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1.
Osteoporosis is a major public health problem in the Western countries and is projected to have a similar impact in the Middle East. It has been suggested that peak bone mineral density (BMD), a major determinant of osteoporotic fractures later in life, may be lower in this part of the world compared with the Western world. The purpose of the Iranian Multicenter Osteoporosis Study was to determine peak bone mass in a randomly chosen sample of healthy Iranian subjects. A total of 5201 participants (2340 males, mean age 42.7+/-13.8) were recruited based on randomized clustered sampling from all regions of five major cities across the country. In women, peak lumbar BMD (1.182+/-0.127 g/cm2) occurred in the 29- to 33-yr age group, whereas peak total femur BMD (1.006+/-0.126 g/cm2) occurred in the 32- to 36-yr age group. In men, peak lumbar BMD (1.181+/-0.153 g/cm2) and femoral BMD (1.096+/-0.159 g/cm2) both occurred in the 20- to 24-yr age group. When standardized to mg/cm2 units using established formulas, Iranian peak bone mass values are comparable with that of Western countries and are generally higher than that of Eastern Asian and Middle Eastern countries.  相似文献   
2.
Neural origins of the P300   总被引:13,自引:0,他引:13  
A review of the literature investigating the neural origins of detection behavior in humans reveals two event-related potential components, P3a and P3b, each with a distinct neural organization and cognitive function.The P3a is involved in automatic novelty detection and characterized by a more anterior cortical distribution, whereas the P3b is concerned with volitional target detection and has a more posterior cortical distribution. Intracranial investigation, studies with patients with focal brain lesions, and functional neuroimaging (fMRI) studies converge with scalp-recorded event-related potential (ERP) data in suggesting that a widespread cortical network gives rise to both automatic and controlled detection behavior. The main regions consistently attributed to generating detection-related brain activation include the temporal-parietal junction, medial temporal complex, and the lateral prefrontal cortex. The extant human and animal literature addressing the neural networks, neuropharmacological underpinnings, and behavioral significance of the P300 potential will be reviewed.  相似文献   
3.
The aim of this study was to determine the relationships between bone mineral density (BMD) and blood pressure in 214 men, age 20–76. BMD measurements were done by dual X‐ray absorptiometry using a Lunar DPXMD densitometer at the lumbar spine (L2–L4) and different femoral regions. Systolic (SBP) and diastolic (DBP) blood pressure were measured using an MPC‐350 sphygmomanometer. Physicians gathered demographic data and participants' dietary intake of calcium were determined by using food frequency questionnaires. After adjusting for age, body mass index, dietary calcium, and exercise history, multiple linear regression models showed that DBP was negatively related to femoral neck BMD (β = ?0.145, P = 0.032) and just shy of significant association with femoral neck BMC (β = ?0.114, P = 0.079). SBP was correlated with femoral neck (r = ?0.171, P = 0.012) and Ward's (r = ?0.186, P = 0.006) BMD but not after adjusting for possible confounders. Further studies are needed to determine whether elevated blood pressure is causally related to the development of low bone mass. Am. J. Hum. Biol. 16:168–171, 2004. © 2004 Wiley‐Liss, Inc.  相似文献   
4.
5.
Limb/digit amputation is a common event in humans caused by trauma, medical illness, or surgery. Although the loss of a digit is not lethal, it affects quality of life and imposes high costs on amputees. In recent years, the increasing interest in limb regeneration has led to enhanced scientific knowledge. However, the limited ability to develop functional limb regeneration in the clinical setting suggests that a challenging issue remains in limb regeneration. Recently, the emergence of regenerative engineering is a promising field to address this challenge and close the gap between science and clinical applications. Cell signalling and molecular mechanisms involved in the limb regeneration process have been extensively studied; however, there is still insufficient data on cell therapy and tissue engineering for limb regeneration. In this review, we intend to focus on therapeutic approaches for limb regeneration that are closely related to gene, immune, and stem cell therapies, as well as tissue engineering approaches that take into consideration the peculiar developmental properties of the limbs. In addition, we attempt to identify the challenges of these strategies for limb regeneration studies in terms of clinical settings and as a road map to accomplish the goal of functional human limb regeneration.  相似文献   
6.
Clinical and Experimental Medicine - The development of new therapies based on tumor biology is one of the main topics in cancer treatment. In this regard, investigating the...  相似文献   
7.
8.
Since 1990 and the invention of the very first generation of ordered mesoporous silica materials, several innovative methodologies have been applied to synthesize, characterize, and modify silica/non-silica mesoporous materials. The growth of the mesoporous materials field has generated significant environmental and economic advantages compared to various other industrial developments. According to the literature, there are several key synthesis approaches and parameters that can affect the structural, textural and morphological characteristics of mesoporous materials. To date, huge attempts have been made to maximize the activities and selectivities of these materials through either the in situ or post-synthesis functionalization of the large interior surface areas and internal mesostructured frameworks in the presence of specific organic/inorganic components. However, the main challenge is to provide good control over the incorporation and distribution of multiple guest components within the mesostructured hosts. Mesostructured materials have received great attention for various applications, such as being used in electronics, medicine, photocatalysis, catalyst supports, catalysis, absorbers, sensors, gas separation, etc. In the current paper, several recent developments have been highlighted and reviewed regarding the fabrication and characterization of siliceous/non-siliceous mesoporous materials via various synthetic approaches. Furthermore, the availability of diverse functionalization methods has been reviewed to provide comprehensive approaches for synthesizing new generations of suitably modified mesoporous materials with superior structural, physicochemical, and textural characteristics.

Since 1990 and the invention of the very first generation of ordered mesoporous silica materials, several innovative methodologies have been applied to synthesize, characterize, and modify silica/non-silica mesoporous materials.  相似文献   
9.

Objective:

Helicobacter pylori (H. pylori) is the most common chronic bacterial infection in humans. Chronic colonization increases the risk of duodenal ulcer and gastric cancer. The risk factors for acquiring the infection have been extensively studied. However, there are conflicting results on the role of breastfeeding in the prevention of H. pylori infection. We conducted a study to evaluate the effects of breastfeeding on the H. Pylori infection in Kurdish children in Sanandaj, IR Iran.

Methods:

A historical cohort study was carried out from January 2011 through December 2012. Totally 221 children who were going to attain 2 years old during the study period were randomly enrolled. They were divided into two groups, i.e. breastfed and non-breastfed. We used H. pylori stool antigen test to detect infection in the selected group of children after age of 2 years and cessation of breastfeeding. Each group was subdivided into two subgroups, infected and non-infected. The associations of breastfeeding with H. pylori infection was assessed using statistical software.

Findings:

We found no difference in the odds of infection between breastfed and non-breastfed groups (OR=0.809, 95% CI [0.453–1.444]). An association between age and the prevalence of infection was found (P=0.008). There was an increase in the odds of infection as the family size grew (OR=1.93, 95% CI [1.04–3.6]) as well as increasing housing density (OR=2.12, 95% CI [1.10–4.10]).

Conclusion:

The data suggests that breastfeeding in infancy does not protect against H. pylori infection for long duration among studied children in Iran. The protective effects of breastfeeding, if any, are at most transient.  相似文献   
10.
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