Improved Optical Waveguide Microcantilever for Integrated Nanomechanical Sensor.

This paper reports on an improved optical waveguide microcantilever sensor with high sensitivity. To improve the sensitivity, a buffer was introduced into the connection of the input waveguide and optical waveguide cantilever by extending the input waveguide to reduce the coupling loss of the junction. The buffer-associated optical losses were examined for different cantilever thicknesses. The optimum length of the buffer was found to be 0.97 µm for a cantilever thickness of 300 nm. With this configuration, the optical loss was reduced to about 40%, and the maximum sensitivity was more than twice that of the conventional structure.

Thinning increases understory diversity and biomass, and improves soil properties without decreasing growth of Chinese fir in southern China.

Sustainable forestry requires adopting more ecosystem-informed perspectives. Tree thinning improves forest productivity by encouraging the development of the understory, which in turn improves species diversity and nutrient cycling, thereby altering the ecophysiological environment of the stand. This study aimed to quantify tree growth, understory vegetation, and soil quality of 9- and 16-year-old Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations in South China, 1-7 years after pre-commercial thinning. The quadratic mean diameter (QMD) and individual tree volume were greatly increased and compensated for the reduced stand yield in thinned stands. In 2011, the stand volume in unthinned and thinned stands were 276.33 and 226.46 and 251.30 and 243.64 m3 ha-1, respectively, for young and middle stage. Therefore, we predicted that over time, the stand volume in thinned stands should exceed that in unthinned stands. The composition, diversity, and biomass of understory vegetation of the plantation monocultures significantly increased after thinning. The effects of thinning management on understory development were dynamic and apparent within 1-2 years post-thinning. Some light-demanding plant species such as Styrax faberi, Callicarpa formosana, Lophatherum gracile, and Gahnia tristis emerged in the shrub and herb layer and became dominant with the larger gaps in the canopy in thinned stands. The trigger effects of thinning management on understory and tree growth were more pronounced in the young stage. The beneficial effects on soil physical and chemical properties were measurable at later stages (7 years after thinning). The strong positive relationship between understory biomass and volume increment (at the tree and stand levels) indicated that understory improvement after thinning did not restrict productivity within Chinese fir stands but rather, benefited soil water content and nutrient status and promoted tree growth.

Comparative Study of Atropine Combined with Sodium Nitroprusside Pretreatment to Prevent Trigemino Cardiac Reflex after Trigeminal Ganglion Compression.

INTRODUCTION: Manipulation of percutaneous compression of the trigeminal ganglion (PCTG) for trigeminal neuralgia (TN) can lead to significant haemodynamic changes, which were termed trigemino cardiac reflex (TCR). Nevertheless, many studies indicated that atropine pretreatment can reduce the incidence of bradycardia and cardiac arrest, but do not take precautions against abrupt rise of blood pressure. AIM: The purpose of our study was to compare control group {patients receiving Sodium Nitro-Prusside (SNP) pretreatment before PCTG} with study groups (patients receiving different doses of atropine combined with SNP pretreatment before PCTG) in cardiovascular parameters {Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Heart Rate (HR)} at 5 periods during Total Intravenous Anaesthesia (TIVA). MATERIALS AND METHODS: In total, 120 patients, who underwent PTCG, were enrolled and randomly assigned into control group {group A (SNP pretreatment before PCTG, n=29)} and study groups {group B (0.002mg /kg atropine combined with SNP pretreatment before PCTG, n=30), C (0.004mg/kg atropine pretreatment before PCTG, n=31) and D (0.006mg/kg atropine combined with SNP pretreatment before PCTG, n=30)}, the relationship between haemodynamic changes and using atropine pretreatment or not was compared. Cardiovascular parameters were measured at five periods: preoperative (T0); before puncture (T1); during compression (T2); 1 min after the compression ended (T3); and 1 min after the procedure ended (T4). Multivariate analysis of variance (MANOVA) and Pearson's χ(2) test were used, and a value of p < 0.05 was considered statistically significant. RESULTS: Compared with the group A, means of SBP and DBP in the study groups (group B, C and D) were not observed significant differences at all time points (p>0.05), the mean values of HR showed significant differences, when compared to group C and group D at T2 and T3 (p<0.001). Meanwhile, means of SBP, DBP and HR comparison in the same group were observed between T1 and T2, to the group A, B and D, means of HR (p>0.05 vs. T1) indicated significant differences, however, there was no significant difference in group C (p>0.05). Furthermore, the incidence of post-compression tachycardia was observed in each group. CONCLUSION: By comparison, it seemed that 0.004mg/kg atropine pretreatment before PCTG was more reasonable for preventing significant haemodynamic changes.

Comparative study of trigeminocardiac reflex after trigeminal ganglion compression during total intravenous anesthesia.

BACKGROUND: Percutaneous compression of the trigeminal ganglion (PCTG) is an alternative surgical treatment for trigeminal neuralgia (TN). Manipulation of PCTG can lead to significant hemodynamic changes, which may increase the risk of cardiovascular complications. However, to our knowledge, few studies have focused on anesthesia experience during PCTG as treatment for TN so far. It was our primary focus on how to ensure the stability of hemodynamics during our clinical anesthesia experience. This study aimed to compare the study group (using sodium nitroprusside [SNP] as soon as the puncture began) with the control group (without using SNP as soon as the puncture began) to investigate cardiovascular parameters (systolic blood pressure [SBP], diastolic blood pressure [DBP], and heart rate [HR]) at 5 periods during total intravenous anesthesia. METHODS: A total of 256 patients who underwent PTCG were enrolled and randomly assigned into the study group (n=137) (using SNP as soon as the puncture began) and the control group (n=119) (without using SNP as soon as puncture began); the relationship between the hemodynamic changes and using SNP or without using SNP was compared. Blood pressure and HR were measured at 5 periods: preoperative (T1), before puncture (T2), during compression (T3), 1 minute after compression ended (T4), and 1 minute after the procedure ended (T5). Multivariate analysis of variance and the Pearson χ test were used, and a value of P<0.05 was considered statistically significant. RESULTS: The mean values of SBP were higher in the control group at the evaluation during T3 (P<0.001 vs. control), T4 (P<0.05 and P=0.040 vs. control), and T5 (P<0.05 and P=0.037 vs. control) and DBP was the only observed significant difference during T3 (P<0.001 vs. control), when compared with the study group. Meanwhile, means of SBP, DBP, and HR comparison in the same group were observed between T2 and T3. In the control group, means of SBP (P<0.001 vs. T2), DBP (P<0.001 vs. T2), and HR (P<0.001 vs. T2) showed significant differences in comparison with control group; means of HR (P<0.001 vs. T2) was the only observed significant difference between T2 and T3 in the study group. However, PTCG elicited significant abrupt bradycardia during T3 in almost all patients. CONCLUSIONS: The control group and the study group were not able to prevent bradycardia elicited during PTCG. Compared with control group, dramatic elevations of the systemic blood pressure can be prevented using intravenous drip SNP as soon as the puncture began during total intravenous anesthesia in the study group. Our findings verify that intravenous drip SNP is an effective method to control abrupt rise of blood pressure.

Perturbing effects of carvedilol on a model membrane system: role of lipophilicity and chemical structure.

Carvedilol, a beta-adrenergic blocker used to treat cardiovascular diseases, protects cell membranes from lipid peroxidative damage. Previous studies suggested the drug resides in a non-polar environment and partitions into cell membranes, perturbing their fluidity. Here differential scanning calorimetry (DSC) and fluorescence spectroscopy were applied to further investigate interactions of carvedilol with a liposome model. Results indicate the association is relatively unaffected by pH or temperature, but could be sensitive to liposome composition. The drug's carbazole group plays the dominant role in bilayer perturbation. Compared with other beta-blockers examined, carvedilol produced the strongest liposome DSC perturbation. Locations of carbazole and carvedilol in the liposome were determined using depth-dependent fluorescent probes. Both compounds are situated in the middle of the bilayer, consistent with strong hydrophobic interactions. This combination of high lipophilicity and specific chemical structure appear required for carvedilol's novel antioxidant activity, and may enhance cardioprotection.