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1.
Inorg Chem ; 63(39): 18296-18303, 2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-39297717

RESUMEN

Lead-free molecular ferroelectrics have garnered considerable attention for their promising potential, but such species with narrow band gap and sensitive photoelectric response are yet inadequate. Herein, we demonstrated the bulk ferroelectric photovoltaic effect in a novel lead-free molecular ferroelectric [C4N2H14][BiI5] with a Curie temperature (Tc) of 366 K and a narrow band gap (Eg) of 1.92 eV. The transformation of the crystal structure from the polar space group P21 to the nonpolar space group P21/m was elucidated using single-crystal X-ray diffraction. Room-temperature (RT) hysteresis loop reveals the intrinsic ferroelectricity of [C4N2H14][BiI5] with a relative small coercive field (Ec ∼ 0.27 kV/cm), saturation polarization (Ps ∼ 1.87 µC/cm2), and remanent polarization (Pr ∼ 1.61 µC/cm2). [C4N2H14][BiI5]-based solar device exhibits significant PV effects with a steady-state photocurrent (Jsc) of 3.54 µA/cm2 and a photovoltage (Voc) of 0.34 V under AM 1.5 G illumination, which can be significantly improved by adjusting the ferroelectric polarization, reaching a maximum Jsc of 140 µA/cm2 and Voc of 0.51 V. This work offers a promising avenue for lead-free molecular ferroelectric materials in the field of optoelectronic devices.

2.
Sensors (Basel) ; 24(16)2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39204852

RESUMEN

With the rapid development of the Industrial Internet of Things in rotating machinery, the amount of data sampled by mechanical vibration wireless sensor networks (MvWSNs) has increased significantly, straining bandwidth capacity. Concurrently, the safety requirements for rotating machinery have escalated, necessitating enhanced real-time data processing capabilities. Conventional methods, reliant on experiential approaches, have proven inefficient in meeting these evolving challenges. To this end, a fault detection method for rotating machinery based on mobileNet in MvWSNs is proposed to address these intractable issues. The small and light deep learning model is helpful to realize nearly real-time sensing and fault detection, lightening the communication pressure of MvWSNs. The well-trained deep learning is implanted on the MvWSNs sensor node, an edge computing platform developed via embedded STM32 microcontrollers (STMicroelectronics International NV, Geneva, Switzerland). Data acquisition, data processing, and data classification are all executed on the computing- and energy-constrained sensor node. The experimental results demonstrate that the proposed fault detection method can achieve about 0.99 for the DDS dataset and an accuracy of 0.98 in the MvWSNs sensor node. Furthermore, the final transmission data size is only 0.1% compared to the original data size. It is also a time-saving method that can be accomplished within 135 ms while the raw data will take about 1000 ms to transmit to the monitoring center when there are four sensor nodes in the network. Thus, the proposed edge computing method shows good application prospects in fault detection and control of rotating machinery with high time sensitivity.

3.
Ecotoxicol Environ Saf ; 216: 112189, 2021 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-33819782

RESUMEN

The largest source of resistant bacteria or viruses is the overuse and misuse of antibiotics in humans and animals. These resistant bacteria or viruses may evolve into superbacteria or superviruses, which causes global plague. Therefore, it is significant to find a highly efficiency and low-cost method to eliminate antibiotics in water environment from inappropriate discharge. Here, a highly active and highly stable heterogeneous catalyst, Cu0.76Co2.24O4/SBA-15 (CCS) was prepared for peroxymonosulfate (PMS) activation in aim of decomposing persistent sulfapyridine (SPD). The reaction mechanism was thoroughly investigated via in situ quenching test and in situ electron paramagnetic resonance. Four reactive species, SO4·-, O2·-, 1O2 and ·OH were generated in Cu0.76Co2.24O4/SBA-15/PMS (CCSP) system. The SO4·- and O2·- were dominant active species responsible for SPD degradation. Co(Ⅱ)↔Co(Ⅲ)↔Co(Ⅱ) redox reaction cycle was constructed due to the different redox potential of Co(Ⅱ)/Co(Ⅲ), HSO5-/SO4∙-, and HSO5-/SO5∙-. Interestingly, Cu(Ⅰ) could urge the redox reaction cycle for PMS activation to be more thermodynamically feasible. Therefore, CCS possessed a highly catalytic activity and excellent stability. Meanwhile, the anions interference test indicated Cl-, NO3-, HCO3-, and H2PO4- had almost no inhibitory effect on SPD degradation over this catalytic system. We sincerely expected that this catalyst system would be applied extensively into antibiotics degradation in real water bodies.

4.
Front Neurorobot ; 18: 1379906, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38601918

RESUMEN

Introduction: Periodicity, self-excitation, and time ratio asymmetry are the fundamental characteristics of the human gait. In order to imitate these mentioned characteristics, a pattern generator with four degrees of freedom is proposed based on cardioid oscillators developed by the authors. Method: The proposed pattern generator is composed of four coupled cardioid oscillators, which are self-excited and have asymmetric time ratios. These oscillators are connected with other oscillators through coupled factors. The dynamic behaviors of the proposed oscillators, such as phase locking, time ratio, and self-excitation, are analyzed via simulations by employing the harmonic balance method. Moreover, for comparison, the simulated trajectories are compared with the natural joint trajectories measured in experiments. Results and discussion: Simulation and experimental results show that the behaviors of the proposed pattern generator are similar to those of the natural lower limb. It means the simulated trajectories from the generator are self-excited without any additional inputs and have asymmetric time ratios. Their phases are locked with others. Moreover, the proposed pattern generator can be applied as the reference model for the lower limb exoskeleton controlling algorithm to produce self-adjusted reference trajectories.

5.
Dalton Trans ; 52(36): 12862-12868, 2023 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-37622468

RESUMEN

Atomically thin two-dimensional (2D) bismuth oxychalcogenides have been considered as promising candidates for high-speed and low-power photoelectronic devices due to their high charge carrier mobility and excellent environmental stability. However, the photoelectric performance of their bulk materials still falls short of expectations. Herein, a novel Bi9O7.5S6/SnS composite film with a type-II heterojunction was successfully prepared by combining hydrothermal and knife-coating techniques. The crystal structure, morphology, and optical properties were systematically investigated. Under 1 V bias voltage, the photocurrent of the Bi9O7.5S6/SnS composite film can be obtained as 107 µA cm-2, which is about 29.9 times and 93.9 times higher than that of bare Bi9O7.5S6 and SnS, respectively. The type-II heterojunction has played a significant role in improving the photoelectric performance of the Bi9O7.5S6/SnS composite film by facilitating the separation and transfer of photo-generated carriers. This work sheds light on the design and development of new bismuth-based composite materials for advanced photoelectric and photocatalytic applications.

6.
Front Endocrinol (Lausanne) ; 13: 821588, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35909512

RESUMEN

Jintrolong® is a long-acting PEGylated recombinant human growth hormone (PEG-rhGH) developed for weekly injection in patients with pediatric growth hormone deficiency (PGHD). Although PEG modification of therapeutic proteins is generally considered safe, concerns persist about the potential for adverse vacuolation in tissues with long-term exposure to PEG-included therapies, particularly in children. We assessed the safety of Jintrolong® in cynomolgus monkeys with an examination of vacuolation in the brain choroid plexus (CP) and reported long-term clinical safety data obtained from children with PGHD. The toxicity of Jintrolong® was assessed following the 52-week administration with doses at 0.3, 1, or 3 mg/kg/week. The levels of vacuolation of CP in animals were dose-dependent and at least partially reversible after a 104- or 157-week recovery period. Vacuolation in the CP epithelium did not lead to obvious subcellular structural or cell functional abnormalities. Compared with the clinical dose of 0.2 mg/kg/week Jintrolong® in PGHD patients, exposure in monkeys under NOAEL 3 mg/kg/week exhibited safety margins greater than 120.5, the predicted minimum dose to induce vacuolation in monkeys is equivalent to 1.29 mg/kg/week in humans, which is 6.45-fold higher than the clinical dose. The safety data acquired in clinical trials for Jintrolong® were also analyzed, which included phase III (360 patients), phase IV (3,000 patients) of 26-week treatment, and a follow-up study with treatment lasting for 3 years. There was no statistically significant difference in the incidence of adverse reactions between the Jintrolong® group and the daily rhGH control group (no PEG), and no new adverse effects (AE) were observed in the Jintrolong® group at the clinical therapeutic dose of 0.2 mg/kg/week.


Asunto(s)
Enanismo Hipofisario , Hormona de Crecimiento Humana , Animales , Niño , Estudios de Seguimiento , Hormona de Crecimiento Humana/efectos adversos , Humanos , Macaca fascicularis , Polietilenglicoles/efectos adversos , Polietilenglicoles/química , Proteínas Recombinantes/efectos adversos
7.
Materials (Basel) ; 14(21)2021 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-34771923

RESUMEN

The rectangular magnetoelectric (ME) composites of Metglas/PZT and Terfenol-D/PZT are prepared, and the effects of a magnetostrictive layer's material characteristics on the magnetoimpedance of ME composite are discussed and experimentally investigated. The theoretical analyses show that the impedance is not only dependent on Young's modulus and the magnetostrictive strain of magnetostrictive material but is also influenced by its relative permeability. Compared with Terfenol-D, Metglas possesses significantly higher magnetic permeability and larger magnetostrictive strain at quite low Hdc due to the small saturation field, resulting in the larger magnetoimpedance ratio. The experimental results demonstrate that the maximum magnetoimpedance ratios (i.e., ΔZ/Z) of Metglas/PZT composite are about 605.24% and 239.98% at the antiresonance and resonance, respectively. Specifically, the maximum ΔZ/Z of Metglas/PZT is 8.6 times as high as that of Terfenol-D/PZT at the antiresonance. Such results provide the fundamental guidance in the design and fabrication of novel multifunction devices based on the magnetoimpedance effect of ME composites.

8.
Sci Prog ; 103(1): 36850419877731, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31829884

RESUMEN

Synchronous control is a fundamental and significant problem for controlling a multi-joint robot. In this article, by applying two coupled Rayleigh oscillators as the referred central pattern generator models for the two joints of a two-degrees-of-freedom robot, the central pattern generator-based coupling control method is proposed for controlling the two-degrees-of-freedom robot's joints. On these bases, the co-simulation model of the two-degrees-of-freedom robot with the proposed central pattern generator-based coupling control method is established via ADAMS and MATLAB/Simulink, and the performance of the central pattern generator-based coupling control method on synchronizing two motions of two-degrees-of-freedom robot's joints is numerically simulated. Furthermore, the experimental setup of a two-degrees-of-freedom robot is established based on the real-time simulations system via the proposed central pattern generator-based coupling control method. And experiments are carried out on the established setup. Simulations and experimental results show that the phase of the controlled two-degrees-of-freedom robot's joints is mutual locked to other, and their motion pattern can be adjusted through the coupling parameter in the central pattern generator-based coupling control method. In conclusion, the proposed central pattern generator-based coupling control method can control the two-degrees-of-freedom robot's joints to produce the coordinated motions and adjust the rhythmic pattern of the two-degrees-of-freedom robot.

9.
J Diabetes ; 12(1): 66-76, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31222955

RESUMEN

BACKGROUND: Because there has been no quality improvement initiatives targeting patients with type 2 diabetes (T2D) receiving basal insulin therapy, this study evaluated the effectiveness of physician-targeted education for optimizing glycemic management in these patients in China. METHODS: This multicenter open-label observational study conducted across China had a baseline sample survey, followed by a 6-month education program, and ended with a post-education sample survey. Education based on T2D treatment guidelines was given at Months 1 and 3, and was reinforced by self-audit every month. Each hospital enrolled 100 patients with T2D receiving basal insulin at both the baseline and post-education survey. The primary outcome was the proportion of hospitals meeting individual improvement goals. The goal setting was based on the proportion of patients achieving HbA1c <7.0% in each hospital at the time of the baseline survey. RESULTS: Overall, the individual improvement goal was achieved by 35 centers (49%). Hospitals with poor glycemic management at the baseline survey had higher possibility to improve at post-education survey. Two large sample surveys at baseline and post-education showed improved glucose management among these hospitals. A higher proportion of patients achieved HbA1c <7.0% in the post-education survey (27.2% vs 36.5%; P < 0.001) with reduced HbA1c levels (8.10% vs 7.72%; P < 0.001). Questionnaires from 723 physicians showed that confidence and practice of basal insulin use were significantly improved. CONCLUSIONS: Physician-targeted education improved glycemic management of patients with T2D in 71 hospitals in China, and was more effective at hospitals with poor glycemic management at the baseline survey.


Asunto(s)
Glucemia/análisis , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hemoglobina Glucada/análisis , Insulina/uso terapéutico , Anciano , Pueblo Asiatico/estadística & datos numéricos , China/epidemiología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/etnología , Femenino , Educación en Salud/métodos , Humanos , Hipoglucemiantes/uso terapéutico , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud/métodos , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Médicos/estadística & datos numéricos , Guías de Práctica Clínica como Asunto/normas , Encuestas y Cuestionarios
10.
Environ Entomol ; 38(4): 1053-60, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19689883

RESUMEN

Edge effects resulting from logging on the distribution of carabid beetles (Coleoptera: Carabidae) were studied across ecotones between regenerating and mature forests established after harvesting of old-growth forests 20 yr prior to this study in southwestern China. Using pitfall traps, beetles were collected along five ecotone transects using nine samples with a distance interval of 25 m each. Although no significant differences were found in species richness and abundance of carabids among all three habitats, i.e., mature forest, young regenerating stand, and edge habitat, rarefaction estimates of species richness indicated that traps in young regenerating stands accumulated species faster than those on mature forest interiors and forest edges. Carabid species composition of the forest edges was more similar to those of the mature forest interiors than to those of the young regenerating stands. Variability in species composition was significantly reduced in young stands, suggesting that the carabid community from young stands is more homogeneous than the one from mature forests. Although most species occurred in all habitats, some species were significantly more abundant in mature forests and/or edges than in young stands. Results indicated that edge effects on forest carabids may persist for at least 20 yr after disturbance.


Asunto(s)
Escarabajos , Ecosistema , Animales , China , Geografía , Densidad de Población
11.
Endocr J ; 56(1): 55-63, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-18840928

RESUMEN

We previously found that cathepsin K (CTSK) played an important role in adipocyte differentiation. However, the underlying molecular mechanism is not clear. Through the time window study, it was observed that CTSK activities were required mainly in the early phases of adipogenic process. At the same time, the expression of type I collagen disappeared. However, type I collagen can still be observed during the whole process when the CTSK inhibitor-E64 was added. The mRNA levels of peroxisome proliferator-activated receptor gamma (PPAR-gamma) and CCAAT/enhancer binding protein alpha (C/EBP-alpha) was also declining. These imply that CTSK may play a role in adipogenesis in early differentiation phases and produce an effect at least partly by degrading type I collagen, which may provides a basis for developing novel therapeutic approaches to treat obesity and the diseases associated with it.


Asunto(s)
Adipocitos/fisiología , Catepsinas/fisiología , Diferenciación Celular , Colágeno Tipo I/metabolismo , Procesamiento Proteico-Postraduccional/fisiología , Células 3T3-L1 , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Adipogénesis/efectos de los fármacos , Adipogénesis/genética , Animales , Proteínas Potenciadoras de Unión a CCAAT/genética , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Catepsina K , Catepsinas/antagonistas & inhibidores , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/genética , Colágeno Tipo I/fisiología , Inhibidores de Cisteína Proteinasa/farmacología , Matriz Extracelular/efectos de los fármacos , Matriz Extracelular/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Leucina/análogos & derivados , Leucina/farmacología , Ratones , PPAR gamma/genética , PPAR gamma/metabolismo , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Factores de Tiempo
12.
Micromachines (Basel) ; 9(11)2018 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-30715038

RESUMEN

Our previous report based on a 10 g (gravity) silicon-based inertial micro-switch showed that the contact effect between the two electrodes can be improved by squeeze-film damping. As an extended study toward its potential applications, the switch with a large proof mass suspended by four flexible serpentine springs was redesigned to achieve 5 g threshold value and enhanced threshold accuracy. The impact of the squeeze-film damping on the threshold value was theoretically studied. The theoretical results show that the threshold variation from the designed value due to fabrication errors can be reduced by optimizing the device thickness (the thickness of the proof mass and springs) and then establishing a tradeoff between the damping and elastic forces, thus improving the threshold accuracy. The design strategy was verified by FEM (finite-element-method) simulation and an experimental test. The simulation results show that the maximum threshold deviation was only 0.15 g, when the device thickness variation range was 16⁻24 µm, which is an adequately wide latitude for the current bulk silicon micromachining technology. The measured threshold values were 4.9⁻5.8 g and the device thicknesses were 18.2⁻22.5 µm, agreeing well with the simulation results. The measured contact time was 50 µs which is also in good agreement with our previous work.

13.
Life Sci ; 81(2): 160-5, 2007 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-17544010

RESUMEN

Changes in AMP-activated protein kinase (AMPK) activity contribute to the regulation of insulin secretion. Troglitazone has been shown to lower serum insulin levels and protect beta cell function. The aim of the present study was to examine the effects of troglitazone on AMPK activity and insulin secretion in beta cells. Isolated rat islets and MIN6 cells were treated for a short (1 h) or a long time (20 h) with troglitazone. One-hour troglitazone treatment activated AMPK and inhibited both glucose-stimulated insulin secretion (GSIS) and the response of insulin secretion to combined stimuli of glucose and palmitate. Long (20 h) treatment with troglitazone caused a sustained phosphorylation of AMPK and acetyl-CoA carboxylase, and increased GSIS after withdrawal of the drug. This study provided evidence that troglitazone activated AMPK in beta cells. In addition to the insulin-sensitizing effects in peripheral tissues, troglitazone also directly inhibits insulin hypersecretion by the elevated glucose and fatty acids, and thus protects beta cells from glucolipotoxicity.


Asunto(s)
Cromanos/farmacología , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Hipoglucemiantes/farmacología , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Tiazolidinedionas/farmacología , Animales , Línea Celular , Glucosa/farmacología , Immunoblotting , Indicadores y Reactivos , Células Secretoras de Insulina/efectos de los fármacos , Masculino , Palmitatos/farmacología , Fosforilación , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Troglitazona
14.
Environ Entomol ; 36(2): 348-55, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17445369

RESUMEN

This paper studied the occurrence of carabid beetles (Coleoptera: Carabidae) in the forest edge, the adjacent forest interior, and the surrounding grassland in southwestern China. Beetles were collected with pitfall traps along five replicated transects. Forest species rarely penetrated into the grassland from the forest interior, and the grassland specialists were not found in the forest interior. The forest edge hosted additional species from the adjacent grassland that increased its overall species richness. Nearly all forest species (23 of 24 species) and grassland species (13 of 15 species) can be found in the forest edge. Carabids of the forest edge were more similar to those of the forest interior than to those of the grassland by ordination and cluster analysis. Based on the specificity and fidelity, carabids can be distinguished into five species groups: habitat generalists, grassland-associated species, forest generalists, forest specialists, and edge-associated species. Multiple linear regression analysis showed that canopy cover and/or shrub cover were the most important factors in determining the richness, abundance, and diversity of carabids. The forest edge may serve as a transition zone for dispersal and re-colonization of carabid beetles from adjacent habitats and therefore is important for natural conservation.


Asunto(s)
Escarabajos/crecimiento & desarrollo , Escarabajos/fisiología , Ecosistema , Animales , Biodiversidad , China , Escarabajos/clasificación , Demografía , Monitoreo del Ambiente , Femenino , Masculino , Densidad de Población , Dinámica Poblacional , Especificidad de la Especie
15.
Zhonghua Nei Ke Za Zhi ; 46(7): 555-8, 2007 Jul.
Artículo en Zh | MEDLINE | ID: mdl-17959077

RESUMEN

OBJECTIVE: To evaluate the metabolic characteristics of insulin secretion and insulin sensitivity in isolated impaired fasting glucose (iIFG) and isolated fasting hyperglycemia (IFH) and to clarify the factors responsible for the development of IFH. METHODS: Receiver operating characteristic curve (ROC) analysis was conducted in 1852 subjects. Three groups were classified according to a 75 g oral glucose tolerance test (OGTT): (1) normal glucose tolerance (NGT), n = 557; (2) iIFG, n = 221; (3) IFH, n = 81. The three groups were compared with insulin secretion (insulinogenic index) and insulin sensitivity (insulin sensitivity index). RESULTS: Using ROC analysis, the optimal cut point of fasting plasma glucose (FPG) related to diabetes diagnosis with OGTT was 6.695 mmol/L and the optimal cut point of FPG related to impaired glucose to lerance (IGT) diagnosis with OGTT was 5.590 mmol/L. From NGT to iIFG and IFH in these subjects, the insulinogenic index and insulin sensitivity index showed gradual decrease. CONCLUSION: Subjects with iIFG and IFH exhibit distinctly impaired early-phase insulin secretion and insulin sensitivity, indicating that both reduced insulin secretion and insulin resistance are the determinants of deterioration from NGT to iIFG and IFH.


Asunto(s)
Diabetes Mellitus Tipo 2/sangre , Hiperglucemia/sangre , Insulina/sangre , Adulto , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatología , Ayuno/sangre , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Hiperglucemia/metabolismo , Hiperglucemia/fisiopatología , Insulina/metabolismo , Resistencia a la Insulina , Secreción de Insulina , Masculino , Persona de Mediana Edad , Curva ROC
16.
Insect Sci ; 24(2): 303-313, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26503128

RESUMEN

Selective logging with natural regeneration is advocated as a near-to-nature strategy and has been implemented in many forested systems during the last decades. However, the efficiency of such practices for the maintenance of forest species are poorly understood. We compared the species richness, abundance and composition of ground-dwelling beetles between selectively logged and unlogged forests to evaluate the possible effects of selective logging in a subtropical broad-leafed forest in southeastern China. Using pitfall traps, beetles were sampled in two naturally regenerating stands after clearcuts (ca. 50 years old, stem-exclusion stage: selectively logged 20 years ago) and two mature stands (> 80 years old, understory re-initiation stage: selectively logged 50 years ago) during 2009 and 2010. Overall, selective logging had no significant effects on total beetle richness and abundance, but saproxylic species group and some abundant forest species significantly decreased in abundance in selectively logged plots compared with unlogged plots in mature stands. Beetle assemblages showed significant differences between selectively logged and unlogged plots in mature stands. Some environmental characteristics associated with selective logging (e.g., logging strategy, stand age, and cover of shrub and moss layers) were the most important variables explaining beetle assemblage structure. Our results conclude that selective logging has no significant impacts on overall richness and abundance of ground-dwelling beetles. However, the negative effects of selective logging on saproxylic species group and some unlogged forest specialists highlight the need for large intact forested areas for sustaining the existence of forest specialist beetles.


Asunto(s)
Escarabajos/fisiología , Agricultura Forestal/métodos , Bosques , Animales , Biodiversidad , China , Ecosistema , Factores de Tiempo
17.
Chin Med J (Engl) ; 119(7): 574-80, 2006 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-16620699

RESUMEN

BACKGROUND: Prolonged exposure of pancreatic beta-cells to fatty acids increases basal insulin secretion but inhibits glucose-stimulated insulin secretion. Rosiglitazone is a new antidiabetic agent of the thiazolidinediones. However, the relationship between thiazolidinediones and insulin secretion is highly controversial. The aim of this study is to explore the effect and mechanism of rosiglitazone on insulin secretion of islets under chronic exposure to free fatty acids (FFA). METHODS: Pancreatic islets were isolated from the pancreata of male Sprague-Dawley rats by the collagenase digestion and by the dextran gradient centrifugation method. The purified islets were cultured in the presence or absence of rosiglitazone and palmitate for 48 hours. The insulin secretion was measured by radioimmunoassay. The mRNA level of peroxisome proliferator-activated receptor gamma, uncoupling protein 2 (UCP-2) and insulin were determined by real-time polymerase chain reaction (PCR). The cell cytotoxicity assay was measured by cell counting kit-8. RESULTS: Islets exposed to elevated palmitate for 48 hours showed an increased basal and a decreased glucose-stimulated insulin secretion (P < 0.01). The mRNA level of UCP-2 was increased by 3.7 fold in the 0.5 mmol/L concentration of palmitate. When islets were cultured with palmitate (0.5 mmol/L) in the presence of rosiglitazone (1.0 micromol/L), both basal and glucose-stimulated insulin secretion reversed to a pattern of control islets (P < 0.05, P < 0.01). The addition of rosiglitazone in the culture medium decreased the mRNA level of UCP-2 by 2.2 fold, having a statistically significant difference (P < 0.05) as compared with islets cultured with palmitate alone. The cell viability was not affected. CONCLUSION: The protective effects of rosiglitazone on insulin secretion of isolated pancreatic islets under chronic exposure to palmitate might be mediated through the downregulation of UCP-2 expression.


Asunto(s)
Ácidos Grasos no Esterificados/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Hipoglucemiantes/farmacología , Insulina/metabolismo , Islotes Pancreáticos/efectos de los fármacos , Proteínas de Transporte de Membrana/genética , Proteínas Mitocondriales/genética , Tiazolidinedionas/farmacología , Animales , Supervivencia Celular/efectos de los fármacos , Secreción de Insulina , Canales Iónicos , Islotes Pancreáticos/metabolismo , Masculino , PPAR gamma/genética , ARN Mensajero/análisis , Ratas , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rosiglitazona , Proteína Desacopladora 2
18.
Trials ; 17(1): 470, 2016 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-27669747

RESUMEN

BACKGROUND: A large proportion of patients with T2DM in China do not meet accepted HbA1c targets despite the availability of guidelines that describe a treatment pathway for achieving glycemic control. The aim of this study is to identify the fasting plasma glucose (FPG) target that will provide the highest control rate of HbA1c <7 % in Chinese patients with T2DM treated with an insulin glargine-based regimen as an adjunct to an established OAD regimen. This information will support improvements in diabetes care management in China. METHODS: Approximately 934 men and women aged ≥18 to ≤65 years with poorly controlled T2DM will be enrolled and randomized to one of three FPG target groups; ≤5.6 mmol/L, ≤6.1 mmol/L, or ≤7.0 mmol/L. They will be initiated on daily insulin glargine (Lantus®) in addition to their usual OAD regimen for 24 weeks. Patients will self-monitor fasting blood glucose (SM-FBG), and the study physician will titrate the basal insulin dose according to the SM-FBG results. In addition, HbA1c and safety will be recorded. We plan to statistically derive the optimal FPG target for an HbA1c of <7 %. DISCUSSION: In China, treatment strategies that would achieve an optimum balance between glycemic control (as per HbA1c) and hypoglycemia are imperative to ensure improvements in the management of T2DM. Furthermore, elucidating the contribution of FPG to HbA1c in Chinese patients with T2DM and identifying a predictable relationship between FPG and HbA1c would be a valuable tool for patient self-management of diabetes. TRIAL REGISTRATION: NCT02545842 . Registered on 8 September 2015.

19.
Environ Entomol ; 45(1): 24-31, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26377249

RESUMEN

Periodic natural disturbances shape the mosaic character of many landscapes and influence the distribution and abundance of organisms. In this study, we tested the effect of ice storm-induced treefall gaps on ground-dwelling beetle assemblages in different-aged successional stands of subtropical broad-leaved forest in southeastern China. We evaluated the relative importance of gap-phase microhabitat type (within gap, gap edge, and interior shaded) within different stand ages (regenerating stands and mature stands) as determinants of changes in beetle diversity and community structure. At 18 replicate sites sampled during 2009-2010, no significant differences were found in species richness and the abundances of the most common beetle species captured in pitfall traps among the three gap-phase microhabitat types, but the abundances of total beetles, as well as fungivorous and phytophagous species groups, were significantly lower in gap microhabitats than in interior shaded microhabitats in mature stands. Beetle assemblage composition showed no significant differences among the three microhabitat types, and only the fauna of gap plots slightly diverged from those of edge and shaded plots in mature stands. Cover of shrubs and stand age significantly affected beetle assemblage structure. Our results suggest that beetle responses to gap-phase dynamics in early successional forests are generally weak, and that effects are more discernible in the mature stands, perhaps due to the abundance responses of forest-specialist species.


Asunto(s)
Biodiversidad , Escarabajos/fisiología , Bosques , Hielo , Árboles/crecimiento & desarrollo , Animales , China
20.
PLoS One ; 11(5): e0154659, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27138752

RESUMEN

The aim of this paper is to increase understanding of the relative importance of the input of geographic and local environmental factors on richness and composition of epigaeic steppe beetles (Coleoptera: Carabidae and Tenebrionidae) along a geographic (longitudinal/precipitation) gradient in the Inner Mongolia grassland. Specifically, we evaluate the associations of environmental variables representing climate and environmental heterogeneity with beetle assemblages. Beetles were sampled using pitfall traps at 25 sites scattered across the full geographic extent of the study biome in 2011-2012. We used variance partitioning techniques and multi-model selection based on the Akaike information criterion to assess the relative importance of the spatial and environmental variables on beetle assemblages. Species richness and abundance showed unimodal patterns along the geographic gradient. Together with space, climate variables associated with precipitation, water-energy balance and harshness of climate had strong explanatory power in richness pattern. Abundance pattern showed strongest association with variation in temperature and environmental heterogeneity. Climatic factors associated with temperature and precipitation variables and the interaction between climate with space were able to explain a substantial amount of variation in community structure. In addition, the turnover of species increased significantly as geographic distances increased. We confirmed that spatial and local environmental factors worked together to shape epigaeic beetle communities along the geographic gradient in the Inner Mongolia grassland. Moreover, the climate features, especially precipitation, water-energy balance and temperature, and the interaction between climate with space and environmental heterogeneity appeared to play important roles on controlling richness and abundance, and species compositions of epigaeic beetles.


Asunto(s)
Escarabajos , Pradera , Análisis Espacial , Distribución Animal , Animales , Biodiversidad , China , Clima
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