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1.
Front Neurosci ; 18: 1368754, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39091347

RESUMO

Objective: Recent studies have shown that transcutaneous vagal nerve stimulation (tVNS) holds promise as a treatment for neurological or psychiatric disease through the ability to modulate neural activity in some brain regions without an invasive procedure. The objective of this study was to identify the neural correlates underlying the effects of tVNS. Methods: Twenty right-handed healthy subjects with normal hearing participated in this study. An auricle-applied tVNS device (Soricle, Neurive Co., Ltd., Gyeongsangnam-do, Republic of Korea) was used to administer tVNS stimulation. A session consisted of 14 blocks, including 7 blocks of tVNS stimulation or sham stimulation and 7 blocks of rest, and lasted approximately 7 min (1 block = 30 s). Functional magnetic resonance imaging (fMRI) was performed during the stimulation. Results: No activated regions were observed in the fMRI scans following both sham stimulation and tVNS after the first session. After the second session, tVNS activated two clusters of brain regions in the right frontal gyrus. A comparison of the activated regions after the second session of each stimulation revealed that the fMRI following tVNS exhibited four surviving clusters. Additionally, four clusters were activated in the overall stimulated area during both the first and second sessions. When comparing the fMRI results after each type of stimulation, the fMRI following tVNS showed four surviving clusters compared to the fMRI after sham stimulation. Conclusion: tVNS could stimulate some brain regions, including the fronto-parietal network. Stimulating these regions for treating neurological or psychiatric disease might require applying tVNS for at least 3.5 min.

2.
Sci Rep ; 14(1): 16373, 2024 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-39014109

RESUMO

The relationship between tinnitus and body composition in specific regions has not been extensively investigated. This study aimed to identify associations between tinnitus and body composition. Individuals with data on physical and otological examination findings, and bioelectrical impedance analysis were included from the ninth Korea National Health and Nutritional Examination Survey. They were divided into a tinnitus group and a non-tinnitus group. Participants with tinnitus were further classified into acute or chronic tinnitus group. The tinnitus group showed significantly higher body fat percentages in each region (arms: P = 0.014; legs: P = 0.029; trunk: P = 0.008; whole body: P = 0.010) and waist circumference (P = 0.007) than the non-tinnitus group, and exhibited lower leg muscle percentage (P = 0.038), total body fluid percentage (P = 0.010), and intracellular fluid percentage (P = 0.009) than the non-tinnitus group in men. Furthermore, men with chronic tinnitus showed a significantly higher trunk fat percentage (P = 0.015) and waist circumference (P = 0.043), and lower intracellular fluid percentage (P = 0.042) than their counterparts without tinnitus. No significant differences in body composition were observed among the groups in the female population. In men, body composition may be associated with tinnitus.


Assuntos
Composição Corporal , Zumbido , Humanos , Zumbido/fisiopatologia , Zumbido/epidemiologia , Masculino , Feminino , Estudos Transversais , Pessoa de Meia-Idade , Adulto , República da Coreia/epidemiologia , Circunferência da Cintura , Impedância Elétrica , Idoso , Inquéritos Nutricionais
3.
Clin Otolaryngol ; 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39048535

RESUMO

OBJECTIVES: Tinnitus is one of the irritating symptoms that should be addressed in adolescents. Since tinnitus affects mental health, it is important to treat it. However, identifying the cause of tinnitus is very challenging and the treatment strategies of tinnitus are controversial. The objective of this study was to identify the prevalence of tinnitus in adolescents and systemic diseases as risk factors of adolescent tinnitus to find evidence for new treatment strategies. MATERIALS AND METHODS: We extracted the subjects and data using the 5th Korea National Health and Nutrition Examination Survey from 2010 to 2012. One thousand five hundred ninety-three adolescents with bilateral normal tympanic membranes and availability of the results of physical, laboratory and audiological examinations, were selected. We evaluated their systemic diseases based on these results and assessed the association of tinnitus with demographic factors, systemic diseases and hearing levels. RESULTS: The prevalence of tinnitus in Korean adolescents was 21.7%. The hearing level was not associated with tinnitus. Tinnitus was significantly associated with age (p = 0.005), 25(OH)-D level (p = 0.007) and anaemia (p = 0.003). After controlling the other factors, age (p = 0.045), 25(OH)-D level (p = 0.041) and anaemia (p = 0.019) were independently related to tinnitus. CONCLUSION: Tinnitus in adolescents was significantly associated with age, vitamin D and anaemia. Physicians should consider the higher likelihood of these deficiencies or diseases in adolescent tinnitus patients. Additionally, recognizing these associations may be helpful in developing treatment strategies for adolescent tinnitus.

4.
Laryngoscope ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39016167

RESUMO

OBJECTIVES: Hearing loss causes numerous functional deficits. However, few studies have been conducted to assess the association between hearing loss and physical inactivity. This study aimed to evaluate the physical activity and sedentary behavior of hearing loss patients and their relation with the use of hearing aids. MATERIALS AND METHODS: We extracted participants over 60 years of age with information on hearing status and physical activities from the eighth Korea National Health and Nutritional Examination Survey conducted from 2019 to 2020. We classified them into four groups: a normal hearing group (≤25 dB), a mild hearing loss group (>25 dB and ≤40 dB), a moderate hearing loss group (>40 dB and ≤50 dB), and a non-serviceable hearing group (>50 dB). Additionally, we extracted hearing aid users with hearing levels exceeding 50 dB. RESULTS: After adjusting other factors, the non-serviceable hearing group walked less frequently than the moderate (p = 0.004) and mild hearing loss group (p < 0.001) and walked less and sat more than the normal hearing group (walking frequency: p < 0.001; walking time: p = 0.020; and sitting time: p = 0.034). Also, the hearing aid users walked more frequently (p = 0.003) and for longer (p = 0.045) than the non-serviceable hearing group. CONCLUSION: Hearing loss is associated with reduced walking and a sedentary lifestyle. The use of hearing aids is associated with improved physical activity. Appropriate interventions, including hearing aids, should be provided to hearing loss patients. LEVEL OF EVIDENCE: 3 (individual cross-sectional study) Laryngoscope, 2024.

5.
Sci Rep ; 14(1): 12899, 2024 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-38839853

RESUMO

While volatile organic compounds (VOCs) impair various organs, their influence on hearing loss (HL) has not been extensively researched. We aimed to identify the association between VOCs and HL or high-frequency hearing loss (HFHL). We extracted data on age, sex, pure tone audiometry, hypertension, occupational noise exposure, and creatinine-corrected urine VOC metabolite concentrations from the eighth Korea National Health and Nutrition Survey. Among the VOC metabolites, N-acetyl-S-(benzyl)-L-cysteine (BMA, P = 0.004), N-acetyl-S-(phenyl)-L-cysteine (SPMA, P = 0.027), and N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA, P < 0.001) showed associations with HL. Additionally, HFHL exhibited significant associations with BMA (P = 0.005), 3- and 4-methylhippuric acid (3, 4 MHA, P = 0.049), mandelic acid (MA, P = 0.015), SPMA (P < 0.001), N-acetyl-S-(3-hydroxypropyl)-L-cysteine (3-HPMA, P < 0.001), and DHBMA (P < 0.001). After controlling other factors, DHBMA were associated with HL (P = 0.021) and HFHL (P = 0.014) and exhibited a linear association with the mean hearing level (ß = 0.054, P = 0.024) and high-frequency hearing level (ß = 0.045, P = 0.037). Since 1,3-butadiene may act as an ototoxic material, early screening for workers exposed to 1,3-butadiene and reducing exposure to 1,3-butadiene in everyday life may be helpful to prevent further HL.


Assuntos
Butadienos , Perda Auditiva , Compostos Orgânicos Voláteis , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Perda Auditiva/induzido quimicamente , Perda Auditiva/etiologia , Compostos Orgânicos Voláteis/urina , Compostos Orgânicos Voláteis/efeitos adversos , República da Coreia/epidemiologia , Adulto , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise , Idoso , Inquéritos Nutricionais , Audiometria de Tons Puros
6.
Artigo em Inglês | MEDLINE | ID: mdl-38716771

RESUMO

North Korean (NK) refugee women face unique challenges in their acculturation process in South Korea (SK), often leading to higher rates of depression among them. This study uses the Multidimensional Individual Difference Acculturation (MIDA) model to examine the role of societal and local community factors in facilitating cultural adaptation and influencing mental health issues, such as depression, among NK refugee women. The study focuses on three predictors from the MIDA model: out-group social support, attachment to NK culture, and daily life experience of discrimination. Data from a sample of 212 NK refugee women in SK were analyzed using structural equation modeling. The findings highlight the crucial role of the social and community environment in attaining a balance between embracing a new culture and preserving one's connection to one's heritage culture. This balance is essential for promoting stable cultural adaptation, sound mental health, and overall well-being, so as to reduce the incidence of depression among NK refugee women. Based on the results, specific intervention strategies are proposed to support the acculturation journey of NK refugee women in SK.

7.
Artigo em Inglês | MEDLINE | ID: mdl-38741699

RESUMO

The stiffness of the extracellular matrix induces differential tension within integrin-based adhesions, triggering differential mechanoresponses. However, it has been unclear if the stiffness-dependent differential tension is induced solely by myosin activity. Here, we report that in the absence of myosin contractility, 3T3 fibroblasts still transmit stiffness-dependent differential levels of traction. This myosin-independent differential traction is regulated by polymerizing actin assisted by actin nucleators Arp2/3 and formin where formin has a stronger contribution than Arp2/3 to both traction and actin flow. Intriguingly, despite only slight changes in F-actin flow speed observed in cells with the combined inhibition of Arp2/3 and myosin compared to cells with sole myosin inhibition, they show a 4-times reduction in traction than cells with myosin-only inhibition. Our analyses indicate that traditional models based on rigid F-actin are inadequate for capturing such dramatic force reduction with similar actin flow. Instead, incorporating the F-actin network's viscoelastic properties is crucial. Our new model including the F-actin viscoelasticity reveals that Arp2/3 and formin enhance stiffness sensitivity by mechanically reinforcing the F-actin network, thereby facilitating more effective transmission of flow-induced forces. This model is validated by cell stiffness measurement with atomic force microscopy and experimental observation of model-predicted stiffness-dependent actin flow fluctuation.

8.
Sci Rep ; 14(1): 7509, 2024 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-38553548

RESUMO

Hearing loss affects some nutrient intake. Disabling hearing loss may exacerbate these issues. We aimed to evaluate nutrient intake and assess deficiencies based on functional hearing status. The study included 6907 participants with information on demographic factors, nutrient intake, weight, height, disease status, and hearing level in the eighth Korea National Health and Nutrition Examination Survey, conducted from 2019 to 2021. We categorized the participants into 3 groups based on their functional hearing status: bilateral hearing, unilateral hearing, and disabling hearing loss. The disabling hearing loss group showed lower intake of most major nutrients (P < 0.05), dietary fiber (P < 0.001), and most minerals and vitamins (P < 0.05), with some insufficiencies. The unilateral hearing group showed lower intake only for potassium (P = 0.036) compared to the bilateral hearing group and significantly higher intake of hydration (P = 0.039), dietary fiber (P = 0.039), and calcium (P = 0.009) than the disabling hearing loss group. Nutrient insufficiency in the disabling hearing loss group was more prominent in women, and was partially resolved by using hearing aids. Clinicians and nutritionists should consider undernourishment in these patients, and appropriate interventions for nutrition and hearing aids should be recommended.


Assuntos
Surdez , Auxiliares de Audição , Perda Auditiva , Humanos , Feminino , Inquéritos Nutricionais , Ingestão de Alimentos , Fibras na Dieta , Dieta
9.
Am J Physiol Heart Circ Physiol ; 326(5): H1180-H1192, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38457352

RESUMO

Endothelial cells (ECs) within the vascular system encounter fluid shear stress (FSS). High, laminar FSS promotes vasodilation and anti-inflammatory responses, whereas low or disturbed FSS induces dysfunction and inflammation. However, the adaptation of endothelial cells (ECs) to dynamically changing FSS patterns remains underexplored. Here, by combining traction force microscopy with a custom flow chamber, we examined human umbilical vein endothelial cells adapting their traction during transitions from short-term low shear to long-term high shear stress. We discovered that the initial low FSS elevates the traction by only half of the amount in response to direct high FSS even after flow changes to high FSS. However, in the long term under high FSS, the flow started with low FSS triggers a substantial second rise in traction for over 10 h. In contrast, the flow started directly with high FSS results in a quick traction surge followed by a huge reduction below the baseline traction in <30 min. Importantly, we find that the orientation of traction vectors is steered by initial shear exposure. Using Granger causality analysis, we show that the traction that aligns in the flow direction under direct high FSS functionally causes cell alignment toward the flow direction. However, EC traction that orients perpendicular to the flow that starts with temporary low FSS functionally causes cell orientation perpendicular to the flow. Taken together, our findings elucidate the significant influence of initial short-term low FSS on lasting changes in endothelial traction that induces EC alignment.NEW & NOTEWORTHY In our study, we uncover that preconditioning with low shear stress yields enduring impacts on endothelial cell traction and orientation, persisting even after transitioning to high-shear conditions. Using Granger causality analysis, we demonstrate a functional link between the direction of cell traction and subsequent cellular alignment across varying shear environments.


Assuntos
Células Endoteliais da Veia Umbilical Humana , Estresse Mecânico , Humanos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Cultivadas , Mecanotransdução Celular , Fatores de Tempo , Adesão Celular
10.
J Gerontol Soc Work ; 67(3): 369-385, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38461468

RESUMO

The Senior Meaning in Life Evaluation scale encompasses not only older adults' personal motivation and growth but also the meaning for them in society and in their relationships: With this scale, we aimed to present their voices. A three-phase process was followed: The scale's items were developed empirically from interviews of older adults; exploratory factor analysis (EFA) was conducted to test convergent and concurrent validity; and finally, confirmatory factor analysis (CFA) was performed. EFA resulted in 18 items grouped into 4 factors (i.e., proactive on life, overcoming emptiness, acceptance in life, and social contribution), which was supported by the CFA.


Assuntos
Inquéritos e Questionários , Humanos , Idoso , Análise Fatorial , Psicometria/métodos , Reprodutibilidade dos Testes
11.
Laryngoscope ; 134(7): 3329-3334, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38314940

RESUMO

OBJECTIVES: Renal impairment and some systemic diseases are associated with hearing loss (HL) in adults. However, studies of these relationship in adolescents are rare. The objective of this study was to determine the association between HL and renal or systemic disease in adolescents. METHODS: Subjects were extracted from the 5th Korea National Health and Nutrition Examination Survey from 2011 to 2012. We included adolescents aged 10-19 years old with normal tympanic membrane and those who underwent a physical and laboratory examination and pure tone audiometry. HL, high-frequency hearing loss (HFHL), albuminuria, impaired glomerular filtration rate, hypertension, diabetes, and obesity were evaluated based on the data. RESULTS: Individuals with microalbuminruia (MIA) exhibited higher prevalence of HL (p = 0.003) and HFHL (p = 0.012) than those without MIA. The prevalence of HL and HFHL appeared to increase according to the severity of albuminuria. Additionally, individuals with HL or HFHL showed lower transferrin saturation (TSAT) than individuals without HL (p = 0.002) or HFHL (p = 0.001). And, HFHL was associated with lower ferritin levels (p = 0.017). HL and HFHL were related to MIA (p = 0.004 and p = 0.022, respectively) and TSAT (p = 0.005 and p = 0.011, respectively) after controlling other factors. CONCLUSION: MIA and TSAT level were independently associated with the HL and HFHL. Since MIA can be easily detected by dipstick test and urine analysis, hearing evaluations for individuals with MIA might be helpful to identify hearing impairments earlier in adolescents. LEVEL OF EVIDENCE: 3 (individual cross-sectional study) Laryngoscope, 134:3329-3334, 2024.


Assuntos
Albuminúria , Humanos , Albuminúria/epidemiologia , Albuminúria/etiologia , Adolescente , Masculino , Feminino , Fatores de Risco , Criança , Prevalência , República da Coreia/epidemiologia , Adulto Jovem , Inquéritos Nutricionais , Audiometria de Tons Puros , Perda Auditiva/epidemiologia , Perda Auditiva/etiologia , Anemia Ferropriva/epidemiologia , Anemia Ferropriva/complicações , Estudos Transversais , Taxa de Filtração Glomerular , Perda Auditiva de Alta Frequência/epidemiologia , Perda Auditiva de Alta Frequência/etiologia , Perda Auditiva de Alta Frequência/diagnóstico
12.
Am J Respir Cell Mol Biol ; 70(4): 308-321, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38271699

RESUMO

Alveolar septation increases gas-exchange surface area and requires coordinated cytoskeletal rearrangement in lung fibroblasts (LFs) to balance the demands of contraction and cell migration. We hypothesized that DBN (drebrin), a modulator of the actin cytoskeleton in neuronal dendrites, regulates the remodeling of the LF cytoskeleton. Using mice bearing a transgelin-Cre-targeted deletion of Dbn in pulmonary fibroblasts and pericytes, we examined alterations in alveolar septal outgrowth, LF spreading and migration, and actomyosin function. The alveolar surface area and number of alveoli were reduced, whereas alveolar ducts were enlarged, in mice bearing the dbn deletion (DBNΔ) compared with their littermates bearing only one dbn-Flox allele (control). Cultured DBNΔ LFs were deficient in their responses to substrate rigidity and migrated more slowly. Drebrin was abundant in the actin cortex and lamella, and the actin fiber orientation was less uniform in lamella of DBNΔ LFs, which limited the development of traction forces and altered focal adhesion dynamics. Actin fiber orientation is regulated by contractile NM2 (nonmuscle myosin-2) motors, which help arrange actin stress fibers into thick ventral actin stress fibers. Using fluorescence anisotropy, we observed regional intracellular differences in myosin regulatory light chain phosphorylation in control LFs that were altered by dbn deletion. Using perturbations to induce and then release stalling of NM2 on actin in LFs from both genotypes, we made predictions explaining how DBN interacts with actin and NM2. These studies provide new insight for diseases such as emphysema and pulmonary fibrosis, in which fibroblasts inappropriately respond to mechanical cues in their environment.


Assuntos
Actinas , Neuropeptídeos , Camundongos , Animais , Actinas/metabolismo , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Pulmão/metabolismo , Citoesqueleto de Actina/metabolismo , Cadeias Leves de Miosina/metabolismo
13.
bioRxiv ; 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37790318

RESUMO

Within the vascular system, endothelial cells (ECs) are exposed to fluid shear stress (FSS), a mechanical force exerted by blood flow that is critical for regulating cellular tension and maintaining vascular homeostasis. The way ECs react to FSS varies significantly; while high, laminar FSS supports vasodilation and suppresses inflammation, low or disturbed FSS can lead to endothelial dysfunction and increase the risk of cardiovascular diseases. Yet, the adaptation of ECs to dynamically varying FSS remains poorly understood. This study focuses on the dynamic responses of ECs to brief periods of low FSS, examining its impact on endothelial traction-a measure of cellular tension that plays a crucial role in how endothelial cells respond to mechanical stimuli. By integrating traction force microscopy (TFM) with a custom-built flow chamber, we analyzed how human umbilical vein endothelial cells (HUVECs) adjust their traction in response to shifts from low to high shear stress. We discovered that initial exposure to low FSS prompts a marked increase in traction force, which continues to rise over 10 hours before slowly decreasing. In contrast, immediate exposure to high FSS causes a quick spike in traction followed by a swift reduction, revealing distinct patterns of traction behavior under different shear conditions. Importantly, the direction of traction forces and the resulting cellular alignment under these conditions indicate that the initial shear experience dictates long-term endothelial behavior. Our findings shed light on the critical influence of short-lived low-shear stress experiences in shaping endothelial function, indicating that early exposure to low FSS results in enduring changes in endothelial contractility and alignment, with significant consequences for vascular health and the development of cardiovascular diseases.

14.
Laryngoscope ; 134(5): 2387-2394, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-37987221

RESUMO

OBJECTIVES: Hearing impairment affects social networks and mental health. Hearing aids (HA) can improve these deficits. However, their effects might be affected by various factors such as economic status (ES). This study aimed to identify how ES could moderate the effects of HA on social networks, depressive mood, and cognition. METHODS: A prospective cohort for new HA users was established and classified into two groups based on their ES: a low ES group (LES group) and a medium to high ES group (MHES group). Audiological examination, Lubben social network scale-18 (LSNS-18), Short form of Geriatric Depression Score, Mini-Mental State Examination in the Korean version of the CERAD Assessment Packet, and surveys for satisfaction with HA were conducted before and at six months after wearing HA. RESULTS: Post-HA application LSNS-18 scores were not improved in the LES group whereas they revealed significant improvement in the MHES group (p = 0.003). The LES group showed lower LSNS-18 score (p = 0.020) and its change (p = 0.042) than the MHES group. Additionally, patients with depressive moods in the MHES group showed better improvements than those in the LES group (p = 0.048). The effects of wearing HA on cognition and satisfaction with HA were not significantly different between the two groups. CONCLUSIONS: HA did not improve social relationships and depressive moods in the LES group. Comprehensive and multidirectional support as well as hearing rehabilitation may be important for patients with LES. LEVEL OF EVIDENCE: 3 (Nonrandomized controlled cohort/follow-up study) Laryngoscope, 134:2387-2394, 2024.


Assuntos
Auxiliares de Audição , Humanos , Idoso , Auxiliares de Audição/psicologia , Saúde Mental , Status Econômico , Estudos Prospectivos , Seguimentos , Rede Social
15.
Opt Express ; 31(24): 40166-40178, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-38041323

RESUMO

Integrated microring resonators are well suited for wavelength-filtering applications in optical signal processing, and cascaded microring resonators allow flexible filter design in coupled-resonator optical waveguide (CROW) configurations. However, the implementation of high-order cascaded microring resonators with high extinction ratios (ERs) remains challenging owing to stringent fabrication requirements and the need for precise resonator tunability. We present a fully integrated on-chip second-order CROW filter using silicon photonic microelectromechanical systems (MEMS) to adjust tunable directional couplers and a phase shifter using nanoscale mechanical out-of-plane waveguide displacement. The filter can be fully reconfigured with regard to both the ER and center wavelength. We experimentally demonstrated an ER exceeding 25 dB and continuous wavelength tuning across the full free spectral range of 0.123 nm for single microring resonator, and showed reconfigurability in second-order CROW by tuning the ER and resonant wavelength. The tuning energy for an individual silicon photonic MEMS phase shifter or tunable coupler is less than 22 pJ with sub-microwatt static power consumption, which is far better than conventional integrated phase shifters based on other physical modulation mechanisms.

16.
Opt Lett ; 48(21): 5611-5614, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37910715

RESUMO

We report on a scalable and programmable integrated Mach-Zehnder interferometer (MZI) with a tunable free spectral range (FSR) and extinction ratio (ER). For the tunable path of the MZI, we designed and utilized a tunable delay line having high flexibility based on silicon photonic microelectromechanical systems (MEMS). By utilizing MEMS, the length of the delay line can be geometrically modified. In this way, there is no optical loss penalty other than the waveguide propagation loss as the number of tunable steps increases. Therefore, our device is more scalable in terms of optical loss than the previous approaches based on cascaded MZIs. In addition, the tuning energy required to reconfigure the length is only 8.46 pJ.

17.
Mol Biol Cell ; 34(12): ar115, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37672339

RESUMO

Directional cell migration is driven by the conversion of oscillating edge motion into lasting periods of leading edge protrusion. Actin polymerization against the membrane and adhesions control edge motion, but the exact mechanisms that determine protrusion period remain elusive. We addressed this by developing a computational model in which polymerization of actin filaments against a deformable membrane and variable adhesion dynamics support edge motion. Consistent with previous reports, our model showed that actin polymerization and adhesion lifetime power protrusion velocity. However, increasing adhesion lifetime decreased the protrusion period. Measurements of adhesion lifetime and edge motion in migrating cells confirmed that adhesion lifetime is associated with and promotes protrusion velocity, but decreased duration. Our model showed that adhesions' control of protrusion persistence originates from the Brownian ratchet mechanism for actin filament polymerization. With longer adhesion lifetime or increased-adhesion density, the proportion of actin filaments tethered to the substrate increased, maintaining filaments against the cell membrane. The reduced filament-membrane distance generated pushing force for high edge velocity, but limited further polymerization needed for protrusion duration. We propose a mechanism for cell edge protrusion in which adhesion strength regulates actin filament polymerization to control the periods of leading edge protrusion.


Assuntos
Actinas , Modelos Biológicos , Actinas/metabolismo , Movimento Celular/fisiologia , Citoesqueleto de Actina/metabolismo , Pseudópodes/metabolismo
18.
Phys Rev Lett ; 130(7): 073802, 2023 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-36867813

RESUMO

Finding a reliable Ising machine for solving nondeterministic polynomial-class problems has attracted great attention in recent years, where an authentic system can be expanded with polynomial-scaled resources to find the ground state Ising Hamiltonian. In this Letter, we propose an extremely low power optomechanical coherent Ising machine based on a new enhanced symmetry breaking mechanism and highly nonlinear mechanical Kerr effect. The mechanical movement of an optomechanical actuator induced by the optical gradient force greatly increases the nonlinearity by a few orders and significantly reduces the power threshold using conventional structures capable of fabrication via photonic integrated circuit platforms. With the simple but strong bifurcation mechanism and remarkably low power requirement, our optomechanical spin model opens a path for chip-scale integration of large-size Ising machine implementations with great stability.

19.
Eur Arch Otorhinolaryngol ; 280(6): 2841-2848, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36656426

RESUMO

PURPOSE: To check the change in growth-for-age after adenotonsillectomy in pre-pubertal children and investigate the affecting factors. METHODS: Two hundred and six pediatric patients who underwent adenotonsillectomy by a single surgeon between January 2011 and December 2014 were included for the retrospective cohort study. The z-scores of height-, weight-, and body mass index (BMI)-for-age were measured before adenotonsillectomy and 1 year after the operation. The Korean version of the obstructive sleep apnea-18 questionnaire (OSA-18), symptom questionnaire, physical examinations, demographic data, and pre-operative z-scores were used to analyze the factors affecting z-score change. RESULTS: Among 206 pediatric patients, 167 patients were normal growth; 19 were undergrowth; and 20 were obese. After the operation, height, weight, and BMI z-scores all increased both in 167 normal-growth patients and 19 undergrowth patients (p value < 0.05). However, in 20 obese patients, only height z-score significantly increased (p value = 0.028). The multiple regression test showed that the sleep disturbance domain of OSA-18 was positively correlated with height z-score change (p value = 0.041), and age was negatively correlated with weight z-score change (p value = 0.016). Pre-operative BMI z-score was negatively correlated (p value = 0.019) and adenoid grade was positively correlated (p value = 0.023) with BMI z-score change. CONCLUSIONS: These findings suggest that adenotonsillectomy may positively affect growth in pre-pubertal children, without undesirable weight gain. Additionally, the sleep disturbance domain of OSA-18 may play a role in predicting post-operative height increase in pre-pubertal children.


Assuntos
Apneia Obstrutiva do Sono , Tonsilectomia , Criança , Humanos , Estudos Retrospectivos , Resultado do Tratamento , Adenoidectomia , Tonsilectomia/efeitos adversos , Obesidade , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/cirurgia
20.
Acta Biomater ; 163: 302-311, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-34781024

RESUMO

Measuring the traction forces produced by cells provides insight into their behavior and physiological function. Here, we developed a technique (dubbed 'black dots') that microcontact prints a fluorescent micropattern onto a flexible substrate to measure cellular traction forces without constraining cell shape or needing to detach the cells. To demonstrate our technique, we assessed human platelets, which can generate a large range of forces within a population. We find platelets that exert more force have more spread area, are more circular, and have more uniformly distributed F-actin filaments. As a result of the high yield of data obtainable by this technique, we were able to evaluate multivariate mixed effects models with interaction terms and conduct a clustering analysis to identify clusters within our data. These statistical techniques demonstrated a complex relationship between spread area, circularity, F-actin dispersion, and platelet force, including cooperative effects that significantly associate with platelet traction forces. STATEMENT OF SIGNIFICANCE: Cells produce contractile forces during division, migration, or wound healing. Measuring cellular forces provides insight into their health, behavior, and function. We developed a technique that calculates cellular forces by seeding cells onto a pattern and quantifying how much each cell displaces the pattern. This technique is capable of measuring hundreds of cells without needing to detach them. Using this technique to evaluate human platelets, we find that platelets exerting more force tend to have more spread area, are more circular in shape, and have more uniformly distributed cytoskeletal filaments. Due to our high yield of data, we were able to apply statistical techniques that revealed combinatorial effects between these factors.


Assuntos
Plaquetas , Tração , Humanos , Microscopia de Força Atômica , Fenômenos Mecânicos , Actinas , Adesão Celular/fisiologia
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