Evaluation of the impact of weak end feedback on the SBS threshold in high-power narrow-linewidth fiber amplifiers.

In this work, we quantitatively investigate the SBS threshold in high-power narrow-linewidth fiber amplifiers seeded with phase-modulated single-frequency lasers in presence of weak end feedback. The impacts of the end feedback and spectral linewidths on the SBS threshold are demonstrated in detail through comparative experiments and numerical simulations, respectively. In the experiment, we have pointed out a practical method to estimate the end reflectivity in high-power fiber amplifiers. Based on this estimation, the SBS threshold characters of the high-power narrow-linewidth fiber amplifiers with different end reflectivity and seed linewidths are investigated. By reducing the end reflectivity, a 2.85 times SBS threshold enhancement has been achieved at the most susceptible linewidth (16.8 GHz). Furthermore, we propose a spectral evolution model to investigate the SBS threshold in high-power narrow-linewidth fiber amplifiers, which is even capable for calculating SBS thresholds of the systems with tens of GHz linewidth while weak end reflection is considered. The simulation results demonstrate that end reflection will obviously affect the SBS threshold when the linewidth of the seed laser is broadened beyond 5 GHz, especially for the spectral linewidth of seed lasers nearing the Brillouin frequency shift. Besides, when the end reflectivity is set to be stronger than -65 dB, the SBS threshold performs a tendency to decline and then rise with the growth of seed linewidth. The experiment and simulation results provide a new optimization sight for the SBS effect suppression in high-power narrow-linewidth fiber amplifiers.

Guiding role of constructivism theory in the teaching of standardized residency training of radiation oncology / 中华医学教育探索杂志

According to the subject characteristics of radiation oncology, three teaching practices were carried out in the teaching of standardized residency training: teaching situation transformation under the guidance of constructivism theory, expanding teaching with points to areas, and organ system-centered medical classroom under the guidance of case analysis. At the same time, it combines the guidance of the residents' active exploration, integrated thinking and cooperative learning. Through the modulation of teaching and learning practices guided by constructivism, the residents' learning and understanding of radiation oncology knowledge and the integration and construction ability of "organ system-centered" medical knowledge are promoted, their active learning potential and innovative thinking ability are stimulated, and finally the teaching quality of this specialty is improved.

Corrigendum: Ivabradine Treatment Reduces Cardiomyocyte Apoptosis in a Murine Model of Chronic Viral Myocarditis.

[This corrects the article DOI: 10.3389/fphar.2018.00182.].

Research progress on chemical constituents and pharmacological effects of Chrysanthemum morifolium and predictive analysis on quality markers / 中草药

As a kind of Chinese medicinal material, Chrysanthemum morifolium is numerous and widely distributed, which has high medicinal value. C. morifolium has a good effect in medicinal and health care, and it is also the first batch of being used for both medicine and food issued by Ministry of Health of China. In recent years, C. morifolium has been widely used in medicine and health foods. Flavonoids, volatile oils, and phenylpropanoids are its main effective components. Based on the review of its chemical composition and pharmacological effects, combined with the definition of Q-marker, this study processed predictive analysis on Q-marker of C. morifolium at aspects of chemical composition, clinical efficacy, pharmacokinetics, traditional medicinal properties, traditional pharmacodynamics, different storage conditions, and different processing methods, which can establish scientific quality standards of C. morifolium.

The cholinergic anti-inflammatory pathway ameliorates acute viral myocarditis in mice by regulating CD4+ T cell differentiation.

Many studies have found that abnormalities in the proportion and differentiation of CD4+ T cells (Th cells) are closely related to the pathogenesis of viral myocarditis (VMC). Our previous research indicates that the cholinergic anti-inflammatory pathway (CAP) attenuates the inflammatory response of VMC and downregulates the expression of cytokines in Th1 and Th17 cells. This suggests that the cholinergic anti-inflammatory pathway likely attenuates the inflammatory response in VMC by altering Th cell differentiation. The aim of this study is to investigate the effect of CAP on CD4+ T cell differentiation in VMC mice. CD4+ T cells in the spleen of VMC mice were obtained and cultured in the presence of nicotine or methyllycaconitine (MLA). Cells were harvested and analyzed for the percentage of each Th cell subset by flow cytometry and transcription factor release by Western blot. Then, we detected the effect of CAP on the differentiation of Th cells in vivo. Nicotine or MLA was used to activate and block CAP, respectively, in acute virus-induced myocarditis. Nicotine treatment increased the proportion of Th2 and Treg cells, decreased the proportion of Th1 and Th17 cells in the spleen, reduced the level of proinflammatory cytokines, and attenuated the severity of myocardium lesions and cellular infiltration in viral myocarditis. MLA administration had the opposite effect. Our result demonstrated that CAP effectively protects the myocardium from virus infection, which may be attributable to the regulation of Th cell differentiation.

Ivabradine Treatment Reduces Cardiomyocyte Apoptosis in a Murine Model of Chronic Viral Myocarditis.

This study was designed to explore the effects of ivabradine on cardiomyocyte apoptosis in a murine model of chronic viral myocarditis (CVMC). Mice were inoculated intraperitoneally with Coxsackievirus B3 at days 1, 14, and 28, respectively. On day 42, the mice were gavaged with ivabradine for 30 days until the 72nd day. The heart of infected mice was dilated and a large number of interstitial fibroblasts infiltrated into the myocardium on day 42. Compared with the untreated CVMC mice, mice treated with ivabradine showed a significant reduction in heart rate and less impairment of left ventricular function on day 72. The positive apoptosis of myocardial cells in the untreated CVMC group was significantly higher than that of the normal group and was significantly reduced after treatment with ivabradine. The expression levels of Bax and Caspase-3 in the untreated CVMC group were significantly higher than those of the normal group and were apparently reduced in the ivabradine-treated group versus the untreated CVMC group. Bcl-2 showed a high expression in the normal group and low expression in the untreated CVMC group, but its expression level in the ivabradine-treated group were higher than that of the untreated CVMC group. These results indicate that ivabradine could attenuate the expression of Caspase-3 by downregulation of Bax and upregulation of Bcl-2 to prevent the deterioration of cardiac function resulting from ventricular myocyte loss by cardiomyocyte apoptosis.

Clinical and electrocardiographic characteristics of infarctional ventricular ectopic beats: An observational study.

The purpose of this study was to explore the clinical and electrocardiographic characteristics of infarctional ventricular ectopic beats (IVEBs).Thirty-eight acute myocardial infarction (AMI) patients with IVEB and 109 AMI patients without IVEB were analyzed. The morphological changes of QRS complex, ST segment, and T wave were compared to IVEB with sinus rhythm from the same period and fully evolved phase.An IVEB QRS complex often revealed the right bundle branch block morphology, in addition to Q wave AMI; no-Q wave AMI also had IVEB. Single-factor analysis found that IVEB often appeared in early AMI (<6 hours), and they were more frequent in inferoposterior with/without right ventricular involvement, large area AMI and thrombolytic reperfusion than in anterior or anteroseptal myocardial infarction, small area AMI, and unthrombolytic nonreperfusion. Multifactors no conditional logistic regression analysis revealed a positive correlation between IVEB and early AMI, AMI size, Killip heart function degree, inferoposterior with/without right ventricular involvement, and thrombolytic reperfusion. The Q wave of IVEB was wider, and the ST segment elevation was higher than those of the same period in sinus rhythms. The infarctional morphological changes of IVEB could be found before the same period in sinus rhythm and elevated myocardial enzymes.IVEBs were not rare. They were useful for early diagnosis and location of AMI.

Right Cervical Vagotomy Aggravates Viral Myocarditis in Mice Via the Cholinergic Anti-inflammatory Pathway.

The autonomic nervous system dysfunction with increased sympathetic activity and withdrawal of vagal activity may play an important role in the pathogenesis of viral myocarditis. The vagus nerve can modulate the immune response and control inflammation through a 'cholinergic anti-inflammatory pathway' dependent on the α7-nicotinic acetylcholine receptor (α7nAChR). Although the role of ß-adrenergic stimulation on viral myocarditis has been investigated in our pervious studies, the direct effect of vagal tone in this setting has not been yet studied. Therefore, in the present study, we investigated the effects of cervical vagotomy in a murine model of viral myocarditis. In a coxsackievirus B3 murine myocarditis model (Balb/c), effects of right cervical vagotomy and nAChR agonist nicotine on echocardiography, myocardial histopathology, viral RNA, and proinflammatory cytokine levels were studied. We found that right cervical vagotomy inhibited the cholinergic anti-inflammatory pathway, aggravated myocardial lesions, up-regulated the expression of TNF-α, IL-1ß, and IL-6, and worsened the impaired left ventricular function in murine viral myocarditis, and these changes were reversed by co-treatment with nicotine by activating the cholinergic anti-inflammatory pathway. These results indicate that vagal nerve plays an important role in mediating the anti-inflammatory effect in viral myocarditis, and that cholinergic stimulation with nicotine also plays its peripheral anti-inflammatory role relying on α7nAChR, without requirement for the integrity of vagal nerve in the model. The findings suggest that vagus nerve stimulation mediated inhibition of the inflammatory processes likely provide important benefits in myocarditis treatment.

Dose-dependent protective effect of nicotine in a murine model of viral myocarditis induced by coxsackievirus B3.

The alpha 7 nicotinic acetylcholine receptor (alpha7 nAChR) was recently described as an anti-inflammatory target in various inflammatory diseases. The aim of this study was to investigate the dose-related effects of nicotine, an alpha7 nAChR agonist, in murine model of viral myocarditis. BALB/C mice were infected by an intraperitoneally injection with coxsackievirus B3. Nicotine was administered at doses of 0.1, 0.2 or 0.4 mg/kg three times per day for 7 or 14 consecutive days. The effects of nicotine on survival, myocardial histopathological changes, cardiac function, and cytokine levels were studied. The survival rate on day 14 increased in a dose-dependent fashion and was markedly higher in the 0.2 and 0.4 mg/kg nicotine groups than in the infected untreated group. Treatment with high-dose nicotine reduced the myocardial inflammation and improved the impaired left ventricular function in infected mice. The mRNA expressions and protein levels of TNF-α, IL-1ß, IL-6, and IL-17A were significantly downregulated in dose-dependent manners in the nicotine treatment groups compared to the infected untreated group. Nicotine dose-dependently reduced the severity of viral myocarditis through inhibiting the production of proinflammatory cytokines. The findings suggest that alpha7 nAChR agonists may be a promising new strategy for patients with viral myocarditis.

The value of detecting plasma microRNA-125a-3p,IGF-2 on monitoring invasion and metastasis in NSCLC / 重庆医学

Objective To investigate the value of detecting plasma microRNA‐125a‐3p(miRNA‐125a‐3p) ,IGF‐2 on monitoring invasion and metastasis in NSCLC ,and to study the correlation between miR‐125a‐3p and IGF‐2 .Methods miR‐125a‐3p transcripts of 20 controls ,73 NSCLC were performed in plasma by quantitative reverse transcription‐polymerase chain reaction(qRT‐PCR) and PCR data was analyzed by the 2‐ΔΔCT method .The expression of IGF‐2 in plasma was detected by ELISA .Results The expression of miR‐125a‐3p in stage Ⅲ /Ⅳ was lower than stage Ⅰ/Ⅱ and the controls(P=0 .001 ,P=0 .005) .There was no statistical differ‐ence between the stage Ⅰ /Ⅱ patients and the controls(P=0 .776) .The expression of miR‐125a‐3p was related with lymph node metastas ,lower expression in positive lymph node metastasis (P=0 .003) .The expression of IGF‐2 in stage Ⅰ /Ⅱ 、stage Ⅲ /Ⅳ was higher than the controls(P=0 .036 ,P=0 .011) .There was no statistical difference between the stageⅠ/Ⅱ and stage Ⅲ/Ⅳ (P=0 .451) . The expression of IGF‐2 was related with lymph node metastas ,higher expression in positive lymph node metastasis (P=0 .037) .The re‐sults showed a negative correlation between miR‐125a‐3p expression and IGF‐2 in plasma(r= -0 .280 ,P=0 .007) .Conclusion Low ex‐pression of miR‐125a‐3p and high expression of IGF‐2 in plasma may play a role in invasion and metastasis of NSCLC .miR‐125a‐3p may play a negative regulatory role on IGF‐2 .

Bis(1,3,4-thia-diazol-2-yl) disulfide.

The title compound, C(4)H(2)N(4)S(4), lies about a twofold rotation axis situated at the mid-point of the central S-S bond. Each of two thia-diazole rings is essentially planar, with an rms deviation for the unique thia-diazole ring plane of 0.0019 (7) Å. C-H⋯N hydrogen bonds link adjacent mol-ecules, forming zigzag chains along the c axis. In addition, these chains are connected by inter-molecular S⋯S inter-actions [S⋯S = 3.5153 (11) Å] , forming corrugated sheets, and further fabricate a three-dimensional supra-molecular structure by inter-molecular N⋯S contacts [S⋯N = 3.1941 (17) Å].

Poly[[tris-[µ-2,2'-(butane-1,4-diyl-dithio)bis-(1,3,4-thia-diazole)-κN:N]copper(II)] bis-(perchlorate)].

In the title compound, {[Cu(C(8)H(10)N(4)S(4))(3)](ClO(4))(2)}(n), the Cu(II) atom is located on a threefold inversion axis coordinated by six N atoms of symmetry-equivalent 2,2'-(butane-1,4-diyl-dithio)bis-(1,3,4-thia-diazole) ligands in a slightly distorted octa-hedral geometry. Adjacent Cu(II) atoms are linked by the bridging bidentate thia-diazole ligands, which are situated about inversion centers. This leads to the formation of a three-dimensional network structure.

catena-Poly[[[bis-[2,2'-(propane-1,3-diyl-dithio)bis-(1,3,4-thia-diazole)-κN]copper(II)]-bis-[µ-2,2'-(propane-1,3-diyldithio)bis-(1,3,4-thia-diazole)-κN:N]] bis-(perchlorate)].

In the title compound, {[Cu(C(7)H(8)N(4)S(4))(4)](ClO(4))(2)}(n), the Cu(II) atom, occupying a crystallographic inversion centre, is six-coordinated by six N atoms of three symmetry-related 2,2'-(propane-1,3-diyldithio)bis-(1,3,4-thia-diazole) (L) ligands in a slightly distorted octa-hedral geometry. The ligand L adopts two kinds of coordination modes in the crystal structure; one is a monodentate coordination mode and serves to complete the octa-hedral coordination of the Cu atom and the other is an N:N'-bidentate bridging mode in a trans configuration, bridging Cu atoms via translation symmetry along the b axis into a chain structure. The perchlorate ions serve as acceptors for inter-molecular C-H⋯O hydrogen bonds, which link the chains into a three-dimensional network.

Poly[[bis-(acetonitrile-κN)bis-[µ(2)-2,2'-(methyl-enedithio)bis-(1,3,4-thia-diazole)-κN:N]copper(II)] bis-(perchlorate) acetonitrile solvate].

In the title compound, {[Cu(C(5)H(4)N(4)S(4))(2)(C(2)H(3)N)(2)](ClO(4))(2)·C(2)H(3)N}(n), the Cu(II) atom occupies a crystallographic inversion centre and is six-coordinated by six N atoms of four symmetry-related 2,2'-(methyl-enedithio)bis-(1,3,4-thia-diazole) (L) ligands and two acetonitrile mol-ecules in a slightly distorted octa-hedral geometry. The ligand L adopts an N:N'-bidentate bridging mode in a trans configuration, bridging the Cu atoms via translation symmetry, forming a two-dimensional layer-like structure. The perchlorate ions serve as acceptors for inter-molecular C-H⋯O hydrogen bonds, which link the layers into a three-dimensional network. The ClO(4) (-) anion is disordered with an occupation ratio of 0.658:0.342.

Poly[µ(2)-chlorido-(µ(2)-3H-1,3,4-thia-diazo-lium-2-thiol-ato-κS:S)silver(I)].

In the title compound, [AgCl(C(2)H(2)N(2)S(2))](n), the Ag(I) ion has a distorted tetra-hedral geometry, defined by two S atoms of two symmetry-related 1,3,4-thia-diazo-lium-2-thiol-ate ligands and two chloride ions. The Ag(I) ions are bridged into a two-dimensional network parallel to the ab plane by chloride ions and thia-diazole ligands. In the network, the Ag(I) ions are separated by 4.0316 (12) Šalong the a axis and by 4.8822 (13) Šalong the b axis. N-H⋯Cl hydrogen bonds are observed within the network.

Effects of intrathecal escin and clonidine in the treatment of neuropathic pain in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of intrathecal escin and clonidine, used alone or in combination, in the treatment of neuropathic pain in rats and the possible mechanism.</p><p><b>METHODS</b>Ninety-six male SD rats weighing 250-300 g were chronically implanted with lumbar intrathecal catheters. One week later, the left L5 and L6 spinal nerve roots were ligated to establish the model of spinal nerve ligation neuropathic pain (SNL). The rats were then randomly divided into 16 groups (n=6), including the control (saline), escin, clonidine, escin+clonidine, and the antagonist groups. Mechanical withdrawal threshold was assessed before and at 5, 10, 20, 30, 40, 50 and 60 min after intrathecal administration was evaluated. The maximal possible effect (MPE) was calculated and the effect of the treatments on the neuropathic pain. Isobolographic analysis was performed to characterize any potential interactions between the drugs.</p><p><b>RESULTS</b>MPE was significantly higher in escin group (20, 40 microg), clonidine group (2, 5, 10 microg) and escin+clonidine group [1/4, 1/2 (escin ED(50)+clonidine ED(50))] than in the saline group (P<0.05). Intrathecal escin (5-40 microg) or clonidine (1-10 microg) alone dose-dependently alleviated neuropathic pain. Isobolographic analysis suggested a synergistic effect between escin and clonidine. Intrathecal pretreatment with yohimbine (20 microg) antagonized the effects of clonidine (P<0.01) and attenuated the action of the combination treatment with escin and clonidine (P<0.05).</p><p><b>CONCLUSION</b>Intrathecal escin and clonidine alone can dose-dependently relieve neuropathic pain. Escin and clonidine produce a synergistic effect for pain relief, which may involve the actions of alpha(2) receptor and Ca(2+) channel.</p>

Comparison of target controlled propofol infusion and sevoflurane inhalational anesthesia in laparoscopic cholecystectomy / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the effects of propofol target controlled infusion (TCI) and sevoflurane inhalational anesthesia on the hemodynamics and postoperative recovery in patients undergoing laparoscopic cholecystectomy.</p><p><b>METHODS</b>Sixty ASA IorII patients scheduled for laparoscopic cholecystectomy were randomized into propofol TCI group (group P) and sevoflurane inhalational anesthesia group (group S). In group P, TCI propofol was maintained after intubation until incision closure with the target concentration at 3 microg/ml. In group S, sevoflurane (end-tidal concentration of 2%) was maintained with oxygen flow rate of 2 L/min until incision closure. Fentanyl and vecuronium were intravenously infused according to the depth of anesthesia during the operation. MAP and HR were measured before anesthesia (T(1)), immediately after intubation (T(2)), at skin incision (T(3)), 10 min after pneumoperitoneum (T(4)) and immediately after completion of the operation (T(5)) respectively. Awake time, postoperative nausea and vomiting of the patients were observed after operation.</p><p><b>RESULTS</b>There was significant difference in MAP and HR at T(4) between the two groups (P<0.05), but not at T(1), T(2), T(3) and T(5) (P>0.05). No significant difference was also found in the awake time between the two groups (P>0.05). The incidence of PONV, however, was significantly lower in group P than in group S (P<0.05).</p><p><b>CONCLUSION</b>Propofol TCI and sevoflurane inhalational anesthesia are all effective in inducing good anesthetic effect, maintaining hemodynamic stability and ensuring rapid recovery, but propofol TCI causes lower incidence of PONV in operations such as laparoscopic cholecystectomy.</p>

Acute normovolemic hemodilution combined with controlled hypotension in patients undergoing liver tumorectomy / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effects of acute normovolemic hemodilution (ANH) combined with controlled hypotension on reducing heterogeneous transfusion and safety during liver tumorectomy.</p><p><b>METHODS</b>Thirty patients undergoing elective liver tumorectomy were randomly divided into 3 groups (10 each), namely ANH group (group A), ANH combined with controlled hypotension group (group B) and control group (group C). All the patients were anesthetized via endotracheal intubation. Before the operation, ANH was performed in groups A and B after anesthesia induction, and controlled hypotension was initiated in group B during tumorectomy. Blood transfusion and fluid infusion were carried out routinely in group C. Hb and Hct were measured before operation, after ANH, and immediately, 1 day and 7 days after the operation. The difference in intraoperative blood loss and heterogeneous blood transfusion volume in the 3 groups was observed.</p><p><b>RESULTS</b>In group A, heterogeneous blood transfusion was avoided in 6 cases and but given in the other cases for an average of 400 ml. In group C, every patient received heterogeneous blood transfusion (664.8-/+248.1 ml), but none of the patients received heterogeneous blood in group B. The difference in transfusion volume between the 3 groups was significant (P<0.01). Hemodynamics was basically stable during operation in the 3 groups.</p><p><b>CONCLUSION</b>ANH combined with controlled hypotension is safe and effective for decreasing and even avoiding homologous blood transfusion in liver tumorectomy.</p>