33694842
Surface-emitting circular DFB, disk-, and ring-Bragg resonator lasers with chirped gratings. II: nonuniform pumping and far-field patterns.
This is a continuation of our previous work [Opt. Express 16, 9155 (2008)]. In this paper we investigate the effect of nonuniform pumping on the modal properties of surface-emitting chirped circular grating lasers. By numerically solving the coupled-mode equations and matching the boundaries we compare and discuss the threshold pump levels and frequency detuning factors for three pumping profiles: uniform, Gaussian, and annular. Depending on the overlap of the pumping and modal profiles, Gaussian pumping results in the lowest threshold pump levels except for the fundamental mode of ring Bragg resonator laser, and annular pumping provides larger threshold discrimination between the fundamental and first-order modes of circular DFB and ring Bragg resonator lasers, which is favorable for single-mode operation in these lasers. We also study the far-field patterns of the fundamental modes of circular DFB, disk-, and ring- Bragg resonator lasers. Circular DFB and ring Bragg resonator lasers have the first-order dominating peak, while disk Bragg resonator laser exhibits the zeroth-order dominating peak.
33831422
Adiabaticity criterion and the shortest adiabatic mode transformer in a coupled-waveguide system.
By analyzing the propagating behavior of the supermodes in a coupled-waveguide system, we have derived a universal criterion for designing adiabatic mode transformers. The criterion relates epsilon, the fraction of power scattered into the unwanted mode, to waveguide design parameters and gives the shortest possible length of an adiabatic mode transformer, which is approximately 2/piepsilon1/2 times the distance of maximal power transfer between the waveguides. The results from numerical calculations based on a transfer-matrix formalism support this theory very well.
575273
Surface-emitting circular DFB, disk- and ring- Bragg resonator lasers with chirped gratings: a unified theory and comparative study.
We have developed a theory that unifies the analysis of the modal properties of surface-emitting chirped circular grating lasers. This theory is based on solving the resonance conditions which involve two types of reflectivities of chirped circular gratings. This approach is shown to be in agreement with previous derivations which use the characteristic equations. Utilizing this unified analysis, we obtain the modal properties of circular DFB, disk-, and ring- Bragg resonator lasers. We also compare the threshold gain, single mode range, quality factor, emission efficiency, and modal area of these types of circular grating lasers. It is demonstrated that, under similar conditions, disk Bragg resonator lasers have the highest quality factor, the highest emission efficiency, and the smallest modal area, indicating their suitability in low-threshold, high-efficiency, ultracompact laser design, while ring Bragg resonator lasers have a large single mode range, high emission efficiency, and large modal area, indicating their suitability for high-efficiency, large-area, high-power applications.
9110371
Surface-emitting circular DFB, disk-, and ring-Bragg resonator lasers with chirped gratings. III: gain saturation effects and above-threshold analysis.
As Part III of this series, this paper focuses on an above-threshold modal analysis which includes gain saturation effects in the surface-emitting chirped circular grating lasers. We derive an exact energy relation which states that, in steady state, the net power generated in the gain medium is equal to the sum of peripheral leakage power and vertical emission power. This relation is particularly useful in checking the accuracy of numerical mode solving. Numerical simulations demonstrate the dependence of required pump level on the vertical emission power and compare the laser threshold and energy conversion efficiency under uniform, Gaussian, and annular pump profiles. A larger overlap between the pump profile and modal intensity distribution leads to a lower threshold and a higher energy conversion efficiency. Finally the dependence of required pump level on device sizes offers us new design guidelines of these lasers for single-mode, high-efficiency, high-power applications.
7754587
Effect of conventional interferon-α in patients with HBeAg-positive chronic hepatitis B: a systematic review and meta-analysis.
BACKGROUND
Although a few studies have tested the effect of interferon-α on chronic hepatitis B, its treatment effect remains uncertain, and the association of treatment effect with intervention characteristics has not been thoroughly explored. This study examined the effect of IFN-α in patients with HBeAg-positive chronic hepatitis B, and investigated the characteristics associated with treatment effect.


METHODS
We searched MEDLINE, Scientific Citation Index, Current Content Connect, Cochrane Controlled Trial Register, and Chinese Biomedical Database, all up to 15 September 2009. We included randomized trials comparing IFN-α to placebo, no treatment, or standard care (SC) in patients with HBeAg-positive chronic hepatitis B. Two reviewers assessed the risk of bias and extracted data, independently and in duplicate. We conducted meta-analyses of the included studies, and subgroup analyses to examine the association of pre-specified characteristics (eg, dose, treatment duration) with treatment effect.


RESULTS
A total of 31 randomized controlled trials, involving 2164 patients, were included. The risk of bias varied across studies. Compared with placebo, no treatment, or SC, IFN-α improved loss of HBeAg (OR 2.36, 95% CI 1.83 to 3.04), HBV DNA undetectability (OR 2.04, 95% CI 1.28 to 3.32), HBeAg seroconversion (OR 1.82, 95% CI 1.26 to 2.62), ALT normalization (OR 1.24, 95% CI 1.01 to 1.56), and loss of HBsAg (OR 2.45, 95% CI 1.22 to 4.91). Treatment effects differed in high versus low dose, and long versus short duration of IFN-α. The effect of high dose IFN-α (OR 3.28, 95% CI 2.31 to 4.66) is statistically larger than that of low dose IFN-α (OR 1.58, 95% CI 1.10 to 2.28) on loss of HBeAg (interaction P = 0.017), and longer IFN-α treatment durations produce greater effects (OR 3.28, 95% CI 2.16 to 5.00) than do shorter durations (OR 1.94, 95% CI 0.42 to 2.66, interaction P = 0.038). High dose IFN-α had a significant effect on HBV DNA undetectability (OR 2.80, 95% CI 2.03 to 3.86), while low dose IFN-α did not (OR 0.93, 95% CI 0.61 to 1.41, interaction P = 0.01); longer treatments significantly improved HBV DNA undetectability (OR 2.58, 95% CI 1.62 to 4.12), but shorter durations did not (OR 1.28, 95% CI 0.83 to 1.97, interaction P = 0.024).


CONCLUSIONS
IFN-α can improve serological, biomedical, and virological response. Higher doses and prolonged treatments appear to have larger treatment benefits than lower doses and shorter treatments. However, the increased adverse reactions and costs associated with higher doses and prolonged treatment warrant caution in applying these results.
24110389
[Isolation of a metsulfuron-methyl-resistant bacteria and cloning and expression of the acetohydroxyacid synthase genes ilvlH].
UNLABELLED
Acetohydroxyacid synthase (EC 4.1.3.18) is the enzyme that catalyses the first step in the synthesis of the branched-chain amino acids valine, leucine and isoleucine in plant, fungi and bacteria, and also is target of the sulfonylurea, imidazolinone, triazolopyrimidine and other acetohydroxyacid synthase inhibitor herbicides.


OBJECTIVE
The purpose of this study is to get the resistant gene, prepare a functional bacteria with acetohydroxyacid synthase, and investigate the relationship between the mutation sites of the acetohydroxyacid synthase and the herbicides-resistant.


METHODS
A metsulfuron-methyl-resistant bacterium Lm10 was isolated from metsulfuron-methyl contaminated soil. Acetohydroxyacid synthase genes ilvIH was amplified from the genome DNA of strains Lm10 by PCR. The ilvI and ilvH were cloned into the bacterial expression vector pET29a(+) respectively.


RESULTS
Strain Lm10 was identified preliminarily as Pseudomonas sp.. It can endure 14000 micromol/L metsulfuron-methyl and showed cross resistance to diffenent acetohydroxyacid synthase inhibitor herbicids, such as chlorsulfuron, imazethapyr, flumetsulam and penoxsulam. The alignment result of the ilvIH amino acid sequence showed that ilvI of strains Lm10 differed from that of strain KT2440 by 6 sites, While the ilvH of the two strains were the same. The gene ilvI and ilvH were functional expressed in the Escherichia coli strain BL21(DE3) respectively. The expressed production pET-I displayed acetohydroxyacid synthase activity and showed resistance to high concentration of metsulfuron-methyl.


CONCLUSION
The ilvI displayed acetohydroxyacid synthase activity. The 6 different sites in ilvI of strains Lml0 probably led to herbicids resistance.
23980348
Genetic Loss of Faah Compromises Male Fertility in Mice1
Abstract Marijuana is the most commonly used illicit drug. Although there is some indication that reproductive functions in males are impaired in chronic marijuana users, the genetic evidence and underlying causes remain largely unknown. Herein we show that genetic loss of Faah, which encodes fatty acid amide hydrolase (FAAH), results in elevated levels of anandamide, an endocannabinoid, in the male reproductive system, leading to compromised fertilizing capacity of sperm. This defect is rescued by superimposing deletion of cannabinoid receptor 1 (Cnr1). Retention of Faah−/− sperm on the egg zona pellucida provides evidence that the capacity of sperm to penetrate the zona barrier is hampered by elevated anandamide levels. Collectively, the results show that aberrant endocannabinoid signaling via CNR1 impairs normal sperm function. Besides unveiling a new regulatory mechanism of sperm function, this study has clinical significance in male fertility.
38806193
Tuning exchange bias in core/shell FeO/Fe3O4 nanoparticles.
Monodisperse 35 nm FeO nanoparticles (NPs) were synthesized and oxidized in a dry air atmosphere into core/shell FeO/Fe(3)O(4) NPs with both FeO core and Fe(3)O(4) shell dimensions controlled by reaction temperature and time. Temperature-dependent magnetic properties were studied on FeO/Fe(3)O(4) NPs obtained from the FeO NPs oxidized at 60 and 100 °C for 30 min. A large exchange bias (shift in the hysteresis loop) was observed in these core/shell NPs. The relative dimensions of the core and shell determine not only the coercivity and exchange field but also the dominant reversal mechanism of the ferrimagnetic Fe(3)O(4) component. This is the first time demonstration of tuning exchange bias and of controlling asymmetric magnetization reversal in FeO/Fe(3)O(4) NPs with antiferromagnetic core and ferrimagnetic shell.
8725029
“Iron-saturated” bovine lactoferrin improves the chemotherapeutic effects of tamoxifen in the treatment of basal-like breast cancer in mice
BackgroundTamoxifen is used in hormone therapy for estrogen-receptor (ER)-positive breast cancer, but also has chemopreventative effects against ER-negative breast cancers. This study sought to investigate whether oral iron-saturated bovine lactoferrin (Fe-Lf), a natural product which enhances chemotherapy, could improve the chemotherapeutic effects of tamoxifen in the treatment of ER-negative breast cancers.MethodsIn a model of breast cancer prevention, female Balb/c mice treated with tamoxifen (5 mg/Kg) were fed an Fe-Lf supplemented diet (5 g/Kg diet) or the base diet. At week 2, 4T1 mammary carcinoma cells were injected into an inguinal mammary fat pad. In a model of breast cancer treatment, tamoxifen treatment was not started until two weeks following tumor cell injection. Tumor growth, metastasis, body weight, and levels of interleukin 18 (IL-18) and interferon γ (IFN-γ) were analyzed.ResultsTamoxifen weakly (IC50 ~ 8 μM) inhibited the proliferation of 4T1 cells at pharmacological concentrations in vitro. In the tumor prevention study, a Fe-Lf diet in combination with tamoxifen caused a 4 day delay in tumor formation, and significantly inhibited tumor growth and metastasis to the liver and lung by 48, 58, and 66% (all P < 0.001), respectively, compared to untreated controls. The combination therapy was significantly (all P < 0.05) more effective than the respective monotherapies. Oral Fe-Lf attenuated the loss of body weight caused by tamoxifen and cancer cachexia. It prevented tamoxifen-induced reductions in serum levels of IL-18 and IFN-γ, and intestinal cells expressing IL-18 and IFN-γ. It increased the levels of Lf in leukocytes residing in gut-associated lymphoid tissues. B, T and Natural killer (NK) cells containing high levels of Lf were identified in 4T1 tumors, suggesting they had migrated from the intestine. Similar effects of Fe-Lf and tamoxifen on tumor cell viability were seen in the treatment of established tumors.ConclusionsThe results indicate that Fe-Lf is a potent natural adjuvant capable of augmenting the chemotherapeutic activity of tamoxifen. It could have application in delaying relapse in tamoxifen-treated breast cancer patients who are at risk of developing ER-negative tumors.