Attosecond pulse generation from $H_2

The behavior of the high-order harmonics and output attosecond pulses from hydrogen molecule ions with various internuclear distances that are exposed to high intensity incoming pulses are investigated. The incoming pulses that are spectrally wide yield from a superposition of monochromatic beams with a constant frequency distance. Our simulations show that the most intense and shortest attosecond pulses can result from hydrogen molecular ions with large internuclear distances which are exposed to irradiation of intense pulses with a frequency width greater than 0.03 a.u.

Experimental investigation of a high-power 1018 nm fiber laser using a 20/400 µm ytterbium-doped fiber.

A 472 W monolithic fiber laser, operating at 1018 nm by employing an active fiber with a low core/cladding diameter ratio of 20/400 µm, is reported in this paper. The slope efficiency and beam quality factor (M2) of the fiber laser are, respectively, 49.4% and 1.17. To realize the setup, the effects of the characteristics of the experimental elements-reflectivity of the output coupling fiber Bragg grating, length of the active fiber, etc.-on the output behavior of the system have been investigated. These are the highest recorded output signal power, efficiency, and beam quality factor in monolithic 1018 nm ytterbium-doped fiber lasers using fibers with a core/cladding diameter ratio of 20/400 µm.

Quantification of diagnostic biomarkers to detect multiple sclerosis lesions employing (1)H-MRSI at 3T.

Proton magnetic resonance spectroscopic imaging ((1)H-MRSI) enables the quantification of metabolite concentration ratios in the brain. The major purpose of the current work is to characterize NAA/Cho, NAA/Cr and Myo/Cr in multiple sclerosis (MS) patients, and to estimate their reproducibility in healthy controls. Twelve MS patients and five healthy volunteers were imaged using (1)H-MRSI at 3T. Eddy current correction was performed using a single-voxel non-water suppressed acquisition on an external water phantom. Time-domain quantification was carried out using subtract-QUEST technique, and based on an optimal simulated metabolite database. Reproducibility was evaluated on the same quantified ratios in five normal subjects. An optimal database was created for the quantification of the MRSI data, consisting of choline (Cho), creatine (Cr), N-acetyl aspartate (NAA), lactate (Lac), lipids, myo-inositol (Myo) and glutamine + glutamate (Glx). Decreasing of NAA/Cr and NAA/Cho ratios, as well as an increase in Myo/Cr ratio were observed for MS patients in comparison with control group. Reproducibility of NAA/Cr, NAA/Cho and Myo/Cr in control group was 0.98, 0.87 and 0.64, respectively, expressed as the squared correlation coefficient R (2) between duplicate experiments. We showed that MRSI alongside the time-domain quantification of spectral ratios offers a sensitive and reproducible framework to differentiate MS patients from normals.

Immune Response of Broiler Chickens Fed Diets Supplemented with Different Level of Chromium Methionine under Heat Stress Conditions.

The objectives of this study were to investigate the immune responses of broiler chickens fed diets supplemented with different level of chromium methionine (CrMet) in heat stress (HS) condition. Two hundred and eighty eight male broiler chickens (Ross 308) were allocated to four treatment groups (supplementation with 0, 200, 400 or 800 ppb Cr in the form of CrMet) in a completely randomized design. The experiment was conducted at heat stressed condition and all birds were kept under temperature of 33±2°C. Antibody titers against Newcastle disease virus (NDV) and infectious bronchitis virus (IBV), heterophil to lymphocyte ratios (H/L), and concentration of plasma cortisol (CPC) were measured at 21 and 42 d. At 42 days of age two birds were chosen randomly from each replicate, slaughtered, spleen and bursa of Fabricius were collected, weighed and expressed as a percentage of live body weight. Antibody titers against NDV and IBV at 21 and 42 days of age in broiler fed supplemental CrMet were higher than in broiler chickens fed control diet (p<0.05). CPC level in broiler chickens fed CrMet were significantly (p<0.05) decreased. Increases in lymphocyte counts and consequently a decrease in heterophil to lymphocyte ratios in broiler chickens fed 800 ppb Cr were observed at 21 and 42 d. Supplementation with CrMet had no significant effect on lymphoid organs of broilers. The results suggest that dietary CrMet supplementation at a level of 800 ppb can improve some immune responses of broiler chickens under heat stress conditions.

Cardiovascular disease and risk factors in patients with type 2 diabetes mellitus in Mashhad, Islamic Republic of Iran.

The aim of this study in 2006-08 was to determine the prevalence and risk factors of CVD in an Iranian population of patients with type 2 diabetes mellitus. History and physical examinations were recorded and laboratory tests were performed in 752 patients attending the Mashhad Endocrine and Metabolism Research Center. The prevalence of CVD was 20.1%. CVD was significantly associated with age, duration of diabetes, hypertension, diabetic retinopathy, metabolic syndrome, renal insufficiency, triglycerides, high-density lipoprotein (HDL) cholesterol, uric acid and triglycerides/HDL ratio. Using a logistic regression model, age, metabolic syndrome and HDL cholesterol were significant independent predictors of CVD. The high prevalence of CVD in Iranian patients with type 2 diabetes underscores the importance of better detection and treatment of metabolic risk factors of CVD in these patients.

Cardiovascular disease and risk factors in patients with type 2 diabetes mellitus in Mashhad, Islamic Republic of Iran

The aim of this study in 2006-08 was to determine the prevalence and risk factors of CVD in an Iranian population of patients with type 2 diabetes mellitus. History and physical examinations were recorded and laboratory tests were performed in 752 patients attending the Mashhad Endocrine and Metabolism Research Center. The prevalence of CVD was 20.1%. CVD was significantly associated with age, duration of diabetes, hypertension, diabetic retinopathy, metabolic syndrome, renal insufficiency, triglycerides, high-density lipoprotein [HDL] cholesterol, uric acid and triglycerides/HDL ratio. Using a logistic regression model, age, metabolic syndrome and HDL cholesterol were significant independent predictors of CVD. The high prevalence of CVD in Iranian patients with type 2 diabetes underscores the importance of better detection and treatment of metabolic risk factors of CVD in these patients

Incidence and risk factors of retinopathy of prematurity in a tertiary eye hospital in Tehran.

AIM: To determine the incidence and risk factors of retinopathy of prematurity (ROP) in premature infants referred to a tertiary eye hospital during 2003-7 to provide preliminary evidence about ROP in Iran. METHODS: In a cross-sectional study, data for premature infants screened for ROP in Farabi Eye Hospital including possible risk factors and eye exams' results were recorded and analysed using chi(2), univariate and multiple regressions. Severe ROP was defined as ROP needing treatment or stage 4 or 5 of ROP. RESULTS: Among 953 premature infants, there were 329 (34.5%) different stages of ROP. Severe ROP was seen in 22.6% (215/953) of infants (16.5%: treatable, 6.1%: advanced untreatable). The mean gestational age (GA) and birth weight (BW) of infants with severe ROP were 28.8 (SD 2.4) weeks and 1256 (389) g respectively. Univariate analysis showed a significant relation between GA, BW, oxygen therapy, blood transfusion and ROP (p<0.001), while multiple-regression methods showed GA, BW and oxygen therapy as independent predictors of ROP (p<0.001, 0.019 and 0.033, respectively). CONCLUSION: The authors observed a relatively high incidence of ROP in this series, especially its severe form affecting relatively more mature infants, which merits further investigation. GA, BW and oxygen therapy were independent ROP determinants.