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1.
BMJ Open Respir Res ; 7(1)2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33023899

RESUMO

Patients with COVID-19 often need therapeutic interventions that are considered high aerosol-generating procedures. These are either being performed by healthcare providers with potentially inadequate personal protective equipment or the procedures are being delayed until patients clear their viral load. Both scenarios are suboptimal. We present a simple, cost-effective method of creating a portable negative pressure environment using equipment that is found in most hospitals to better protect healthcare providers and to facilitate more timely care for patients with COVID-19.


Assuntos
Betacoronavirus , Infecções por Coronavirus/prevenção & controle , Exposição Ocupacional/prevenção & controle , Salas Cirúrgicas/métodos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Campos Cirúrgicos , Aerossóis , Humanos , Pressão , Sucção
2.
Am J Vet Res ; 81(10): 827-831, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32969730

RESUMO

OBJECTIVE: To compare initial leak pressure (ILP) between cadaveric canine and synthetic small intestinal segments that did and did not undergo enterotomy. SAMPLE: Eight 8-cm grossly normal jejunal segments from 1 canine cadaver and eight 8-cm synthetic small intestinal segments. PROCEDURES: Intestinal segments were randomly assigned to undergo enterotomy (6 cadaveric and 6 synthetic segments) or serve as untreated controls (2 cadaveric and 2 synthetic segments). For segments designated for enterotomy, a 2-cm full-thickness incision was created along the antimesenteric border. The incision was closed in a single layer with 4-0 suture in a simple continuous pattern. Leak testing was performed with intestinal segments occluded at both ends and infused with dilute dye solution (999 mL/h) until the solution was observed leaking from the suture line or serosal tearing occurred. Intraluminal pressure was continuously monitored. The ILP at construct failure was compared between cadaveric and synthetic control segments and between cadaveric and synthetic enterotomy segments. RESULTS: Mean ± SD ILP did not differ significantly between cadaveric (345.11 ± 2.15 mm Hg) and synthetic (329.04 ± 24.69 mm Hg) control segments but was significantly greater for cadaveric enterotomy segments (60.77 ± 15.81 mm Hg), compared with synthetic enterotomy segments (15.03 ± 6.41 mm Hg). CONCLUSIONS AND CLINICAL RELEVANCE: Leak testing should not be used to assess the accuracy or security of enterotomy suture lines in synthetic intestinal tissue. Synthetic intestinal tissue is best used for students to gain confidence and proficiency in performing enterotomies before performing the procedure on live animals.


Assuntos
Procedimentos Cirúrgicos do Sistema Digestório/veterinária , Doenças do Cão , Anastomose Cirúrgica/veterinária , Animais , Cadáver , Cães , Pressão , Técnicas de Sutura/veterinária , Suturas
3.
Pediatrics ; 146(4)2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32994176

RESUMO

A healthy Hispanic boy was born via cesarean delivery after an uncomplicated pregnancy. At 4 weeks old , his parents brought him to the emergency department for bruising on both soles of the feet. At 6 weeks old, his parents brought him to primary care for new bruises on his arms and back. After evaluation, primary care referred the patient to the emergency department. The parents denied any recent trauma, fever, cough, decreased urine, or change in appetite. Because of 2 episodes of unexplained bruising, the Department of Children and Families was granted emergency custody of the child. Hematology and ophthalmology did not identify any clear abnormalities. Skeletal surveys were normal. Dermatology was consulted. The examination was normal except for pink blanching patches on the upper back and linearly arranged pink blanching papules on the right lower leg. No crusting, erosions, hyperpigmentation, purpura, petechiae, or ecchymoses were seen. These lesions completely resolved the next day. He tested positive for dermatographism and developed similar lesions on his soles after pushing his feet down onto a soft surface. The intermittent urticarial skin changes were most consistent with physical urticaria. Such lesions could be mistaken for trauma; however, blood vessel damage typically results in progressive coloration changes for >1 day. At the emergency court hearing, given the concurring medical opinions of the dermatologist, pediatrician, and Child Protective Services, the judge returned full custody to the parents. This case reveals the value of dermatologic expertise in assessing skin changes, particularly those associated with physical abuse.


Assuntos
Pressão/efeitos adversos , Urticária/diagnóstico , Serviços de Proteção Infantil , Dermatologia , Diagnóstico Diferencial , Humanos , Lactente , Masculino , Abuso Físico , Encaminhamento e Consulta
4.
PLoS One ; 15(8): e0230224, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764766

RESUMO

The term "oral frailty" reflects the fact that oral health is associated with physical frailty and mortality. The gold standard methods for evaluating the swallowing function have several problems, including the need for specialized equipment, the risk of radiation exposure and aspiration, and general physicians not possessing the requisite training to perform the examination. Hence, several simple and non-invasive techniques have been developed for evaluating swallowing function, such as those for measuring tongue pressure and tongue thickness. The aim of this study was to investigate the relationship between tongue thickness ultrasonography and tongue pressure in the Japanese elderly. We evaluated 254 elderly patients, who underwent tongue ultrasonography and tongue pressure measurement. To determine tongue thickness, we measured the vertical distance from the surface of the mylohyoid muscle to the tongue dorsum using ultrasonography. The results of the analyses revealed that tongue thickness was linearly associated with tongue pressure in both sexes. In male participants, dyslipidemia, lower leg circumference, and tongue pressure were independently and significantly associated with tongue thickness. In female participants, body mass index and tongue pressure were independently and significantly associated with tongue thickness. The optimal cutoff for tongue thickness to predict the tongue pressure of < 20 kPa was 41.3 mm in males, and 39.3 mm in females. In the Japanese elderly, tongue thickness using ultrasonography is associated with tongue pressure. Tongue thickness and tongue pressure, which are sensitive markers for oral frailty, decrease with age. We conclude that tongue ultrasonography provides a less invasive technique for determining tongue thickness and predicts oral frailty for elderly patients.


Assuntos
Deglutição/fisiologia , Língua/fisiologia , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Feminino , Fragilidade , Humanos , Japão , Masculino , Força Muscular/fisiologia , Saúde Bucal , Pressão , Ultrassonografia/métodos
5.
Plast Reconstr Surg ; 146(2): 309-320, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32740581

RESUMO

BACKGROUND: Adipose-derived stem cells are considered as candidate cells for regenerative plastic surgery. Measures to influence cellular properties and thereby direct their regenerative potential remain elusive. Hyperbaric oxygen therapy-the exposure to 100% oxygen at an increased atmospheric pressure-has been propagated as a noninvasive treatment for a multitude of indications and presents a potential option to condition cells for tissue-engineering purposes. The present study evaluates the effect of hyperbaric oxygen therapy on human adipose-derived stem cells. METHODS: Human adipose-derived stem cells from healthy donors were treated with hyperbaric oxygen therapy at 2 and 3 atm. Viability before and after each hyperbaric oxygen therapy, proliferation, expression of surface markers and protein contents of transforming growth factor (TGF)-ß, tumor necrosis factor-α, hepatocyte growth factor, and epithelial growth factor in the supernatants of treated adipose-derived stem cells were measured. Lastly, adipogenic, osteogenic, and chondrogenic differentiation with and without use of differentiation-inducing media (i.e., autodifferentiation) was examined. RESULTS: Hyperbaric oxygen therapy with 3 atm increased viability, proliferation, and CD34 expression and reduced the CD31/CD34/CD45 adipose-derived stem cell subset and endothelial progenitor cell population. TGF-ß levels were significantly decreased after two hyperbaric oxygen therapy sessions in the 2-atm group and decreased after three hyperbaric oxygen therapy sessions in the 3-atm group. Hepatocyte growth factor secretion remained unaltered in all groups. Although the osteogenic and chondrogenic differentiation were not influenced, adipogenic differentiation and autodifferentiation were significantly enhanced, with osteogenic autodifferentiation significantly alleviated by hyperbaric oxygen therapy with 3 atm. CONCLUSION: Hyperbaric oxygen therapy with 3 atm increases viability and proliferation of adipose-derived stem cells, alters marker expression and subpopulations, decreases TGF-ß secretion, and skews adipose-derived stem cells toward adipogenic differentiation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.


Assuntos
Adipogenia/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Engenharia Celular/métodos , Células-Tronco Mesenquimais/efeitos dos fármacos , Oxigênio/administração & dosagem , Tecido Adiposo/citologia , Adulto , Biomarcadores/metabolismo , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citocinas/metabolismo , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Masculino , Células-Tronco Mesenquimais/fisiologia , Pessoa de Meia-Idade , Pressão , Cultura Primária de Células/métodos
6.
J Chromatogr A ; 1626: 461279, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797811

RESUMO

We report on a comparative study of the basic separation kinetics of commercial packed bed columns and a micro-pillar array column (µPAC) working in the 1-10µL/min flow rate range, i.e., operating in the area of capillary flow LC. This is done using a basic test mixture of 8 alkylphenones under both isocratic and gradient separation conditions. Care was taken the µPAC and the packed bed columns have similar volumes (around 10µL) and hence also similar t0-times when compared at the same flow rate. In addition, the isocratic mobile phase composition and gradient programs were selected such to have similar elution windows (in absolute times) for all 4 column types. It was found that the µPAC produces significantly more theoretical plates (up to 3 times) in the 1-4µL/min range, while, the packed bed columns perform better at the higher flow rates because of the relatively large inter-pillar distance in the µPAC. Under gradient conditions, the µPAC produces a clearly higher peak capacity than any of the three packed bed columns over the entire range of investigated flow rates, albeit that this is also partly to be owed to the steeper gradient that needed to be used in the µPAC in order to maintain a similar elution window on all columns.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cinética , Pressão
7.
Neurocrit Care ; 33(2): 597-603, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32770341

RESUMO

BACKGROUND: Many COVID-19 patients with neurological manifestations and respiratory failure remain dependent on mechanical ventilation and require tracheostomy, which is an aerosol generating procedure (AGP). The risk of SARS-CoV-2 transmission to healthcare staff during AGPs is well documented, and negative-pressure rooms are often unavailable. Innovative techniques to decrease risk to healthcare providers during AGPs are necessary. Our objective was to demonstrate the feasibility of percutaneous dilatational tracheostomy (PDT) performed using a novel prefabricated low-cost negative-pressure tent (AerosolVE). METHODS: Retrospective review of consecutive PDT procedures performed by neurointensivists on intubated adult patients with COVID-19 using the AerosolVE tent during the pandemic under an innovative clinical care protocol. The AerosolVE negative-pressure tent consists of a clear plastic canopy with slits for hand access attached to a U-shaped base with air vents. Air within the tent is drawn through a high-efficiency particulate air filter and released outside. Preliminary testing during simulated AGPs demonstrated negligible escape of particulate matter beyond the tent. The main outcome measure was successful completion of PDT and bronchoscopy within the AerosolVE tent, without complications. RESULTS: The patients were a 53-year-old man with multifocal ischemic stroke and acute respiratory distress syndrome (ARDS), 53-year-old woman with cerebellar hemorrhage and ARDS, and a 69-year-old man with ARDS. Pre-procedure FiO2 requirement was 40-50% and positive end-expiratory pressure (PEEP) 8-12 cm H2O. The tent was successfully positioned around the patient and PDT completed with real-time ultrasound guidance in all 3 patients. Bronchoscopy was performed to confirm tube position and perform pulmonary toilet. No complications occurred. CONCLUSIONS: It is feasible to perform PDT on intubated COVID-19 patients using the AerosolVE negative-pressure tent. This is a promising low-cost device to decrease risk to healthcare providers during AGPs.


Assuntos
Betacoronavirus , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/transmissão , Equipamentos de Proteção , Traqueostomia/instrumentação , Idoso , Infecções por Coronavirus/diagnóstico , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia Viral/diagnóstico , Pressão
8.
PLoS One ; 15(8): e0237382, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817709

RESUMO

BACKGROUND: Pes planus (flatfoot) is a common deformity characterized by the midfoot arch collapses during walking. As the midfoot is responsible for shock absorption, persons with flatfoot experience increased risk of injuries such as thumb valgus, tendinitis, plantar fasciitis, metatarsal pain, knee pain, lower-back pain with prolonged uphill, downhill, and level walking, depriving them of the physical and mental health benefits of walking as an exercise. METHODS: Fifteen female college students with flatfoot were recruited. A wireless plantar-pressure system was used to measure the stance time, cadence, plantar pressure, and contact area. Parameters were compared between wearing flat and arch-support insoles using a two-way repeated measures ANOVA with on an incline, decline, and level surface, respectively. The significance level α was set to 0.05. The effect size (ES) was calculated as a measure of the practical relevance of the significance using Cohen's d. RESULTS: On the level surface, the stance time in the arch-support insole was significantly shorter than in the flat insole (p<0.05; ES = 0.48). The peak pressure of the big toe in the arch-support insole was significantly greater than in the flat insole on the uphill (p<0.05; ES = 0.53) and level surfaces (p<0.05; ES = 0.71). The peak pressure of the metatarsals 2-4 and the contact area of the midfoot in the arch-support insole were significantly greater than in the flat insole on all surfaces (all p< 0.05). CONCLUSIONS: These results imply that wearing an arch-support insole provides benefits in the shortened stance time and generation of propulsion force to the big toe while walking on uphill and level surfaces and to the metatarsals 2-4 while walking on the level surface. More evenly distributed contact areas across the midfoot may help absorb shock during uphill, downhill and level walking.


Assuntos
Pé Chato/fisiopatologia , Órtoses do Pé , Fenômenos Mecânicos , Pressão , Adulto , Desenho de Equipamento , Feminino , Humanos , Fatores de Tempo , Caminhada
9.
PLoS One ; 15(8): e0237836, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841245

RESUMO

Lake Kivu, East Africa, is well known for its huge reservoir of dissolved methane (CH4) and carbon dioxide (CO2) in the stratified deep waters (below 250 m). The methane concentrations of up to ~ 20 mmol/l are sufficiently high for commercial gas extraction and power production. In view of the projected extraction capacity of up to several hundred MW in the next decades, reliable and accurate gas measurement techniques are required to closely monitor the evolution of gas concentrations. For this purpose, an intercomparison campaign for dissolved gas measurements was planned and conducted in March 2018. The applied measurement techniques included on-site mass spectrometry of continuously pumped sample water, gas chromatography of in-situ filled gas bags, an in-situ membrane inlet laser spectrometer sensor and a prototype sensor for total dissolved gas pressure (TDGP). We present the results of three datasets for CH4, two for CO2 and one for TDGP. The resulting methane profiles show a good agreement within a range of around 5-10% in the deep water. We also observe that TDGP measurements in the deep waters are systematically around 5 to 10% lower than TDGP computed from gas concentrations. Part of this difference may be attributed to the non-trivial conversion of concentration to partial pressure in gas-rich Lake Kivu. When comparing our data to past measurements, we cannot verify the previously suggested increase in methane concentrations since 1974. We therefore conclude that the methane and carbon dioxide concentrations in Lake Kivu are currently close to a steady state.


Assuntos
Gases/análise , Lagos/química , África Oriental , Dióxido de Carbono/análise , Metano/análise , Pressão , Risco
10.
PLoS One ; 15(8): e0237090, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764796

RESUMO

Plantar pressure force data derived from gait and posture are commonly used as health indicators for foot diagnosis, injury prevention, and rehabilitation. This study developed a wearable plantar pressure force measurement and analysis (WPPFMA) system based on a flexible sensor matrix film to monitor plantar pressure force in real time. The developed system comprised a flexible sensor matrix film embedded in the insole of the shoe, a wearable data acquisition (DAQ) device with a Bluetooth module, and dedicated software with an intuitive graphical user interface for displaying the plantar pressure force data from receivers by using a terminal unit (laptop or smart-phone). The flexible sensor matrix film integrated 16 piezoresistive cell sensors to detect pressure force at different anatomical zones of the plantar and under different body positions. The signals from the flexible sensor matrix film were collected using the DAQ module embedded in the shoe and transmitted to the receivers through Bluetooth. The real-time display and analysis software can monitor, visualize, and record the detailed plantar pressure force data, such as average pressure force, maximum pressure force, and pressure force distributions and variations over time. The outcomes of the trials in which the system was worn revealed the applicability of the developed WPPFMA system for monitoring plantar pressure force under static and dynamic wearing conditions. The plantar pressure force data derived from this system provide valuable insights for personal foot care, gait analysis, and clinical diagnosis.


Assuntos
Doenças do Pé/diagnóstico , Pé/fisiologia , Análise da Marcha/instrumentação , Monitorização Fisiológica/instrumentação , Dispositivos Eletrônicos Vestíveis , Fenômenos Biomecânicos , Estudos de Viabilidade , Doenças do Pé/fisiopatologia , Humanos , Postura/fisiologia , Pressão , Sapatos , Smartphone , Software
11.
PLoS One ; 15(8): e0237246, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776952

RESUMO

Postural control provides insight into health concerns such as fall risk but remains relatively untapped as a vital sign of health. One understudied aspect of postural control involves transient responses within center of pressure (CoP) data to events such as vision occlusion. Such responses are masked by common whole-trial analyses. We hypothesized that the transient behavior of postural control would yield unique and clinically-relevant information for quiet stance compared to traditionally calculated whole-trial CoP estimates. Three experiments were conducted to test different aspects of this central hypothesis. To test whether transient, epoch-based characteristics of CoP estimates provide different information than traditional whole-trial estimates, we investigated correlations between these estimates for a population of young adults performing three 60-second trials of quiet stance with eyes closed. Next, to test if transient behavior is a result of sensory reweighting after eye closure, we compared transient characteristics between eyes closed and eyes open conditions. Finally, to test if there was an effect of age on transient behavior, we compared transient characteristics during eyes closed stance between populations of young and older adults. Negligible correlations were found between transient characteristics and whole-trial estimates (p>0.08), demonstrating limited overlap in information between them. Additionally, transient behavior was exaggerated during eyes closed stance relative to eyes open (p<0.044). Lastly, we found that transient characteristics were able to distinguish between younger and older adults, supporting their clinical relevance (p<0.029). An epoch-based approach captured unique and potentially clinically-relevant postural control information compared to whole-trial estimates. While longer trials may improve the reliability of whole-trial estimates, including a complementary assessment of the initial transient characteristics may provide a more comprehensive characterization of postural control.


Assuntos
Envelhecimento , Equilíbrio Postural , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pressão , Visão Ocular , Adulto Jovem
12.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 34(8): 1036-1040, 2020 Aug 15.
Artigo em Chinês | MEDLINE | ID: mdl-32794675

RESUMO

At present, the 2019-nCoV epidemic situation is in severe and complex period. In order to prevent the virus from invading and infecting, it is very important and urgent for medical personnel to protect themselves. However, in the process of using protective equipment by medical personnel, the performance of device related pressure injuries (DRPI) caused by pain, numbness, redness, and even breakage caused by the equipment has seriously endangered the health of medical personnel. This article, based on Prevention and Treatment of Pressure Ulcers/Injuries: Quick Reference Guide 2019, references, and clinical experiences of wound specialists in West China Hospital of Sichuan University, summarize the preventive and protective measures of West China Hospital for medical personnel to prevent DRPI, so as to provide clinical preventive measurements for medical personnel.


Assuntos
Infecções por Coronavirus/epidemiologia , Falha de Equipamento , Equipamento de Proteção Individual/efeitos adversos , Pneumonia Viral/epidemiologia , Ferimentos e Lesões/prevenção & controle , Betacoronavirus , China , Pessoal de Saúde , Humanos , Pandemias , Pressão
13.
J Chromatogr A ; 1625: 461267, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709320

RESUMO

We describe the design and performance evaluation of a portable gas chromatograph suitable for the analysis of volatile organic and odorous compounds at trace levels. The system comprises a carbon nanotube sponge preconcentrator, an electronic pressure control (EPC) unit, a temperature-programmable column module, and a fast-response photoionization detector. A built-in tablet computer controls instrumental parameters and chromatogram display functions. The compact GC with dimensions of 35 cm (l) × 26 cm (w) × 15 cm (h) is self-contained, weighing less than 5 kg without a battery pack, and uses no auxiliary compressed gases. Our design has three main advantages over conventional portable GCs: recharging configuration of ambient air as the carrier gas using a miniature diaphragm pump, precise control of column flow by the built-in canister and EPC system, and rapid thermal desorption of the preconcentrator facilitated by intrinsic resistivity of the carbon nanotube sponge. A 30 m, 0.28 mm I.D. capillary column operated at a head pressure of 14 psi provided a peak capacity of 55 for a 10 min isothermal analysis. The temperature-programmability feature could decrease the analysis time of less than 5 min for vapor mixture of benzene, toluene, ethylbenzene, and o-xylene. More than a 100-fold increase in sensitivity by preconcentrating a sample adsorption volume of 90 mL resulted in improved detection limits of 0.13 (benzene), 0.20 (toluene), 0.23 (ethylbenzene), and 0.28 (o-xylene) ppb (v/v). Our instrument displayed good stability and reproducibility of retention times (< 0.14% RSD) and intensities (< 4.5% RSD) for continuous measurements using the preconcentrator over 10 h. Thus, continuous and on-site determinations of trace volatile organic compounds in air samples with this instrument appear feasible.


Assuntos
Poluentes Atmosféricos/análise , Cromatografia Gasosa/métodos , Sistemas Computacionais , Hidrocarbonetos Aromáticos/análise , Compostos Orgânicos Voláteis/análise , Calibragem , Gases/análise , Limite de Detecção , Nanotubos de Carbono/química , Odorantes/análise , Pressão , Reprodutibilidade dos Testes , Temperatura , Fatores de Tempo
15.
J Laryngol Otol ; 134(8): 735-738, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32718361

RESUMO

BACKGROUND: Coronavirus disease 2019 is an international pandemic. One of the cardinal features is acute respiratory distress syndrome, and proning has been identified as beneficial for a subset of patients. However, proning is associated with pressure-related side effects, including injury to the nose and face. METHOD: This paper describes a pressure-relieving technique using surgical scrub sponges. This technique was derived based on previous methods used in patients following rhinectomy. CONCLUSION: The increased use of prone ventilation has resulted in a number of referrals to the ENT team with concerns regarding nasal pressure damage. The described technique, which is straightforward and uses readily available materials, has proven effective in relieving pressure in a small number of patients.


Assuntos
Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pressão/efeitos adversos , Decúbito Ventral/fisiologia , Respiração Artificial/métodos , Tampões de Gaze Cirúrgicos/normas , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Infecções por Coronavirus/virologia , Desenho de Equipamento/métodos , Traumatismos Faciais/prevenção & controle , Humanos , Nariz/lesões , Nariz/cirurgia , Posicionamento do Paciente/métodos , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , Pneumonia Viral/virologia
16.
PLoS One ; 15(7): e0233988, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32615583

RESUMO

Light touch with an earth-fixed reference point improves balance during quite standing. In our current study, we implemented a paradigm to assess the effects of disrupting the right posterior parietal cortex on dynamic stabilization of body sway with and without Light Touch after a graded, unpredictable mechanical perturbation. We hypothesized that the benefit of Light Touch would be amplified in the more dynamic context of an external perturbation, reducing body sway and muscle activations before, at and after a perturbation. Furthermore, we expected sway stabilization would be impaired following disruption of the right Posterior Parietal Cortex as a result of increased postural stiffness. Thirteen young adults stood blindfolded in Tandem-Romberg stance on a force plate and were required either to keep light fingertip contact to an earth-fixed reference point or to stand without fingertip contact. During every trial, a robotic arm pushed a participant's right shoulder in medio-lateral direction. The testing consisted of 4 blocks before TMS stimulation and 8 blocks after, which alternated between Light Touch and No Touch conditions. In summary, we found a strong effect of Light Touch, which resulted in improved stability following a perturbation. Light Touch decreased the immediate sway response, steady state sway following re-stabilization, as well as muscle activity of the Tibialis Anterior. Furthermore, we saw gradual decrease of muscle activity over time, which indicates an adaptive process following exposure to repetitive trials of perturbations. We were not able to confirm our hypothesis that disruption of the rPPC leads to increased postural stiffness. However, after disruption of the rPPC, muscle activity of the Tibialis Anterior is decreased more compared to sham. We conclude that rPPC disruption enhanced the intra-session adaptation to the disturbing effects of the perturbation.


Assuntos
Lobo Parietal/fisiologia , Equilíbrio Postural/fisiologia , Tato/fisiologia , Adulto , Mapeamento Encefálico , Retroalimentação Sensorial , Feminino , Humanos , Masculino , Contração Muscular , Neuronavegação , Pressão , Estresse Mecânico , Estimulação Magnética Transcraniana , Adulto Jovem
17.
J Chromatogr A ; 1625: 461286, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709336

RESUMO

In the past two decades, supercritical fluid chromatography has evolved from a niche application to a comprehensive technology and a fully-fledged alternative to conventional high-performance liquid chromatography. In this study, we have focused on chiral separation of synthetic cathinones in gradient supercritical fluid chromatography coupled to mass spectrometry using an inverse gradient of a make-up solvent. Synthetic cathinones possess an amphetamine-like effect and, therefore, are frequently being offered on the Internet as a replacement for illicit drugs. Cathinones are chiral compounds, however, they are usually marketed and used as racemic mixtures. Since the effect of individual enantiomers can significantly vary, there is a need for the development of enantioseparation methods enabling to study the biological effects of individual enantiomers. Since cathinones are basic molecules, they are easily protonated (positively charged) under weakly acidic mobile phase conditions, which is a typical feature of supercritical mobile phases with an alcohol as an organic modifier. The positively charged species represent ideal analytes for ion exchangers, such as chiral zwitterion ion exchangers Chiralpak ZWIX (+) and Chiralpak ZWIX (-), which possess a positively and negatively charged unit in the molecular structure of the selectors. The presence of the positive charge in the selector's structure, functioning as a counter-ion for the positively charged analytes, significantly reduces the required amount of a buffer, which is plausible for hyphenation of such a separation system with mass spectrometry. For mass spectrometry hyphenated to supercritical fluid chromatography, the use of a make-up solvent is required to avoid analyte precipitation when using a low concentration of an organic co-solvent (modifier) in the super-/subcritical mobile phase. Hereby, we introduce a unique approach, which is based on the gradient introduction of the make-up to the post-column effluent. Using this approach, it is possible to keep constant the overall amount of the organic solvent (modifier and make-up) introduced into the mass spectrometer when using a gradient of the organic modifier. We show that the developed gradient elution method facilitates the chiral separation of all employed analytes, while the mobile-phase gradient compensation by the inverse make-up gradient enables their detection with high signal intensities.


Assuntos
Alcaloides/química , Alcaloides/isolamento & purificação , Cromatografia com Fluido Supercrítico/métodos , Espectrometria de Massas/métodos , Reologia , Solventes/química , Alcaloides/síntese química , Cromatografia Líquida de Alta Pressão , Pressão , Estereoisomerismo , Temperatura
18.
J Chromatogr A ; 1625: 461117, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709364

RESUMO

To obtain consistent chromatographic behavior, it is important to develop resin packing methods in accordance with the characteristics of each resin. Resins, particularly those with a significant level of compressibility, require proper knowledge of the packing methodology to ensure scalable performance. The study demonstrates the applicability of pressure-flow modeling based on the Blake-Kozeny equation for cellulose based resins, using the MEP HyperCel (Pall) resin as a case study. This approach enabled the understanding of the appropriate bed compressibility and the determination of the minimum column diameter that can predict bed integrity during commercial manufacturing scale operation. Studies suggested that scale-dependent wall effects become negligible for column diameters exceeding 20 cm. Pressure-flow modeling produced a minimum compression recommendation of 0.206 for the MEP HyperCel resin. Columns with diameters up to 80 cm packed with this bed compression yielded incompressible beds with pressure-flow curves consistent with model predictions. Model parameter (particle diameter, viscosity, porosity) values were then varied to demonstrate how changing operating conditions influence model predictions. This analysis supported the successful troubleshooting of unexpected high pressures at the commercial manufacturing scale using MEP HyperCel resin, further supporting the applicability of this approach.


Assuntos
Produtos Biológicos/isolamento & purificação , Cromatografia Líquida/métodos , Anticorpos Monoclonais/isolamento & purificação , Géis/química , Porosidade , Pressão , Viscosidade
19.
J Chromatogr A ; 1625: 461299, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709342

RESUMO

The work describes a novel supercritical fluid chromatography method for the separation of four stereoisomers, RZ(+), SZ(-), RE(+) and SE(-) of luliconazole, an antifungal agent on amylose tris[(S)-α-methylbenzyl carbamate] based Chiralpak IH column. The effect of organic modifiers (methanol, ethanol and isopropanol), column temperature and back pressure were evaluated for their selective separation. A consistent elution order, RZ(+) > SZ(-) > RE(+) > SE(-) was observed in all the modifiers. Amongst the three modifiers, the best result in terms of selectivity, resolution and analysis time was obtained with isopropanol. Analytical separation (Rs > 1.5) of RZ(+) and SZ(-) & RE(+) and SE(-) pairs was achieved with a mobile phase consisting of CO2: isopropanol (80: 20, v/v) within 5.0 min. The retention of isomers increased with increase in temperature and decreased with increase in pressure, which was more prominent for RE(+) and SE(-) isomers. The van't Hoff plots revealed that the chiral separation process was essentially entropy driven. Molecular docking was performed to understand the type of chiral recognition between the stereoisomers and the chiral stationary phase and to understand their elution orders under optimized conditions. The results suggested hydrogen bonding and π-π interactions, as the dominant interaction modes. The elution order and binding energy of the interactions were in good agreement with the experimental results. Quantitative studies of RE(+) luliconazole the pharmacologically active isomer was also performed using a marketed formulation.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Imidazóis/química , Imidazóis/isolamento & purificação , Simulação de Acoplamento Molecular , Entropia , Ligação de Hidrogênio , Fenilcarbamatos/química , Pressão , Reprodutibilidade dos Testes , Estereoisomerismo , Termodinâmica
20.
PLoS One ; 15(7): e0235314, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645051

RESUMO

OBJECTIVES: 1) Determine the effects of old age on sensorimotor responses to a fatiguing work-like task. 2) Explore how old age influences the relationships between task fatigability, everyday perceptions of fatigability, and sensorimotor function. METHODS: Healthy young (N = 17, 9W) and older (N = 13, 10W) adults completed the Pittsburgh Fatigability Scale to assess everyday perceptions of physical (PF) and mental fatigability and performed a repetitive tapping task to fatigue. Before and after the task, grip strength was assessed using a hand-grip dynamometer and touch-pressure sensitivity was measured (shoulder, hand) using Semmes-Weinstein monofilaments. RESULTS: Older, but not young adults, had increased touch-pressure sensitivity at the shoulder after fatigue (interaction, p = 0.007). No changes in grip strength were observed (p>0.05). Task fatigability was not different between young and old adults (p>0.05). Having less task fatigability was associated with lower PF, higher grip strength, and higher touch-pressure sensitivity at the hand (ρ = 0.37-0.58, p<0.05), with the hand sensation association also observed in the old adult subgroup (ρ = 0.56, p = 0.046). CONCLUSIONS: With old age, there were fatigue-related alterations to sensory but not physical function. While task fatigability was associated with perceptual, physical, and sensory features, sensory features appear to have a more important role with old age.


Assuntos
Envelhecimento/fisiologia , Fadiga/fisiopatologia , Atividade Motora/fisiologia , Extremidade Superior/fisiopatologia , Adulto , Feminino , Humanos , Masculino , Fadiga Mental/fisiopatologia , Pessoa de Meia-Idade , Percepção , Pressão , Estatísticas não Paramétricas , Análise e Desempenho de Tarefas , Tato/fisiologia , Adulto Jovem
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