Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Environ Sci Technol ; 56(9): 5763-5774, 2022 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-35442651

RESUMEN

This study reexamined the mechanisms for oxidative organic degradation by the binary mixture of periodate and H2O2 (PI/H2O2) that was recently identified as a new advanced oxidation process. Our findings conflicted with the previous claims that (i) hydroxyl radical (•OH) and singlet oxygen (1O2) contributed as the primary oxidants, and (ii) •OH production resulted from H2O2 reduction by superoxide radical anion (O2•-). PI/H2O2 exhibited substantial oxidizing capacity at pH < 5, decomposing organics predominantly by •OH. The likelihood of a switch in the major oxidant under varying pH conditions was revealed. IO4- as the major PI form under acidic conditions underwent one-electron reduction by H2O2 to yield radical intermediates, whereas H2I2O104- preferentially occurring at pH > 7 caused 1O2 generation through two-electron oxidation of H2O2. PI reduction by O2•- was suggested to be a key reaction in •OH production, on the basis of the electron paramagnetic resonance detection of methyl radicals in the dimethyl sulfoxide solutions containing PI and KO2, and the absence of deuterated and 18O-labeled hydroxylated intermediates during PI activation using D2O and H218O2. Finally, simple oxyanion mixing subsequent to electrochemical PI and H2O2 production achieved organic oxidation, enabling a potential strategy to minimize the use of chemicals.


Asunto(s)
Peróxido de Hidrógeno , Oxidantes , Espectroscopía de Resonancia por Spin del Electrón , Radical Hidroxilo , Oxidación-Reducción , Ácido Peryódico , Superóxidos/metabolismo
2.
Small ; 15(14): e1805361, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30821937

RESUMEN

Cryopreservation is essential to effectively extend the shelf life of delicate biomaterials while maintaining proper levels of cell functions. Cryopreservation requires a cryoprotective agent (CPA) to suppress intracellular ice formation during freezing, but it must be removed prior to clinical use due to its toxicity. Conventional multistep CPA loading and unloading approaches are time consuming, often creating osmotic shocks and causing mechanical injuries for biological samples. An efficient surface-acoustic-wave- (SAW-) based lab-on-a-chip (LoC) for fast loading and removal of CPAs is presented here. With the SAW-based multistep CPA loading/removal approach, high concentration (3 m) CPA can be successfully loaded and removed in less than 1 min. Results show that the technique causes the least harm to umbilical cord matrix mesenchymal stem cells as compared to conventional method, and an average of 24% higher cell recovery rate is achieved, while preserving the integrity and morphology of the cells. This device is the first of its kind to combine high loading/unloading efficiency, high cell viability, and high throughput into one LoC device, offering not only a more efficient and safer route for CPA loading and removal from cells, but also paving the way for other cryopreservation-dependent applications.


Asunto(s)
Acústica , Membrana Celular/metabolismo , Criopreservación , Crioprotectores/metabolismo , Dispositivos Laboratorio en un Chip , Acústica/instrumentación , Transporte Biológico , Proliferación Celular , Supervivencia Celular , Matriz Extracelular/metabolismo , Colorantes Fluorescentes/química , Humanos , Células Madre Mesenquimatosas/citología , Propiedades de Superficie , Cordón Umbilical/citología
3.
Cryobiology ; 85: 95-104, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30219374

RESUMEN

For most of the cells, water permeability and plasma membrane properties play a vital role in the optimal protocol for successful cryopreservation. Measuring the water permeability of cells during subzero temperature is essential. So far, there is no perfect segmentation technique to be used for the image processing task on subzero temperature accurately. The ice formation and variable background during freezing posed a significant challenge for most of the conventional segmentation algorithms. Thus, a robust and accurate segmentation approach that can accurately extract cells from extracellular ice that surrounding the cell boundary is needed. Therefore, we propose a convolutional neural network (CNN) architecture similar to U-Net but differs from those conventionally used in computer vision to extract all the cell boundaries as they shrank in the engulfing ice. The images used was obtained from the cryo-stage microscope, and the data was validated using the Hausdorff distance, means ±â€¯standard deviation for different methods of segmentation result using the CNN model. The experimental results prove that the typical CNN model extracts cell borders contour from the background in its subzero state more coherent and effective as compared to other traditional segmentation approaches.


Asunto(s)
Algoritmos , Criopreservación/métodos , Hielo/análisis , Procesamiento de Imagen Asistido por Computador/métodos , Redes Neurales de la Computación , Congelación , Células HeLa , Humanos , Microscopía
4.
J Therm Biol ; 76: 58-67, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30143298

RESUMEN

Cryosurgery is a promising novel minimally invasive surgical technique to eradicate carcinoma and non-carcinoma tissues by freezing. In this research, we applied a transient 3D two-phase refrigerant flow model inside the LN2 boiling chamber as well as a bioheat transfer model inside the tissues to evaluate the optimized ablation outcome during prostatic cryosurgery. For the evaluation of the scenarios, a defect function was used that considers non-ablated target tissue (prostate/cancer tissue) as well as ablated healthy tissue, in which the ablated tissue was evaluated using a temperature threshold. Three different configurations using three LN2 cryoprobes were analyzed during the modeling study, and the best configuration with the three LN2 cryoprobes positioned isoscelesly was found. For this configuration, temperature distributions and temperature profiles at specific points within the tissue were investigated numerically. Owing to its low computational cost, the 3D coupled model has an advantage in accurate modeling cryosurgery for curing numerous diseases.


Asunto(s)
Criocirugía/instrumentación , Criocirugía/métodos , Neoplasias de la Próstata/terapia , Temperatura Corporal , Humanos , Masculino , Modelos Biológicos , Próstata/fisiología , Próstata/fisiopatología , Neoplasias de la Próstata/fisiopatología , Termografía
5.
Phys Chem Chem Phys ; 18(29): 19595-604, 2016 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-27332984

RESUMEN

Unique octagonal shaped BiOCl nanosheets (NS) dominantly exposed with high energy {001} crystal facets have been fabricated via a simple hydrothermal route without using organic surfactants. The dynamics of photogenerated charge carriers have been studied by time-resolved photoluminescence spectroscopy. The fitting parameters of the decay kinetics were used to calculate both the intensity weighted average lifetime (〈τ〉int.), as well as the amplitude weighted average lifetime (〈τ〉amp.) of the photogenerated charge carriers. The 〈τ〉int. and 〈τ〉amp. values for {001} BiOCl NS, i.e., 17.23 ns and 1.94 ns, respectively, were observed to be significantly higher than the corresponding values obtained for pristine BiOCl such as 2.52 ns and 1.07 ns, respectively. Significant quenching of the PL emission intensity of {001} BiOCl NS reflected the enhanced separation of the photogenerated charge carriers. Reduced thickness and in situ iodine doping was favorable to minimize the recombination tendency. The photocatalytic activity was monitored via the photodegradation of RhB under visible light illumination (λ > 400 nm). {001} BiOCl NS exhibited superior performance when compared to pristine BiOCl in terms of the rapid degradation kinetics and higher photonic efficiency. The photocatalytic efficiency of {001} BiOCl NS was 2.8 times higher than pristine BiOCl. Iodine doping induced extended the optical absorption in the visible region and improved the separation of the photogenerated charge carriers, which played an important role to enhance the photocatalytic activity. The photodegradation mechanism was systematically studied using various radical quenchers and it was revealed that photogenerated holes (h(+)) and superoxide radicals (˙O(2-)) actively participated whereas hydroxyl (OH˙) radicals had a negligible contribution in the photodegradation of RhB. {001} BiOCl NS has shown a higher photocurrent density and lower charge transfer resistance analyzed through photoelectrochemical and electrochemical impedance measurements. This study highlights the fabrication of unique octagonal BiOCl NS with improved separation of charge carriers across high energy crystal facts to design a highly efficient photocatalyst.

6.
Cureus ; 16(3): e55643, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38586810

RESUMEN

Introduction Meniscus tear is a commonly encountered sports-related injury requiring surgical intervention due to knee mobility dysfunction and discomfort. Previously, it has been thought that these are non-functional vestigial structures and they used to be excised commonly. Recent studies have shown that meniscal repair gives superior results when compared with partial meniscectomy. Methods This quasi-experimental study was conducted at the Orthopedics Department, Khyber Teaching Hospital, Peshawar, Pakistan. A total of 92 patients of both genders with meniscal injuries were included. Forty-six of them underwent meniscal repair (Group A), and 46 underwent partial meniscectomy (Group B). Functional outcome was noted after 12 weeks and recorded. Results The age range was from 18 to 50 years with a mean of 28.630±6.64 years in Group A and 29.630±8.12 years in Group B. Functional outcome was excellent in 44 (95.7%) patients who underwent meniscal repair as compared to 23 (50%) patients who underwent partial meniscectomy (P= 0.000). Conclusion It is concluded that meniscal repair should be pursued over partial meniscectomy when surgically treating meniscal tears.

7.
Chemosphere ; 361: 142330, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38759805

RESUMEN

Solar-driven artificial photosynthesis offers a promising avenue for hydrogen peroxide (H2O2) generation, an efficient and economical replacement for current methods. The efficiency and selectivity hurdles of the two-electron oxygen reduction reaction (ORR) in solar-to- H2O2 conversion are substantial barriers to large scale production. In this manuscript, a simple biomass-assisted synthesis was performed to produce oxygen-enriched carbon quantum dots (OE-CQDs) from spent coffee waste, acting as an efficient photocatalyst for solar-powered H2O2 production. OE-CQDs can stabilize and store light-generated electrons effectively, boosting charge separation and enhancing photocatalytic performance with longevity. The maximal photocatalytic H2O2 production was achieved viz the utilization of OE-CQDs with generation rate of 356.86 µmol g-1 h-1 by retaining 80% activity without any external sacrificial donors. The outstanding performance of synthesized OE-CQDs under light exposure at wavelength (λ) of 280 nm has been ensured by the quantum yield value of 9.4% upon H2O2 generation. The combinatorial benefits of OE-CQDs with their authentic crystalline structure and oxygen enrichment, is expected to be enhancing the ORR activity through accelerating charge transfer, and optimizing oxygen diffusion. Consequently, our eco-friendly method holds considerable promise for creating highly efficient, metal-free photocatalysts for artificial H2O2 production.


Asunto(s)
Carbono , Café , Peróxido de Hidrógeno , Oxígeno , Puntos Cuánticos , Luz Solar , Puntos Cuánticos/química , Oxígeno/química , Catálisis , Peróxido de Hidrógeno/química , Carbono/química , Café/química , Oxidación-Reducción , Procesos Fotoquímicos
8.
Plants (Basel) ; 12(3)2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36771731

RESUMEN

Cadmium (Cd) is a non-essential and toxic metal that accumulates in plant's tissues and diminishes plant growth and productivity. In the present study, differential root transcriptomic analysis was carried out to identify Cd stress-responsive gene networks and functional annotation under Cd stress in wheat seedlings. For this purpose, the Yannong 0428 wheat cultivar was incubated with 40 µm/L of CdCl2·2.5H2O for 6 h at three different seedling growth days. After the quality screening, using the Illumina Hiseq 2000 platform, more than 2482 million clean reads were retrieved. Following this, 84.8% to 89.3% of the clean reads at three time points under normal conditions and 86.5% to 89.1% of the reads from the Cd stress condition were mapped onto the wheat reference genome. In contrast, at three separate seedling growth days, the data analysis revealed a total of 6221 differentially expressed genes (DEGs), including 1543 (24.8%) up-regulated genes and 4678 (75.8%) down-regulated genes. In total, 120 DEGs were co-expressed throughout all the growth days, whereas 1096, 1088, and 2265 DEGs were found to be selectively up-/down-regulated at 7d, 14d, and 30d, respectively. However, the clustering of DEGs, through utilizing the Kyoto Encyclopedia of Genes and Genomes (KEGG), revealed that the DEGs in the metabolic category were frequently annotated for phenylpropanoid biosynthesis. In comparison, a considerable number of DEGs were linked to protein processing in the endoplasmic reticulum under the process of genetic information processing. Similarly, in categories in organismal systems and cellular processes, DEGs were found in plant hormone signal transduction pathways, and DEGs were identified in the plant-pathogen interaction pathway, respectively. However, DEGs in "endocytosis pathways" were enriched in environmental information processing. In addition, in-depth annotations of roughly specific heavy metal stress-response genes and pathways were also mined, and the expression patterns of eight DEGs were studied using quantitative real-time PCR. The results were congruent with the findings of RNA sequencing regarding transcript abundance in the studied wheat cultivar.

9.
Micromachines (Basel) ; 14(6)2023 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-37374756

RESUMEN

Organic optoelectronic devices have received appreciable attention due to their low cost, mechanical flexibility, band-gap engineering, lightness, and solution processability over a broad area. Specifically, realizing sustainability in organic optoelectronics, especially in solar cells and light-emitting devices, is a crucial milestone in the evolution of green electronics. Recently, the utilization of biological materials has appeared as an efficient means to alter the interfacial properties, and hence improve the performance, lifetime and stability of organic light-emitting diodes (OLEDs). Biological materials can be known as essential renewable bio-resources obtained from plants, animals and microorganisms. The application of biological interfacial materials (BIMs) in OLEDs is still in its early phase compared to the conventional synthetic interfacial materials; however, their fascinating features (such as their eco-friendly nature, biodegradability, easy modification, sustainability, biocompatibility, versatile structures, proton conductivity and rich functional groups) are compelling researchers around the world to construct innovative devices with enhanced efficiency. In this regard, we provide an extensive review of BIMs and their significance in the evolution of next-generation OLED devices. We highlight the electrical and physical properties of different BIMs, and address how such characteristics have been recently exploited to make efficient OLED devices. Biological materials such as ampicillin, deoxyribonucleic acid (DNA), nucleobases (NBs) and lignin derivatives have demonstrated significant potential as hole/electron transport layers as well as hole/electron blocking layers for OLED devices. Biological materials capable of generating a strong interfacial dipole can be considered as a promising prospect for alternative interlayer materials for OLED applications.

10.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 7): o2088-9, 2012 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-22798769

RESUMEN

The asymmetric unit of the title compound, C(15)H(18)BrN(3)O(2)S, contains two independent mol-ecules in both of which the (thia-zine)C=N-N double bond exhibits an E conformation. The cyclo-hexyl rings adopt chair conformations while the thia-zine rings are in sofa conformations. The mean planes of these rings are oriented at dihedral angles of 64.43 (13) and 28.6 (2)° in the two independent mol-ecules while the aromatic and thia-zine rings are twisted by dihedral angles of 8.73 (8) and 13.07 (2)°, respectively. In the crystal, C-H⋯O and C-H⋯Br inter-actions connect mol-ecules into chains propagating along the a axis.

11.
Artículo en Inglés | MEDLINE | ID: mdl-36278442

RESUMEN

BACKGROUND: Gold nanoparticles have the potential to be used as a carrier in drug delivery system due to their small size, large surface area and short circulation time in blood. OBJECTIVE: This study aims that doxorubicin conjugation with gold nanoparticles (AuNPs) may reduce its toxicity as well as improve therapeutic efficacy. METHODS: Five groups of Albino rats were used; 1: healthy control, 2: Injured, 3: injured and treated with Dox, 4: Injured and treated with AuNPs, 5: Injured and treated with AuNPs: Dox. At the end of the experiment, blood and liver tissues were processed for biochemical and histopathological analysis. The expression of collagen, HO-1, IL-6 and TNF-α genes involved in liver fibrosis was observed through real-time PCR. RESULTS: At the end of the experiment, it was observed that the body weights of DOX treated rats decreased by 0.72%, however, AuNPs and Au: DOX treated rats were 15.3% and 29.13% respectively. The percentage of liver protection determined through alanine aminotransferase and aspartate aminotransferase levels in DOX, AuNPs and AuNPs: DOX treated groups were 39.21%, 79.26%, 98.17% and 47.77%, 84.17%, 97.92% respectively. That represents better recovering liver in Dox-AuNPs treated rats compared to others. Histopathological and gene expression studies further support the findings. The mRNA expression levels of inflammatory and oxidative stress related genes HO-1, IL-6 and TNF-α were upregulated in the injured group but downregulated in the treated group. CONCLUSION: As depicted through biochemical, histopathological and gene expression studies, Au: DOX conjugate group seems to be protective against liver fibrosis.

12.
Int J Lab Hematol ; 43(1): 93-98, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32931145

RESUMEN

AIMS: To assess the seasonal variations in hematological disorders among patients diagnosed on the basis of bone marrow biopsy, who attended National Institute of Blood Diseases (NIBD) clinics during 2006 to 2015. METHODS: We retrospectively reviewed the 10-year records of hematological disorders among patients' NIBD clinics from year 2006 to 2015. All cases of aplastic anemia (AA), acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), immune thrombocytopenic purpura (ITP), and acute promyelocytic leukemia (APML) were categorized on the basis of the seasons in which they were diagnosed such as winter (December-February), spring (March-May), southwest monsoon periods (June-September), and retreating monsoon period (October and November). Statistical analysis was performed by using SPSS and STATA. Inferential statistics were explored using the chi-square test for heterogeneity to evaluate seasonal variations. P-value <0.05 was taken as significant. RESULTS: A total of 1982 cases were reviewed. Men were predominantly higher (n = 1190, 60%) as compared to women (n = 792, 40%). Frequency of ALL was found to be higher (513, 25.9%), followed by ITP (504, 25.4%), AML (490, 24.7%), AA (396, 20%), while APML was observed in only 79 (4%) patients. Seasonal variations in the diagnosis of hematological disorders were observed (P-value < .001), except in APML diagnosis (P-value = .445). Significant seasonal variations were also detected in both genders in stratified analysis. CONCLUSION: The finding of this study has reported an increase in the hematological disorder during 2006 to 2015. Particularly, majority of the cases were reported in southwest monsoon period, whereas least cases were reported in retreating period. Significant seasonal and yearly variations were detected in all diagnosis except the APML.


Asunto(s)
Enfermedades Hematológicas/diagnóstico , Enfermedades Hematológicas/epidemiología , Estaciones del Año , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores Sexuales
13.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 4): o741, 2010 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-21580586

RESUMEN

The title compound, C(16)H(25)NO(2)S, is a sulfonamide derivative with the substitution of propyl and cyclo-hexyl groups at the N atom. The least-squares plane through all six C atoms of the cyclo-hexyl ring forms a dihedral angle of 58.88 (12)° with the toluene ring. No hydrogen-bonding inter-actions are present in the crystal structure.

14.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 4): o979, 2010 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-21580776

RESUMEN

In the title compound, C(15)H(17)NO(2)S, the aromatic rings are oriented at a dihedral angle of 32.8 (1)°. The ethyl group and phenyl ring on the N atom adopt a staggered conformation with respect to the O atoms.

15.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 11): o2867, 2009 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-21578454

RESUMEN

The title compound, C(14)H(21)NO(2)S, synthesized by N-methyl-ation of cyclo-hexyl-amine sulfonamide with ethyl iodide is of inter-est as a precursor to biologically active sulfur-containing heterocyclic compounds. There are two independent mol-ecules in the asymmetric unit. The dihedral angles between the mean planes of the phenyl ring and the cyclo-hexyl ring are 40.29 (11) and 37.91 (13)° in the two mol-ecules.

16.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 11): o2892, 2009 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-21578475

RESUMEN

The title compound, C(13)H(19)NO(2)S, was synthesized by the reaction of N-cyclo-hexyl-amine-benzene-sulfonamide and methyl iodide. The crystal packing is stabilized by weak inter-molecular C-H⋯O hydrogen bonds.

17.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3053, 2009 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-21578785

RESUMEN

In the title compound, C(19)H(23)NO(2)S, the cyclo-hexyl ring exists in a chair form. The dihedral angle between the two terminal phenyl rings is 86.70 (6)°. No significant inter-actions are observed except for a weak intra-molecular C-H⋯O hydrogen bond.

18.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3102, 2009 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-21578829

RESUMEN

The title compound, C(15)H(21)NO(2)S, synthesized by N-alkyl-ation of cyclo-hexyl-amine benzene-sulfonamide with allyl iodide, is of inter-est as a precursor to biologically active sulfur-containing heterocyclic compounds. The cyclo-hexane ring is in a chair form and its mean plane makes a dihedral angle of 53.84 (12)° with the phenyl ring.

19.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3107, 2009 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-21578833

RESUMEN

The crystal structure of the title compound, C(14)H(21)NO(2)S, is a polymorph of the structure reported by Khan et al. [Acta Cryst. (2009), E65, o2867] which is also monoclinic (space group P2(1)/c). The unit cell in the title structure is approximately half the volume of the previously reported polymorph and the asymmetric unit of the title compound contains one mol-ecule rather than two independent mol-ecules in the other polymorph. In the title mol-ecule, the cyclo-hexane ring is in the typical chair form. In the crystal structure, mol-ecules are linked via weak inter-molecular C-H⋯O inter-actions, forming a chain along the b-axis direction.

20.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3109, 2009 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-21578835

RESUMEN

In the title compound, C(20)H(25)NO(2)S, the cyclo-hexyl ring exists in a chair form and the mean plane through all six atoms makes dihedral angles of 56.12 (9) and 55.19 (10)° with the benzene and phenyl rings, respectively. The dihedral angle between the two aromatic rings is 77.23 (7)°. A weak intra-molecular C-H⋯O interaction occurs.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA