Significant improvements in stability and reproducibility of atomic-scale atomic force microscopy in liquid.

Recent advancement of dynamic-mode atomic force microscopy (AFM) for liquid-environment applications enabled atomic-scale studies on various interfacial phenomena. However, instabilities and poor reproducibility of the measurements often prevent systematic studies. To solve this problem, we have investigated the effect of various tip treatment methods for atomic-scale imaging and force measurements in liquid. The tested methods include Si coating, Ar plasma, Ar sputtering and UV/O3 cleaning. We found that all the methods provide significant improvements in both the imaging and force measurements in spite of the tip transfer through the air. Among the methods, we found that the Si coating provides the best stability and reproducibility in the measurements. To understand the origin of the fouling resistance of the cleaned tip surface and the difference between the cleaning methods, we have investigated the tip surface properties by x-ray photoelectron spectroscopy and contact angle measurements. The results show that the contaminations adsorbed on the tip during the tip transfer through the air should desorb from the surface when it is immersed in aqueous solution due to the enhanced hydrophilicity by the tip treatments. The tip surface prepared by the Si coating is oxidized when it is immersed in aqueous solution. This creates local spots where stable hydration structures are formed. For the other methods, there is no active mechanism to create such local hydration sites. Thus, the hydration structure formed under the tip apex is not necessarily stable. These results reveal the desirable tip properties for atomic-scale AFM measurements in liquid, which should serve as a guideline for further improvements of the tip treatment methods.

A metabolomic study on the effect of intravascular laser blood irradiation on type 2 diabetic patients.

Intravenous laser blood irradiation (ILBI) is widely applied in the treatment of different pathologies including diabetes mellitus. The aim of this study is to evaluate the effects of ILBI on the metabolites of blood in diabetic type 2 patients using metabolomics. We compared blood samples of nine diabetic type 2 patients, using metabolomics, before and after ILBI with blue light laser. The results showed significant decrease in glucose, glucose 6 phosphate, dehydroascorbic acid, R-3-hydroxybutyric acid, L-histidine, and L-alanine and significant increase in L-arginine level in blood and blood sugar in the patients have reduced significantly (p < 0.05). This study clearly demonstrated a significant positive effect of ILBI on metabolites of blood in diabetic type 2 patients. These findings support the therapeutic potential of ILBI in diabetic patients.

Comparison of ultrasonography with submentovertex films and computed tomography scan in the diagnosis of zygomatic arch fractures.

OBJECTIVES: The aim of this study was to compare ultrasonography with CT scan and submentovertex films in the visualization of zygomatic arch fractures. METHODS: 17 patients, 10 men and 7 women, with suspected fracture of the zygomatic arch were studied. The data from CT and plain films were compared with the ultrasonographic findings (Aloka 3500 (Tokyo, Japan) ultrasound equipment with a 7.5 MHz transducer). The probe was situated over the fractured arch transversely to evaluate its whole length. All of the sonograms were taken and interpreted by the same sonologist, who was not aware of the results of the CT and the plain films. RESULTS: Ultrasound was accurate in assessing the fractured arches with sensitivity of 88.2% (15 of the 17 patients, with two false negatives) and specificity of 100% (no false positives). CONCLUSION: Ultrasound is accurate in the visualization of zygomatic arch fractures and can be used as an adjunct to plain films to reduce the overall radiation exposure.

Saccular damage in patients with high-frequency sensorineural hearing loss.

Subjects with high frequency sensorineural hearing loss (HF-SNHL) without retrocochlear pathology are those group which certainly encountered inner ear damaging factors. This study was designed to evaluate the effects of cochlear damaging factors on the sacculocollic pathway. Fifty patients (76 ears) with varying degrees of HF-SNHL but without clinical manifestations of vestibular pathology tested for vestibular evoked myogenic potentials (VEMP). The results were compared with those of 18-healthy referents (32 ears) examined in the same way. Subjects with HF-SNHL greater than 40 dB HL showed significantly more saccular deterioration, estimated as negative VEMP responses than did the referents. This suggests subclinical disturbances of the vestibular system especially of the saccule in these patients. The underlying mechanism may be simultaneous damage to both the cochlea and saccule by the same factors.

Effects of levothyroxine suppressive therapy on bone mineral density in premenopausal women.

BACKGROUND: Levothyroxine (L-T4) is widely prescribed for treating thyroid disorders, but its effect on bone mineral density (BMD), is being debated. OBJECTIVES: We studied the effect of supraphysiologic doses of L-T4 on BMD in a group of premenopausal women. PATIENTS AND METHODS: We included 50 women (mean age=36.8 +/- 7.6 years) receiving L-T4 for at least 1 year for treating their benign cold thyroid nodules. Serum T3, T4, thyroid-stimulating hormone (TSH), parathyroid hormone (PTH), calcium, and phosphate and urine calcium and sodium levels of all patients were measured. Bone density at femoral neck and lumbar (L1-L4) regions was measured, using dual energy X-ray absorptiometry (DXA). RESULTS: No significant decrease was detected in the bone density of the subjects treated with L-T4 compared with the control group. CONCLUSION: L-T4 treatment for 1 year is not associated with increased risk of osteoporosis in premenopausal women but other potential adverse effects still need to be monitored in women receiving L-T4 especially long-term.

Brain death: recent ethical and religious considerations in Iran.

The Islamic Republic of Iran has a long history of medicine. The principles derived from core Islamic teachings provide a comprehensive moral, ethical, and legal framework for the practice of medicine. The issue of brain death has significant impact on the procurement of organs from cadavers. It is a major subject of debate and interest to bioscientists, legal experts, religious scholars, and the general public. Laws related to the ethical and legal aspects of cadaver organ donation from the brain dead have not been defined in many Muslim countries. This report presents recent advances in Iranian law with regard to the ethics of organ transplantation and the definition of brain death.

Metabolic and clinical effects of Ramadan fasting in patients with type II diabetes.

OBJECTIVE: To evaluate the effects of fasting on anthropometric indices and carbohydrate and lipid metabolism in patients with type II diabetes. DESIGN: Observational non-interventional study. PLACE AND DURATION OF STUDY: : Diabetes clinic, Shariati Hospital, Tehran, Iran during Ramadan 1419 (winter 1998-99). PATIENTS AND METHODS: Fifty-seven volunteers with type II diabetes underwent anthropometric and biochemical evaluation before and on the 14th and 28th days of Ramadan. Biochemical markers were measured by standard laboratory methods and anthropometric indices by WHO criteria. Statistical analysis was done by ANOVA for repeated measurements and Friedman's two-way ANOVA using SPSSv6 software. RESULTS: Daily cholesterol intake increased in all subjects (p<0.03). Body mass index increased in women (p<0.03), but BMI and waist-hip ratio both decreased in men (p<0.01). Blood pressure, fasting blood glucose and serum fructosamine did not change during the study. Plasma insulin (p<0.05), C-peptide (p<0.01) and insulin resistance (p<0.01) decreased only in men. Total and LDL cholesterol increased significantly in all subjects during the study. CONCLUSION: Ramadan fasting does not alter carbohydrate metabolism or tissue insulin sensitivity in patients with type II diabetes given appropriate dietary education and rescheduling of oral hypoglycaemic medication. Lipid profile is unfavourably altered due to changes in both diet and biochemical response to starvation.