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1.
Adv Sci (Weinh) ; : e2308955, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38647404

RESUMO

The adjustable structures and remarkable physicochemical properties of 2D monoelemental materials, such as silicene and germanene, have attracted significant attention in recent years. They can be transformed into silicane (SiH) and germanane (GeH) through covalent functionalization via hydrogen atom termination. However, synthesizing these materials with a scalable and low-cost fabrication process to achieve high-quality 2D SiH and GeH poses challenges. Herein, groundbreaking 2D SiH and GeH materials with varying compositions, specifically Si0.25Ge0.75H, Si0.50Ge0.50H, and Si0.75Ge0.25H, are prepared through a simple and efficient chemical exfoliation of their Zintl phases. These 2D materials offer significant advantages, including their large surface area, high mechanical flexibility, rapid electron mobility, and defect-rich loose-layered structures. Among these compositions, the Si0.50Ge0.50H electrode demonstrates the highest discharge capacity, reaching up to 1059 mAh g-1 after 60 cycles at a current density of 75 mA g-1. A comprehensive ex-situ electrochemical analysis is conducted to investigate the reaction mechanisms of lithiation/delithiation in Si0.50Ge0.50H. Subsequently, an initial assessment of the c-Li15(SixGe1- x)4 phase after lithiation and the a-Si0.50Ge0.50 phase after delithiation is presented. Hence, this study contributes crucial insights into the (de)lithiation reaction mechanisms within germanane-silicane alloys. Such understanding is pivotal for mastering promising materials that amalgamate the finest properties of silicon and germanium.

2.
Environ Sci Pollut Res Int ; 31(19): 28620-28631, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38561535

RESUMO

In recent years, there has been a significant rise in the utilization of amino-functionalized polystyrene nanoplastics (PS-NH2). This surge in usage can be attributed to their exceptional characteristics, including a substantial specific surface area, high energy, and strong reactivity. These properties make them highly suitable for a wide range of industrial and medical applications. Nevertheless, there is a growing apprehension regarding their potential toxicity to aquatic organisms, particularly when considering the potential impact of heavy metals like lead (Pb) on the toxicity of PS-NH2. Herein, we examined the toxic effects of sole PS-NH2 (90 nm) at five concentrations (e.g., 0, 0.125, 0.25, 0.5, and 1 mg/L), as well as the simultaneous exposure of PS-NH2 and Pb2+ (using two environmental concentrations, e.g., 20 µg/L for Pb low (PbL) and 80 µg/L for Pb higher (PbH)) to the microalga Chlorella vulgaris. After a 96-h exposure, significant differences in chlorophyll a content and algal growth (biomass) were observed between the control group and other treatments (ANOVA, p < 0.05). The algae exposed to PS-NH2, PS-NH2 + PbL, and PS-NH2 + PbH treatment groups exhibited dose-dependent toxicity responses to chlorophyll a content and biomass. According to the Abbott toxicity model, the combined toxicity of treatment groups of PS-NH2 and PbL,H showed synergistic effects. The largest morphological changes such as C. vulgaris' size reduction and cellular aggregation were evident in the medium treated with elevated concentrations of both PS-NH2 and Pb2+. The toxicity of the treatment groups followed the sequence PS-NH2 < PS-NH2 + PbL < PS-NH2 + PbH. These results contribute novel insights into co-exposure toxicity to PS-NH2 and Pb2+ in algae communities.


Assuntos
Antioxidantes , Chlorella vulgaris , Chumbo , Peroxidação de Lipídeos , Poliestirenos , Chlorella vulgaris/efeitos dos fármacos , Chumbo/toxicidade , Poliestirenos/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade
3.
Small ; 19(12): e2206430, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36642833

RESUMO

The attention on group III-VI compounds in the last decades has been centered on the optoelectronic properties of indium and gallium chalcogenides. These outstanding properties are leading to novel advancements in terms of fundamental and applied science. One of the advantages of these compounds is to present laminated structures, which can be exfoliated down to monolayers. Despite the large knowledge gathered toward indium and gallium chalcogenides, the family of the group III-VI compounds embraces several other noncommon compounds formed by the other group III elements. These compounds present various crystal lattices, among which a great deal is offered from layered structures. Studies on aluminium chalcogenides show interesting potential as anodes in batteries and as semiconductors. Thallium (Tl), which is commonly present in the +1 oxidation state, is one of the key components in ternary chalcogenides. However, binary Tl-Q (Q = S, Se, Te) systems and derived films are still studied for their semiconducting and thermoelectric properties. This review aims to summarize the biggest features of these unusual materials and to shed some new light on them with the perspective that in the future, novel studies can revive these compounds in order to give rise to a new generation of technology.

4.
Membranes (Basel) ; 12(10)2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36295678

RESUMO

Mixed-matrix membranes (MMMs) possess the unique properties and inherent characteristics of their component polymer and inorganic fillers, or other possible types of additives. However, the successful fabrication of compact and defect-free MMMs with a homogeneous filler distribution poses a major challenge, due to poor filler/polymer compatibility. In this study, we use two-dimensional multi-layered Ti3C2Tx MXene nanofillers to improve the compatibility and CO2/CH4 separation performance of cellulose triacetate (CTA)-based MMMs. CTA-based MMMs with TiO2-based 1D (nanotubes) and 0D (nanofillers) additives were also fabricated and tested for comparison. The high thermal stability, compact homogeneous structure, and stable long-term CO2/CH4 separation performance of the CTA-2D samples suggest the potential application of the membrane in bio/natural gas separation. The best results were obtained for the CTA-2D sample with a loading of 3 wt.%, which exhibited a 5-fold increase in CO2 permeability and 2-fold increase in CO2/CH4 selectivity, compared with the pristine CTA membrane, approaching the state-of-the-art Robeson 2008 upper bound. The dimensional (shape) effect on separation performance was determined as 2D > 1D > 0D. The use of lamellar stacked MXene with abundant surface-terminating groups not only prevents the aggregation of particles but also enhances the CO2 adsorption properties and provides additional transport channels, resulting in improved CO2 permeability and CO2/CH4 selectivity.

5.
Membranes (Basel) ; 11(11)2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34832091

RESUMO

This study explored the underlying synergy between titanium dioxide nanotube (TNT) and carbon nanotube (CNT) hybrid fillers in cellulose triacetate (CTA)-based mixed matrix membranes (MMMs) for natural gas purification. The CNT@TNT hybrid nanofillers were blended with CTA polymer and cast as a thin film by a facile casting technique, after which they were used for single gas separation. The hybrid filler-based membrane depicted a higher CO2 uptake affinity than the single filler (CNT/TNT)-based membrane. The gas separation results indicate that the hybrid fillers (TNT@CNT) are strongly selective for CO2 over CH4 and H2 over CH4. The increment in the CO2/CH4 and H2/CH4 selectivities compared to the pristine CTA membrane was 42.98 from 25.08 and 48.43 from 36.58, respectively. Similarly, the CO2 and H2 permeability of the CTA-TNT@CNT membrane increased by six- and five-fold, respectively, compared to the pristine CTA membrane. Such significant improvements in CO2/CH4 and H2/CH4 separation performance and thermal and mechanical properties suggest a feasible and practical approach for potential biogas upgrading and natural gas purification.

6.
Membranes (Basel) ; 11(10)2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34677542

RESUMO

The study of the effects associated with the compatibility of the components of the hybrid filler with polymer matrix, which ultimately decide on achieving mixed matrix membranes (MMMs) with better gas separation properties, is essential. Herein, a facile solution casting process of simple incorporating CeO2@GO hybrid inorganic filler material is implemented. Significant improvements in material and physico-chemical properties of the synthesized membranes were observed by SEM, XRD, TGA, and stress-strain measurements. Usage of graphene oxide (GO) with polar groups on the surface enabled forming bonds with ceria (CeO2) nanoparticles and CTA polymer and provided the homogeneous dispersion of the nanofillers in the hybrid MMMs. Moreover, increasing GO loading concentration enhanced both gas permeation in MMMs and CO2 gas uptakes. The best performance was achieved by the membrane containing 7 wt.% of GO with CO2 permeability of 10.14 Barrer and CO2/CH4 selectivity 50.7. This increase in selectivity is almost fifteen folds higher than the CTA-CeO2 membrane sample, suggesting the detrimental effect of GO for enhancing the selectivity property of the MMMs. Hence, a favorable synergistic effect of CeO2@GO hybrid fillers on gas separation performance is observed, propounding the efficient and feasible strategy of using hybrid fillers in the membrane for the potential biogas upgrading process.

7.
Membranes (Basel) ; 11(8)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34436395

RESUMO

Due to the high affinity of ceria (CeO2) towards carbon dioxide (CO2) and the high thermal and mechanical properties of cellulose triacetate (CTA) polymer, mixed-matrix CTA-CeO2 membranes were fabricated. A facile solution-casting method was used for the fabrication process. CeO2 nanoparticles at concentrations of 0.32, 0.64 and 0.9 wt.% were incorporated into the CTA matrix. The physico-chemical properties of the membranes were evaluated by SEM-EDS, XRD, FTIR, TGA, DSC and strain-stress analysis. Gas sorption and permeation affinity were evaluated using different single gases. The CTA-CeO2 (0.64) membrane matrix showed a high affinity towards CO2 sorption. Almost complete saturation of CeO2 nanoparticles with CO2 was observed, even at low pressure. Embedding CeO2 nanoparticles led to increased gas permeability compared to pristine CTA. The highest gas permeabilities were achieved with 0.64 wt.%, with a threefold increase in CO2 permeability as compared to pristine CTA membranes. Unwanted aggregation of the filler nanoparticles was observed at a 0.9 wt.% concentration of CeO2 and was reflected in decreased gas permeability compared to lower filler loadings with homogenous filler distributions. The determined gas selectivity was in the order CO2/CH4 > CO2/N2 > O2/N2 > H2/CO2 and suggests the potential of CTA-CeO2 membranes for CO2 separation in flue/biogas applications.

8.
Membranes (Basel) ; 11(6)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072897

RESUMO

In this study, defect-free facilitated transport mixed matrix membrane (MMM) with high loading amount of UiO-66-NH2 nanoparticles as metal-organic frameworks (MOFs) was fabricated. The MOFs were covalently bonded with poly (vinyl alcohol) (PVA) to incorporate into a poly (vinyl amine) (PVAm) matrix solution. A uniform UiO-66-NH2 dispersion up to 55 wt.% was observed without precipitation and agglomeration after one month. This can be attributed to the high covalent interaction at interfaces of UiO-66-NH2 and PVAm, which was provided by PVA as a functionalized organic linker. The CO2 permeability and CO2/N2 and selectivity were significantly enhanced for the fabricated MMM by using optimal fabrication parameters. This improvement in gas performance is due to the strong impact of solubility and decreasing diffusion in obtained dense membrane to promote CO2 transport with a bicarbonate reversible reaction. Therefore, the highest amount of amine functional groups of PVAm among all polymers, plus the abundant amount of amines from UiO-66-NH2, facilitated the preferential CO2 permeation through the bicarbonate reversible reaction between CO2 and -NH2 in humidified conditions. XRD and FTIR were employed to study the MMM chemical structure and polymers-MOF particle interactions. Cross-sectional and surface morphology of the MMM was observed by SEM-EDX and 3D optical profilometer to detect the dispersion of MOFs into the polymer matrix and explore their interfacial morphology. This approach can be extended for a variety of polymer-filler interfacial designs for gas separation applications.

9.
Chemosphere ; 280: 130725, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33964753

RESUMO

Presence of nanoplastics within aqueous media has raised concerns about their adverse impacts on aquatic organisms. This study evaluated toxic effects of amino-functionalized polystyrene nanoplastics (PS-NH2) with diameters of 90 (PS-NH2-90), 200 (PS-NH2-200) and 300 (PS-NH2-300) nm on green microalgae Chlorella vulgaris. A dose-dependent toxicity response by PS-NH2-90 and/or PS-NH2-200 on biomass and photosynthetic pigment (chlorophyll a) end-points of C. vulgaris was observed. Whereas varied concentrations of PS-NH2-300 had no significant toxic effect on biomass and chlorophyll a end-points compared to control groups (p > 0.05). A comparison of toxicity of similar concentrations of PS-NH2-90, PS-NH2-200 and PS-NH2-300 showed small-sized PS-NH2 were more toxic than large-sized PS-NH2 (toxicity of PS-NH2 increased in the order PS-NH2-300 < PS-NH2-200 < PS-NH2-90). With decreasing PS-NH2 size, greater morphological changes and loss of original shape were observed, so that algal density/size reduced, and cell aggregations increased. Since PS-NH2 have high affinity to C. vulgaris due to electrostatic interaction with polysaccharide wall of algae, this could be as the main reason for formation of large aggregates at high concentrations of PS-NH2 compared to low concentrations of PS-NH2 used in algae medium. At high concentrations, PS-NH2 may act as intermediaries for connection of algal cells and therefore formation of aggregates. Field emission scanning electron microscopy images confirmed that high amounts of PS-NH2-90 were found to be embedded and adsorbed on algal cells, thereby limiting transfer of materials, gas exchange and energy between the aqueous medium and algal cells. These data may have serious ecological health implications, as C. vulgaris are important primary producers responsible for producing oxygen in aquatic environments.


Assuntos
Chlorella vulgaris , Microalgas , Poluentes Químicos da Água , Biomassa , Clorofila A , Microplásticos , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade
10.
Membranes (Basel) ; 10(9)2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32911723

RESUMO

Poly(ionic liquid)s are an innovative class of materials with promising properties in gas separation processes that can be used to boost the neat polymer performances. Nevertheless, some of their properties such as stability and mechanical strength have to be improved to render them suitable as materials for industrial applications. This work explored, on the one hand, the possibility to improve gas transport and separation properties of the block copolymer Pebax® 1657 by blending it with poly[3-ethyl-1-vinyl-imidazolium] diethyl phosphate (PEVI-DEP). On the other hand, Pebax® 1657 served as a support for the PIL and provided mechanical resistance to the samples. Pebax® 1657/PEVI-DEP composite membranes containing 20, 40, and 60 wt.% of PEVI-DEP were cast from solutions of the right proportion of the two polymers in a water/ethanol mixture. The PEVI-DEP content affected both the morphology of the dense membranes and gas transport through the membranes. These changes were revealed by scanning electron microscopy (SEM), time-lag, and gravimetric sorption measurements. Pebax® 1657 and PEVI-DEP showed similar affinity towards CO2, and its uptake or solubility was not influenced by the amount of PIL in the membrane. Therefore, the addition of the PIL did not lead to improvements in the separation of CO2 from other gases. Importantly, PEVI-DEP (40 wt.%) incorporation affected and improved permeability and selectivity by more than 50% especially for the separation of light gases, e.g., H2/CH4 and H2/CO2, but higher PEVI-DEP concentrations lead to a decline in the transport properties.

11.
Fish Physiol Biochem ; 46(4): 1461-1468, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32430645

RESUMO

This study aimed to investigate the effect of fractionated seminal plasma on characteristics of common carp Cyprinus carpio cryopreserved sperm. Nanosep® centrifugal devices yielded four seminal plasma fractions with different total protein content ranging in molecular weight from less than 17 to almost 74 kDa. Each protein fraction was added to semen extender medium prior to freezing. Spermatozoon motility characteristics and DNA integrity were analyzed in supplemented and non-supplemented cryopreserved samples. The cryopreservation process strongly affected the swim-up sperm quality. Treatment with fractions 1, 2, 3, and 4 was associated with significantly higher spermatozoon motility rate and curvilinear velocity than seen in extender only, with highest values obtained with fraction 4 (78.21 ± 2.41% and 168.05 ± 4.46 µm/s, respectively). Significantly less DNA damage, expressed as percent tail DNA (12.23 ± 1.27) and olive tail moment (0.68 ± 0.12), was recorded in fraction 4. The findings indicated that addition of fractionated seminal plasma to cryopreservation medium can preserve the quality of common carp sperm. The protective effect of each fraction varied, suggesting the presence of distinct components exerting different effects on cryopreserved sperm function.


Assuntos
Carpas/fisiologia , Criopreservação/veterinária , Preservação do Sêmen/veterinária , Sêmen/fisiologia , Espermatozoides/fisiologia , Análise de Variância , Animais , Aquicultura , Ensaio Cometa/veterinária , Dano ao DNA , Fragmentação do DNA , Masculino , Preservação do Sêmen/métodos , Motilidade dos Espermatozoides
12.
Environ Sci Pollut Res Int ; 27(17): 22120-22126, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32304044

RESUMO

This study was performed to explore acute toxicity of biologically synthesized gold nanoparticles (AuNPs) to a model organism Daphnia magna. Hence, using aqueous extract of marine macroalga Saccharina japonica, two AuNPs including SJ-AuNPs-72 (72.6 ± 43.8 nm) and SJ-AuNPs-10 (10.8 ± 2.8 nm) were synthesized. These AuNPs were characterized by different techniques such as UV-Vis spectrophotometry, transmission electron microscopy (TEM), dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDX). The 48-h LC50 values of SJ-AuNPs-72 and SJ-AuNPs-10 to D. magna were 1.57 ± 0.07 and 2.69 ± 0.12 mg/L, respectively, showing greater toxicity of SJ-AuNPs-72. After exposure of daphnids to treatments, AuNPs were accumulated in gut tract, and lipid droplets under the Daphnia carapace were also observed. Whereas studies on toxicity of biosynthesized AuNPs are still scarce, the achievements of this work are helpful for understanding the toxicity of biosynthesized AuNPs to crustacean D. magna.


Assuntos
Nanopartículas Metálicas , Alga Marinha , Animais , Daphnia , Difusão Dinâmica da Luz , Ouro , Extratos Vegetais , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Environ Res ; 185: 109433, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32247152

RESUMO

The increasing production of eco-friendly nanoparticles like biosynthesized nanoparticles (BNPs) calls for study on their environmental and biological safety. Herein, the impact of natural organic matter on the toxicity of BNPs was studied. Using leaf extract of herbal plant Allium fistulosum, the Allium fistulosum-silver nanoparticles (AF-AgNPs) were synthesized with the yield of around 100% and used to explore the impacts of natural organic matter (Suwannee river humic acid) on their toxicity to green microalgae Chlorella vulgaris. The results showed that the as-prepared AF-AgNPs could decrease the end-points of biomass and chlorophyll a content of C. vulgaris in a dose-dependent manner. In addition, AF-AgNPs enhanced algal aggregation and decreased size of cells, especially at higher concentrations. However, organic matter showed an ameliorative effect on the toxicity of AF-AgNPs, and significant enhancement of biomass and chlorophyll a content (p < 0.05) were observed in media treated with higher contents of AF-AgNPs. Organic matter could also prevent more cellular aggregation and size reduction of C. vulgaris. Our results are helpful for understanding the effects of organic matter on the toxicity of BNPs to aquatic organisms.


Assuntos
Chlorella vulgaris , Nanopartículas Metálicas , Microalgas , Clorofila A , Nanopartículas Metálicas/toxicidade , Prata/toxicidade
14.
ACS Appl Mater Interfaces ; 11(1): 990-997, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30561980

RESUMO

Metal-organic framework (MOF) nanosheets have emerged as promising materials for the construction of molecular sieve membranes due to their nanoscale thickness and highly oriented pore arrays. However, the development of defect-free MOF nanosheet membranes from rigid MOF nanosheets with efficient permselectivity and robust mechanical strength still remains a big challenge. Herein, we develop a facile GO-induced assembly strategy to design continuous and uniform two-dimensional MOF composite membranes, in which the copper 1,4-benzene dicarboxylate (CuBDC) nanosheets present a layer-stacking arrangement. With the assistance of flexible GO, the voids between the junctions of rigid MOF nanosheets are well-repaired, and the interlayer bonding interactions are strengthened, resulting in the fabrication of a continuous nanosheet membrane with robust mechanical strength. The obtained MOF nanosheet-based membranes display remarkable H2/CO2 separation performance with a superior H2 permeance of 9.6 × 10-7 mol m-2 s-1 Pa-1 and an ideal separation selectivity of 95.1 due to the well-defined size exclusion effect, showing great promise for H2 separation and purification. The repair strategy described here could also provide the blueprint for the development of other nanosheet-based membranes.

16.
Fertil Steril ; 90(1): 84-91, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17889864

RESUMO

OBJECTIVE: To determine whether laser-assisted hatching can improve clinical outcome of assisted reproductive techniques in patients with advanced female age, with recurrent implantation failure, or who are using frozen-thawed embryos. DESIGN: A prospective randomized study. SETTING: The infertility and IVF unit at a research facility in Iran. PATIENT(S): Four hundred ten patients with advanced female age (> or =37 y), 796 patients with recurrent implantation failure (for > or =2 cycles), and 180 patients with frozen-thawed embryos. INTERVENTION(S): Patients were divided equally into test and control groups. On the day of embryo transfer, the zona pellucida of the selected embryos in the test group were opened about 40 mum by using an infrared optical laser system, whereas in the control group they were all intact. MAIN OUTCOME MEASURE(S): Clinical pregnancy rates and implantation rates. RESULT(S): In the patients with advanced female age or recurrent implantation failure, the clinical pregnancy and implantation rates were similar for the test and control groups. However, in the patients with frozen-thawed embryos, the rates were statistically significantly higher in the test group as compared with those of the control group (31.2% and 12.8% vs. 11.1% and 4.2%, respectively). CONCLUSION(S): The laser-assisted hatching improved the pregnancy and implantation rates in patients with frozen-thawed embryos but had no effect in patients with advanced female age or recurrent implantation failure.


Assuntos
Criopreservação , Implantação do Embrião , Transferência Embrionária , Infertilidade/terapia , Raios Infravermelhos , Lasers , Técnicas de Reprodução Assistida , Zona Pelúcida/efeitos da radiação , Adulto , Fatores Etários , Feminino , Humanos , Gravidez , Taxa de Gravidez , Estudos Prospectivos , Falha de Tratamento
17.
J Reprod Med ; 52(6): 503-12, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17694968

RESUMO

OBJECTIVE: To investigate the structure of epithelial cells from the human oviduct and uterus on extracellular matrix (ECM) gel in the first passage. STUDY DESIGN: Human oviducts and endometrial tissues were obtained from patients undergoing total hysterectomy; the epithelial cells, having been isolated by enzyme digestion, were cultured on polystyrene plastic surfaces. The epithelial nature of the cells was confirmed by immunocytochemistry, and their morphology was examined by microscopy. Cells of an epithelial nature were then trypsinized and cultured on an ECM gel-coated filter insert for 5 days. The cells, in parallel with the tissues, were subsequently prepared for transmission electron microscopy. RESULTS: Plastic-cultured cells had no sign of differentiation and appeared as elongated spindle cells in sections. These cells looked columnar and highly polarized after being cultured on ECM gel surfaces. They were similar to epithelial cells from the corresponding tissue fragment. Cultured on ECM gel, the ciliated epithelial cells of human oviducts appeared ultrastructurally similar to glandular cells from the human uterus. Cilia did not form under culture conditions. CONCLUSIONS: It seems that human uterine and oviduct epithelial cells can acquire polarized morphology and differentiated states on ECM gel after having lost it on plastic surfaces and that ECM gel by itself is not enough to induce cilia formation in culture.


Assuntos
Técnicas de Cultura de Células , Células Epiteliais/ultraestrutura , Tubas Uterinas/citologia , Útero/citologia , Diferenciação Celular , Células Cultivadas , Cílios/ultraestrutura , Matriz Extracelular , Feminino , Géis , Humanos , Imuno-Histoquímica , Fase Luteal/fisiologia , Microscopia Eletrônica de Transmissão , Plásticos
18.
Curr Neurovasc Res ; 4(3): 153-60, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17691968

RESUMO

The CD133(+) bone marrow cell (BMC) population includes primitive multipotent stem cells which induce neoangiogenesis. Studies suggested transplantation of these cells to infarcted myocardium can have a favorable impact on tissue perfusion and contractile performance. We assessed the feasibility, safety and functional outcomes of autologus CD133(+) BMC transplantation during coronary artery bypass grafting (CABG) in patients with recent myocardial infarction. In a prospective, nonrandomized, open-label study, 27 patients with recent myocardial infarction underwent CABG and intramyocardial injection of autologous bone marrow-derived CD133(+) cells (18 patients, BMC group) or CABG alone (9 patients, control group). At 6 months after CABG, the Wall Motion Score Index (WMSI) was significantly reduced for akinetic/dyskinetic segments treated with CD133(+) cells compared with the control group (P<0.006). Likewise, comparison between baseline and follow up results of dobutamine stress echocardiography and myocardial perfusion scintigraphy showed improvement of myocardial viability and local perfusion of the infarcted zone of the BMC group compared with the control group. No complications related to CD133(+) cell transplantation were noted, either procedurally or during postoperative at a mean of 14 months follow up. In patients with recent myocardial infarction, transplantation of CD133(+) cells to the peri-infarct zone during CABG surgery is feasible and safe, with no evidence of early or late adverse events. Moreover, these cells might restore tissue viability and improve perfusion of the infarcted myocardium, suggesting that they may induce myogenesis as well as angiogenesis.


Assuntos
Antígenos CD/metabolismo , Células da Medula Óssea/metabolismo , Transplante de Medula Óssea/métodos , Glicoproteínas/metabolismo , Infarto do Miocárdio/cirurgia , Peptídeos/metabolismo , Transplante Autólogo/métodos , Antígeno AC133 , Células da Medula Óssea/fisiologia , Contagem de Células , Seguimentos , Humanos , Estudos Prospectivos , Estudos Retrospectivos , Resultado do Tratamento
19.
World J Gastroenterol ; 13(24): 3359-63, 2007 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-17659676

RESUMO

AIM: To evaluate safety and feasibility of autologous bone marrow-enriched CD34+ hematopoietic stem cell Tx through the hepatic artery in patients with decompensated cirrhosis. METHODS: Four patients with decompensated cirrhosis were included. Approximately 200 mL of the bone marrow of the patients was aspirated, and CD34+ stem cells were selected. Between 3 to 10 million CD34+ cells were isolated. The cells were slowly infused through the hepatic artery of the patients. RESULTS: Patient 1 showed marginal improvement in serum albumin and no significant changes in other test results. In patient 2 prothrombin time was decreased; however, her total bilirubin, serum creatinine, and Model of End-Stage Liver Disease (MELD) score worsened at the end of follow up. In patient 3 there was improvement in serum albumin, porthrombin time (PT), and MELD score. Patient 4 developed radiocontrast nephropathy after the procedure, and progressed to type 1 hepatorenal syndrome and died of liver failure a few days later. Because of the major side effects seen in the last patient, the trial was prematurely stopped. CONCLUSION: Infusion of CD34+ stem cells through the hepatic artery is not safe in decompensated cirrhosis. Radiocontrast nephropathy and hepatorenal syndrome could be major side effects. However, this study does not preclude infusion of CD34+ stem cells through other routes.


Assuntos
Células da Medula Óssea/citologia , Transplante de Células-Tronco Hematopoéticas , Cirrose Hepática/terapia , Adulto , Antígenos CD34/análise , Sobrevivência Celular , Feminino , Artéria Hepática , Humanos , Masculino , Pessoa de Meia-Idade , Transplante Autólogo
20.
Reprod Biomed Online ; 13(6): 823-32, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17169204

RESUMO

Blastomere fragmentation is one of the most significant defects in cleaving embryos. Scientists believed that removing the fragments was a possible way to reduce their unwanted effects. This hypothesis has been tested in some studies in which the development of human fragmented embryos was followed in vivo after all fragments were removed, but little is known about the potential for in-vitro development of such embryos, which is the subject of the present study. For this purpose, 4-6 cell surplus human embryos were scored according to the degree and pattern of fragmentation into four grades, allocated into two groups of control and fragmentation removal (experimental) and cultured sequentially. At the end of day 6 of culture, in the experimental group especially in grade IV blastocyst rate, size and number of blastomeres in each blastocyst were all improved compared with those of the control group (42.3 versus 20.0%; 19,205.7 +/- 1060.3 versus 15,825.9 +/- 448.7 microm(2) and 100.14 +/- 13.48 versus 63.75 +/- 19.79 respectively, P < 0.05). In the grade IV embryos, apoptotic index was also significantly reduced after embryo fragmentation removal (3.40 +/- 0.88 versus 22.99 +/- 4.45, P < 0.05). In conclusion, fragmentation removal had a positive effect on human fragmented embryos and produced the best quality blastocysts.


Assuntos
Blastocisto/citologia , Adulto , Apoptose , Blastômeros/citologia , Contagem de Células , Separação Celular , Desenvolvimento Embrionário , Feminino , Humanos , Técnicas In Vitro , Masculino
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