, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37922152

RESUMO

In this study, the effects of zigzag hydrogen bonding and slidable cross-linking on the design of stretchable elastomers were explored. Poly(ether-thiourea) (TU), capable of generating strong zigzag hydrogen bonds without crystallization, was introduced as the main chain in the non-cross-linked region of the developed elastomer. Consequently, the toughness of the TU-based elastomer was 14 times higher than that of elastomers formed using linear poly(ethylene glycol), despite the relatively low molecular weight of TU (∼3k). When a slidable polyrotaxane cross-linker was introduced into the TU-based elastomer, its flexibility became twice as high as that of the rigid polymer cross-linker. Moreover, the mechanical properties of the elastomer were prevented from deterioration against repeated deformation under the limited strain condition of 150%.

19.
Sci Rep ; 13(1): 17371, 2023 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-37833409

RESUMO

Sarcopenia is a progressive loss of muscle mass and strength that is associated with increasing the risk of falls, musculoskeletal diseases, and chronic metabolic diseases. However, the animal models adopted to study sarcopenia face limitations since the functional tests conducted on human cannot be directly adapted to animals because the animals do not follow instructions. Moreover, current preclinical research tools for muscle function assessment, such as the rotarod, grip strength, and treadmill, have limitations, including low-intensity simple movements, evaluator subjectivity, and limited power indicators. Hence, in this study, we present a new jumping-power assessment tool in a preclinical rodent model to demonstrate muscle functions. To overcome the light weight and command issues in the rodent model, we developed an electrical stimulation-assisted jump power assessment device. Precisely, the device utilizes a load cell with a 0.1 g resolution and a 50 points/s data acquisition rate to capture the short period of the mouse jump. Additionally, interdigitated electrodes are used to electrically stimulate the mice and make them jump. While our primary focus in this article is the validation of the newly developed jump power assessment device, it is worth noting that this tool has several potential utilities. These include the phenotypic comparison of sarcopenia models, the exploration of muscle function reduction mechanisms, muscle function-related blood biomarkers, and the evaluation of drug intervention effects.


Assuntos
Doenças Musculares , Sarcopenia , Humanos , Animais , Camundongos , Sarcopenia/patologia , Força Muscular/fisiologia , Músculo Esquelético/patologia , Força da Mão/fisiologia , Doenças Musculares/patologia
20.
Small ; 19(50): e2305005, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37688312

RESUMO

Rationally engineered porous structures enable lightweight broadband electromagnetic (EM) wave absorbers for countering radar signals or mitigating EM interference between multiple components. However, the scalability of such structures has been hindered by their limited mechanical properties resulting from low density. Herein, an additively manufactured Kelvin foam-based EM wave absorber (KF-EMA) is reported that exhibits multifunctionality, namely EM wave absorption and light-weighted load-bearing structures with constant relative stiffness made possible using bending-dominated lattice structures. Based on tuning design parameters, such as the backbone structures and constituent materials, the proposed KF-EMA features a multilayered 3D-printed design with geometrically optimized KF structures made of carbon black-based backbone composites. The developed KF-EMA demonstrated an absorbance greater than 90% at frequencies ranging from 5.8 to 18 GHz (average EM wave absorption rates of 95.89% and maximum of 99.1% at 15.8 GHz), while the low-density structures of the absorber (≈200 kg m-3 ) still maintained a compression index between the stiffness and relative density (n = 2) under compression. The design strategy paves the way for using metamaterials as mechanically reinforced EM wave absorbers that enable multifunctionality by optimizing unit-cell parameters through a single and low-density structure.

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