Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 104
Filtrar
1.
Int J Oral Maxillofac Surg ; 53(8): 672-676, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38556432

RESUMO

Bizarre parosteal osteochondromatous proliferations (BPOPs) are distinct clinical-pathological entities that demonstrate combinations of atypical-appearing osseous and chondromatous tissues. These lesions are usually reactive in nature. Histopathologically, 'bizarre' cartilage is a characteristic feature of this lesion. BPOPs usually represent slow-growing painless bony hard protuberances that arise from the surface of affected bone cortices, typically the metacarpals, metatarsals, and phalanges. The occurrence of these lesions in the skull and jaws is sporadic. This case report highlights the clinical presentation, histopathological characteristics, and management of BPOP arising from the supraorbital rim in a 61-year-old female patient.


Assuntos
Osteocondroma , Humanos , Feminino , Pessoa de Meia-Idade , Osteocondroma/patologia , Osteocondroma/diagnóstico por imagem , Osteocondroma/cirurgia , Diagnóstico Diferencial , Osso Temporal/patologia , Osso Temporal/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Neoplasias Ósseas/patologia , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/cirurgia , Biópsia
2.
Rev Gastroenterol Mex (Engl Ed) ; 89(1): 25-30, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-36707393

RESUMO

INTRODUCTION AND AIM: Thiopurine-related leukopenia is associated with polymorphisms in the thiopurine methyltransferase (TPMT) and nucleoside diphosphate-linked moiety X type motif 15 (NUDT15) genes. However, those polymorphisms explain only a fraction of thiopurine-related leukopenia. Our aim was to study the role of an inosine triphosphate pyrophosphatase (ITPA) polymorphism in patients with inflammatory bowel disease (IBD) and thiopurine-related leukopenia that was unexplained by the TPMT and NUDT15 polymorphisms. MATERIAL AND METHODS: We enrolled consecutive IBD patients on thiopurines (azathioprine or 6-mercaptopurine) from January 2019-March 2020, at a tertiary care center in North India. The presence of the ITPA (C.94C > A) polymorphism was evaluated in all patients, along with its association with thiopurine-related leukopenia. RESULTS: Of the 33 patients (from a total of 119 patients) that developed leukopenia, 8 had the TPMT (n = 1) or NUDT15 (n = 7) polymorphism. Of the remaining 111 patients, their mean age was 36.36 ±â€¯13.54 years and 57 (51.3%) were males. Twenty-five (21.01%) had unexplained leukopenia. The ITPA polymorphism was detected in 4 (16%) patients in the unexplained leukopenia group and 24 (27.9%) patients in the non-leukopenia group (p = 0.228). The odds ratio for predicting leukopenia with the ITPA polymorphism was 0.4921 (95% CI 0.1520-1.5830, p = 0.234). CONCLUSION: The ITPA (C.94C > A) polymorphism was frequently detected in the study population but was not predictive for leukopenia in patients with IBD on thiopurine therapy.

3.
AJNR Am J Neuroradiol ; 44(3): 236-246, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36657945

RESUMO

PET with amino acid tracers provides additional insight beyond MR imaging into the biology of gliomas that can be used for initial diagnosis, delineation of tumor margins, planning of surgical and radiation therapy, assessment of residual tumor, and evaluation of posttreatment response. Hybrid PET MR imaging allows the simultaneous acquisition of various PET and MR imaging parameters in a single investigation with reduced scanning time and improved anatomic localization. This review aimed to provide neuroradiologists with a concise overview of the various amino acid tracers and a practical understanding of the clinical applications of amino acid PET MR imaging in glioma management. Future perspectives in newer advances, novel radiotracers, radiomics, and cost-effectiveness are also outlined.


Assuntos
Neoplasias Encefálicas , Glioma , Humanos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/patologia , Aminoácidos , Glioma/diagnóstico por imagem , Glioma/terapia , Glioma/patologia , Tomografia por Emissão de Pósitrons/métodos , Imageamento por Ressonância Magnética/métodos
4.
Clin Radiol ; 77(8): 613-620, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35589431

RESUMO

AIM: To investigate if the pattern of fluorine-18-labelled sodium fluoride (18F-NaF) uptake on integrated positron-emission tomography (PET)/magnetic resonance imaging (MRI) of bone marrow lesions (BML) and osteophytes differs between different knee compartments. MATERIALS AND METHODS: Sixteen patients with no prior history of knee injury with or without pain were recruited for the study. The images of both knees were acquired on simultaneous PET/MRI. The acquisition was done after 45 minutes of intravenous injection of 18F-NaF 185-370 MBq (5-10 mCi) for 40 minutes. Each knee was divided into eight compartments patella, trochlea, medial central femur, lateral central femur, medial posterior femur, lateral posterior femur, medial tibia, lateral tibia, and cruciate ligament insertion specifically for BML. BML and osteophytes were scored using MRI Osteoarthritis Knee Score (MOAKS) criteria and their corresponding maximum standardised uptake values (SUVmax) recorded. RESULTS: BML and osteophytes both showed statistically significant differences among knee compartments, i.e., p-value <0.000 and < 0.043 respectively. SUVmax for BML and osteophytes was greatest in the medial tibia. CONCLUSION: 18F-NaF PET/MRI showed that BML and osteophytes had differential uptake values due to bone remodelling amongst the various knee compartments and this may help to design disease-modifying osteoarthritis drugs in the future.


Assuntos
Doenças Ósseas , Osteoartrite do Joelho , Osteófito , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/patologia , Imageamento por Ressonância Magnética/métodos , Osteoartrite do Joelho/diagnóstico por imagem , Osteófito/patologia , Tomografia por Emissão de Pósitrons/métodos , Fluoreto de Sódio
6.
Plants (Basel) ; 10(9)2021 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-34579374

RESUMO

Climate extremes are becoming more frequent with global climate change and have the potential to cause major ecological regime shifts. Along the northern Gulf of Mexico, a coastal wetland in Texas suffered sudden vegetation dieback following an extreme precipitation and flooding event associated with Hurricane Harvey in 2017. Historical salt marsh dieback events have been linked to climate extremes, such as extreme drought. However, to our knowledge, this is the first example of extreme precipitation and flooding leading to mass mortality of the salt marsh foundation species, Spartina alterniflora. Here, we investigated the relationships between baseline climate conditions, extreme climate conditions, and large-scale plant mortality to provide an indicator of ecosystem vulnerability to extreme precipitation events. We identified plant zonal boundaries along an elevation gradient with plant species tolerant of hypersaline conditions, including succulents and graminoids, at higher elevations, and flood-tolerant species, including S. alterniflora, at lower elevations. We quantified a flooding threshold for wetland collapse under baseline conditions characterized by incremental increases in flooding (i.e., sea level rise). We proposed that the sudden widespread dieback of S. alterniflora following Hurricane Harvey was the result of extreme precipitation and flooding that exceeded this threshold for S. alterniflora survival. Indeed, S. alterniflora dieback occurred at elevations above the wetland collapse threshold, illustrating a heightened vulnerability to flooding that could not be predicted from baseline climate conditions. Moreover, the spatial pattern of vegetation dieback indicated that underlying stressors may have also increased susceptibility to dieback in some S. alterniflora marshes.Collectively, our results highlight a new mechanism of sudden vegetation dieback in S. alterniflora marshes that is triggered by extreme precipitation and flooding. Furthermore, this work emphasizes the importance of considering interactions between multiple abiotic and biotic stressors that can lead to shifts in tolerance thresholds and incorporating climate extremes into climate vulnerability assessments to accurately characterize future climate threats.

8.
Proc Natl Acad Sci U S A ; 118(15)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33827929

RESUMO

We previously determined that several diets used to rear Aedes aegypti and other mosquito species support the development of larvae with a gut microbiota but do not support the development of axenic larvae. In contrast, axenic larvae have been shown to develop when fed other diets. To understand the mechanisms underlying this dichotomy, we developed a defined diet that could be manipulated in concert with microbiota composition and environmental conditions. Initial studies showed that axenic larvae could not grow under standard rearing conditions (27 °C, 16-h light: 8-h dark photoperiod) when fed a defined diet but could develop when maintained in darkness. Downstream assays identified riboflavin decay to lumichrome as the key factor that prevented axenic larvae from growing under standard conditions, while gut community members like Escherichia coli rescued development by being able to synthesize riboflavin. Earlier results showed that conventional and gnotobiotic but not axenic larvae exhibit midgut hypoxia under standard rearing conditions, which correlated with activation of several pathways with essential growth functions. In this study, axenic larvae in darkness also exhibited midgut hypoxia and activation of growth signaling but rapidly shifted to midgut normoxia and arrested growth in light, which indicated that gut hypoxia was not due to aerobic respiration by the gut microbiota but did depend on riboflavin that only resident microbes could provide under standard conditions. Overall, our results identify riboflavin provisioning as an essential function for the gut microbiota under most conditions A. aegypti larvae experience in the laboratory and field.


Assuntos
Aedes/crescimento & desenvolvimento , Microbioma Gastrointestinal , Riboflavina/biossíntese , Aedes/microbiologia , Animais , Escherichia coli/metabolismo , Escherichia coli/patogenicidade
9.
J Stomatol Oral Maxillofac Surg ; 122(3): 319-324, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32911101

RESUMO

Distraction osteogenesis is a popular treatment modality to lengthen the mandible. It is commonly performed in wide varieties of craniofacial syndromes, temporomandibular joint (TMJ) ankylosis, and obstructive sleep apnea cases requiring a significant amount of mandibular lengthening. There are many complications associated with mandibular distraction osteogenesis procedure and the breakage of the distractor is very rare. There are few reports in the literature mentioning the breakage of a distractor. This article highlights an up-to-date knowledge of the etiology and prevention of mandibular distractor breakage and a case report which was managed well after bilateral internal mandibular distractor breakage. This is the first case report describing the spontaneous bilateral mandibular distractor breakage during the active phase of distraction osteogenesis.


Assuntos
Anquilose , Micrognatismo , Osteogênese por Distração , Transtornos da Articulação Temporomandibular , Humanos , Mandíbula/cirurgia , Osteogênese por Distração/efeitos adversos , Transtornos da Articulação Temporomandibular/diagnóstico , Transtornos da Articulação Temporomandibular/etiologia , Transtornos da Articulação Temporomandibular/cirurgia
10.
Indian Heart J ; 72(6): 477-481, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33357634

RESUMO

AIM: Ensuring adherence to guideline-directed medical therapy (GDMT) is an effective strategy to reduce mortality and readmission rates for heart failure (HF). Use of a checklist is one of the best tools to ensure GDMT. The aim was to develop a consensus document with a robust checklist for stabilized acute decompensated HF patients with reduced ejection fraction. While there are multiple checklists available, an India-specific checklist that is easy to fill and validated by regional and national subject matter experts (SMEs) is required. METHODOLOGY: A total of 25 Cardiology SMEs who consented to participate from India discussed data from literature, current evidence, international guidelines and practical experiences in two national and four regional meetings. RESULTS: Recommendations included HF management, treatment optimization, and patient education. The checklist should be filled at four time points- (a) transition from intensive care unit to ward, (b) at discharge, (c) 1st follow-up and (d) subsequent follow-up. The checklist is the responsibility of the consultant or the treating physician which can be delegated to a junior resident or a trained HF nurse. CONCLUSION: This checklist will ensure GDMT, simplify transition of care and can be used by all doctors across India. Institutions, associations, and societies should recommend this checklist for adaptability in public and private hospital. Hospital administrations should roll out policy for adoption of checklist by ensuring patient files have the checklist at the time of discharge and encourage practice of filling it diligently during follow-up visits.


Assuntos
Consenso , Gerenciamento Clínico , Insuficiência Cardíaca/terapia , Volume Sistólico/fisiologia , Doença Aguda , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Incidência , Índia/epidemiologia , Readmissão do Paciente/tendências
11.
J Sep Sci ; 43(7): 1256-1264, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32012437

RESUMO

Process streams of agro-food industries are often large and viscous. In order to fractionate such a stream the viscosity can be reduced by either a high temperature or dilution, the former is not an option in case of temperature sensitive components. Such streams are diluted prior to chromatographic fractionation, resulting in even larger volumes and high energy costs for sub-sequential water removal. The influence of feed viscosity on the performance of simulated moving bed chromatography has been investigated in a case study of the recovery of a γ-aminobutyric acid rich fraction from tomato serum. This work addresses the chromatographic system design, evaluates results from a pilot scale operation, and uses these to calculate the productivity and water use at elevated feed concentration. At the two higher feed viscosities (2.5 and 4 mPa·s) water use is lower and productivity higher, compared to the lowest feed viscosity (1 mPa·s). The behavior of the sugars for different feed viscosities can be described well by the model using the ratio of feed to eluent as dilution factor. The behavior of γ-aminobutyric acid is highly concentration dependent and the recovery could not be accurately predicted.


Assuntos
Solanum lycopersicum/química , Ácido gama-Aminobutírico/isolamento & purificação , Viscosidade , Ácido gama-Aminobutírico/química
12.
Ann Bot ; 125(2): 365-376, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-31532484

RESUMO

BACKGROUND AND AIMS: Coastal wetlands have evolved to withstand stressful abiotic conditions through the maintenance of hydrologic feedbacks between vegetation production and flooding. However, disruption of these feedbacks can lead to ecosystem collapse, or a regime shift from vegetated wetland to open water. To prevent the loss of critical coastal wetland habitat, we must improve understanding of the abiotic-biotic linkages among flooding and wetland stability. The aim of this research was to identify characteristic landscape patterns and thresholds of wetland degradation that can be used to identify areas of vulnerability, reduce flooding threats and improve habitat quality. METHODS: We measured local- and landscape-scale responses of coastal wetland vegetation to flooding stress in healthy and degrading coastal wetlands. We hypothesized that conversion of Spartina patens wetlands to open water could be defined by a distinct change in landscape configuration pattern, and that this change would occur at a discrete elevation threshold. KEY RESULTS: Despite similarities in total land and water cover, we observed differences in the landscape configuration of vegetated and open water pixels in healthy and degrading wetlands. Healthy wetlands were more aggregated, and degrading wetlands were more fragmented. Generally, greater aggregation was associated with higher wetland elevation and better drainage, compared with fragmented wetlands, which had lower elevation and poor drainage. The relationship between vegetation cover and elevation was non-linear, and the conversion from vegetated wetland to open water occurred beyond an elevation threshold of hydrologic stress. CONCLUSIONS: The elevation threshold defined a transition zone where healthy, aggregated, wetland converted to a degrading, fragmented, wetland beyond an elevation threshold of 0.09 m [1988 North American Vertical Datum (NAVD88)] [0.27 m mean sea level (MSL)], and complete conversion to open water occurred beyond 0.03 m NAVD88 (0.21 m MSL). This work illustrates that changes in landscape configuration can be used as an indicator of wetland loss. Furthermore, in conjunction with specific elevation thresholds, these data can inform restoration and conservation planning to maximize wetland stability in anticipation of flooding threats.


Assuntos
Ecossistema , Áreas Alagadas , Conservação dos Recursos Naturais , Poaceae
13.
J Chromatogr A ; 1613: 460688, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-31813564

RESUMO

Diffusion inside pores is the rate limiting step in many preparative chromatographic separations and a key parameter for process design in weak interaction aqueous chromatographic separations employed in food and bio processing. This work aims at relating diffusion inside porous networks to properties of stationary phase and of diffusing molecules. Intraparticle diffusivities were determined for eight small molecules in nine different stationary phases made from three different backbone materials. Measured intraparticle diffusivities were compared to the predictive capability of the correlation by Mackie and Meares and the parallel pore model. All stationary phases were analyzed for their porosity, apparent pore size distribution and tortuosity, which are input parameters for the models. The parallel pore model provides understanding of the occurring phenomena, but the input parameters were difficult to determine experimentally. The model predictions of intraparticle diffusion were of limited accuracy. We show that prediction can be improved when combining the model of Mackie and Meares with the fraction of accessible pore volume. The accessible pore volume fraction can be determined from inverse size exclusion chromatographic measurements. Future work should further challenge the improved model, specifically widening the applicability to greater accessible pore fractions (> 0.7) with corresponding higher intraparticle diffusivities (Dp/Dm  > 0.2). A database of intraparticle diffusion and stationary phase pore property measurements is supplied, to contribute to general understanding of the relationship between intraparticle diffusion and pore properties.


Assuntos
Cromatografia em Gel , Difusão , Modelos Químicos , Porosidade
14.
Phys Chem Chem Phys ; 21(28): 15854-15860, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31282515

RESUMO

Multiferroic Y-doped BiFeO3 (BY10FO) thin films were deposited on FTO coated glass substrate using sol-gel spin coating technique. Y-doping causes structural distortion without changing the structure of the parent BiFeO3 (rhombohedral: R3c). The M-H hysteresis curve reveals that the BY10FO film exhibits saturation magnetization at a low-coercive field by suppressing the spiral spin modulated structure. The bipolar resistive switching behavior has been investigated on a Ag/BY10FO/FTO hetero-structure through conventional I-V curve measurements and the device can produce an ON/OFF ratio of around 12 over 30 complete testing cycles. The space charge limited current and Schottky barrier emission conduction mechanism play a crucial role in switching the states between HRS and LRS. The impedance spectroscopy analysis at HRS and LRS confirms the significant degradation of resistance from MΩ to kΩ. The switching mechanism in the hetero-structure is due to migration and recombination of oxygen vacancies present in the film. The non-degradation of the Ag/BY10FO/FTO device after several testing cycles confirms that the switching of resistance between ON and OFF states is reproducible, reversible and controllable to be used for possible future non-volatile resistive random access memory application.

16.
PLoS One ; 12(9): e0183431, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28902904

RESUMO

Coastal wetland responses to sea-level rise are greatly influenced by biogeomorphic processes that affect wetland surface elevation. Small changes in elevation relative to sea level can lead to comparatively large changes in ecosystem structure, function, and stability. The surface elevation table-marker horizon (SET-MH) approach is being used globally to quantify the relative contributions of processes affecting wetland elevation change. Historically, SET-MH measurements have been obtained at local scales to address site-specific research questions. However, in the face of accelerated sea-level rise, there is an increasing need for elevation change network data that can be incorporated into regional ecological models and vulnerability assessments. In particular, there is a need for long-term, high-temporal resolution data that are strategically distributed across ecologically-relevant abiotic gradients. Here, we quantify the distribution of SET-MH stations along the northern Gulf of Mexico coast (USA) across political boundaries (states), wetland habitats, and ecologically-relevant abiotic gradients (i.e., gradients in temperature, precipitation, elevation, and relative sea-level rise). Our analyses identify areas with high SET-MH station densities as well as areas with notable gaps. Salt marshes, intermediate elevations, and colder areas with high rainfall have a high number of stations, while salt flat ecosystems, certain elevation zones, the mangrove-marsh ecotone, and hypersaline coastal areas with low rainfall have fewer stations. Due to rapid rates of wetland loss and relative sea-level rise, the state of Louisiana has the most extensive SET-MH station network in the region, and we provide several recent examples where data from Louisiana's network have been used to assess and compare wetland vulnerability to sea-level rise. Our findings represent the first attempt to examine spatial gaps in SET-MH coverage across abiotic gradients. Our analyses can be used to transform a broadly disseminated and unplanned collection of SET-MH stations into a coordinated and strategic regional network. This regional network would provide data for predicting and preparing for the responses of coastal wetlands to accelerated sea-level rise and other aspects of global change.


Assuntos
Mudança Climática , Ecossistema , Monitoramento Ambiental/normas , Água do Mar , Áreas Alagadas , Alabama , Monitoramento Ambiental/métodos , Florida , Golfo do México , Serviços de Informação/organização & administração , Serviços de Informação/normas , Louisiana , Mississippi , Projetos de Pesquisa/normas , Estudos de Amostragem , Texas
17.
AJNR Am J Neuroradiol ; 38(5): 899-907, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28341716

RESUMO

BACKGROUND AND PURPOSE: Differentiating glioma recurrence from treatment-induced necrosis can be a challenge on conventional imaging. This study aimed to assess the diagnostic performance of each functional MR imaging and PET parameter derived by using simultaneous FDG-PET/MR imaging individually and in combination in the evaluation of suspected glioma recurrence. MATERIALS AND METHODS: Thirty-five treated glioma patients with 41 enhancing lesions (World Health Organization grade II = 9, III = 13, IV = 19) on MR imaging after an operation followed by radiation therapy and/or chemotherapy formed part of this study. Using PET/MR imaging, we calculated the normalized mean relative CBV, mean ADC, Cho/Cr, and maximum and mean target-to-background ratios. Statistical analysis was performed to determine the diagnostic performance of each parameter by receiver operating characteristic analysis individually and in combination with multivariate receiver operating characteristic analysis for the detection of glioma recurrence. Histopathology or clinicoradiologic follow-up was considered the criterion standard. RESULTS: Of 35 patients, 25 (30 lesions) were classified as having a recurrence and 10 (11 lesions) patients as having treatment-induced necrosis. Parameters like rCBVmean (mean relative CBV), ADCmean, Cho/Cr, and maximum and mean target-to-background ratios were statistically significant in the detection of recurrent lesions with an accuracy of 77.5%, 78.0%, 90.9%, 87.8%, and 87.8%, respectively. On multivariate receiver operating characteristic analysis, the combination of all 3 MR imaging parameters resulted in an area under the curve of 0.913 ± 0.053. Furthermore, an area under the curve of 0.935 ± 0.046 was obtained when MR imaging parameters (ADCmean and Cho/Cr) were combined with the PET parameter (mean target-to-background ratio), demonstrating an increase in diagnostic accuracy. CONCLUSIONS: Simultaneous PET/MR imaging with FDG offers correlative and synergistic multiparametric assessment of glioma recurrence with increased accuracy and clinical utility.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Glioma/diagnóstico por imagem , Imagem Multimodal/métodos , Necrose/diagnóstico por imagem , Recidiva Local de Neoplasia/diagnóstico por imagem , Neuroimagem/métodos , Adulto , Idoso , Neoplasias Encefálicas/patologia , Diagnóstico Diferencial , Feminino , Fluordesoxiglucose F18 , Glioma/patologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Tomografia por Emissão de Pósitrons/métodos , Curva ROC , Estudos Retrospectivos
18.
J Chromatogr A ; 1493: 49-56, 2017 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-28318565

RESUMO

In industrial liquid separation processes chromatography often has a key function in the optimization of yield and purity. For the design of an industrial system, chromatographic processes are generally simulated using mathematical models, tested and optimized at laboratory level, and then scaled up to pilot and subsequently industrial scale. To describe the system, experimental data and model data need to be fitted and extra column contribution must be determined. This paper describes the influence of extra-column volume on overall separation efficiency for lab scale and its impact on the design of large scale systems. Measurement of extra-column contribution was investigated in terms of mean retention time and variance using two different methods the commonly used zero dead volume connector and as an alternative the zero length column. Further a technique is presented to estimate extra-column contribution to band broadening for different injection volumes, velocities, and tracers based on representative measurements. When scaling up, often contribution of extra-column volume from laboratory equipment is neglected assuming to be on the safe side, however column efficiency is often lower than efficiency measured for the entire chromatographic system. Relation between system efficiency and column efficiency was investigated using laboratory data and the lumped kinetic model. Depending on the ratio of extra-column volume to retention volume in the system, deduced column efficiency was up to 20% smaller than overall system efficiency. This ratio revealed the misleading nature of the term efficiency loss, when describing influence of extra-column volume on column efficiency. A scheme, which relates the relative variance of the system to the relative extra-column volume, provided an assessment of under- or overestimation of column efficiency. In this article it is shown how scaling up a system based on laboratory data, where extra-column volume contribution is not accounted for, may severely overestimate column efficiency. This overestimation results in underestimated column dimensions at pilot and industrial scale, and hence underperformance of the industrial system.


Assuntos
Cromatografia Líquida/instrumentação , Cromatografia Líquida/métodos , Modelos Teóricos , Cinética
19.
Obesity (Silver Spring) ; 25(2): 317-322, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28124502

RESUMO

OBJECTIVE: Weight stigma is a chronic stressor that may increase cardiometabolic risk. Some individuals with obesity self-stigmatize (i.e., weight bias internalization, WBI). No study to date has examined whether WBI is associated with metabolic syndrome. METHODS: Blood pressure, waist circumference, and fasting glucose, triglycerides, and high-density lipoprotein cholesterol were measured at baseline in 178 adults with obesity enrolled in a weight-loss trial. Medication use for hypertension, dyslipidemia, and prediabetes was included in criteria for metabolic syndrome. One hundred fifty-nine participants (88.1% female, 67.3% black, mean BMI = 41.1 kg/m2 ) completed the Weight Bias Internalization Scale and Patient Health Questionnaire (PHQ-9, to assess depressive symptoms). Odds ratios and partial correlations were calculated adjusting for demographics, BMI, and PHQ-9 scores. RESULTS: Fifty-one participants (32.1%) met criteria for metabolic syndrome. Odds of meeting criteria for metabolic syndrome were greater among participants with higher WBI, but not when controlling for all covariates (OR = 1.46, 95% CI = 1.00-2.13, P = 0.052). Higher WBI predicted greater odds of having high triglycerides (OR = 1.88, 95% CI = 1.14-3.09, P = 0.043). Analyzed categorically, high (vs. low) WBI predicted greater odds of metabolic syndrome and high triglycerides (Ps < 0.05). CONCLUSIONS: Individuals with obesity who self-stigmatize may have heightened cardiometabolic risk. Biological and behavioral pathways linking WBI and metabolic syndrome require further exploration.


Assuntos
Síndrome Metabólica , Obesidade/psicologia , Obesidade/terapia , Aceitação pelo Paciente de Cuidados de Saúde , Autoimagem , Estigma Social , Adulto , Idoso , Peso Corporal , Feminino , Humanos , Masculino , Síndrome Metabólica/sangue , Pessoa de Meia-Idade , Fatores de Risco , Inquéritos e Questionários , Circunferência da Cintura , Adulto Jovem
20.
Compr Psychiatry ; 73: 97-104, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27930952

RESUMO

INTRODUCTION: Food addiction is a controversial concept. The potential influence of food addiction on patients' psychosocial functioning and well-being has not been well established. The purpose of this study was to examine the relationships between psychosocial functioning (depressive symptoms and health-related quality of life [HRQOL]) and food addiction as measured by the Yale Food Addiction Scale (YFAS). We also explored whether food addiction contributed additional variance in explaining psychosocial functioning, beyond demographic and clinical factors (e.g., binge eating). METHODS: The sample included 178 participants (mean age=44.2±11.2years; BMI=40.9±5.9kg/m2; 88.2% female; 70.8% Black) with obesity seeking treatment for weight loss. Participants completed the Medical Outcomes Study 36-Item Short-Form Health Survey, Impact of Weight on Quality of Life-Lite, Patient Health Questionnaire, YFAS, and Questionnaire on Eating and Weight Patterns-5. RESULTS: Twelve (6.7%) participants met criteria for food addiction, with 4 (33.3%) of these participants having co-occurring binge eating disorder. After adjusting for covariates, the number of food addiction symptoms accounted for 6.5% to 16.3% of additional variance in general HRQOL, 5.0% to 21.5% in weight-related HRQOL, and 19.1% in symptoms of depression. CONCLUSIONS: In this treatment-seeking sample of participants, we found a low prevalence of food addiction, suggesting that addictive-like eating is unlikely to be a causal mechanism for most people with obesity. However, individuals who met criteria for food addiction had reduced psychosocial functioning compared to those who did not meet criteria. Individuals with addictive-like eating may require additional psychosocial support.


Assuntos
Comportamento Aditivo/psicologia , Transtorno da Compulsão Alimentar/psicologia , Comportamento Alimentar/psicologia , Obesidade/psicologia , Adulto , Comportamento Aditivo/complicações , Comportamento Aditivo/epidemiologia , Transtorno da Compulsão Alimentar/complicações , Transtorno da Compulsão Alimentar/epidemiologia , Peso Corporal , Estudos Transversais , Depressão/complicações , Depressão/epidemiologia , Depressão/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pennsylvania/epidemiologia , Prevalência , Qualidade de Vida
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...