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1.
Eur J Appl Physiol ; 123(6): 1147-1165, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36690907

RESUMO

Muscle glucose transport activity increases with an acute bout of exercise, a process that is accomplished by the translocation of glucose transporters to the plasma membrane. This process remains intact in the skeletal muscle of individuals with insulin resistance and type 2 diabetes mellitus (T2DM). Exercise training is, therefore, an important cornerstone in the management of individuals with T2DM. However, the acute systemic glucose responses to carbohydrate ingestion are often augmented during the early recovery period from exercise, despite increased glucose uptake into skeletal muscle. Accordingly, the first aim of this review is to summarize the knowledge associated with insulin action and glucose uptake in skeletal muscle and apply these to explain the disparate responses between systemic and localized glucose responses post-exercise. Herein, the importance of muscle glycogen depletion and the key glucoregulatory hormones will be discussed. Glucose uptake can also be stimulated independently by hypoxia; therefore, hypoxic training presents as an emerging method for enhancing the effects of exercise on glucose regulation. Thus, the second aim of this review is to discuss the potential for systemic hypoxia to enhance the effects of exercise on glucose regulation.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Insulina , Exercício Físico/fisiologia , Glucose/metabolismo , Resistência à Insulina/fisiologia , Músculo Esquelético/fisiologia , Hipóxia/metabolismo
2.
J Environ Manage ; 246: 547-556, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31202019

RESUMO

Chitosan-magnetic-graphene oxide (CMGO) nanocomposite was prepared for arsenic adsorption. The nanocomposite was characterized through BET, FTIR, FESEM, EDX, and VSM analyses. These characterizations confirmed the formation of CMGO nanocomposites with high specific surface area (152.38 m2/g) and excellent saturation magnetization (49.30 emu/g). Batch adsorption experiments were conducted to evaluate the performance of the nanocomposite in the adsorption of arsenic from aqueous solution. The effects of operational parameters, adsorption kinetic, equilibrium isotherm and thermodynamics were evaluated. The removal efficiency of arsenic increased with increasing adsorbent dosage and contact time. However, the effect of pH followed a different pattern, with the removal efficiency increasing from acidic to neutral pH, and then decreasing at alkaline conditions. The highest adsorption capacity (45 mg/g) and removal efficiency (61%) were obtained at pH 7.3. The adsorption kinetic followed a pseudo-second-order kinetic model. The analysis of adsorption isotherm shows that the adsorption data fitted well to Langmuir isotherm model, indicating a homogeneous process. Thermodynamic analysis shows that the adsorption of As(III) is exothermic and spontaneous. The superparamagnetic properties of the nanocomposite enabled the separation and recovery of the nanoparticles using an external magnetic field. Thus, the developed nanocomposite has a potential for arsenic remediation.


Assuntos
Arsênio , Quitosana , Grafite , Nanocompostos , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Óxidos
3.
J Environ Manage ; 204(Pt 1): 75-81, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28865309

RESUMO

The main problem of landfill leachate is its diverse composition comprising many persistent organic pollutants which must be removed before being discharge into the environment. This study investigated the treatment of raw landfill leachate using electrocoagulation process. An electrocoagulation system was designed with iron as both the anode and cathode. The effects of inter-electrode distance, initial pH and electrolyte concentration on colour and COD removals were investigated. All these factors were found to have significant effects on the colour removal. On the other hand, electrolyte concentration was the most significant parameter affecting the COD removal. Numerical optimization was also conducted to obtain the optimum process performance. Under optimum conditions (initial pH: 7.73, inter-electrode distance: 1.16 cm, and electrolyte concentration (NaCl): 2.00 g/L), the process could remove up to 82.7% colour and 45.1% COD. The process can be applied as a pre-treatment for raw leachates before applying other appropriate treatment technologies.


Assuntos
Eletrocoagulação/métodos , Ferro/química , Poluentes Químicos da Água/química , Eletrodos , Concentração de Íons de Hidrogênio
4.
BMC Genomics ; 16: 784, 2015 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-26466991

RESUMO

BACKGROUND: EAV-HP is an ancient retrovirus pre-dating Gallus speciation, which continues to circulate in modern chicken populations, and led to the emergence of avian leukosis virus subgroup J causing significant economic losses to the poultry industry. We mapped EAV-HP integration sites in Ethiopian village chickens, a Silkie, Taiwan Country chicken, red junglefowl Gallus gallus and several inbred experimental lines using whole-genome sequence data. RESULTS: An average of 75.22 ± 9.52 integration sites per bird were identified, which collectively group into 279 intervals of which 5 % are common to 90 % of the genomes analysed and are suggestive of pre-domestication integration events. More than a third of intervals are specific to individual genomes, supporting active circulation of EAV-HP in modern chickens. Interval density is correlated with chromosome length (P < 2.31(-6)), and 27 % of intervals are located within 5 kb of a transcript. Functional annotation clustering of genes reveals enrichment for immune-related functions (P < 0.05). CONCLUSIONS: Our results illustrate a non-random distribution of EAV-HP in the genome, emphasising the importance it may have played in the adaptation of the species, and provide a platform from which to extend investigations on the co-evolutionary significance of endogenous retroviral genera with their hosts.


Assuntos
Animais Domésticos/genética , Galinhas/genética , Evolução Molecular , Retroviridae/genética , Animais , Animais Domésticos/virologia , Galinhas/virologia , Genoma , Filogenia , Aves Domésticas/genética , Aves Domésticas/virologia , Retroviridae/patogenicidade , Integração Viral/genética
5.
Oral Dis ; 21(3): 314-9, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24989645

RESUMO

OBJECTIVES: The chronic periodontitis (CP) and psoriasis share common risk factors and co-morbidities. This study was designed to explore how frequently CP is associated with patients with psoriasis compared to systemic healthy subjects. MATERIALS AND METHODS: The periodontal clinical parameters probing depth (PD), periodontal attachment level (PAL), and presence or absence of radiographic bone loss (J Periodontol, 78, 2007, 1387) were recorded in 33 psoriasis subjects and 35 healthy subjects. The severity of psoriasis was assessed and recorded by Psoriasis Area and Severity Index as described earlier by Cohen et al (J Dermatolog Treat, 16, 2005, 308). The other oral health characteristics were also recorded. RESULTS: Probing depth and PAL showed significant higher values in psoriasis group compared with healthy group. It was also found that periodontal status was associated with severity of psoriasis. CONCLUSIONS: The results showed a link between CP and psoriasis. This suggests the need for a multidisciplinary approach to manage psoriasis patients with chronic periodontitis, especially in relation to current and future treatment.


Assuntos
Periodontite Crônica/complicações , Perda da Inserção Periodontal/etiologia , Psoríase/complicações , Índice de Gravidade de Doença , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Índice Periodontal
6.
J Econ Entomol ; 108(4): 1646-54, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26470305

RESUMO

Epiphyas postvittana (Walker) (light-brown apple moth) is a polyphagous herbivore of economic significance, which also feeds on Vitis vinifera L. The E. postvittana-V. vinifera interacting system also involves the participation of the fungus Botrytis cinerea Persoon ex Fries. We have been exploring the relationship among E. postvittana-V. vinifera-B. cinerea over the past two years. In this article, we report the preference and performance of the larvae of E. postvittana raised solely on a synthetic diet incorporated with the mycelial material of B. cinerea (Diet B). To characterize the effect of fungus on the development of E. postvittana, another synthetic diet was prepared that included the lyophilized leaf material of V. vinifera (Diet C). When raised on Diets B and C, a decrease in the duration of larval development and an increase in the survival and fecundity rate of E. postvittana occurred. Diet B influenced the pupal mass, but a significant increase occurred when the larvae were fed on Diet C. The larval emergence rate was the greatest in E. postvittana raised on Diet B, followed by those on Diet C. The F(2) generation of the larvae reared on Diet B showed similar effects as F(1) on the life-history performance of the larvae. Diet B enhanced the life-history performance of E. postvittana, although the larvae of E. postvittana showed little preference to Diet B. The greater fertility rate of E. postvittana reared on Diet B suggests the importance of sterols as shown in Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae) and in a few Myrmicinae (Hymenoptera: Formicidae), which serve as precursors to different ecdysteroids that regulate many critical processes through embryonic development.


Assuntos
Botrytis/fisiologia , Mariposas/crescimento & desenvolvimento , Mariposas/microbiologia , Vitis/crescimento & desenvolvimento , Ração Animal/análise , Animais , Dieta , Comportamento Alimentar , Larva/crescimento & desenvolvimento , Larva/microbiologia , Micélio/fisiologia , Óvulo/crescimento & desenvolvimento , Óvulo/microbiologia , Extratos Vegetais/química , Pupa/crescimento & desenvolvimento , Pupa/microbiologia
7.
Nano Lett ; 14(5): 2436-42, 2014 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-24742056

RESUMO

Mirrors and optical cavities can modify and enhance matter-radiation interactions. Here we report that chemically synthesized Au nanoplates can serve as micrometer-size mirrors that enhance electrodynamic interactions. Because of their plasmonic properties, the Au nanoplates enhance the brightness of scattered light from Ag nanoparticles near the nanoplate surface in dark-field microscopy. More importantly, enhanced optical trapping and optical binding of Ag nanoparticles are demonstrated in interferometric optical traps created from a single laser beam and its reflection from individual Au nanoplates. The enhancement of the interparticle force constant is ≈20-fold more than expected from the increased intensity due to standing wave interference. We show that the additional stability for optical binding arises from the restricted axial thermal motion of the nanoparticles that couples to and reduces the fluctuations in the lateral plane. This new mechanism greatly advances the photonic synthesis of ultrastable nanoparticle arrays and investigation of their properties.

8.
Bull Entomol Res ; 104(2): 117-36, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24280006

RESUMO

Many hemipteroids are major pests and vectors of microbial pathogens, infecting crops. Saliva of the hemipteroids is critical in enabling them to be voracious feeders on plants, including the economically important ones. A plethora of hemipteroid salivary enzymes is known to inflict stress in plants, either by degrading the plant tissue or by affecting their normal metabolism. Hemipteroids utilize one of the following three strategies of feeding behaviour: salivary sheath feeding, osmotic-pump feeding and cell-rupture feeding. The last strategy also includes several different tactics such as lacerate-and-flush, lacerate-and-sip and macerate-and-flush. Understanding hemipteroid feeding mechanisms is critical, since feeding behaviour directs salivary composition. Saliva of the Heteroptera that are specialized as fruit and seed feeders, includes cell-degrading enzymes, auchenorrhynchan salivary composition also predominantly consists of cell-degrading enzymes such as amylase and protease, whereas that of the Sternorhyncha includes a variety of allelochemical-detoxifying enzymes. Little is known about the salivary composition of the Thysanoptera. Cell-degrading proteins such as amylase, pectinase, cellulase and pectinesterase enable stylet entry into the plant tissue. In contrast, enzymes such as glutathione peroxidase, laccase and trehalase detoxify plant chemicals, enabling the circumvention of plant-defence mechanisms. Salivary enzymes such as M1-zinc metalloprotease and CLIP-domain serine protease as in Acyrthosiphon pisum (Aphididae), and non-enzymatic proteins such as apolipophorin, ficolin-3-like protein and 'lava-lamp' protein as in Diuraphis noxia (Aphididae) have the capacity to alter host-plant-defence mechanisms. A majority of the hemipteroids feed on phloem, hence Ca++-binding proteins such as C002 protein, calreticulin-like isoform 1 and calmodulin (critical for preventing sieve-plate occlusion) are increasingly being recognized in hemipteroid-plant interactions. Determination of a staggering variety of proteins shows the complexity of hemipteroid saliva: effector proteins localized in hemipteran saliva suggest a similarity to the physiology of pathogen-plant interactions.


Assuntos
Hemípteros/enzimologia , Proteínas e Peptídeos Salivares/metabolismo , Animais , Comportamento Alimentar
9.
Environ Monit Assess ; 186(6): 3553-66, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24464401

RESUMO

Organic sewage pollution is the major stressor that affects benthic communities in the coastal waters. In the present study involving a once-off sampling (July-August 2003) of a sewage treatment plant (STP) outfall and areas 6 km farther into the sea, we tried to estimate the severity of organic pollution on marine macrobenthos over a pollution gradient in the inshore waters (station depths, 5-30 m) off a heavily urbanized tropical city, on the east coast of India. Multivariate ordination analyses revealed two different groups of faunal assemblages. Group I is associated with sites impacted by the sewage outfall and group II with the locations 3-6 km away in the open sea. Polychaetes and amphipods were the predominant fauna with significant taxonomic differences between the assemblages. Despite the homogeneity in sediment texture, the two-fold increase in sediment organic matter near the sewage outfall area supported r-strategists, while group II locations favoured K-strategists. Approximation through benthic opportunistic polychaetes amphipods (BOPA) index and information on the key taxa responsible for the observed assemblage patterns corroborated these findings. Thus, the present findings revealed how organic sewage pollution influences benthic diversity in coastal waters by supporting communities of opportunistic characteristics. We advocate inclusion of community traits and compatible analytical tools (statistical approaches) in studies of similar nature so that the observations could be compared and broad remedial measures could be evolved.


Assuntos
Monitoramento Ambiental , Invertebrados/crescimento & desenvolvimento , Esgotos/análise , Poluentes da Água/análise , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/crescimento & desenvolvimento , Índia , Invertebrados/classificação , Clima Tropical , Poluição da Água/estatística & dados numéricos
10.
Neuroradiology ; 55(9): 1081-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23740097

RESUMO

INTRODUCTION: Cervical spine MRI with the neck in extension has been well described over the last 10 years, but its clinical value remains unknown. METHODS: We performed extension imaging in 60 patients in whom the initial neutral study showed borderline cord compression. Images were assessed using a previously validated grading system for cord compression. Multiple linear and area measurements were also obtained. Images were scored blindly and randomly. Inter- and intra-rater variability were determined in a subset of 20 cases. Independent clinical assessment utilised the Ranwat criteria. RESULTS: For most parameters inter/intra-observer variance of kappa/ICC > 0.6 was highly satisfactory. Standard MR was poor at discriminating between patients with and without myelopathy (ROC analysis, area under the curve (AUC), 0.52). This was considerably improved with extension imaging (AUC, 0.60), or by using the change in compression score between neutral and extension studies. Most measurements were not helpful; however, the ratio of cord area/CSF area at the level of maximum compression on extended images was the best discriminator (AUC, 0.71), as well as the presence of T2 change in cord substance (AUC, 0.68). CONCLUSION: This is the first study to demonstrate added clinical value utilising extension MRI. In this cohort of difficult patients, when there was no T2 signal change in the cord, the presence of clinical myelopathy could only be predicted by utilising the data from extension imaging.


Assuntos
Algoritmos , Vértebras Cervicais/patologia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Pescoço/patologia , Compressão da Medula Espinal/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
11.
Eur J Appl Physiol ; 113(7): 1731-6, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23400568

RESUMO

Acute hypoxia may alter autonomic cardiovascular reflexes during orthostasis. Heart rate variability (HRV), arterial blood pressure (MAP), and respiratory sinus arrhythmia (RSA) were recorded during supine (SUP) and passive head up tilt (HUT) in eight healthy humans, spontaneously breathing either room air or 10% O2 in N2. In the time domain, heart rate increased and variability decreased with HUT in both trials, with no difference between trials. In the frequency domain, normalized low frequency HRV increased, and normalized high frequency HRV decreased with HUT in both trials, with no difference between trials. MAP was 74.9 (8.6) and 77.5 (11.7) mmHg when SUP in the room air and hypoxia trials, respectively. A significant increase in MAP occurred with HUT in the room air trial but not in the hypoxia trial. In both trials, end tidal CO2 decreased with HUT, with no difference between trials. In the room air trial, end tidal O2 increased with HUT, whereas during the hypoxia trial, end tidal O2 decreased with HUT. The distribution of heart beats relative to the phase of ventilation (%HBIN and %HBOUT) was similar in both trials: the %HBIN was 43.5 (3.3) % and %HBOUT was 56.5 (4.2) % breathing room air when SUP, and 45.5 (3.0) and 54.5 (3.2) when hypoxic and SUP. For both trials, this distribution did not change with HUT. As both HRV and RSA showed similar responses to HUT when spontaneously breathing either room air or 10% O2 in N2, we suggest that autonomic cardiovascular reflexes are preserved during acute hypoxia.


Assuntos
Pressão Sanguínea , Movimentos da Cabeça , Frequência Cardíaca , Hipóxia/fisiopatologia , Adulto , Sistema Nervoso Autônomo/fisiologia , Sistema Cardiovascular/inervação , Feminino , Humanos , Masculino , Ventilação Pulmonar , Volume de Ventilação Pulmonar
12.
BMJ Glob Health ; 8(Suppl 1)2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36657810

RESUMO

Many countries are adopting essential packages of health services (EPHS) to implement universal health coverage (UHC), which are mostly financed and delivered by the public sector, while the potential role of the private health sector (PHS) remains untapped. Currently, many low-income and lower middle-income countries (LLMICs) have devised EPHS; however, guidance on translating these packages into quality, accessible and affordable services is limited. This paper explores the role of PHS in achieving UHC, identifies key concerns and presents the experience of the Diseases Control Priorities 3 Country Translation project in Afghanistan, Ethiopia, Pakistan, Somalia, Sudan and Zanzibar. There are key challenges to engagement of the PHS, which include the complexity and heterogeneity of private providers, their operation in isolation of the health system, limitations of population coverage and equity when left to PHS's own choices, and higher overall cost of care for privately delivered services. Irrespective of the strategies employed to involve the PHS in delivering EPHS, it is necessary to identify private providers in terms of their characteristics and contribution, and their response to regulatory tools and incentives. Strategies for regulating private providers include better statutory control to prevent unlicensed practice, self-regulation by professional bodies to maintain standards of practice and accreditation of large private hospitals and chains. Potentially, purchasing delivery of essential services by engaging private providers can be an effective 'regulatory approach' to modify provider behaviour. Despite existing experience, more research is needed to better explore and operationalise the role of PHS in implementing EPHS in LLMICs.


Assuntos
Serviços de Saúde , Setor Privado , Humanos , Setor Público , Cobertura Universal do Seguro de Saúde , Paquistão
13.
BMJ Glob Health ; 8(7)2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37479500

RESUMO

The Lancet Commission on Diagnostics highlighted a huge gap in access to diagnostic testing even for basic tests, particularly at the primary care level, and emphasised the need for countries to include diagnostics as part of their universal health coverage benefits packages. Despite the poor state of diagnostic-related services in low-income and middle-income countries (LMICs), little is known about the extent to which diagnostics are included in the health benefit packages. We conducted an analysis of seven Asian LMICs-Cambodia, India, Indonesia, Nepal, Pakistan, Philippines, Viet Nam-to understand this issue. We conducted a targeted review of relevant literature and applied a health financing framework to analyse the benefit packages available in each government-sponsored scheme. We found considerable heterogeneity in country approaches to diagnostics. Of the seven countries, only India has developed a national essential diagnostics list. No country presented a clear policy rationale on the inclusion of diagnostics in their scheme and the level of detail on the specific diagnostics which are covered under the schemes was also generally lacking. Government-sponsored insurance expansion in the eligible populations has reduced the out-of-pocket health payment burden in many of the countries but overall, there is a lack of access, availability and affordability for diagnostic-related services.


Assuntos
Programas Nacionais de Saúde , Humanos , Indonésia , Nepal , Paquistão , Filipinas , Vietnã , Camboja , Índia
14.
Nanotechnology ; 23(20): 205704, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-22543565

RESUMO

Using scanning laser Doppler vibrometer we have identified sources of noise in contact mode high-speed atomic force microscope images and the cantilever dynamics that cause them. By analysing reconstructed animations of the entire cantilever passing over various surfaces, we identified higher eigenmode oscillations along the cantilever as the cause of the image artefacts. We demonstrate that these can be removed by monitoring the displacement rather than deflection of the tip of the cantilever. We compare deflection and displacement detection methods whilst imaging a calibration grid at high speed and show the significant advantage of imaging using displacement.


Assuntos
Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Microscopia de Força Atômica/métodos , Nanopartículas/química , Nanopartículas/ultraestrutura , Gravação em Vídeo/métodos , Imagens de Fantasmas , Vibração
15.
Case Rep Obstet Gynecol ; 2022: 7520243, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35178260

RESUMO

Heterotopic pregnancies, although rare in natural conceptions, have increased in incidence with use of assisted reproductive techniques (ART). Double heterotopic pregnancy in addition to an intrauterine pregnancy is exceedingly rare. In this case, we present a patient who underwent ovulation induction and intrauterine insemination (IUI) and was found on ultrasound to have a live heterotopic pregnancy. Intraoperatively, both fallopian tubes were grossly swollen and engorged. Bilateral salpingectomy was performed. Pathology identified gestational products in both fallopian tubes consistent with a double heterotopic pregnancy. Postoperatively, the intrauterine pregnancy resulted in a live birth. Although double heterotopic pregnancy and an intrauterine pregnancy is exceedingly rare, this case emphasizes the importance of routinely inspecting the contralateral fallopian tube at the time of surgery for an ectopic pregnancy, particularly in patients undergoing ovulation induction.

16.
ACS Omega ; 7(14): 11788-11798, 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35449937

RESUMO

Herein, we present a new type of high-performance catalyst for aerobic oxidation of organosulfur compounds based on tungsten carbide. The synthesis of tungsten carbide was performed via microwave irradiation of the precursors, which makes it possible to obtain a catalyst in just 15 min. The synthesized catalyst was investigated by a variety of physicochemical methods: X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, electron microscopy, and N2 adsorption/desorption. It was shown that active centers containing tungsten in the transition oxidation state (+4) play a key role in the activation of oxygen. The main factors influencing the conversion of dibenzothiophene (DBT) were investigated. It should be noted that 100% conversion of DBT can be achieved under relatively mild conditions: 120 °C, 3 h, 6 bar, and 0.5% wt catalyst. The catalyst retained its activity for at least six oxidation/regeneration cycles. The simplicity and speed of synthesis of the proposed catalyst in combination with its high activity and stability open broad prospects for its further use both for oxidative desulfurization and for other reactions of aerobic oxidation of organic substrates.

17.
Biophys J ; 100(4): 1100-8, 2011 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-21320456

RESUMO

Mechanical properties of biological molecular aggregates are essential to their function. A remarkable example are double-stranded DNA viruses such as the φ29 bacteriophage, that not only has to withstand pressures of tens of atmospheres exerted by the confined DNA, but also uses this stored elastic energy during DNA translocation into the host. Here we show that empty prolated φ29 bacteriophage proheads exhibit an intriguing anisotropic stiffness which behaves counterintuitively different from standard continuum elasticity predictions. By using atomic force microscopy, we find that the φ29 shells are approximately two-times stiffer along the short than along the long axis. This result can be attributed to the existence of a residual stress, a hypothesis that we confirm by coarse-grained simulations. This built-in stress of the virus prohead could be a strategy to provide extra mechanical strength to withstand the DNA compaction during and after packing and a variety of extracellular conditions, such as osmotic shocks or dehydration.


Assuntos
Fagos Bacilares/química , Capsídeo/química , Estresse Mecânico , Fagos Bacilares/efeitos dos fármacos , Fagos Bacilares/ultraestrutura , Capsídeo/efeitos dos fármacos , Simulação por Computador , Análise de Elementos Finitos , Glutaral/farmacologia , Microscopia de Força Atômica , Modelos Moleculares , Nanotecnologia
18.
J Urol ; 186(3): 1053-8, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21784480

RESUMO

PURPOSE: We analyzed the association between unilateral multicystic dysplastic kidney and subsequent contralateral infundibular stenosis, which can result in progressive calyceal dilatation, and has been linked to global hyperfiltration injury and renal impairment. MATERIALS AND METHODS: During the last 10 years 200 children presented with unilateral multicystic dysplastic kidney. Of these children 5 subsequently exhibited contralateral infundibular stenosis. We reviewed the published data on multicystic dysplastic kidney as well as infundibular stenosis to examine this association further. RESULTS: Three patients underwent open surgical exploration since rapid progression with associated parenchymal thinning was detected. Literature review failed to identify any discussion of infundibular stenosis in studies focusing on long-term followup of children with a unilateral multicystic dysplastic kidney. Several case reports and case series discuss this condition in association with other collecting system anomalies. However, these anomalies are hypothesized to be part of a disease spectrum resulting from aberrant formation of the collecting system. Bilateral involvement has been reported in fewer than 10 cases. CONCLUSIONS: Our cases represent a part of the spectrum of pyelocalyceal dysgenesis that can have bilateral involvement of varying degrees. Of particular concern was the delayed presentation in some of our patients and the progressive nature of the lesions. Although exceedingly rare, we wish to highlight the association of multicystic dysplastic kidney and progressive infundibular stenosis of the contralateral kidney and renal impairment.


Assuntos
Nefropatias/etiologia , Pelve Renal , Rim Displásico Multicístico/complicações , Criança , Constrição Patológica , Progressão da Doença , Feminino , Humanos , Recém-Nascido , Masculino , Estudos Prospectivos
19.
Nanotechnology ; 22(29): 295504, 2011 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-21680959

RESUMO

Cantilevered or suspended nanowires show promise for force or mass sensing applications due to their small mass, high force sensitivity and high frequency bandwidth. To use these as quantitative sensors, their bending stiffness or mass must be calibrated experimentally, often using thermally driven vibration. However, this can be difficult because nanowires are slightly asymmetric, which results in two spatially orthogonal bending eigenmodes with closely spaced frequencies. This asymmetry presents problems for traditional stiffness calibration methods, which equate the measured thermal vibration spectrum near a resonance to that of a single eigenmode. Moreover, the principal axes may be arbitrarily rotated with respect to the measurement direction. In this work, the authors propose a method for calibrating the bending stiffness and mass of such nanowires' eigenmodes using a single measurement taken at an arbitrary orientation with respect to the principal axes.

20.
Nanotechnology ; 22(45): 455502, 2011 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-22020109

RESUMO

This work investigates the effects of asymmetric cross-sectional geometry on the resonant response of silicon nanowires. The work demonstrates that dimensional variances of less than 2% qualitatively alter a nanosystem's near-resonant response, yielding a non-Lorentzian frequency response structure, which is a direct consequence of resonant mode splitting. Experimental results show that this effect is independent of device boundary conditions, and can be easily modeled using continuous beam theory. Proper understanding of this phenomenon is believed to be essential in the characterization of the dynamic response of resonant nanowire systems, and thus the predictive design of such devices.

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