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1.
Phys Chem Chem Phys ; 26(5): 4466-4473, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38240134

RESUMO

Global air quality has deteriorated significantly in recent years due to large emissions from the transformation industry and combustion vehicles. This issue requires the development of portable, highly sensitive, and selective gas sensors. Nanostructured materials, including defective graphene, have emerged as promising candidates for such applications. In this work, we investigated the B-doped topological line defect in graphene as a sensing material for various gas molecules (CO, CO2, NO, and NH3) based on a combination of density functional theory and the non-equilibrium Green's function method. The electronic transport calculations reveal that the electric current can be confined to the line defect region by gate voltage control, revealing highly reactive sites. The B-doped topological line defect is metallic, favoring the adsorption of NO and NH3 over CO and CO2 molecules. We notice changes in the conductance after gas molecule adsorption, producing a sensitivity of 50% (16%) for NO (NH3). In addition, the recovery time for nitride gases was calculated for different temperatures and radiation frequencies. At 300 K the ultraviolet (UV) has a fast recovery time compared to the visible (VIS) one by about two orders of magnitude. This study gives an understanding of how engineering transport properties at the microscopic level (by topological line defect and chemical B-doping) leads to promising nanosensors for detecting nitride gas.

2.
J Chem Phys ; 160(5)2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38341700

RESUMO

This study leverages two-pulse femtosecond stimulated Raman spectroscopy (2FSRS) to characterize molecular systems with avoided crossings (ACs) and conical intersections (CIs) in their low-lying excited electronic states. By simulating 2FSRS spectra of microscopically inspired ACs and CIs models, we demonstrate that 2FSRS not only delivers valuable information on the molecular parameters characterizing ACs and CIs but also helps distinguish between these two systems.

3.
Cell Mol Neurobiol ; 43(5): 2005-2020, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36138280

RESUMO

Chronic diabetic conditions have been associated with certain cerebral complications, that include neurobehavioral dysfunctional patterns and morphological alterations of neurons, especially the hippocampus. Neuroanatomical studies done by the authors have shown decreased total dendritic length, intersections, dendritic length per branch order and nodes in the CA1 hippocampal region of the diabetic brain as compared to its normal control group, indicating reduced dendritic arborization of the hippocampal CA1 neurons. Epigenetic alterations in the brain are well known to affect age-associated disorders, however its association with the evolving diabetes-induced damage in the brain is still not fully understood. DNA hypermethylation within the neurons, tend to silent the gene expression of several regulatory proteins. The findings in the study have shown an increase in global DNA methylation in palmitic acid-induced lipotoxic Neuro-2a cells as well as within the diabetic mice brain. Inhibiting DNA methylation, restored the levels of HSF1 and certain HSPs, suggesting plausible effect of DNMTs in maintaining the proteostasis and synaptic fidelity. Neuroinflammation, as exhibited by the astrocyte activation (GFAP), were further significantly decreased in the 5-azadeoxycytidine group (DNMT inhibitor). This was further evidenced by decrease in proinflammatory cytokines TNF⍺, IL-6, and mediators iNOS and Phospho-NFkB. Our results suggest that changes in DNA methylation advocate epigenetic dysregulation and its involvement in disrupting the synaptic exactitude in the hippocampus of diabetic mice model, providing an insight into the pathophysiology of diabetes-induced neuroepigenetic changes.


Assuntos
Disfunção Cognitiva , Diabetes Mellitus Experimental , Animais , Camundongos , Metilação de DNA/genética , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/genética , Encéfalo , Disfunção Cognitiva/genética , Citocinas , Hipocampo
4.
Europace ; 25(10)2023 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-37738408

RESUMO

AIMS: We report a series of patients with Electrical Storm (ES) who underwent bilateral stellate ganglion ablation by using conventional radio frequency (RFA). METHODS AND RESULTS: The procedure was done with fluoroscopic guidance using the COSMAN™ 1A RF Generator and a 22G RF needle (5 cm length and 5 mm active tip). Six patients, four male and two female (mean age 55 ± 7 years and mean LVEF-42 ± 21%) with ES underwent the procedure under fluoroscopic guidance. All patients experienced recurrent ICD shocks or required multiple external defibrillation shocks. There were no procedural complications. All patients survived free of ES at discharge. At a mean follow-up of 22 ± 8months, all were alive free of ES but two patients received appropriate shocks for VT and one patient had VT terminated by ATP. CONCLUSION: This small series of cases is a proof of concept that neuromodulation by conventional RFA targeting bilateral stellate ganglia appears safe, feasible, and effective in treating selected unstable patients with ES.


Assuntos
Ablação por Cateter , Taquicardia Ventricular , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/cirurgia , Taquicardia Ventricular/etiologia , Gânglio Estrelado/diagnóstico por imagem , Gânglio Estrelado/cirurgia , Simpatectomia/métodos , Ablação por Cateter/efeitos adversos , Ablação por Cateter/métodos , Resultado do Tratamento
5.
Crit Care ; 27(1): 487, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-38082302

RESUMO

BACKGROUND: There is limited evidence to guide interventions that promote cost-effectiveness in adult intensive care units (ICU). The aim of this consensus statement is to identify globally applicable interventions for best ICU practice and provide guidance for judicious use of resources. METHODS: A three-round modified online Delphi process, using a web-based platform, sought consensus from 61 multidisciplinary ICU experts (physicians, nurses, allied health, administrators) from 21 countries. Round 1 was qualitative to ascertain opinions on cost-effectiveness criteria based on four key domains of high-value healthcare (foundational elements; infrastructure fundamentals; care delivery priorities; reliability and feedback). Round 2 was qualitative and quantitative, while round 3 was quantitative to reiterate and establish criteria. Both rounds 2 and 3 utilized a five-point Likert scale for voting. Consensus was considered when > 70% of the experts voted for a proposed intervention. Thereafter, the steering committee endorsed interventions that were identified as 'critical' by more than 50% of steering committee members. These interventions and experts' comments were summarized as final considerations for best practice. RESULTS: At the conclusion of round 3, consensus was obtained on 50 best practice considerations for cost-effectiveness in adult ICU. Finally, the steering committee endorsed 9 'critical' best practice considerations. This included adoption of a multidisciplinary ICU model of care, focus on staff training and competency assessment, ongoing quality audits, thus ensuring high quality of critical care services whether within or outside the four walls of ICUs, implementation of a dynamic staff roster, multidisciplinary approach to implementing end-of-life care, early mobilization and promoting international consensus efforts on the Green ICU concept. CONCLUSIONS: This Delphi study with international experts resulted in 9 consensus statements and best practice considerations promoting cost-effectiveness in adult ICUs. Stakeholders (government bodies, professional societies) must lead the efforts to identify locally applicable specifics while working within these best practice considerations with the available resources.


Assuntos
Atenção à Saúde , Unidades de Terapia Intensiva , Adulto , Humanos , Análise Custo-Benefício , Reprodutibilidade dos Testes , Consenso , Técnica Delphi
6.
Childs Nerv Syst ; 39(7): 1821-1829, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37199787

RESUMO

INTRODUCTION: Globally, spina bifida (SB) occurs more often in low- and middle-income countries, where the healthcare demands are often quite challenging. Several social/societal issues and/or lack of government support makes for incomplete SB management in many areas. Clearly, neurosurgeons should be knowledgeable about initial closure techniques and the basics of SB management, but must also advocate for the patients outside our immediate scope of care. METHODS: Recently, the Comprehensive Policy Recommendations for the Management of Spina Bifida and Hydrocephalus in Low- and Middle-Income Countries (CHYSPR) and the Intersectoral Global Action Plan on Epilepsy and other Neurological Disorders (IGAP) publications emphasized the need for a more unified approach to SB care. Although both documents discuss other neurological conditions, they support SB as a congenital malformation needing attention. RESULTS: We identified several similarities for comprehensive SB care in these approaches - including education, governance, advocacy, and the need for continuum of care. Prevention was recognized as the most important aspect for SB going forward. A significant return of investment was noted, and both documents recommend more active neurosurgical involvement (i.e., folic acid fortification). CONCLUSION: A new call for holistic and comprehensive care for SB management is recognized. Neurosurgeons are called upon to use solid science to educate governments and actively participate to advocate for better care and most importantly, prevention. Folic acid fortification schemes are mandatory and neurosurgeons should advocate for global strategies.


Assuntos
Hidrocefalia , Disrafismo Espinal , Humanos , Países em Desenvolvimento , Disrafismo Espinal/terapia , Ácido Fólico , Políticas
7.
J Fish Dis ; 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37818735

RESUMO

Tilapia parvovirus (TiPV) has been associated with heavy mortalities in tilapia as a single infection or in co-infection with Tilapia lake virus (TiLV). In this study, TiPV was detected in farmed Nile tilapia, Oreochromis niloticus, from two geographical regions of India, Maharashtra and Uttar Pradesh. TiPV-specific polymerase chain reaction (PCR) reported earlier was used in the screening. Tilapia collected from Maharashtra showed characteristic clinical signs, and TiPV was detected along with TiLV and/or Aeromonas spp. However, fish from Uttar Pradesh were apparently healthy and only TiPV could be detected in these samples. A high prevalence of TiPV was recorded from both the geographical locations, Maharashtra and Uttar Pradesh (59.6% and 95.0% respectively). The virus could be detected in tissues such as the spleen, liver, kidney, brain and mucus. The spleen appeared to be the best tissue for detecting TiPV in apparently healthy tilapia. The presence of TiPV was further confirmed through sequencing the PCR products, isolation of the virus in the cell line and electron microscopy. Sequences of the NS1 gene of the two TiPV isolates showed similarity to the earlier reported TiPV isolates. The virus could be successfully propagated in O. niloticus Liver (OnL) cell line, and cytopathic effect was observed as early as 3 days post-infection. Furthermore, the presence of non-enveloped icosahedral to round virus particles measuring about 26-35 nm could be demonstrated in the cytoplasm and nucleus of infected OnL cells in transmission electron microscopy. With this confirmation of the presence of the virus, India is the third country to report TiPV after China and Thailand. The detection of TiPV in co-infection cases with TiLV and in apparently healthy Nile tilapia suggests its wide distribution and potential synergistic effect in co-infection cases. Therefore, this emerging virus needs holistic attention to understand its virulence, host-specificity and epidemiological risk factors.

8.
Environ Geochem Health ; 45(11): 8403-8415, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37624440

RESUMO

Exorbitant concentrations of toxic metals in the soil from anthropogenic activities are environmental hazards and key health risk concerns to humans. The subsistence food garden soils have minimum anthropogenic interventions. The ecotoxicological risk potentials of the metals in subsistence food garden settings are unexplored. The metals (Cr, Cu, Pb, and Ni) concentration were assessed in the surface soil fractions (2 mm and 0.2 mm) of food gardens (N = 20) on the floodplains of Watut River, Papua New Guinea. The threshold limits, index of geo-accumulation (Igeo), contamination factor (CF), pollution load index (PLI), and potential ecological risk index (PERI) served as potential risk indicators of metals. Regardless of soil particle size, the descending order of median metals concentration was Cr > Cu > Ni > Pb. The concentration of Cu and Ni in the soil particles exceeded the WHO threshold limits in 100% and 50% of the food garden soils, respectively. Metal enrichment led to severe pollution in 100% gardens (Igeo > 5). Cr, Cu, and Ni contamination factors were > 1 in 95% of the food gardens. The PERI values indicated a lower ecological risk of the metals (PERI < 100). The median concentration of Cu, Igeo, and CF values for Cu in the 2 mm soil particles were significantly greater than in 0.2 mm. The results suggested exposure of subsistence food gardens soils to geogenic metal contamination and the need to carefully choose appropriate soil particle size for the soil health assessments.


Assuntos
Metais Pesados , Poluentes do Solo , Humanos , Solo , Jardins , Rios , Monitoramento Ambiental/métodos , Metais Pesados/toxicidade , Metais Pesados/análise , Papua Nova Guiné , Chumbo , Medição de Risco , Poluentes do Solo/toxicidade , Poluentes do Solo/análise , China
9.
J Food Sci Technol ; 60(7): 2042-2049, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37206417

RESUMO

The present study aims at utilizing wheat bran and resultant atta to produce biodegradable-edible plates as an alternative to plastic plates. The edible plates were prepared using different combinations of wheat bran and resultant atta in different ratios viz., WB, 90:10 (WR10); 80:20 (WR20), 70:30 (WR30). Using farinograph, it was observed that the higher the bran higher the water absorption. The doughs from the blends were prepared with water at two different temperatures (100 °C and 27 °C), sheeted, moulded and baked. Plates produced from WR10, 20, 30 were analysed further and based on break test, leak test and sensory WR30 was chosen as the best. WR 30 was found to leak at 23.01 ± 0.24 min with hot water and 85.42 ± 0.11 min with water at room temperature. Moisture, ash, fat, protein, and total dietary fibre content was 4.3 ± 0.016, 4.90 ± 0.08, 3.86 ± 0.075, 16.06 ± 0.082 and 26.92 ± 0.166 respectively. Shelf-life predicted for plate was 250-285 days based on MSI studies done.

10.
Med J Armed Forces India ; 79(5): 487-493, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37719900

RESUMO

This article aims to propose a design for Eye Injury Registry (EIR) model for Indian Armed Forces, to make ophthalmologists and non-ophthalmologists aware about the existence as well as the usefulness of such a registry. This is a perspective study. The EIR model for Armed Forces was designed based on the relevant sources in PubMed, Scopus and Embase including registries of pioneering countries like United States and Canada. A questionnaire based on the model dimensions was developed (Cronbach's alpha>0.7) and filled by 04 senior ophthalmologists in Armed Forces, all of who had a significant experience in dealing with various types of ocular trauma, to give expert opinions, which were then applied to the proposed model to finalize it. In Armed Forces, a registry and reporting on eye injury along with a systematic collection of standard data on eye injuries will help ophthalmologists in the successful prevention. Such a registry and its large database once formed will permit elaborate epidemiologic investigations, highlighting preventable sources of injury, emerging patterns of trauma in our services, and the best possible treatment protocols to be adopted, for successful outcomes. EIR in Armed Forces can help in the collection of eye injury data, thereby improving the quality-of-care and expansion of prevention strategies for ocular injuries. It is a step to make a truly effective data bank, which will be instrumental in combating such preventable ocular injuries and in turn go a very long way in achieving the final goal of preventing up to 90% of such injuries.

11.
12.
Chromosoma ; 130(1): 3-14, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33222024

RESUMO

Homologous recombination (HR) is one of the key pathways to repair double-strand breaks (DSBs). Rad51 serves an important function of catalysing strand exchange between two homologous sequences in the HR pathway. In higher organisms, rad51 function is indispensable with its absence leading to early embryonic lethality, thus precluding any mechanistic probing of the system. In contrast, the absence of Drosophila rad51 (spn-A/rad51) has been associated with defects in the germline, without any reported detrimental consequences to Drosophila somatic tissues. In this study, we have performed a systematic analysis of developmental defects in somatic tissues of spn-A mutant flies by using genetic complementation between multiple spn-A alleles. Our current study, for the first time, uncovers a requirement for spn-A in somatic tissue maintenance during both larval and pupal stages. Also, we show that spn-A mutant exhibits patterning defects in abdominal cuticle in the stripes and bristles, while there appear to be only subtle defects in the adult wing and eye. Interestingly, spn-A mutant shows a discernible phenotype of low temperature sensitivity, suggesting a role of spn-A in temperature sensitive cellular processes. In summary, our study describes the important role played by spn-A/rad51 in Drosophila somatic tissues.


Assuntos
Morte Celular , Dano ao DNA , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Mutação , Rad51 Recombinase/metabolismo , Temperatura , Animais , Padronização Corporal , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Células Germinativas , Recombinação Homóloga , Masculino , Meiose , Fenótipo , Rad51 Recombinase/genética
13.
Tetrahedron Lett ; 88: 153590, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34908617

RESUMO

Remdesivir, the first drug approved by the FDA to treat COVID-19, is in high demand for patients infected with the SARS-CoV-2 virus. Herein, we report a facile approach minimizing the protecting group manipulations to afford remdesivir in good overall yield.

14.
BMC Med Imaging ; 22(1): 89, 2022 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-35568820

RESUMO

BACKGROUND: Segmenting brain tumor and its constituent regions from magnetic resonance images (MRI) is important for planning diagnosis and treatment. In clinical routine often an experienced radiologist delineates the tumor regions using multimodal MRI. But this manual segmentation is prone to poor reproducibility and is time consuming. Also, routine clinical scans are usually of low resolution. To overcome these limitations an automated and precise segmentation algorithm based on computer vision is needed. METHODS: We investigated the performance of three widely used segmentation methods namely region growing, fuzzy C means and deep neural networks (deepmedic). We evaluated these algorithms on the BRATS 2018 dataset by choosing randomly 48 patients data (high grade, n = 24 and low grade, n = 24) and on our routine clinical MRI brain tumor dataset (high grade, n = 15 and low grade, n = 28). We measured their performance using dice similarity coefficient, Hausdorff distance and volume measures. RESULTS: Region growing method performed very poorly when compared to fuzzy C means (fcm) and deepmedic network. Dice similarity coefficient scores for FCM and deepmedic algorithms were close to each other for BRATS and clinical dataset. The accuracy was below 70% for both these methods in general. CONCLUSION: Even though the deepmedic network showed very high accuracy in BRATS challenge for brain tumor segmentation, it has to be custom trained for the low resolution routine clinical scans. It also requires large training data to be used as a stand-alone algorithm for clinical applications. Nevertheless deepmedic may be a better algorithm for brain tumor segmentation when compared to region growing or FCM.


Assuntos
Neoplasias Encefálicas , Processamento de Imagem Assistida por Computador , Algoritmos , Neoplasias Encefálicas/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Reprodutibilidade dos Testes
15.
Int J Neurosci ; : 1-10, 2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36469636

RESUMO

BACKGROUND: Allopregnanolone (3α, 5α-tetrahydroprogesterone) is an inhibitory neurosteroid synthesized from progesterone via 5α-reductase activity in the brain and has anxiolytic, antidepressant, sedative, anticonvulsant, and analgesic activity. Altered levels of allopregnanolone cause anxiety, depression, premenstrual syndrome, and psychiatric disorders. Although allopregnanolone exerts most of its actions by modulating GABAA receptor, NMDA receptor, BDNF expression, and PXR activity, a recent study showed its effects are blocked by mifepristone on lordosis behavior which indicates the involvement of progestin or glucocorticoid receptors in the effects of allopregnanolone since mifepristone blocks both these receptors. However, whether these receptors are involved in acute anxiolytic or antidepressant-like effects is unknown. METHODS: Adult male Wistar rats were used to study whether the prior administration of mifepristone would alter the effects of allopregnanolone in the elevated plus maze (EPM) and forced swim test (FST) was evaluated. RESULTS: 10 mg/Kg dose of allopregnanolone increased percent open arm entries in the EPM, whereas 3 mg/Kg dose of allopregnanolone decreased percent immobility in the FST. Mifepristone administration resulted in a U-shaped response in the FST (with 1 mg/Kg, s.c., decreasing the immobility time) without significantly impacting the behavior in the EPM. In combination studies, mifepristone blocked the anxiolytic and antidepressant effects of allopregnanolone. CONCLUSION: The current study provides evidence for the first time that progestin or glucocorticoid receptors are involved in the acute anxiolytic and antidepressant effects of allopregnanolone. Understanding the mechanism of action of allopregnanolone will help us design better therapeutic strategies to treat neuropsychiatric diseases such as depression and anxiety.

16.
Environ Monit Assess ; 194(4): 267, 2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35262801

RESUMO

Soil erosion in semi-arid climate leading to the development of ravine lands is the most severe form of land degradation. Ravine lands are formed when soil is not fully covered by the vegetation throughout the year and sporadic vegetation is not able to bind the soil particles from being washed away by rainfall. Throughout the globe, ravine lands have severe limitations for their rehabilitation and sustainable utilization as a consequence of its unique topographical features. Climatic and edaphic stresses make crop production extremely challenging in these lands. Practicing sole cropping promotes erosion, produces low crop yield, utilizes high energy, and emits greenhouse gasses (GHGs). Tree cultivation either sole or in combination with crops (agroforestry) has a strong potential to control erosion, produce sustainable economic yield, reduce energy consumption, and sequester greater amount of atmospheric carbon dioxide in biomass and soil carbon pools besides providing various ecosystem services. Therefore, practicing agroforestry could be a promising approach to obtain the greater environmental and economic benefits in the ravine lands. The present study was conducted on three systems, i.e., sole crop cultivation (cowpea + castor), agroforestry (sapota + cowpea + castor), and sole sapota plantation, to evaluate their impact on soil erosion, runoff, system productivity, profitability, energetics, and carbon sequestration during the 4-year period (2017-2020). The results revealed that agroforestry reduced the total soil loss and runoff by 37.7% and 19.1%, respectively, compared to the sole crop cultivation. Likewise, the highest system productivity as cowpea equivalent yield (CEY) was obtained under agroforestry system that increased the CEY by 162% and 81.9%, compared to sole crop and sole tree plantation, respectively. The climate change mitigation potential in terms of net carbon balance was observed highest in sole tree plantation (8.4 t/ha) followed by agroforestry system (5.9 t/ha) and lowest in sole cropping system (-2.8 t/ha). Therefore, an agroforestry system could be recommended for controlling soil erosion, improving system productivity and profitability, and reducing energy consumption as well as mitigating climate change in ravine lands.


Assuntos
Mudança Climática , Ecossistema , Agricultura , Monitoramento Ambiental , Solo , Erosão do Solo
17.
Indian J Crit Care Med ; 26(9): 1062, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36213708

RESUMO

How to cite this article: Kumar A, Sabharwal P, Gupta P, Singh VK, Rao BK. Reply to Letter to the Editor: A Fatal Case of Acute Disseminated Encephalomyelitis-A Diagnosis to Ponder in Pandemic. Indian J Crit Care Med 2022;26(9):1062.

18.
Artigo em Inglês | MEDLINE | ID: mdl-35937413

RESUMO

Background: Lockdown during COVID-19 led to teachers and children shifting to online classes, using visual display terminals (VDTs) for education, resulting in increased screen time. The present study was done to assess and understand the nature and magnitude of the problem and to suggest preventive or remedial measures. Methods: A questionnaire-based cross-sectional study was conducted. The questionnaire was prepared for an online survey (using Google Forms) and circulated among school children belonging to different schools across India using multiple groups on social media. Results: A total of 3327 participants from 46 schools across India participated in the survey. We found a marked rise in cumulative screen time for both teachers and students before and during the lockdown. There was a threefold increase in the number of participants with a cumulative screen time 6 h or more compared to the pre-COVID era. Teachers (older participants) had worse symptom scores than students. Larger screens, like televisions, were better VDTs compared to smartphones, tablets, or laptops. Conclusions: School administrators and policymakers should pay due attention to institutionalizing the guidelines about class duration, appropriate screens, and stipulating break duration during online classes, which will continue to remain the predominant mode of education for teachers and students alike, at least in the near future.

19.
Anal Biochem ; 612: 113896, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32818506

RESUMO

Biologics manufacturers must continually monitor the attachment of carbohydrates, called glycans, to their products, because any variability can impact safety and efficacy. To help the industry meet this challenge, the United States Pharmacopeial Convention (USP) offers glycan reference standards and validated methods for glycoprofiling using high-performance liquid chromatography (HPLC). The industry has recently adopted more advanced technologies for glycan analysis, including ultra-high performance liquid chromatography (UHPLC) and mass spectrometry. In this study, we confirm that USP's glycan reference standards are compatible with UHPLC by demonstrating comparable peak separation and glycan identification to HPLC methods. The improved resolving power and shorter run-times of UHPLC also allowed us to identify many of the minor glycan components present in USP's glycan reference standards. These more comprehensively characterized glycan reference standards will enable manufacturers to assess the micro-heterogeneity that can negatively impact the safety and efficacy of biological products.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/normas , Polissacarídeos/análise , Anticorpos Monoclonais/análise , Glicosilação , Espectrometria de Massas , Padrões de Referência
20.
Phys Chem Chem Phys ; 23(2): 1694-1705, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33427252

RESUMO

The effect of Mg2+ and In3+ substitution on the structural, magnetic, magnetostrictive and dielectric properties of NiFe2O4 samples derived through sintering of nanocrystalline ceramic powders is investigated. Namely, NiFe2O4, NiMg0.2Fe1.8O4 and NiIn0.2Fe1.8O4 nanopowders were synthesized by a tartrate-gel route followed by calcination at 500 °C, pelletization and sintering at 1200 °C for 2 h. The average particle size was found to decrease from ∼13 nm (for NiFe2O4) to ∼9 nm and ∼7 nm for as-synthesized Mg2+ and In3+ substituted NiFe2O4 samples (after calcination), respectively. However, after sintering a better grain growth occurs for the In3+ substituted sample, as confirmed through the microscopy and dielectric results. Due to the replacement of smaller Fe3+ cations by larger In3+ and Mg2+ cations at the tetrahedral (Td) and octahedral (Oh) interstitial positions, respectively, in the spinel structure of NiFe2O4, the lattice parameters increase in both the cases. The Td site occupation of In3+ leads to higher magnetization for the NiIn0.2Fe1.8O4 sample, but Oh site occupation of Mg2+ leads to lower magnetization for the NiMg0.2Fe1.8O4 sample, in comparison to the pure NiFe2O4 sample. Furthermore, the Curie temperatures (TC) and magnetocrystalline anisotropy constants (K1) for both the samples are considerably lower than the parent compound, with all the parameters being the lowest for the In3+ substituted sample because the Td occupation of non-magnetic In3+ drastically decreases the A-O-B magnetic superexchange interactions. The above alteration to the magnetic interactions alters the magnitude of maximum magnetostriction (λmax), which is explained based on the occupation of the Mg2+ and In3+ cations in our samples. The obtained magnetostriction properties of our samples are very useful for magnetostriction based sensor application.

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