Generation of optical frequency combs with a CaF2 resonator

We demonstrate optical frequency combs using the fluorite whispering gallery mode resonator as a nonlinear Kerr medium. Two regimes of generation are observed, giving the record low repetition rate of 13 GHz, equal to the cavity's free spectral range (FSR) or high repetition rates of multiples of cavity FSR. An intermediate regime was also observed. Raman lasing spectrum similar to modulation instability in fibers was observed for the first time to the best of our knowledge

The effect of gag reflex on cardiac sympatovagal tone

Objectives: Heart velocity may be influenced by gagging. The medulla oblongata receives the afferents of gag reflex. Neuronal pools of vomiting, salivation and cardiac parasympathetic fibers are very close in this area. So, their activities may be changed by spillover from each other. Using the heart rate variability (HRV) analysis, the effect of gagging on cardiac sympatovagal balance was studied. Methods: ECG was recorded from 9 healthy nonsmoker volunteer students for 10 minutes in the sitting position between 10 and 11 AM. Gagging was elicited by tactile stimulation of the posterior pharyngeal wall. At 1 kHz sampling rate, HRV was calculated. The mean of heart rate at low and high frequencies (LF: 0.04-0.15; HF: 0.15-0.4 Hz) were compared before and after the stimulus. Results: The mean of average heart rate, LF and HF in normalized units (nu) and the ratio of them (LF/HF) before and after the gagging were 89.9 ± 3 and 95.2 ± 3 bpm; 44.2 ± 5.8 and 21.2 ± 4; 31.1 ± 5.3 and 39.4 ± 3.8; and 1.7 ± 0.3 and 0.6 ± 0.2 respectively. Conclusion: Gagging increased heart velocity and had differential effect on two branches of cardiac autonomic nerves. The paradoxical relation between average heart rate and HRV indexes of sympatovagal tone may be due to unequal rate of change in autonomic fiber activities which is masked by 5 minutes interval averaging. © OMSB, 2012

Passively mode locked Raman laser

We report on the observation of a novel mode locked optical comb generated at the Raman offset (Raman comb) in an optically pumped crystalline whispering gallery mode resonator. Mode locking is confirmed via measurement of the radio-frequency beat note produced by the optical comb on a fast photodiode. Neither the conventional Kerr comb nor hyper-parametric oscillation is observed when the Raman comb is present

Effect of ethanolic extract of Safflower on naloxone-induced morphine withdrawal signs in mice

Background and aims: Safflower (Carthamus tinctorius L.) from Asteraceae family has different biological activities including analgesic, antidepressant, anti-inflammatory, antispasmodic and neuroprotective effects. This study designed to evaluate its effect on naloxone -induced morphine withdrawal signs. Methods: In this experimental study, male NMRI mice (25-30 g) were randomly divided into 5 groups of 8: control groups received morphine and normal saline (10 ml/kg) and other groups received fluoxetine (20mg/kg) and different doses of ethanolic extract of Safflower (100, 200 and 400mg/kg). Morphine dependency was induced by intraperitoneal (i.p.) injection of increasing doses (50-75 mg/kg) of morphine. Withdrawal signs were elicited by naloxone (5 mg/kg, i.p.) and number of jumpings and also presence of climbing, writing, wet dog shakes, teeth chattering, diarrhea, grooming and rearing during a 30 min period. The data were expressed with one-way ANOVA followed by Tukey test and Mann-Whitney U test for comparison of checked signs data and they were analyzed with SPSS 19 software. Results: The ethanolic extract at all doses (100, 200 and 400 mg/kg, i.p., P<0.001) and fluoxetine (20 mg/kg, i.p., P<0.01) significantly inhibited the number of jumps. Additionally, all doses of extract reduced the grooming and writing (P<0.05). Only 200 and 400 mg/kg of extract reduced the other checked signs including climbing, rearing and teeth chattering. All doses of extract couldn’t reduce wet dog shake and diarrhea significantly (P>0.05). Fluoxetine significantly inhibited the other signs except wet dog shakes and diarrhea. Conclusion: These findings indicated that Safflower extract has therapeutic potential in management of opiate withdrawal signs and this is comparable to the effect of fluoxetine. However, further studies need for clarify their exact mechanism of action

The clinical study of wound healing after laparotomy in Cyprinus carpio

However the different stages of wound healing in animals have been comprehensively investigated, but this issue has received little attention in regard with the fishes. Since only limited information on the subject was available, this study was carried out. To study wound healing in fish, 171 one year old Cyprinus carpio were divided into three groups. Each group consisted of 32 carps and the rest were used as the controls. The fishes were nesthetized by MS 222 (100 ppm in 30 l) and kept in this condition using a circulator, then incised about 3-4 cm along the midline from posterior thorax to near the anal area. The abdominal organs were observed and manipulated allowed by the closure of abdominal wall. The abdominal incision was closed one layer in simple interrupted pattern. The incision in the first group was sutured by chromic cut gut # 1, the second group by plain cut gut # 2 and the third group by polyglycolic acid suture # 3/0. After the operation the fishes sere kept in three different aquaria and were checked clinically every 5th day for 50 days. Local wound inflammation was classified as moderate in 40.6% and mild in 1.25% in the first group (chromic cut gut #1). In the second group (plain cut gut #2) severe inflammation was noticed in 53.12%, moderate inflammation in 0.25% and mild in 15.62% of the fishes, but in the third group (polyglycolic acid suture # 3/0) the inflammation was mild in 18.75% of the fishes. The results proved that the plain cut gut suture had the highest inflammation rate and the polyglycolic suture had the lowest rate. The wounds surfaces in third group healed smoother than the other two groups. Therefore using polyglycolic acid suture in fish surgery can be recommended

Comparison anti-giardia activity of Satureja hortensis alcoholic extract and metronidazole in vitro

Background and aims: Giardiasis is known as intestinal infection and created by the flagellate protozoan Giardia lamblia. Some studies showed that phenolic components, present in plant extracts and essential oils, have anti-Giardia activity. The current study was performed to compare anti-Giardia activity of Satureja hortensis (SH) alcoholic extract and metronidazole in vitro. Methods: In this Laboratory-experimental study, it was separated cysts from the feces by Bingham procedure with minor modification. The numbers of cysts were calculated with Hemusytumetr and the purified cysts of Giardia lamblia (500 µl) were exposed with 500 µl of extract at concentrations of 10, 100 and 200 mg/ml and 125 mg/kg of metronidazole for 30, 60 and 120 min. The numbers of dead and live cysts was enumerated with a microscope. Results: Findings in the currnt studyshowed an increase in anti-Giardia activity of extract at high concentrations with increasing time. SH, at 100 mg/ml killed 53 in 30 min, 68 in 60 min and 78 in 120 min. Also, the extract killed by 62 in 30 min, about 88 in 60 minutes and 92 in 120 minutes. The drug had similar effects in 60 and 120 minutes, but it killed 83 in 30 minutes. Conclusion: SH alcoholic extract showed anti-Giardia activity at high rates and more time. Thus, SH extract at 200 mg may be suitable alternative for Metronidazole, without side effects. However, anti-Giardia activity of SH needs to more attentions, especially clinical investigations

Study of embryotoxicity of mentha piperita l. during organogenesis in balb/c mice

Mentha piperita (Labiatae), commonly known as peppermint is a native Iranian herb which is used in folk medicine for various purposes. This study was carried out to reveal the teratogenic effect of Mentha piperita on mice fetuses. In this experimental study, pregnant Balb/c mice divided to four groups. Case group received 600 (treatment I) and 1200 (treatment II) mg/kg/day the hydroalcoholic extract of Mentha piperita during 6-15 of gestational days and one control group received normal saline during GD6-GD15 by gavages and other control group did not receive any matter during 6-15 of gestational days. Mice sacrificed at GD18 and embryos were collected. Macroscopic observation was done by stereomicroscope. 20 fetuses of each group were stained by Alizarin red-S and Alcian blue staining method. The Mean weight of fetuses decreased in treatment groups rather than control (P<0.05) but CRL there was no significant difference between treatments and controls groups. In the treatment I (600 mg/kg/day) and treatment II (1200 mg/kg/day), normal saline and control group, no gross congenital malformations were observed in fetuses. Treated fetuses also had no delayed bone ossification as determined by Alizarin red-S and Alcian blue staining method. This study showed that the hydroalcoholic extract of Mentha piperita (600 and 1200 mg/ kg/day) has no teratogenic effect in mice fetuses if used continuously during embryonic period

Structure of bottle-brush brushes under good solvent conditions. A molecular dynamics study

We report a simulation study for bottle-brush polymers grafted on a rigid backbone. Using a standard coarse-grained bead-spring model extensive molecular dynamics simulations for such macromolecules under good solvent conditions are performed. We consider a broad range of parameters and present numerical results for the monomer density profile, density of the untethered ends of the grafted flexible backbones and the correlation function describing the range that neighboring grafted bottle-brushes are affected by the presence of the others due to the excluded volume interactions. The end beads of the flexible backbones of the grafted bottle-brushes do not access the region close to the rigid backbone due to the presence of the side chains of the grafted bottle-brush polymers, which stretch further the chains in the radial directions. Although a number of different correlation lengths exist as a result of the complex structure of these macromolecules, their properties can be tuned with high accuracy in good solvents. Moreover, qualitative differences with "typical" bottle-brushes are discussed. Our results provide a first approach to characterizing such complex macromolecules with a standard bead spring model.Comment: To appear in Journal of Physics Condensed Matter (2011