9,378 research outputs found
Effect of the chosen incision on corneal astigmatism after implantable collamer lens surgery
AIM: To evaluate the effect of the chosen incision on corneal astigmatism after implantable collamer lens(ICL)surgery.<p>METHODS: The study included 195 eyes of 102 patients, and all eyes were randomly divided into two groups: the chosen incision group(Group A, 97 eyes)and temporal corneal incision(Group B, 98 eyes). Before the operation, and 1wk,1mo and 3mo after the operation, each patient was examined with corneal topography to observe the changes of corneal astigmatism. <p>RESULTS: Preoperative corneal astigmatisms were(1.26±0.35)D in group A and(1.28±0.38)D in group B, thus there was no statistically significant difference(<i>P</i>>0.05). One week postoperatively, the astigmatism were(0.93±0.29)D in group A and(1.32±0.33)D in group B. One month postoperatively, the astigmatism were(0.85±0.16)D in group A and(1.27±0.18)D in group B. Three months postoperatively, the astigmatism were(0.80±0.13)D in group A and(1.25±0.20)D in group B. The differences between the two groups were statistically significant(<i>P</i><0.01). <p>CONCLUSION: The chosen incision can reduce postoperative astigmatism to a certain extent after ICL surgery
Observation of spin-orbit magnetoresistance in metallic thin films on magnetic insulators
A magnetoresistance effect induced by the Rashba spin-orbit interaction was
predicted, but not yet observed, in bilayers consisting of normal metal and
ferromagnetic insulator. Here, we present an experimental observation of this
new type of spin-orbit magnetoresistance (SOMR) effect in a bilayer structure
Cu[Pt]/Y3Fe5O12 (YIG), where the Cu/YIG interface is decorated with nanosize Pt
islands. This new MR is apparently not caused by the bulk spin-orbit
interaction because of the negligible spin-orbit interaction in Cu and the
discontinuity of the Pt islands. This SOMR disappears when the Pt islands are
absent or located away from the Cu/YIG interface, therefore we can
unambiguously ascribe it to the Rashba spin-orbit interaction at the interface
enhanced by the Pt decoration. The numerical Boltzmann simulations are
consistent with the experimental SOMR results in the angular dependence of
magnetic field and the Cu thickness dependence. Our finding demonstrates the
realization of the spin manipulation by interface engineering.Comment: 12 pages, 4 figures, 14 pages in supplementary. To appear on Science
Advance
How tyramine β-hydroxylase controls the production of octopamine, modulating the mobility of beetles
Biogenic amines perform many kinds of important physiological functions in the central nervous system (CNS) of insects, acting as neuromodulators, neurotransmitters, and neurohormones. The five most abundant types of biogenic amines in invertebrates are dopamine, histamine, serotonin, tyramine, and octopamine (OA). However, in beetles, an important group of model and pest insects, the role of tyramine beta-hydroxylase (T beta H) in the OA biosynthesis pathway and the regulation of behavior remains unknown so far. We therefore investigated the molecular characterization and spatiotemporal expression profiles of T beta H in red flour beetles (Triboliun castaneum). Most importantly, we detected the production of OA and measured the crawling speed of beetles after dsTcT beta H injection. We concluded that TcT beta H controls the biosynthesis amount of OA in the CNS, and this in turn modulates the mobility of the beetles. Our new results provided basic information about the key genes in the OA biosynthesis pathway of the beetles, and expanded our knowledge on the physiological functions of OA in insects
Effect of a poloxamer 407-based thermosensitive gel on minimization of thermal injury to diaphragm during microwave ablation of the liver.
AIM: To assess the insulating effect of a poloxamer 407 (P407)-based gel during microwave ablation of liver adjacent to the diaphragm.
METHODS: We prepared serial dilutions of P407, and 22.5% (w/w) concentration was identified as suitable for ablation procedures. Subsequently, microwave ablations were performed on the livers of 24 rabbits (gel, saline, control groups, n = 8 in each). The P407 solution and 0.9% normal saline were injected into the potential space between the diaphragm and liver in experimental groups. No barriers were applied to the controls. After microwave ablations, the frequency, size and degree of thermal injury were compared histologically among the three groups. Subsequently, another 8 rabbits were injected with the P407 solution and microwave ablation was performed. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and creatinine (Cr) in serum were tested at 1 d before microwave ablation and 3 and 7 d after operation.
RESULTS: In vivo ablation thermal injury to the adjacent diaphragm was evaluated in the control, saline and 22.5% P407 gel groups (P = 0.001-0.040). However, there was no significant difference in the volume of ablation zone among the three groups (P \u3e 0.05). Moreover, there were no statistical differences among the preoperative and postoperative gel groups according to the levels of ALT, AST, BUN and Cr in serum (all P \u3e 0.05).
CONCLUSION: Twenty-two point five percent P407 gel could be a more effective choice during microwave ablation of hepatic tumors adjacent to the diaphragm. Further studies for clinical translation are warranted
Effects of thermal stratification and mixing on the vertical distribution of dissolved oxygen in aquaculture ponds
Thermal stratification and mixing in aquaculture ponds can seriously affect the vertical distribution of dissolved oxygen (DO) and result in a lack of DO in ponds. Therefore, revealing the vertical distribution of DO in aquaculture ponds influenced by thermal stratification and mixing can provide a theoretical basis for aquaculture water management. Here, we explore the impacts of thermal stratification and mixing on the vertical distribution of DO in two aquaculture ponds under different weather conditions. The results showed that thermal stratification mainly occurs during the daytime, and mixing occurs at nighttime. Water thermal stratification appears 4 h after sunrise, while mixing occurs 1 h after nightfall. When the Richardson index is less than 0.25, the mixing direction is unstable. In the daytime, the vertical distribution of DO, chlorophyll a (Chl-a), and phytoplankton abundance varied with thermal stratification and mixing. The concentration of DO gradually dropped with increasing water depth during the nighttime. The concentration of DO was lowest in the early morning and peaked in the afternoon. Multiple regression analysis demonstrated that water temperature (WT), Chl-a, and phytoplankton abundance provided the best model for the vertical distribution of DO. Based on our results, DO regulation can provide important insights for aquaculture pond management
LC/MS Guided Isolation of Alkaloids from Lotus Leaves by pH-Zone-Refining Counter-Current Chromatography
The traditional methods used in natural product separation primarily target the major components and the minor components may thus be lost during the separation procedure. Consequently, it’s necessary to develop efficient methods for the preparative separation and purification of relatively minor bioactive components. In this paper, a LC/MS method was applied to guide the separation of crude extract of lotus (Nelumbo nucifera Gaertn.) leaves whereby a minor component was identified in the LC/MS analysis. Afterwards, an optimized pH-zone-refining CCC method was performed to isolate this product, identified as N-demethylarmepavine. The separation procedure was carried out with a biphasic solvent system composed of hexane-ethyl acetate-methyl alcohol-water (1:6:1:6, v/v) with triethylamine (10 mM) added to the upper organic phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase eluent. Two structurally similar compounds – nuciferine and roemerine – were also obtained from the crude lotus leaves extract. In total 500 mg of crude extract furnished 7.4 mg of N-demethylarmepavine, 45.3 mg of nuciferine and 26.6 mg of roemerine with purities of 90%, 92% and 96%, respectively. Their structures were further identified by HPLC/ESI-MSn, FTICR/MS and the comparison with reference compounds
Effects of polymerase, template dilution and cycle number on PCR based 16 S rRNA diversity analysis using the deep sequencing method
- …