Yb-fiber-pumped, high-beam-quality, idler-resonant mid-infrared picosecond optical parametric oscillator.

We report an Yb-fiber-pumped picosecond optical parametric oscillator (OPO) delivering high average power in excellent beam quality throughout the mid-infrared (mid-IR). Using MgO:PPLN as the nonlinear crystal and configured as a singly-resonant oscillator in the mid-IR idler wave, the OPO provides up to 3.5 W average power in high spatial quality with M2<1.8 across a continuous tuning range of 4028-2198 nm, with M2<1.5 at 4000 nm. It can also deliver as much as 4.3 W of signal power in an output beam with M2<1.4 across 1446-2062 nm. The extracted idler exhibits a passive power stability better than 0.46% rms over 1 hour across the entire mid-IR tuning range. We have also investigated OPO cavity length detuning behavior about the zero-group-velocity-mismatch crossing point and its effects on output power.

Picosecond difference-frequency-generation in orientation-patterned gallium phosphide.

We report the generation of tunable high-repetition-rate picosecond radiation in the mid-infrared using the new quasi-phase-matched nonlinear material of orientation-patterned gallium phosphide (OP-GaP). The source is realized by single-pass difference-frequency-generation (DFG) between the output signal of a picosecond optical parametric oscillator (OPO) tunable across 1609-1637 nm with input pump pulses at 1064 nm in OP-GaP, resulting in tunable radiation across 3040-3132 nm. Using a 40-mm-long crystal, we have generated up to 57 mW of DFG average power at ~80 MHz repetition rate for a pump power of 5 W and signal power of 0.9 W, with >30 mW over >50% of the tuning range. The DFG source exhibits a passive power stability better than 3.2% rms over 1 hour in good spatial beam quality. To the best of our knowledge, this is the first picosecond frequency conversion source based on OP-GaP.

Continuous-wave, single-pass, single-frequency second-harmonic-generation at 266 nm based on birefringent-multicrystal scheme.

We report the implementation of a compact cascaded multicrystal scheme based on birefringent crystals in critical phase-matching, for the generation of continuous-wave (cw) radiation in the deep ultraviolet (UV). The approach comprises a cascade of 4 single-pass second-harmonic-generation (SHG) stages in ß-BaB2O4 (BBO) pumped by a single-frequency cw green source at 532 nm. A deep-UV cw output power of 37.7 mW at 266 nm has been obtained with a high passive power stability of 0.12% rms over more than 4 hours. Characterization and optimization of the system in each stage has been systematically performed. Angular phase-matching acceptance bandwidth under tight focusing in BBO, and spectral properties of the deep-UV radiation, have been studied. Theoretical calculations for SHG in the cascaded scheme based on birefringent phase-matching have been performed, and enhancement in UV power compared to single-stage single-pass scheme are studied. Theoretical comparison of BBO with other potential crystals for deep-UV generation in cascaded multicrystal scheme is also presented.

Fiber-laser-based, green-pumped, picosecond optical parametric oscillator using fan-out grating PPKTP.

We report a stable, Yb-fiber-laser-based, green-pumped, picosecond optical parametric oscillator (OPO) for the near-infrared based on periodically poled potassium titanyl phosphate (PPKTP) nonlinear crystal, using fan-out grating design and operating near room temperature. The OPO is continuously tunable across 726-955 nm in the signal and 1201-1998 nm in the idler, resulting in a total signal plus idler wavelength coverage of 1026 nm by grating tuning at a fixed temperature. The device generates up to 580 mW of average power in the signal at 765 nm and 300 mW in the idler at 1338 nm, with an overall extraction efficiency of up to 52% and a pump depletion >76%. The extracted signal at 765 nm and idler at 1746 nm exhibit excellent passive power stability better than 0.5% and 0.8% rms, respectively, over 1 h with good beam quality in TEM00 mode profile. The output signal pulses have a Gaussian temporal duration of 13.2 ps, with a FWHM spectral bandwidth of 3.4 nm at 79.5 MHz repetition rate. Power scaling limitations of the OPO due to the material properties of PPKTP are studied.

Mitochondrial function and gastrointestinal diseases.

Mitochondria are dynamic organelles that function in cellular energy metabolism, intracellular and extracellular signalling, cellular fate and stress responses. Mitochondria of the intestinal epithelium, the cellular interface between self and enteric microbiota, have emerged as crucial in intestinal health. Mitochondrial dysfunction occurs in gastrointestinal diseases, including inflammatory bowel diseases and colorectal cancer. In this Review, we provide an overview of the current understanding of intestinal epithelial cell mitochondrial metabolism, function and signalling to affect tissue homeostasis, including gut microbiota composition. We also discuss mitochondrial-targeted therapeutics for inflammatory bowel diseases and colorectal cancer and the evolving concept of mitochondrial impairment as a consequence versus initiator of the disease.

Diabetes distress and its clinical determinants in patients with type II diabetes.

AIM: The present study aimed to determine the status of diabetes distress and its clinical determinants in type II diabetes patients. METHODS: This descriptive-analytical study was performed on 220 patients with t diabetes referred to Diabetes Clinic of Imam Khomeini Hospital in Ardabil, Iran. The samples were selected using convenience sampling method. Data collection tools included demographic and disease form and Diabetes Mellitus Scale (DDS). Data analysis was performed using SPSS software version 22 via descriptive (frequency, mean, standard deviation) and inferential statistics (compare means, Pearson correlation coefficient and stepwise multiple regression). RESULTS: The average duration of diabetes was 7.64 (SD = 4.68) years. 63.7% of the patients had moderate to severe diabetes-related distress. Emotional burden dimension had the highest score among the subscales of diabetes distress. In addition, there was a correlation between positive family history (p = 0.017), duration of diabetes (p = 0.028) and type of treatment (p = 0.47) and diabetes distress. HemoglobinA1C levels, body mass index and triglyceride were the major predictors of diabetes distress. CONCLUSIONS: Considering the high prevalence of diabetes distress in patients with type II diabetes, it seems that paying attention to clinical predictors of distress and screening of patients with diabetes is a reasonable and accessible method for health care providers and patients to improve their disease management.

Post-reperfusion Syndrome and Outcome Variables after Orthotopic Liver Transplantation.

BACKGROUND: Post-reperfusion syndrome (PRS) is an important complication during liver transplantation. OBJECTIVE: We studied the occurrence and severity of PRS in patients who underwent orthotopic liver transplantation (OLT) to investigate how PRS was correlated to clinical variables and outcomes. METHODS: We retrospectively recorded intra- and peri-operative data for 184 adult patients who received cadaveric OLT during a 3-year period from 2005 to 2008. Patients were divided into two groups according to the severity of PRS: Group 1 (mild or no PRS) comprised 152 patients; and group 2 (significant PRS) consisted of 32 patients. RESULTS: There were no significant differences in demographic and pre-operative data between groups. Group 2 had more total blood loss than group 1 (p=0.036), especially after reperfusion (p=0.023). Group 2 required more packed red cell transfusions (p=0.005), more fresh frozen plasma (p=0.003) and more platelets (p=0.043) than group 1. Fibrinolysis was more frequent in group 2 (p=0.004). Hospital stay in group 2 was significantly longer than in group 1 (p=0.034), but the frequencies of other outcomes including infection, retransplantation, dialysis, rejection and extended donor criteria did not differ significantly between groups. CONCLUSIONS: Bleeding, blood transfusion and fibrinolysis occurred more often in the group of severe PRS after reperfusion. Although postoperative complications like rejection, infection and the dialysis rate were not significantly different in the two groups, hospital stay was more prolonged in the group with severe PRS.

Anti-infectives-induced adverse drug reactions in hospitalized patients.

OBJECTIVES: To assess the rate and seriousness of adverse drug reactions (ADRs) attributable to anti-infective agents in hospitalized patients; to estimate the likelihood of experiencing anti-infectives-induced ADRs at different length of drug usage in the hospital; to compare different classes of anti-infectives in inducing ADRs; to determine the impact of age and sex on anti-infectives-induced ADRs. DESIGN: Prospective cohort study. PARTICIPANTS: Patients admitted to the infectious diseases department at a university teaching hospital, on Sunday to Wednesday, over a 9 months period, who received at least one anti-infective agent were eligible to enter the study. MAIN OUTCOME MEASURES: Any suspected noxious and untoward medical events, including laboratory tests abnormalities following anti-infective therapy. METHODS: All patients admitted have received at least one anti-infective drug. Anti-infective agents induced ADRs were detected by interviewing patients and daily chart review. The seriousness, causality, and type of reactions were classified based on World Health Organization (WHO) definitions. Chi-square analysis was performed to assess the influence of sex and age on occurring ADRs. Both Kaplan-Meier and life table method were used to estimate the time to occur the ADR in anti-infective users. To compare the estimated risk of ADRs induced by different classes of anti-infectives, odds ratios were estimated. In all classes of anti-infectives, the odds ratio of each class was estimated with regard to anti-tuberculosis agents, which had the highest prevalence of ADRs. RESULTS: During the study period, 460 patients were entered the study. During the same period, 38 ADRs were recognized of which 20 (42%) were serious. The most recognized ADRs were suspected to be induced by anti-tuberculosis agents (29.8%). However in comparing with anti-tuberculosis agents, anti-fungal agents were associated with the highest ADR rate (odds ratio [OR], 4.21; 95% confidence interval [CI], 1.41-1.256) whereas cephalosporines were associated with the lowest rate, (OR, 0.1; 95%CI, 0.04-0.26). The survival analysis shows that the likelihood of experiencing an ADR was increased at first 14 days of drug therapy. Also Chi-square analysis shows that greater risk of anti-infectives-induced ADRs was observed in women. CONCLUSION: The rate of ADRs induced by anti-infective agents in this study was 8.2%. This is higher than a standard (5%) which has been reported in other studies. This study also shows that some of the classes of anti-infective agents like anti-fungals need more attention.