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1.
Sci Rep ; 10(1): 22026, 2020 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-33328574

RESUMO

Picophytoplankton (PicoP) are increasingly recognized as significant contributors to primary productivity and phytoplankton biomass in coastal and estuarine systems. Remarkably though, PicoP composition is unknown or not well-resolved in several large estuaries including the semi-lagoonal Neuse River Estuary (NRE), a tributary of the second largest estuary-system in the lower USA, the Pamlico-Albemarle Sound. The NRE is impacted by extreme weather events, including recent increases in precipitation and flooding associated with tropical cyclones. Here we examined the impacts of moderate to extreme (Hurricane Florence, September 2018) precipitation events on NRE PicoP abundances and composition using flow cytometry, over a 1.5 year period. Phycocyanin-rich Synechococcus-like cells were the most dominant PicoP, reaching ~ 106 cells mL-1, which highlights their importance as key primary producers in this relatively long residence-time estuary. Ephemeral "blooms" of picoeukaryotic phytoplankton (PEUK) during spring and after spikes in river flow were also detected, making PEUK periodically major contributors to PicoP biomass (up to ~ 80%). About half of the variation in PicoP abundance was explained by measured environmental variables. Temperature explained the most variation (24.5%). Change in total dissolved nitrogen concentration, an indication of increased river discharge, explained the second-most variation in PicoP abundance (15.9%). The short-term impacts of extreme river discharge from Hurricane Florence were particularly evident as PicoP biomass was reduced by ~ 100-fold for more than 2 weeks. We conclude that precipitation is a highly influential factor on estuarine PicoP biomass and composition, and show how 'wetter' future climate conditions will have ecosystem impacts down to the smallest of phytoplankton.

2.
Cir Cir ; 88(4): 420-427, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32567593

RESUMO

Objective: To assess whether the accuracy in locoregional staging using magnetic resonance imaging (MRI) in rectal cancer (primary or post-chemoradiotherapy) improves by adding diffusion-weighted imaging, according to the radiologist's degree of experience. Method: Retrospective study on 100 MRI records (1.5 T, 2011-2016) from patients with rectal cancer (reference standard: histology of surgical specimens). Ten radiologists (three experienced in rectal cancer, three specialized in other areas and four residents) individually reviewed each case twice: first, evaluating just high-resolution T2-weighted sequences; second, evaluation of diffusion-weighted plus high-resolution ones. The analysis focused on the differentiation between early (0-I) and advanced (II-IV) stages. Accuracy, sensitivity/specificity and predictive values were calculated. Results: Experienced radiologists showed some worsening by adding diffusion-weighted imaging, mainly at primary staging (accuracy: 0.769 to 0.701). Inexperienced radiologists presented a post-chemoradiotherapy improvement (accuracy: 0.574 to 0.642; specificity of 19.1 to 29.8%), although with no other remarkable changes. Residents demonstrated a worsening at primary staging by adding diffusion (accuracy: 0.670 to 0.633; specificity: 45.8 to 39.6%), but post-chemoradiotherapy improvement (sensitivity: 80.6 to 87%). The differences between both reviews were not statistically significant. Conclusions: No significant differences were found in the distinction between early and advanced rectal tumors secondary to adding diffusion-weighted imaging to high-resolution T2-weighted sequences.

3.
Arthrosc Tech ; 9(6): e755-e759, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32577348

RESUMO

Nanofractured autologous matrix-induced chondrogenesis (NAMIC©) is a 1-step technique that combines nanofracture needling to induce bone marrow stimulation (BMS) and the use of cell-free collagen matrix to optimize cartilage regeneration. In this Technical Note, we describe a modification of the NAMIC procedure using mosaicplasty trephines to prepare the lesion surface and to shape collagen implants in an all-arthroscopic approach (A-NAMIC). This technique is indicated for the treatment of International Cartilage Repair Society grade III to IV knee chondral lesions of ≤4 cm2. After damaged cartilage is debrided, trephines are used to create a flat, circular lesion surfaces. Subsequently, BMS is performed with nanofracture, eliciting reproducible and stop-controlled subchondral bone perforations of 9-mm depth and 1-mm width. The collagen membrane is then cut to size with the trephine, placed over the prepared defect, and secured with fibrin glue, preventing loss of regenerating cells and growth factors to the joint space. Using trephines allows the rapid and precise creation of smooth defect surfaces with known dimensions, ensuring optimal lesion coverage. Additionally, nanofracture reduces trabecular compaction and allows for a deeper access to subchondral bone in comparison with conventional microfracture, improving lesion filling and production of cartilage with higher hyaline content.

4.
Ann Endocrinol (Paris) ; 81(2-3): 78-82, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32340849

RESUMO

PURPOSE: To describe pre- to post-treatment changes in clinical activity score (CAS) and exophthalmometry in patients with Graves orbitopathy treated with tocilizumab (TCZ). MATERIAL AND METHODS: Eight Mexican patients presenting with active Graves orbitopathy (CAS>3/7) previously treated with glucocorticoids received 1 monthly dose of TCZ for 6 months. CAS, EUGOGO severity assessment and exophthalmometry were used to evaluate clinical status, with serum measurement of thyroid-stimulating hormone receptor antibodies (TR-Ab) for biochemical evaluation before and after application of TCZ. RESULTS: Eight patients were analyzed: 6 male (75%), 2 female (25%): mean age, 45.9±11.2 years; mean weight, 85±18.3 kg. Mean TR-Ab level at treatment outset was 291.9±96.4%, mean CAS 4.1±0.3 and mean exophthalmometry 21.2±3.2 mm. After TCZ treatment, mean TR-Ab level fell to 172.7±54% (P=0.001), mean CAS to 1.1±0.6 (P=0.001) and mean exophthalmometry to 19.3±2 mm (P=0.02). CONCLUSIONS: TCZ is a therapeutic option for glucocorticoid-resistant orbitopathy, and should be considered in second line due to the cost of treatment or in first line in patients with contraindications to intravenous GC pulse therapy.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Resistência a Medicamentos/efeitos dos fármacos , Glucocorticoides/uso terapêutico , Oftalmopatia de Graves/tratamento farmacológico , Adulto , Estudos de Coortes , Feminino , Oftalmopatia de Graves/sangue , Oftalmopatia de Graves/patologia , Humanos , Imunoglobulinas Glândula Tireoide-Estimulantes/sangue , Masculino , México , Pessoa de Meia-Idade , Resultado do Tratamento
5.
Radiol Med ; 125(6): 522-530, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32020526

RESUMO

OBJECTIVE: To assess the added value of diffusion-weighted imaging (DWI) to high-resolution T2-weighted sequences (HRT2w) in MRI detection of extramural venous infiltration (EMVI), according to the previous experience of radiologists. METHODS: A cross-sectional study of a retrospective database including 1.5 T MRI records from 100 patients with biopsy-proven rectal cancer (2011-2016; 75 male/25 female, average 63 y/o), which included primary staging (54) and post-chemoradiotherapy follow-up MRIs (46). The reference standard was histology of surgical specimens. All cases were individually blindly reviewed by ten radiologists: three specialists in abdominal radiology, three specialized in different areas and four residents. In each case, the presence of EMVI was assessed twice: first, using just HRT2w; second, with DWI added to HRT2w. The results were pooled by experience, analyzing sensitivity, specificity, accuracy (area under ROC curve), likelihood ratios, predictive values and overstaging/understaging. RESULTS: Addition of DWI improved diagnostic performance by specialists radiologists, particularly post-chemoradiotherapy (accuracy 0.74-0.84; positive likelihood ratio 3.9-9.1; overstaging 16-8%), less so at primary staging (specificity 76-87.2%; overstaging 21-11%). Non-specialist radiologists also improved, but only at primary staging (accuracy 0.59-0.63). Residents showed small changes, except for notably increased sensitivity in both primary staging (35.7-43%) and post-chemoradiotherapy (41.7-58.3%) staging, at the expense of increased overstaging. CONCLUSIONS: The addition of DWI improved the diagnostic performance of EMVI by experienced radiologists, downgrading overstaging, especially in post-chemoradiotherapy follow-up. It resulted in fewer changes for inexperienced radiologists (enhanced primary staging) and residents (increased sensitivity).


Assuntos
Imagem de Difusão por Ressonância Magnética , Neoplasias Retais/patologia , Neoplasias Retais/terapia , Neoplasias Vasculares/diagnóstico por imagem , Neoplasias Vasculares/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Quimiorradioterapia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , Estudos Retrospectivos , Veias
6.
J Endocr Soc ; 4(2): bvz018, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32104752

RESUMO

We report on the case of an 8-year-old Mexican male, with a 3-year-old clinical diagnosis of familial hypercholesterolemia, and the difficulties encountered in his treatment while in our care. His treatment started with a regimen consisting of ezetimibe/simvastatin, cholestyramine, and a dietary plan of 1600 calories, with a limited intake of 200 mg of cholesterol per day. Problems arose when the patient's low-density lipoprotein cholesterol (LDL) levels did not meet ideal targets, which prompted the use of LDL cholesterol apheresis (not available in Mexico) for 6 months. As a last resort, PCSK9 inhibitors were administered but the LDL levels remained in the 600 mg/dL range. AmbryGenetics conducted a genetic test employing the Sanger method. The results suggested that there were 2 different mutations for each allele of the same LDL receptor gene (c.249delTinsGG and p.(Cys109Arg)), located in exons 3 and 4, respectively. We identified compound heterozygous mutations in our index case, with him having both the p.C109R mutation (from the maternal lineage), as well as a c.249delTinsGG mutation (from the paternal lineage). The p.C109R mutation has been previously reported, not only in Mexico, but in European regions (Germany, Czech Republic, Ireland, Italy) as well. Functional studies indicated a residual enzymatic activity of 15% to 30% for heterozygotes. To date, the variant c.249delTinsGG has not been reported. This case study illustrates the fact that in Mexico there are limited options available for treatment in such a scenario. As medical professionals, we are limited by the tools at our disposal.

7.
ACS Appl Mater Interfaces ; 12(5): 5901-5908, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31971770

RESUMO

Silicon has shown promise for use as a small band gap (1.1 eV) absorber material in photoelectrochemical (PEC) water splitting. However, the limited stability of silicon in acidic electrolyte requires the use of protection strategies coupled with catalysts. Herein, spin coating is used as a versatile method to directly coat silicon photoanodes with an IrOx oxygen evolution reaction (OER) catalyst, reducing the processing complexity compared to conventional fabrication schemes. Biphasic strontium chloride/iridium oxide (SrCl2:IrOx) catalysts are also developed, and both catalysts form photoactive junctions with silicon and demonstrate high photoanode activity. The iridium oxide photoanode displays a photocurrent onset at 1.06 V vs reversible hydrogen electrode (RHE), while the SrCl2:IrOx photoanode onsets earlier at 0.96 V vs RHE. The differing potentials are consistent with the observed photovoltages of 0.43 and 0.53 V for the IrOx and SrCl2:IrOx, respectively. By measuring the oxidation of a reversible redox couple, Fe(CN)63-/4-, we compare the charge carrier extraction of the devices and show that the addition of SrCl2 to the IrOx catalyst improves the silicon-electrolyte interface compared to pure IrOx. However, the durability of the strontium-containing photoanode remains a challenge, with its photocurrent density decreasing by 90% over 4 h. The IrOx photoanode, on the other hand, maintained a stable photocurrent density over this timescale. Characterization of the as-prepared and post-tested material structure via Auger electron spectroscopy identifies catalyst film cracking and delamination as the primary failure modes. We propose that improvements to catalyst adhesion should further the viability of spin coating as a technique for photoanode preparation.

8.
Dalton Trans ; 49(12): 3892-3900, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-31894216

RESUMO

The electrochemical oxygen evolution reaction (OER) is the half-cell reaction for many clean-energy production technologies, including water electrolyzers and metal-air batteries. However, its sluggish kinetics hinders the performance of those technologies, impeding them from broader implementation. Recently, we reported the use of zirconium phosphate (ZrP) as a support for transition metal catalysts for the oxygen evolution reaction (OER). These catalysts achieve promising overpotentials with high mass activities. Herein, we synthesize ZrP structures with controlled morphology: hexagonal platelets, rods, cubes, and spheres, and subsequently modify them with Co(ii) and Ni(ii) cations to assess their electrochemcial OER behavior. Through inductively coupled plasma mass-spectrometry measurements, the maximum ion exchange capacity is found to vary based on the morphology of the ZrP structure and cation selection. Trends in geometric current density and mass activity as a function of cation selection are discussed. We find that the loading and coverage of cobalt and nickel species on the ZrP supports are key factors that control OER performance.

9.
Math Biosci Eng ; 18(1): 22-56, 2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33525079

RESUMO

In this paper, we present a deep learning framework for solving two-dimensional elliptic equations with singular forces on arbitrary domains. This work follows the ideas of the physical-inform neural networks to approximate the solutions and the immersed boundary method to deal with the singularity on an interface. Numerical simulations of elliptic equations with regular solutions are initially analyzed in order to deeply investigate the performance of such methods on rectangular and irregular domains. We study the deep neural network solutions for different number of training and collocation points as well as different neural network architectures. The accuracy is also compared with standard schemes based on finite differences. In the case of singular forces, the analytical solution is continuous but the normal derivative on the interface has a discontinuity. This discontinuity is incorporated into the equations as a source term with a delta function which is approximated using a Peskin's approach. The performance of the proposed method is analyzed for different interface shapes and domains. Results demonstrate that the immersed boundary neural network can approximate accurately the analytical solution for elliptic problems with and without singularity.

10.
Abdom Radiol (NY) ; 44(11): 3674-3682, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31332499

RESUMO

PURPOSE: To analyze changes in MRI diagnostic accuracy in main rectal tumor (T) evaluation resulting from the use of diffusion-weighted imaging (DWI), according to the degree of experience of the radiologist. METHODS: This is a cross-sectional study of a database including one hundred 1.5 T MRI records (2011-2016) from patients with biopsy-proven rectal cancer, including primary staging and post-chemoradiotherapy follow-up. All cases were individually blindedly reviewed by ten radiologists: three experienced in rectal cancer, three specialized in other areas, and four residents. Each case was assessed twice to detect perirectal infiltration: first, evaluating just high-resolution T2-weighted sequences (HRT2w); second, evaluation of DWI plus HRT2w sequences. Results were pooled by experience, calculating accuracy (area under ROC curve), sensitivity and specificity, predictive values, likelihood ratios, and overstaging/understaging. Histology of surgical specimens provided the reference standard. RESULTS: DWI significantly improved specificity by experienced radiologists in primary staging (63.2% to 75.9%) and, to a lesser extent, positive likelihood ratio (2.06 to 2.87); minimal changes were observed post-chemoradiotherapy, with a slight decrease of accuracy (0.657 to 0.626). Inexperienced radiologists showed a similar pattern, but with slight enhancement post-chemoradiotherapy (accuracy 0.604 to 0.621). Residents experienced small changes, with increased sensitivity/decreased specificity in both primary (69% to 72%/67.2% to 64.7%) and post-chemoradiotherapy (68.1% to 73.6%/47.3% to 44.6%) staging. CONCLUSIONS: Adding DWI to HRT2w significantly improved specificity for the detection of perirectal infiltration at primary staging by experienced radiologists and also by inexperienced ones, although to a lesser extent. In the post-neoadjuvant treatment subgroup, only minimal changes were observed.


Assuntos
Quimiorradioterapia , Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias Retais/diagnóstico por imagem , Neoplasias Retais/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Colonoscopia , Estudos Transversais , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Invasividade Neoplásica , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Neoplasias Retais/patologia , Estudos Retrospectivos , Sensibilidade e Especificidade
11.
J Endocr Soc ; 3(3): 537-543, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30788455

RESUMO

Doege-Potter syndrome with acromegaloid facial changes is extremely rare. Uncooked cornstarch along with glucocorticoids have been used as supportive care in patients with non-islet cell tumor hypoglycemia (NICTH). Preoperative embolization of hepatic solitary fibrous tumors (SFT) with NICTH has yielded unsatisfactory results. Herein we present the case of a 61-year-old man with a 3-month history of severe frequent hypoglycemic episodes and acromegaloid facial changes. During a spontaneous hypoglycemia (26 mg/dL), laboratory values showed a hypoinsulinemic pattern with low levels of GH, IGFPB3, and an IGF2/IGF1 ratio of 8.5:1. Cross-sectional imaging revealed a large (16 × 13 × 11 cm) hepatic tumor, and cytology was consistent with SFT. A preoperative right portal embolization was performed in an effort to induce normal remnant liver hypertrophy to allow for safe tumor resection. After the procedure, uncooked starch treatment followed by prednisone was started, achieving complete remission of hypoglycemic episodes in the preoperative setting. He subsequently underwent partial hepatectomy. The histologic diagnosis was compatible with a potentially malignant SFT. The patient had an excellent outcome with complete remission of hypoglycemia, improvement of facial acromegaloid changes, and no further evidence of disease. To our knowledge, this is the first case of a patient with Doege-Potter syndrome with acromegaloid facial changes induced by a potentially malignant liver SFT, treated successfully with a multimodal approach consisting of uncooked cornstarch, low-dose prednisone, preoperative embolization, and complete surgical resection. The use of cornstarch and low-dose glucocorticoids may be an adequate treatment in advance of undergoing surgery.

12.
Rev. sanid. mil ; 72(5/6): 332-338, sep.-dic. 2018. tab
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1020883

RESUMO

Resumen La obesidad representa uno de los problemas más importantes de salud de nuestros tiempos; hoy en día se considera un desafío sanitario en los países desarrollados, así como en los que se encuentran en vías de desarrollo, ya que han adoptado los hábitos alimenticios típicos del mundo desarrollado pero, además, por todas las comorbilidades asociadas. La obesidad se asocia con un espectro muy amplio de alteraciones fisiopatológicas como: sobrecarga de volumen, hipertensión, desregulación metabólica, activación neurohumoral e inflamación sistémica. Los genes involucrados en la obesidad son varios y se relacionan con diferentes procesos: en la regulación del apetito, los comportamientos de búsqueda de alimentos y la eficiencia metabólica. La pérdida de peso con cambios de estilo de vida (alimentación y ejercicio) es un camino adecuado para mejorar la salud en pacientes con factores de riesgo asociados a la obesidad. Aunque existen tratamientos medicamentosos y quirúrgicos para lograr la pérdida de peso, éstos no son elegidos de primera intención y sólo son usados cuando el tratamiento primario ha fallado.


Abstract Obesity represents one of the most important health problems of our times, nowadays it is considered a health challenge in developed countries, as well as in those that are developing, as they have adopted the typical eating habits of the developed world, but also because of all the associated comorbidities. Obesity is associated with a very broad spectrum of pathophysiological changes such as: volume overload, hypertension, metabolic dysregulation, neurohumoral activation and systemic inflammation. The genes involved in obesity are several and are related to different processes: in the regulation of appetite, the behaviors of food search and metabolic efficiency. Weight loss with changes in lifestyle (diet and exercise) is an adequate way to improve health in patients with risk factors associated with obesity. Although there are medical and surgical treatments to achieve weight loss, these are not chosen as first intention and are only used when the primary treatment has failed.

13.
Rev. sanid. mil ; 72(3/4): 258-263, may.-ago. 2018. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1004498

RESUMO

Resumen El síndrome de Prader-Willi en un trastorno multisistémico; se caracteriza en la infancia por hipotonía, dificultades para la alimentación, retraso en el desarrollo e hipoplasia genital. En la adolescencia y edad adulta, la problemática se centra en las alteraciones del comportamiento, la ausencia de saciedad y el retraso mental leve o moderado. Su diagnóstico temprano requiere una alta sospecha clínica y estudios especiales (estudios de metilación e hibridación fluorescente in situ). La detección temprana se realiza con el fin de disminuir la morbilidad y mortalidad de los pacientes. Existe una clara necesidad de un enfoque multidisciplinario para facilitar el diagnóstico temprano y optimizar el manejo y tratamiento para mejorar la calidad de vida. Se presentan seis casos de SPW que tienen seguimiento en la Unidad de Especialidades Médicas a fin de conocer la prevalencia del SPW, ya que en la actualidad no se cuenta con ningún registro que la documente.


Abstract Prader-Willi syndrome in a multisystem disorder; it is characterized in childhood by hypotonia, feeding difficulties, developmental delay and genital hypoplasia. In adolescence and adulthood, the problem focuses on behavioral changes, the absence of satiety and mild or moderate mental retardation. Its early diagnosis requires a high clinical suspicion and special studies (methylation studies and fluorescent in situ hybridization). An early detection reduces the morbidity and mortality of patients. There is a clear need for a multidisciplinary approach to facilitate early diagnosis and optimize management and treatment to improve quality of life. There are six cases of SPW that are followed in the Medical Specialties Unit; we report them in order to know the prevalence of PWS, since at present there is no record documenting it.

14.
J Psychiatr Pract ; 24(1): 2-14, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29320378

RESUMO

This study examined the utility of fluoxetine in the treatment of 5 children, aged 5 to 14 years, diagnosed with selective mutism who also demonstrated symptoms of social anxiety. A nonconcurrent, randomized, multiple-baseline, single-case design with a single-blind placebo-controlled procedure was used. Parents and the study psychiatrist completed multiple methods of assessment including Direct Behavior Ratings and questionnaires. Treatment outcomes were evaluated by calculating effect sizes for each participant as an individual and for the participants as a group. Information regarding adverse effects with an emphasis on behavioral disinhibition and ratings of parental acceptance of the intervention was gathered. All 5 children experienced improvement in social anxiety, responsive speech, and spontaneous speech with medium to large effect sizes; however, children still met criteria for selective mutism at the end of the study. Adverse events were minimal, with only 2 children experiencing brief occurrences of minor behavioral disinhibition. Parents found the treatment highly acceptable.


Assuntos
Fluoxetina/farmacologia , Mutismo/tratamento farmacológico , Fobia Social/tratamento farmacológico , Inibidores de Captação de Serotonina/farmacologia , Adolescente , Criança , Pré-Escolar , Feminino , Fluoxetina/administração & dosagem , Fluoxetina/efeitos adversos , Humanos , Masculino , Inibidores de Captação de Serotonina/administração & dosagem , Inibidores de Captação de Serotonina/efeitos adversos , Método Simples-Cego , Resultado do Tratamento
15.
Chemosphere ; 144: 975-81, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26433935

RESUMO

In this work, α-Fe2O3 nanofibers were synthesized via electrospinning and characterized to observe optimal morphological and dimensional properties towards chromate removal. The Fe2O3 nanofiber samples were tested in aqueous solutions containing chromate (CrO4(2-)) to analyze their adsorption capabilities and compare them with commercially-available Fe2O3 nanoparticles. Synthesized Fe2O3 nanofibers were observed with a variety of different average diameters, ranging from 23 to 63 nm, while having a constant average grain size at 34 nm, point zero charge at pH 7.1, and band gap at 2.2 eV. BET analysis showed an increase in specific surface area with decreasing average diameter, from 7.2 to 59.2 m(2)/g, due to the increased surface area-to-volume ratio with decreasing nanofiber size. Based on CrO4(2-) adsorption isotherms at pH 6, adsorption capacity of the Fe2O3 nanofibers increased with decreasing diameter, with the 23 nm sized nanofibers having an adsorption capacity of 90.9 mg/g, outperforming the commercially-available Fe2O3 nanoparticles by nearly 2-fold. Additionally, adsorption kinetics was also analyzed, increasing with decreasing nanofiber diameter. The enhanced performance of the nanofiber is suggested to be caused solely due to the increased surface area, in part by its size and morphology. Electrospun Fe2O3 nanofibers provide a promising solution for effective heavy metal removal through nanotechnology-integrated treatment systems.


Assuntos
Cromatos/isolamento & purificação , Compostos Férricos/química , Nanofibras/química , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Cromatos/química , Cinética , Tamanho da Partícula , Propriedades de Superfície , Poluentes Químicos da Água/química
16.
J Hazard Mater ; 299: 141-8, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26101968

RESUMO

In this work, Ag-TiO2 composite nanofibers were fabricated by electrospinning, where the composition and crystallinity were tuned by controlling the precursor composition and annealing conditions. Characterization revealed that bulk-embedded Ag nanoparticles inhibited anatase-to-rutile phase transformation and a decrease in band gap from 3.2 down to 2.8 eV with increase in the Ag content. The photocatalytic activity of 0.5 at.% Ag-TiO2 nanofibers toward phenol degradation was the greatest, outperforming both unmodified TiO2 nanofibers and commercially available TiO2 Aeroxide(®) P25 by a factor of ∼3. The high reactivity of the low content Ag-TiO2 nanofibers can be attributed to the addition of electron traps, which provide efficient carrier separation and, therefore, decreased recombination. However, further increase in Ag content led to lower photoreactivity, most likely due to the growth of the Ag nanoparticles, which suggests an optimal size of 2 to 3 nm for the Ag nanoparticles at 0.5 at.% provided the greatest photoreactivity. Ag-TiO2 nanofibers show great promise as innovative and highly performing nanomaterials for future nanotechnology-based treatment systems, particularly when the photoreactivity demonstrate herein is used in synergy with the established antimicrobial activity of nano-Ag.

17.
BMC Infect Dis ; 13: 442, 2013 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-24053690

RESUMO

BACKGROUND: Tuberculosis continues to be one of the leading causes of death worldwide and in the American region. Although multidrug-resistant tuberculosis (MDR-TB) remains a threat to TB control in Panama, few studies have focused in typing MDR-TB strains. The aim of our study was to characterize MDR Mycobacterium tuberculosis clinical isolates using PCR-based genetic markers. METHODS: From 2002 to 2004, a total of 231 Mycobacterium tuberculosis isolates from TB cases country-wide were screened for antibiotic resistance, and MDR-TB isolates were further genotyped by double repetitive element PCR (DRE-PCR), (GTG)5-PCR and spoligotyping. RESULTS: A total of 37 isolates (0.85%) were resistant to both isoniazid (INH) and rifampicin (RIF). Among these 37 isolates, only two (5.4%) were resistant to all five drugs tested. Dual genotyping using DRE-PCR and (GTG)5-PCR of MDR Mycobacterium tuberculosis isolates revealed eight clusters comprising 82.9% of the MDR-TB strain collection, and six isolates (17.1%) showed unique fingerprints. The spoligotyping of MDR-TB clinical isolates identified 68% as members of the 42 (LAM9) family genotype. CONCLUSION: Our findings suggest that MDR Mycobacterium tuberculosis is highly clustered in Panama's metropolitan area corresponding to Panama City and Colon City, and our study reveals the genotype distribution across the country.


Assuntos
Antituberculosos/farmacologia , Farmacorresistência Bacteriana Múltipla , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Genótipo , Humanos , Epidemiologia Molecular , Dados de Sequência Molecular , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/efeitos dos fármacos , Panamá/epidemiologia , Filogenia , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia
18.
J Chem Ecol ; 39(7): 1045-54, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23881443

RESUMO

Fungal infections are increasing worldwide, including in the aquatic environment. Microbiota that coexist with marine life can provide protection against fungal infections by secretion of metabolites with antifungal properties. Our laboratory has developed mass spectrometric methodologies with the goal of improving our functional understanding of microbial metabolites and guiding the discovery process of anti-infective agents from natural sources. GA40, a Bacillus amyloliquefaciens strain isolated from an octocoral in Panama, displayed antifungal activity against various terrestrial and marine fungal strains. Using matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS), the molecular species produced by this microbe were visualized in a side-by-side interaction with two representative fungal strains, Aspergillus fumigatus and Aspergillus niger. The visualization was performed directly on the agar without the need for extraction. By evaluating the spatial distributions, relative intensities and m/z values of GA40 secreted metabolites in the fungal interactions and singly grown control colonies, we obtained insight into the antifungal activity of secreted metabolites. Annotation of GA40 metabolites observed in MALDI-IMS was facilitated by MS/MS networking analysis, a mass spectrometric technique that clusters metabolites with similar MS/MS fragmentation patterns. This analysis established that the predominant GA40 metabolites belong to the iturin family. In a fungal inhibition assay of A. fumigatus, the GA40 iturin metabolites were found to be responsible for the antifungal properties of this Bacillus strain.


Assuntos
Antozoários/microbiologia , Antifúngicos/análise , Aspergillus fumigatus/fisiologia , Aspergillus niger/fisiologia , Bacillus/fisiologia , Animais , Bacillus/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Simbiose
19.
Proc Natl Acad Sci U S A ; 110(28): E2611-20, 2013 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-23798442

RESUMO

The ability to correlate the production of specialized metabolites to the genetic capacity of the organism that produces such molecules has become an invaluable tool in aiding the discovery of biotechnologically applicable molecules. Here, we accomplish this task by matching molecular families with gene cluster families, making these correlations to 60 microbes at one time instead of connecting one molecule to one organism at a time, such as how it is traditionally done. We can correlate these families through the use of nanospray desorption electrospray ionization MS/MS, an ambient pressure MS technique, in conjunction with MS/MS networking and peptidogenomics. We matched the molecular families of peptide natural products produced by 42 bacilli and 18 pseudomonads through the generation of amino acid sequence tags from MS/MS data of specific clusters found in the MS/MS network. These sequence tags were then linked to biosynthetic gene clusters in publicly accessible genomes, providing us with the ability to link particular molecules with the genes that produced them. As an example of its use, this approach was applied to two unsequenced Pseudoalteromonas species, leading to the discovery of the gene cluster for a molecular family, the bromoalterochromides, in the previously sequenced strain P. piscicida JCM 20779(T). The approach itself is not limited to 60 related strains, because spectral networking can be readily adopted to look at molecular family-gene cluster families of hundreds or more diverse organisms in one single MS/MS network.


Assuntos
Família Multigênica , Espectrometria de Massas em Tandem/métodos , Sequência de Aminoácidos , Bacillus/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/genética , Pseudomonas/genética
20.
Rev. cuba. obstet. ginecol ; 38(3): 415-423, jul.-set. 2012.
Artigo em Espanhol | LILACS | ID: lil-649879

RESUMO

Introducción: el síndrome de resistencia completa a los andrógenos, feminización testicular o síndrome de Morris, puede presentarse en uno de cada 20 000 a 64 000 recién nacidos varones. Objetivo: presentar un caso con genotipo masculino y fenotipo femenino dado por desarrollo mamario, con genitales externos femeninos con hipoplasia de los labios mayores y menores y la vagina muy corta que termina en un fondo de saco ciego. Métodos: se valora en la consulta a una paciente adolescente de 19 años de edad con amenorrea primaria y contacto sexual insatisfactorio (imposibilidad de penetración). Resultados: se comprueba al examen vagina rudimentaria de unos dos centímetros y escaso desarrollo de genitales externos. En los exámenes complementarios se comprueban cifras de testosterona y LH aumentadas, así como el estradiol disminuido y un cariotipo 46 XY por lo que se sospecha síndrome de Morris y se planifica intervención quirúrgica combinada en un tiempo (vaginal y abdominal) donde se realiza anexectomía total derecha por video laparoscopia y reconstrucción de vagina por técnica de Williams. Posoperatorio satisfactorio y seguimiento ulterior por consulta donde se comprueba vagina funcional y estabilidad emocional de la paciente. Conclusiones: el estudio anatomo-patológico comprueba la existencia de ovario y testículo en la muestra quirúrgica lo que confirma el diagnóstico de síndrome de Morris o de resistencia completa a los andrógenos


Introduction:the syndrome of complete androgen resistance, testicular feminization or Morris syndrome may occur in one in 20 000 to 64 000 of male newborns. Objective: to present a case with male genotype and female phenotype given by breast development, female external genitalia with hypoplasia of the labia and very short vagina ending in a blind pouch Methods: a 19 year- old female patient is assisted in consultation due primary amenorrhea and unsatisfactory sexual contact (impossibility of penetration). Results: at examination, we found a rudimentary vagina of about two inches and underdeveloped external genitalia. The exams confirmed increased LH and testosterone levels and decreased estradiol. It is also found a 46 XY karyotype, so Morris syndrome is suspected. Combined surgery is planned for the vagina and abdomen. Total videolaparoscopy right adnexectomy and vaginal reconstruction by technique of Williams are performed. We had satisfactory postoperative and subsequent follow-up consultation where functional vagina and emotional stability of the patient were checked. Conclusions: the pathological study verifies the existence of ovary and testis in the surgical specimen confirming the diagnosis of Morris syndrome or complete androgen resistance


Assuntos
Humanos , Masculino , Feminino , Adolescente , Síndrome de Resistência a Andrógenos , Vagina/anormalidades , Amenorreia/genética , Relatos de Casos
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