Nonlinear photoresponse of NaYF4:Yb,Er@NaYF4 nanocrystals under green CW excitation: a comprehensive study

One of the efficient and well-known upconverting nanomaterials is NaYF₄:Yb,Er@NaYF₄, which emits photoluminescence at 545 nm and 660 nm under an excitation of 980 nm. Here, the nonlinearity of β-NaYF₄:Yb,Er@NaYF₄ at 532 nm is investigated using three nonlinear approaches. For the first time, the nonlinear optical conjugation of NaYF₄:Yb,Er@NaYF₄ nanocrystals is observed using the degenerate four-wave mixing method. In the optical bistability study, the optical hysteresis of NaYF₄:Yb,Er@NaYF₄ is measured using the Mach–Zehnder interferometer nonlinear ring cavity, and the results of bistability loops show different behaviors at different power regimes. Finally, the Z-scan technique is used for determining the nonlinear absorption and refraction coefficients, which are calculated in the order of 10⁻⁴ (cm W⁻¹) and 10⁻⁸ (cm² W⁻¹), respectively. The results indicate that by increasing incident powers, optical behaviour changes in both optical bistability and Z-scan. Therefore, the results exhibit that the β-NaYF₄:Yb,Er@NaYF₄ nanocrystals have nonlinear photoresponses at both 980 and 532 nm, which could be promising for photonic devices based on NIR light and visible light.

NaYF₄:Yb,Er@NaYF₄ is an efficient and well-known upconverting nanomaterials at 980 nm, also it has strong optical nonlinearity at 532 nm related to energy states of the Yb/Er system which is determined by a unique approach.     

Systemic lupus erythematosus in Iran: a study of 2280 patients over 33 years

Objective: Systemic lupus erythematosus (SLE) as a chronic autoimmune disease has a worldwide distribution. There is a wide variation in the natural history of SLE among different ethnic and geographic groups. The aim of this study was to show the manifestations of SLE in Iranian patients. Methods: The study was on manifestations of SLE according to the database of the Rheumatology Research Center (RRC), Tehran, Iran, on registered patients during the period of 1976 to 2009. Results: A total of 2280 SLE patients (2052 female and 228 male) were studied. The female : male ratio was 9 : 1 and the mean age at presentation was 24.4 ± 10.4 years. Prevalence of manifestations included: musculoskeletal (83.2%), cutaneous (81.1%), renal (65.4%), neuropsychiatric (23.4%), pulmonary (21.5%), cardiac (17.2%), and hematologic (66.4%) symptoms. There was positive antinuclear antibodies in 86.4% and anti‐DNA in 82.3% of patients. Overlap syndrome and positive family history with other autoimmune diseases were detected in 7.6% and 3.4% of patients, respectively. Conclusion: In our patients the prevalence of cutaneous involvement was similar to those of nearby countries (with similar climate). Renal involvement was seen more than some other countries especially more than European countries, while other manifestations (such as hematologic and joint involvement) were similar to European countries (with similar ethnicity). We may conclude that genetic and/or climatic factors may lead to different presentations of lupus.     

Liver Histology Changes in Nonalcoholic Steatohepatitis after One Year of Treatment with Probucol

BACKGROUND: Probucol, a lipid-lowering agent with antioxidant effects, is effective in normalizing liver enzymes in patients with nonalcoholic steatohepatitis (NASH). We studied changes in the liver histology of patients with NASH after use of probucol for one year. METHODS: Ten patients with biopsy-proven NASH were included. Subjects were given 500 mg probucol daily. Liver biopsies were performed before treatment and after one year. RESULTS: Eight patients completed treatment. The mean alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels decreased from 94 and 55 to 41 and 26, respectively (P = 0.004 and 0.001 respectively). The scores for hepatic steatosis and necroinflammation decreased from 7.4 to 5.6 (P = 0.03). The fibrosis score changed from 1.1 to 1.3 (P = 0.79). No adverse drug effects were observed. CONCLUSION: Probucol is effective in normalizing aminotransferase levels in patients with NASH. It also significantly reduces the histology grade of steatohepatitis after one year of treatment.     

Evaluation of the validity of a rapid method for measuring high and low haemoglobin levels in whole blood donors

Background

Haemoglobin screening methods need to be highly sensitive to detect both low and high haemoglobin levels and avoid unnecessary rejection of potential blood donors. The aim of this study was to evaluate the accuracy of measurements by HemoCue in blood donors.

Materials and methods

Three hundred and fourteen randomly selected, prospective blood donors were studied. Single fingerstick blood samples were obtained to determine the donors'' haemoglobin levels by HemoCue, while venous blood samples were drawn for measurement of the haemoglobin level by both HemoCue and an automated haematology analyser as the reference method. The sensitivity, specificity, predictive values and correlation between the reference method and HemoCue were assessed. Cases with a haemoglobin concentration in the range of 12.5–17.9 g/dL were accepted for blood donation.

Results

Analysis of paired results showed that haemoglobin levels measured by HemoCue were higher than those measured by the reference method. There was a significant correlation between the reference method and HemoCue for haemoglobin levels less than 12.5 g/dL. The correlation was less strong for increasing haemoglobin levels. Linear correlation was poor for haemoglobin levels over 18 g/dL. Thirteen percent of donors, who had haemoglobin levels close to the upper limit, were unnecessarily rejected.

Discussion

HemoCue is suitable for screening for anaemia in blood donors. Most donors at Yazd are males and a significant percentage of them have haemoglobin values close to the upper limit for acceptance as a blood donor; since these subjects could be unnecessarily rejected on the basis of HemoCue results and testing with this method is expensive, it is recommended that qualitative methods are used for primary screening and accurate quantitative methods used in clinically suspicious cases or when qualitative methods fail.     

Endovascular abdominal aortic stenosis treatment with the optimed self‐expandable nitinol stent

Purpose: To evaluate the safety and feasibility of self‐expandable stents (OptiMed) for treatment of abdominal aortic stenosis in the situations in which the aortic stenosis locates near the origin of celiac, superior mesenteric, renal and inferior mesenteric arteries. Methods: Five consecutive patients scheduled for endovascular treatment of abdominal aortic stenosis by self‐expandable nitinol stent (Sinus‐Aorta/OptiMed) implantation. The diameter of the stent was chosen as 10–30% more than that of the normal portion of the aorta above the stenosis. Long stents of 60 mm or longer were chosen. After stent deployment, balloon postdilation was performed with a balloon in patients with residual gradient > 5 mm Hg. Results: All patients were successfully treated with the OptiMed stents. The balloon predilation was performed in one patient due to severe stenosis. The mean diameter and length of the stents deployed were 20.4 ± 2.9 (range, 16–24 mm) and 64 ± 8.9 (range, 60–80 mm), respectively. The balloon postdilation was performed in all cases. The mean diameter of the balloons was 13.6 ± 1.5 (range, 12–15 mm). The mean diameter of stenosis increased from 4.8 ± 1.9 to 14.4 ± 1.8 mm after stent placement. The mean peak systolic gradient decreased from 46.8 ± 31.5 mm Hg to 0.8 ± 1.8 mm Hg. During follow‐up (22.8 ± 14.3 months), none of the patients had restenosis within the stent, occlusion of any branches of the aorta, or other related complications. Conclusions: In our small series, we observed that abdominal aortic stenosis can be successfully and effectively treated with OptiMed stents in the situations in which the stenotic segment is located next to the origins of the main visceral branches of abdominal aorta. © 2009 Wiley‐Liss, Inc.     

Ischemia promotes renin activation and angiotensin formation in sympathetic nerve terminals isolated from the human heart: contribution to carrier-mediated norepinephrine release

We recently reported that in the ischemic human heart, locally formed angiotensin II activates angiotensin II type 1 (AT(1)) receptors on sympathetic nerve terminals, promoting reversal of the norepinephrine transporter in an outward direction (i.e., carrier-mediated norepinephrine release). The purpose of this study was to assess whether cardiac sympathetic nerve endings contribute to local angiotensin II formation, in addition to being a target of angiotensin II. To this end, we isolated sympathetic nerve endings (cardiac synaptosomes) from surgical specimens of human right atrium and incubated them in ischemic conditions (95% N(2,) sodium dithionite, and no glucose for 70 min). These synaptosomes released large amounts of endogenous norepinephrine via a carrier-mediated mechanism, as evidenced by the inhibitory effect of desipramine on this process. Norepinephrine release was further enhanced by preincubation of synaptosomes with angiotensinogen and was prevented by two renin inhibitors, pepstatin-A and BILA 2157BS, as well as by the angiotensin-converting enzyme inhibitor enalaprilat and the AT(1) receptor antagonist EXP 3174 [2-N-butyl-4-chloro-1-[2'-(1H-tetrazol-5-yl)biphenyl-4-yl] methyl]imidazole-5-carboxylic acid]. Western blot analysis revealed the presence of renin in cardiac sympathetic nerve terminals; renin abundance increased ~3-fold during ischemia. Thus, renin is rapidly activated during ischemia in cardiac sympathetic nerve terminals, and this process eventually culminates in angiotensin II formation, stimulation of AT(1) receptors, and carrier-mediated norepinephrine release. Our findings uncover a novel autocrine/paracrine mechanism whereby angiotensin II, formed at adrenergic nerve endings in myocardial ischemia, elicits carrier-mediated norepinephrine release by activating adjacent AT(1) receptors.     

An In Vitro Stereomicroscopic Evaluation of Bioactivity between Neo MTA Plus,Pro Root MTA,BIODENTINE & Glass Ionomer Cement Using Dye Penetration Method

The ideal root end filling material should form a tight seal in the root canal by adhering to the cavity walls. Several materials have been used for root end filling. The present study aims to find out and compare the bioactivity of Neo MTA Plus, Pro Root MTA White, BIODENTINE & glass ionomer cement as root end filling materials using 1% methylene blue as tracer. Materials and methods: 80 extracted human permanent maxillary anterior teeth were used in the study. They were divided into four groups. Specimens were sectioned transversely in the cervical area to separate the crown from the root. The root canal was obturated with gutta percha and zinc oxide eugenol sealers. Thereafter, each sample was resected apically by removing 3 mm of the apex and filled with different materials. Samples were kept in buffering solution at 37 °C until the recommended evaluation periods. The specimens were then suspended in 1% methylene blue for 24 h, prior to the analysis. The teeth were then sectioned, and dye penetration was examined, photographed, and evaluated under a stereomicroscope. Results: Vertical dye penetration showed significant differences across different groups. The minimum dye penetration was seen in Neo MTA plus followed by BIODENTINE, Pro Root MTA and maximum in GIC. There was no significant difference in dye penetration between Neo MTA plus and BIODENTINE both at fifteen days and one-month intervals. Conclusion: The present study suggests Neo MTA plus and BIODENTINE should be the preferred material for root end filling.     

Risk factors of gestational diabetes mellitus using results of a prospective population-based study in Iranian pregnant women

Aims

Early identification of at-risk groups is an important step in preventing gestational diabetes and its subsequent side effects. This study aimed to evaluate the risk factors of gestational diabetes based on the International Association of Diabetes and Pregnancy Study Groups criteria in Ahvaz.

Advances in the diagnosis and treatment of tuberculosis

Although truly major advances that would revolutionize tuberculosis (TB) diagnosis and treatment have not been realized, we are beginning to see the innovations that have been prompted by the recognition of the economic potential of the market for new diagnostic tests and treatments for TB and considerably increased public and private funding. Despite the enormous global burden of TB and the overall low rates of case detection worldwide, conventional approaches to diagnosis have, until recently, relied on tests that have major limitations. In this review of advances in diagnosis, we focus on strengths and limitations of newer tests that are available for the diagnosis of latent and active tuberculosis and rapid detection of drug resistance, specifically, tests that measure release of IFN-gamma in response to stimulation by Mycobacterium tuberculosis antigens, nucleic acid amplification for identification of M. tuberculosis complex, and rapid tests for detecting drug resistance. Standard regimens for treating TB have not changed for more than 30 yr and still require a minimum of 6 mo to have a high likelihood of a lasting cure. In this article, we focus on important changes in the philosophy of treatment, emphasizing the responsibility of the provider to assure successful completion of treatment, and on the roles of existing anti-TB agents and newer drugs such as rifabutin, rifapentine, and fluoroquinolones.     

Prevention of tuberculosis in HIV-infected patients

PURPOSE OF REVIEW: The pandemic of HIV infection has contributed to a significant increase in tuberculosis rates worldwide. Tuberculosis is one of the most common opportunistic infections in HIV-infected patients, and the leading cause of death. In order to control tuberculosis in areas with high rates of co-infection, strategies must be developed to prevent tuberculosis in HIV-infected individuals. RECENT FINDINGS: Recent reviews have highlighted the burden of HIV-related tuberculosis in the world and the necessary steps that must be taken to control tuberculosis in certain high-risk regions like sub-Saharan Africa. The Centers for Disease Control and Prevention has recently published guidelines for the use of the diagnostic test QuantiFERON-TB Gold, and cautioned about interpretation of this test in HIV-infected patients because of a lack of information regarding performance in these individuals. Perhaps the most significant studies over the past year have reported the impact that treating HIV infection can have on the risk of tuberculosis. SUMMARY: HIV and tuberculosis continue to be linked in a global pandemic. In addition to the standard approaches to tuberculosis control, such as the diagnosis and treatment of tuberculosis and latent tuberculosis infection, recent studies have demonstrated that treatment of HIV itself may also have a role in tuberculosis control.