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1.
Br J Haematol ; 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39072725

RESUMO

International societies have conflicting recommendations on whether bone marrow aspirate/biopsy (BMB) is needed during workup for isolated thrombocytopenia. Our objective was to determine if thrombocytopenia in patients aged ≥60 years is associated with an increased incidence of haematological malignancy. We performed a retrospective population-based cohort study in patients aged ≥60 years between January 1, 2009 to December 31, 2019. Exposed patients had specialist consultation for thrombocytopenia, with platelet count <100 × 109/L, but normal haemoglobin and white blood cell count. Unexposed patients were those who never had specialist consultation for thrombocytopenia and whose platelets were ≥100 × 109/L. The primary outcome was the diagnosis of haematological malignancy using a competing risk of death model. During 4.0 years (IQR 2.2-6.7) of follow-up, 378/4930 exposed (19.1/1000PY, 95% CI 17.1-21.0), and 204/17556 unexposed patients (2.5/1000PY, 95% CI 2.2-2.8) were diagnosed with haematological malignancy (HR 15.5 (95% CI 11.3-21.4, p < 0.0001) in year 1, and 5.3 (95% CI 4.4-6.6, p < 0.0001) in years 2+). This finding persisted in analyses stratified by sex, age, severity, or duration of thrombocytopenia, and treatment with corticosteroids within 2 weeks of consultation. This study found a strong association between isolated thrombocytopenia and haematological malignancy in patients ≥60 years, supporting consideration of diagnostic testing including BMB during outpatient specialist consultation.

2.
Langmuir ; 35(49): 16377-16387, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31702932

RESUMO

Slippery liquid-infused porous surfaces (SLIPS) are gaining remarkable attention and have advanced performance in many fields. Although all SLIPS are related to lubricant-impregnation within nano/microstructures on a surface, they differ in many aspects, such as the morphology of droplets, the state of cloaking, the wetting edge, and the lubricant thickness. Requirements of the droplet morphology on SLIPS might change according to a specific application. A molecular-dynamics-based numerical model that can correctly simulate SLIPS is developed and is validated by comparing against the theoretical predictions for all possible stable states for a given droplet, lubricant, and solid surface. On the basis of this model, a detailed analysis of the equilibrium states is conducted. In particular, we discover that the four possible stable states on SLIPS predicted by theoretical studies can be extended to eight states by considering the effects of lubricant thickness and surface geometry in addition to the interfacial tension and surface wettability. These findings could be used to determine the conditions under which a thermodynamically stable state exists on SLIPS. The dynamic behavior of a nanodroplet on SLIPS is also studied, which provides insight into how a proper increase in the lubricant thickness might increase the sliding velocity. The above findings and developed model are expected to provide significant guidelines for designing SLIPS.

3.
Langmuir ; 35(29): 9430-9440, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31282674

RESUMO

Heat transfer enhancement in dropwise condensation is widely investigated on a superhydrophobic surface with the advances in surface engineering, but the influence of a large amount of noncondensable gas (NCG) has not been clarified. In this work, the condensation heat transfer with a large amount of NCG is investigated by developing a multiphase lattice Boltzmann model for a multicomponent system. First, the condensation of a single droplet on a hydrophobic surface with NCG is simulated, demonstrating the capacity of the present model to capture the behaviors of different components during phase change and predict the significant influence of even a small fraction of the NCG on heat transfer. Then, solid surfaces with mixed wettability are built by introducing a fraction of hydrophilic parts to enhance heat transfer. It is found that there exists an optimized proportion which could maximize the condensation heat transfer efficiency corresponding to a specific mass fraction of NCG. Furthermore, the mechanism of this optimized proportion is revealed by examining the dynamic behaviors of condensation in a typical case, as a balance between a promotion of the nucleation rate and a put off of transition to filmwise condensation.

4.
ACS Appl Mater Interfaces ; 16(29): 37853-37864, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-38980937

RESUMO

The radiative cooling has great potential for electronic device cooling without requiring any energy consumption. However, a low thermal conductivity of most radiative cooling materials limits their application. Herein, a multishape codoping strategy was proposed to achieve collaborative enhancement of thermal conductivity and radiative properties. The hBN-coated hollow SiO2 particles were prepared based on electrostatic self-assembly technology, which were then mixed with hBN platelets and doped into a poly(vinylidene fluoride-co-hexafluoropropylene) substrate. Discrete dipole approximation theory was employed to reveal the mechanism and optimize the particle size. The results showed that the multishape codoping method can significantly improve the radiative performance, with 94.9% reflectivity and 91.2% emissivity. In addition, this zero-dimensional and two-dimensional composite doping structure facilitated the formation of a thermal conduction network, which enhanced the thermal conductivity of the film up to 1.32 W m-1 K-1. The high thermal conductivity radiative cooling film can decrease the heater temperature from 58.8 to 31.3 °C, with a further reduction of temperature by 7.2 °C compared to the radiative cooling substrates with low thermal conductivity. The net cooling power of the film can reach 102.5 W m-2 under direct sunlight. This work provides a novel strategy for high-efficiency electronic device cooling.

5.
Oral Dis ; 19(1): 73-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22776263

RESUMO

OBJECTIVES: Glycogen synthase kinase-3ß (GSK-3ß)/ß-catenin signaling mediates osteogenesis in response to mechanical loading. We tested the hypothesis that local administration of a GSK-3ß inhibitor could stimulate new bone formation in the expanding premaxillary suture. MATERIALS AND METHODS: Thirty-five Sprague-Dawley rats were subjected to premaxillary suture expansion using a helix spring. The experimental rats were given one or two local injections of SB-415286, a small-molecule GSK-3ß inhibitor. Animals were administered calcein and sacrificed on day 7 to quantify new bone formation. To evaluate the proliferation and differentiation of osteoblasts, rats were labeled with bromodeoxyuridine on day 1 and sacrificed on day 2 or 4. ß-catenin expression was evaluated by immunohistochemical staining. RESULTS: Two injections of SB-415286 led to an elevation of ß-catenin expression and an increase in the number of proliferating osteoblasts in expanding sutures on day 2 and day 4. Consequently, new bone formation in the suture increased significantly on day 7. CONCLUSIONS: These results suggest that local delivery of a GSK-3ß inhibitor could stimulate bone formation in the expanding premaxillary suture by eliciting ß-catenin signaling. GSK-3ß could be a pharmaceutical target for improving the effect of orthodontic treatments such as rapid palatal expansion.


Assuntos
Suturas Cranianas/efeitos dos fármacos , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Maxila/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Aminofenóis/farmacologia , Animais , Antimetabólitos , Bromodesoxiuridina , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Fluoresceínas , Corantes Fluorescentes , Glicogênio Sintase Quinase 3 beta , Masculino , Maleimidas/farmacologia , Osteoblastos/efeitos dos fármacos , Técnica de Expansão Palatina/instrumentação , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , beta Catenina/análise , beta Catenina/efeitos dos fármacos
6.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 58(7): 670-676, 2023 Jun 30.
Artigo em Chinês | MEDLINE | ID: mdl-37400197

RESUMO

Objective: To investigate the effects of two-step retraction and en-masse retraction on tooth movement pattern of anterior teeth and posterior anchorage with clear aligners using three-dimensional finite element analysis. Methods: A finite element model of maxillary first premolar extraction case undergoing clear aligner treatment was established based on maxillofacial cone-beam CT data of a 24-year-old adult male with individual normal occlusion, who visited Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine for impacted mandibular third molar in June, 2022. The initial tooth displacement of five anterior retraction protocols (two-step with canine retraction, two-step with incisor bodily retraction, two-step with incisor retraction-overtreatment, en-masse bodily retraction, and en-masse retraction-overtreatment) were evaluated. Results: Two step with canine retraction caused distal tipping of the canine and labial tipping of the incisors (0.18° for central incisor and 0.13° for lateral incisor). Two step with incisor retraction caused mesial tipping of the canine. In two step with bodily retraction protocol, uncontrolled lingual tipping was found in central incisor (0.29°) and lateral incisor (0.32°). In two-step with incisor retraction-overtreatment protocol, the movement pattern of the incisors didn't change, but the inclinations reduced to 0.21° and 0.18°. En-masse retraction caused distal tipping of the canine. In en-masse bodily retraction protocol, uncontrolled lingual tipping was also found in central incisor (0.19°) and lateral incisor (0.27°). In en-masse retraction-overtreatment protocol, the central incisor showed controlled lingual tipping (0.02°) and the lateral incisor showed palatal root movement (0.03° labial inclination). Posterior teeth exhibited mesial tipping in all five protocols. Conclusion: En-masse retraction with incisor overtreatment was beneficial to incisor torque control in clear aligner treatment.

7.
ACS Appl Mater Interfaces ; 12(23): 26555-26565, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32419445

RESUMO

The surface dynamic wettability during droplet nucleation and growth involved with phase change is different from the static wettability formed from a sessile drop. Revealing this dynamic wettability of the lubricant-impregnated surfaces (LISs) and identification of the consistency between the wettability during condensation and the static wettability are of significant importance. In this study, we investigated condensation of water droplets on LISs using molecular dynamics simulations. All possible morphologies on LISs were investigated considering the effects of interfacial tension and lubricant thickness. The exploration of droplet behaviors from nucleation to growth and coalescence revealed four nucleation mechanisms and six growth modes. The lubricant was observed to be beneficial for the formation of droplets and maintaining dropwise condensation mode. The present investigation also established that the consistency between the wettability during condensation and the static wettability was determined by the solid-water-oil interface and the lubricant thickness. A map was proposed which helps in deciding whether the wettability during condensation is the same as the static wettability on LIS.

8.
Phys Rev E Stat Nonlin Soft Matter Phys ; 79(2 Pt 2): 027701, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19391876

RESUMO

The conventional Navier-Stokes-Fourier equations with no-slip boundary conditions are unable to capture the phenomenon of gas thermal transpiration. While kinetic approaches such as the direct simulation Monte Carlo method and direct solution of the Boltzmann equation can predict thermal transpiration, these methods are often beyond the reach of current computer technology, especially for complex three-dimensional flows. We present a computationally efficient nonequilibrium thermal lattice Boltzmann model for simulating temperature-gradient-induced flows. The good agreement between our model and kinetic approaches demonstrates the capabilities of the proposed lattice Boltzmann method.

9.
Phys Rev E Stat Nonlin Soft Matter Phys ; 78(2 Pt 2): 026706, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18850972

RESUMO

Accurate evaluation of damping in laterally oscillating microstructures is challenging due to the complex flow behavior. In addition, device fabrication techniques and surface properties will have an important effect on the flow characteristics. Although kinetic approaches such as the direct simulation Monte Carlo (DSMC) method and directly solving the Boltzmann equation can address these challenges, they are beyond the reach of current computer technology for large scale simulation. As the continuum Navier-Stokes equations become invalid for nonequilibrium flows, we take advantage of the computationally efficient lattice Boltzmann method to investigate nonequilibrium oscillating flows. We have analyzed the effects of the Stokes number, Knudsen number, and tangential momentum accommodation coefficient for oscillating Couette flow and Stokes' second problem. Our results are in excellent agreement with DSMC data for Knudsen numbers up to Kn=O(1) and show good agreement for Knudsen numbers as large as 2.5. In addition to increasing the Stokes number, we demonstrate that increasing the Knudsen number or decreasing the accommodation coefficient can also expedite the breakdown of symmetry for oscillating Couette flow. This results in an earlier transition from quasisteady to unsteady flow. Our paper also highlights the deviation in velocity slip between Stokes' second problem and the confined Couette case.

10.
RSC Adv ; 8(69): 39341-39351, 2018 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-35558060

RESUMO

To promote the water vapor condensation efficiency in the presence of a non-condensable gas, both high nucleation rate and efficient droplet departure are desired on the condensing surface. Superhydrophobic surfaces with large water contact angles ensure the dropwise condensation mode and efficient droplet departure ability. Alternatively, efficient nucleation requires the surface to be hydrophilic. To combine these two seemingly contradictory factors on a single surface, we presented a copper-based hydrophilic-slippery surface in this study by depositing a lubricant (trimethoxysilane) on the microstructured copper substrate. The water droplet had both low contact angles and sliding angles on the surface, and stable dropwise condensation could be realized with and without non-condensable gas. The present hydrophilic-slippery surface demonstrated promising potential to enhance condensation heat transfer, particularly for cases with non-condensable gas. Improved droplet mobility was observed as compared to a superhydrophobic surface, hydrophobic surface, and hydrophobic-slippery surface. The most attractive feature lies in the enhanced nucleation process due to hydrophilicity, which is more favorable as it requires small subcooling degree and large non-condensable gas content. By revealing that a sliding angle could be accompanied by a small contact angle, this hydrophilic-slippery surface could improve our understanding in designing new functional surfaces for phase change, anti-icing, self-cleaning, and anti-fouling applications.

11.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 52(9): 543-548, 2017 Sep 09.
Artigo em Chinês | MEDLINE | ID: mdl-29972918

RESUMO

Objective: To evaluate the efficiency of maxillary expansion with clear aligners and to analyze the possible influence factors. Methods: Thiry-one clear aligner cases (Invisalign) with maxillary expansion were enrolled in this study. The three-dimensional (3D) digital models of pre-treatment, planned in Clincheck software and post-treatment were collected. Upper dental arch width, buccal inclination of posterior teeth, and the expansion efficiency (expansion acquired/expansion planned) were measured and calculated. The impact of factors such as planned buccal inclination, planned expansion amount, attachment, and the mode of expansion on the expansion efficiency were analyzed. Results: The increases of upper arch width in canine, 1st and 2nd premolar, 1st and 2nd molar were (2.0±1.3), (2.8±1.5), (3.0±1.4), (1.8±1.0) and 0.5 (0.1, 1.1) mm, with their efficiency of 68%, 70%, 68%, 55% and 29%, respectively. The posterior teeth showed significantly more buccal inclination than the planned position (P<0.05). However, the most buccally inclined tooth detected in 1st molars was only 3.1°±3.9°. When the planned inter-molar width increase was less than 2 mm (n=15), the expansion efficiency of premolars was higher compared with those cases with the planned inter-molar width increase more than 2 mm (n=16, P<0.05). The planned buccal inclination, attachments, and the expansion mode had no significant effect on the expansion efficiency (P>0.05). Conclusions: The expansion of maxillary arch with clear aligners was achieved by the buccal movement of the posterior teeth with limited buccal inclination. The efficiency of expansion declines from 1st premolars to second molars. The planned inter-molar width had a significant influence on the efficiency of premolar expansion.


Assuntos
Técnica de Expansão Palatina/instrumentação , Terapia Assistida por Computador , Adolescente , Dente Pré-Molar/anatomia & histologia , Arco Dental/anatomia & histologia , Humanos , Má Oclusão/terapia , Maxila/anatomia & histologia , Dente Molar/anatomia & histologia , Software , Técnicas de Movimentação Dentária
12.
Sci Rep ; 6: 19192, 2016 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-26754316

RESUMO

The effect of surface wettability on condensation heat transfer in a nanochannel is studied with the molecular dynamics simulations. Different from the conventional size, the results show that the filmwise mode leads to more efficient heat transfer than the dropwise mode, which is attributed to a lower interfacial thermal resistance between the hydrophilic surface and the condensed water compared with the hydrophobic case. The observed temperature jump at the solid-liquid surface confirms that the hydrophilic properties of the solid surface can suppress the interfacial thermal resistance and improve the condensation heat transfer performance effectively.

13.
Sci Rep ; 6: 27274, 2016 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-27270997

RESUMO

Recovery of both latent heat and condensate from boiler flue gas is significant for improving boiler efficiency and water conservation. The condensation experiments are carried out to investigate the simultaneous heat and mass transfer across the nanoporous ceramic membranes (NPCMs) which are treated to be hydrophilic and hydrophobic surfaces using the semicontinuous supercritical reactions. The effects of typical parameters including coolant flow rate, vapor/nitrogen gas mixture temperature, water vapor volume fraction and transmembrane pressure on heat and mass transfer performance are studied. The experimental results show that the hydrophilic NPCM exhibits higher performances of condensation heat transfer and condensate recovery. However, the hydrophobic modification results in remarkable degradation of heat and condensate recovery from the mixture. Molecular dynamics simulations are conducted to establish a hydrophilic/hydrophobic nanopore/water liquid system, and the infiltration characteristics of the single hydrophilic/hydrophobic nanopore is revealed.

14.
J Dent Res ; 84(2): 166-71, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15668335

RESUMO

Runx2 is a transcription factor prerequisite for chondrocyte maturation and osteoblast differentiation. We tested the hypothesis that Runx2 is responsible for signaling chondrocyte maturation and endochondral ossification in the condyle during mandibular advancement. Fifty 35-day-old Sprague-Dawley rats were fitted with functional appliances for 3, 7, 14, 21, and 30 days. Experimental animals with 50 matched controls were labeled with bromodeoxyuridine for evaluation of the invasion of chondroclasts and osteoblasts into condylar cartilage. Mandibular advancement elicited Runx2 expression in condylar cartilage, and subsequently led to an expansion of type X collagen domain in the hypertrophic layer. Stronger Runx2 mRNA signals in subchondral bone corresponded with the increase in the recruitment of osteoblasts and chondroclasts, which preceded the increase of new bone formation in the condyle. Thus, Runx2 mediates chondrocyte terminal maturation and endochondral ossification in the mandibular condyle in response to mandibular advancement.


Assuntos
Condrócitos/metabolismo , Colágeno Tipo X/metabolismo , Proteínas de Ligação a DNA/fisiologia , Avanço Mandibular , Côndilo Mandibular/metabolismo , Osteogênese/fisiologia , Fatores de Transcrição/fisiologia , Animais , Cartilagem Articular/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core , Proteínas de Ligação a DNA/genética , Feminino , Imuno-Histoquímica , Modelos Animais , RNA Mensageiro/análise , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Fator de Transcrição AP-2 , Fatores de Transcrição/genética
15.
Phys Rev E Stat Nonlin Soft Matter Phys ; 72(1 Pt 2): 016703, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16090130

RESUMO

A thermal boundary condition for a double-population thermal lattice Boltzmann equation (TLBE) is introduced and numerically demonstrated. The unknown distribution population at the boundary node is decomposed into its equilibrium part and nonequilibrium parts, and then the nonequilibrium part is approximated with a first-order extrapolation of the nonequilibrium part of the populations at the neighboring fluid nodes. Numerical tests with Dirichlet and Neumann boundary constraints show that the numerical results of the TLBE together with the present boundary schemes agree well with the analytical solutions and those of the finite-volume method.

16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 72(5 Pt 2): 056301, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16383739

RESUMO

A lattice Boltzmann method is developed for gaseous slip flow at the pore scale in microscale porous geometries. Flow characteristics through various porous structures are studied for different Knudsen numbers and inlet to outlet pressure ratios. It is found that the gas permeability is larger than the absolute permeability of porous media due to the gas slippage effect. Furthermore, the rarefaction influence on the gas permeability is more evident for porous structures with low porosity. The Klinkenberg equation is confirmed for the simulated porous structures. However, the second-order term of the Knudsen number (Kn2) cannot be neglected for gaseous flow with relatively high Knudsen numbers. A model for predicting the pressure drop of the flow through microscale porous media is presented based on the Ergun equation and the Carman-Kozeny equation by taking into account the effects of gas rarefaction and compressibility.

17.
J Nanosci Nanotechnol ; 15(4): 3259-64, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26353574

RESUMO

Silica aerogel is almost transparent for wavelengths below 8 µm where significant energy is transferred by thermal radiation. The radiative heat transfer can be restricted at high temperature if doped with carbon powder in silica aerogel. However, different particle sizes of carbon powder doping have different spectral extinction coefficients and the doped carbon powder will increase the solid conduction of silica aerogel. This paper presents a theoretical method for determining the optimal carbon doping in silica aerogel to minimize the energy transfer. Firstly we determine the optimal particle size by combining the spectral extinction coefficient with blackbody radiation and then evaluate the optimal doping amount between heat conduction and radiation. Secondly we develop the Monte Carlo numerical method to study radiative properties of carbon-gradient-doped silica aerogel to decrease the radiative heat transfer further. The results indicate that the carbon powder is able to block infrared radiation and thus improve the thermal insulating performance of silica aerogel effectively.

18.
Int J Epidemiol ; 30(1): 52-7, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11171856

RESUMO

BACKGROUND: Studies in developed countries have shown that reduced fetal growth is related to raised blood pressure in childhood and adult life. Little is known about this association in developing countries, where fetal growth retardation is common. METHODS: In 1994-1995, we measured blood pressure in 1570 3-6-year-old children living in China, Guatemala, Chile, Nigeria and Sweden. We related their blood pressure to patterns of fetal growth, as measured by body proportions at birth. The children were all born after 37 weeks gestation and weighed more than 2.5 kg at birth. RESULTS: In each country, blood pressure was positively related to the child's current weight. After adjusting for this and gender, systolic pressure was inversely related to size at birth in all countries except Nigeria. In Chile, China and Guatemala, children who were proportionately small at birth had raised systolic pressure. For example, in Chile, systolic pressure adjusted for current weight increased by 4.9 mmHg (95% CI : 2.1, 7.7) for every kilogram decrease in birthweight, by 1 mmHg (95% CI : 0.4, 1.6) for every centimetre decrease in birth length, and by 1.3 mmHg (95% CI : 0.4, 2.2) for every centimetre decrease in head circumference at birth. In Sweden, systolic pressure was higher in children who were disproportionately small, that is thin, at birth. Systolic pressure increased by 0.3 mmHg (95% CI : 0.0, 0.6) for every unit (kg/m3) decrease in ponderal index at birth. These associations were independent of the duration of gestation. CONCLUSIONS: Raised blood pressure among children in three samples from China, Central and South America is related to proportionate reduction in body size at birth, which results from reduced growth throughout gestation. The relation between fetal growth and blood pressure may be different in African populations. Proportionately reduced fetal growth is the prevalent pattern of fetal growth retardation in developing countries, and is associated with chronic undernutrition among women. Improvement in the nutrition and health of girls and young women may be important in preventing cardiovascular disease in developing countries.


Assuntos
Peso ao Nascer , Pressão Sanguínea/fisiologia , Estatura , Desenvolvimento Embrionário e Fetal/fisiologia , Criança , Pré-Escolar , Chile , China , Países em Desenvolvimento/estatística & dados numéricos , Guatemala , Humanos , Pessoa de Meia-Idade , Nigéria , Suécia
19.
Int J Epidemiol ; 17(3): 608-17, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3209341

RESUMO

The long-term sequelae of vasectomy were studied in a retrospective cohort study of 4596 vasectomized and 4340 nonvasectomized farmers from eight rural communes in Sichuan, People's Republic of China. The mean duration since the operation was 14.5 years with a range of 10 to 25 years. At the time of evaluation the vasectomized men were generally healthier than the non-vasectomized for a wide range of health indicators including clinical signs of cardiovascular disease, resting ECG changes, positive ECG changes following a maximal stress test, or fundus abnormalities. The lack of association between vasectomy and cardiovascular disease noted in Europe and the USA is supported by the present study conducted in a population with a low prevalence of cardiovascular disease and risk factors.


PIP: A study was conducted in Sichuan, China to further determine if any correlation exists between vasectomy and the risk of heart disease. In a retrospective analysis of 4596 men who had received vasectomies and 4340 who had not been vasectomized, it was found that the cardiovascular status of men who had had a vasectomy was actually better that those who had not. The mean duration since the operation was 14.5 years with a range of 10-25 years. The results confirmed past conclusions that vasectomy is not linked with coronary disease. Testing for other endpoints and areas such as stomach ulcer and hypertension indicated that men who had received a vasectomy were in general in better health. Resting ECG changes and positive ECG changes following a stress test further confirmed the results. Mortality associated with vasectomy was also examined with no negative connection found. Vasectomy has been extensively studied and has been proven repeatedly to be a safe procedure that is not linked to adverse effects.


Assuntos
Doenças Cardiovasculares/etiologia , Indicadores Básicos de Saúde , Inquéritos Epidemiológicos , Vasectomia/efeitos adversos , Adulto , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/fisiopatologia , China , Colesterol/sangue , Estudos de Coortes , Eletrocardiografia , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória , Estudos Retrospectivos , Fatores de Risco , População Rural
20.
J Dent Res ; 83(5): 434-8, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15111639

RESUMO

Indian hedgehog (Ihh) is a critical mediator transducing mechanical signals to stimulate chondrocyte proliferation. To clarify the cellular signal transduction pathway that senses and converts mechanical signals into tissue growth in mandibular condyle, we evaluated Ihh expression and its relation to the kinetics of replicating mesenchymal cells in condylar cartilage during natural growth and mandibular advancement. Thirty-five-day-old Sprague-Dawley rats were fitted with functional appliances. Experimental animals with matched controls were doubly labeled with iododeoxyuridine and bromodeoxyuridine so that we could evaluate the cycles of the proliferative mesenchymal cells. Mandibular advancement triggered Ihh expression in condylar cartilage. A higher level of Ihh expression coincided with the increase of the replicating mesenchymal cells' population and the shortening of the turnover time. These findings suggested that Ihh acts as a mediator of mechanotransduction that converts mechanical signals resulting from anterior mandibular displacement to stimulate cellular proliferation in condylar cartilage.


Assuntos
Cartilagem/citologia , Côndilo Mandibular/citologia , Mecanotransdução Celular/fisiologia , Transativadores/fisiologia , Animais , Bromodesoxiuridina , Cartilagem/crescimento & desenvolvimento , Divisão Celular/fisiologia , Condrócitos/fisiologia , Feminino , Proteínas Hedgehog , Idoxuridina , Avanço Mandibular , Côndilo Mandibular/crescimento & desenvolvimento , Mesoderma/citologia , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Fase S/fisiologia , Coloração e Rotulagem
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