The Problems and Countermeasures in the Applied Study on Multimodal Teaching Mode of Higher Vocational College English Teaching

With the informational technology continuously developing and the main communication way --- textual means changing, the multimodal communication is developing as the leading one, meanwhile, multimodal teaching mode has gradually become the main mode in the English teaching field. This article mainly discusses how to improve the English teaching effect by using multimodal teaching mode in higher vocational college English teaching.

Beta-amyloid precursor protein cleavage enzyme-1 expression in adult rat retinal neurons in the early period after lead exposure

Previous studies have reported that non-human primates and rodents exposed to lead during brain development may become dependent on the deposition of pre-determined β-amyloid protein （Aβ）,and exhibit upregulation of β-site amyloid precursor protein expression in old age.However,further evidence is required to elucidate the precise relationship and molecular mechanisms underlying the effects of early lead exposure on excessive Aβ production in adult mammals.The present study investigated the effects of lead exposure on expression of β-amyloid precursor protein cleavage enzyme-1 （BACE-1） in the rat retina and the production of Aβ in early development,using the retina as a window for studying Alzheimer＇s disease.Adult rats were intraocularly injected with different doses of lead acetate （10μmol/L,100μmol/L,1 mmol/L,10 mmol/L and 100 mmol/L）.The results revealed that retinal lead concentration,BACE-1 and its cleavage products β-C-terminal fragment and retina Aβ1-40 were all significantly increased in almost all of the lead exposure groups 48 hours later in a dose-dependent manner.The only exception was the 10μmol/L group.The distribution of BACE-1 in the retina did not exhibit obvious changes,and no distinctive increase in the activation of retinal microglia was apparent.Similarly,retinal synaptophysin expression did not exhibit any clear changes.These data suggest that lead exposure can result in the upregulation of retinal neuron BACE-1 expression in the early period of development and further increase the overproduction of Aβ1-40 in the retina.Our results provided novel insight into the molecular mechanisms underlying environmentally-induced Alzheimer＇s disease.

Synthesis and Electrochemical Properties of Mg-doped LiNi_(0.6)Co_(0.2)Mn_(0.2)O_2 Cathode Materials for Li-ion Battery

The layered LiNi0.6Co0.2-xMn0.2MgxO2 （x=0.00,0.03,0.05,0.07） cathode materials were prepared by a co-precipitation method.The properties of the Mg-doped LiNi0.6Co0.2Mn0.2O2 were investigated by X-ray diffraction （XRD）,scanning electron microscopy （SEM）,and electrochemical measurements.XRD studies showed that the Mg-doped LiNi0.6Co0.2Mn0.2O2 had the same layered structure as the undoped LiNi0.6Co0.2Mn0.2O2.The SEM images exhibited that the particle size of Mg-doped LiNi0.6Co0.2Mn0.2O2 was finer than that of the undoped LiNi0.6Co0.2 Mn0.2O2 and that the smallest particle size is only about 1μm.The Mg-doped LiNi0.6Co0.2Mn0.2O2 samples were investigated on the Li extraction/insertion performances through charge/discharge,cyclic voltammogram （CV）,and electrochemical impedance spectra（EIS）.The optimal doping content of Mg was that x= 0.03 in the LiNi0.6Co0.2-xMn0.2MgxO2 samples to achieve high discharge capacity and good cyclic stability.The electrode reaction reversibility and electronic conductivity was enhanced,and the charge transfer resistance was decreased through Mg-doping.The improved electrochemical performances of the Mg-doped LiNi0.6Co0.2Mn0.2O2 cathode materials are attributed to the addition of Mg 2＋ ion by stabilizing the layer structure.

The correlation between rat retinal nerve fiber layer thickness around optic disc by using optical coherence tomography and histological measurements

·AIM: To explore the correlation between the retinal nerve fiber layer (RNFL) thickness by using optical coherence tomography (OCT) and by histological measurements in normal adult rats and optic nerve transected rats. · METHODS: The RNFL thickness of 36 rats was scanned in a circle 3.46mm far from the optic disc by OCT. The two experimental groups were the normal group ( =20 rats) and the optic nerve transected group ( =16 rats). The latter group included 4 groups ( =4 /group) surviving for 1 day, 3, 5 and 7 days. Then the RNFL thickness of the same retina area was also measured by NF -200 immunohistochemical staining method. Linear regression was used to analyze the correlation between the data obtained from these two methods. ·RESULTS: The RNFL thickness of normal right eyes around optic disc by OCT was 72.35 ±5.71μm and that of the left eyes was 72.65 ±5.88μm ( =0.074). The RNFL thickness of the corresponding histological section by immunohistochemistry was 37.54 ±4.05μm (right eyes) and 37.38 ±4.23μm (left eyes) ( =0.059). There was a good correlation between the RNFL thickness measured by OCT and that measured by histology (R 2 =0.8131). After optic nerve transection, the trend of the RNFL thickness was thinner with the prolonged survival time. The correlation of the thickness detected by the above two methods was approximately (R 2 =0.8265). Value of the RNFL thickness in rats around optic disc measured by OCT was obviously higher than that measured by common histological measurement in normal adult rats and optic nerve transected rats. ·CONCLUSION: The RNFL thickness measured by OCT has a strong correlation with that measured by histological method. Through OCT scanning, we found that the thickness of RNFL gradually becomes thinner in a time-dependent manner.

An inhibition of ceruloplasmin expression induced by cerebral ischemia in the cortex and hippocampus of rats

Objective To explore effects of cerebral ischemia on the ceruloplasmin （Cp） expression in the cortex and hippoc-ampus of rats. Methods Male Wistar rats were randomly divided into cerebral ischemia group and control group. Cerebral ischemia was induced by ligating bilateral common carotid arteries and the ischemic rats were further subgrouped according to ischemia time. The control rats received a sham operation. The expression of Cp mRNA in the cortex and hippocampus was measured by reverse transcription polymerase chain reaction （RT-PCR）. The Cp expression was shown by immunohistochemistrical （streptavidin peroxidase, SP） method. Results In ischemia group, the expression of Cp mRNA in the cortex and hippocampus decreased compared with that in control group （P 〈 0.01）; and the longer rats experienced cerebral ischemia, the lower Cp mRNA expressed. By immunohistochemistry, Cp was shown expressed in the neural cells including epithelial cells of choroid plexus, ependymal cells, astrocytes of cortex and hippocampus, and vascular endothelial cells, but not in pyramidal cells and granulosa cells of cortex and hippocampus. Cp levels in the cortex and hippocampus decreased in rats suffering from cerebral ischemia for 3 d, 7 d and 28 d but not in rats exposed to ischemia for 1 d compared with that in control group （P 〈 0.05）. Iron concentration correlated negatively with Cp expression in the cortex and hippocampus of rats exposure to ischemia （the cortex, r=-0.831, P〈0.01; the hippocampus, r=-0.809, P〈0.01）. Conclusion Cerebral ischemia inhibited Cp expression in the cortex and hippocampus of rats. The decrease of Cp might be involved in iron deposition in neurons.

Applied anatomy of the cervical region of the recurrent laryngeal nerve

BACKGROUND AND OBJECTIVE： To avoid recurrent laryngeal nerve （RLN） injury during thyroid surgery, it is important to identify the nerve and to follow its projection carefully to discriminate it from the inferior thyroid artery. DESIGN, TIME AND SETTING： All studies were performed at the Anatomy Division of Shaoyang Medical College from May 2003 to May 2004 with repeated measurement design. MATERIALS： Fifty embalmed adult corpses, comprising 20 females and 30 males, were obtained by donation. METHODS AND MAIN OUTCOME MEASURES： The projection, branches, and the relationship of the RLN to the inferior thyroid artery were observed. RESULTS： The RLN in all cases ascended through the tracheoesophageal groove at the isthmus superior levels of the thyroid gland. However, the RLN in 14 cases were situated inferior to the isthmus of the thyroid gland; 11 cases were to the right side and 2 cases to the left side, projected in the tracheoesophageal groove, and ascended away from the groove after 4.5-6.5 mm. The RLN typically ramified at the thyroid isthmus plane （44 cases, 44% of all cases）. The RLN branches were variable. Type 2 rami were most common in the RLN, accounting for 55%; the second most common was RLN branches with no rami. RLN braches with type 3 rami, 4 rami, and 5 rami were less common. Approximately 54% of nerves were situated behind the main branch artery. The nerves located adjacent to the arteries, and between the arterial branches, were similar; the former applied to 19 cases, accounting for 19%, whereas the latter applied to 18 cases, accounting for 18%. Left nerves behind the artery, and right nerves before the artery, were more common. There were significant differences between the left and right nerves （P 〈 0.01）. CONCLUSION： There was not a significant difference in the projection of the RLN, while a significant difference in the number of RLN branches existed. In addition, the anatomical relationship of the RLN and the inferior thyroid artery exhibited side differences.

[Gly14]-Humanin Protects Against Amyloid b Peptide-Induced Impairment of Spatial Learning and Memory in Rats

Alzheimer disease （AD）, a progressive neurodegenerative disorder, is characterized by cognitive decline and the accumulation of senile plaques in the brain. Amyloid β protein （Aβ） in the plaques is thought to be responsible for the memory loss in AD patients. [Glyl4]- humanin （HNG）, a derivative of humanin （HN）, has much stronger neuroprotective effects than natural HN in vitro. However, clarification of the Aβ active center and the neuroprotective mechanism of HN still need in vivo evidence. The present study first compared the in vivo bio- logical effects of three Aβ fragments （1-42, 31-35, and 35-31） on spatial memory in rats, and investigated the neuroprotective effects and molecular mechanisms of HNG. The results showed that intrahippocampal injection of Aβ1-2 and Aβ1-35 almost equally impaired spatial learning and memory, but the reversed sequence Aβ1-31 did not have any effect; a high dose of Aβ1-35 （20 nmol） produced a more detrimental response than a low dose （2 nmol）; Aβ1-35 injection also disrupted gene and protein expression in the hippocampus, with up-regulation of caspase3 and down-regulation of STAT3; pretreatment with HNG not only protected spatial memory but also rescued STAT3 from Aβ-induced disruption; and the neuropro- tective effects of HNG were effectively counteracted by genistein, a specific tyrosine kinase inhibitor. These results clearly show that sequence 31-35 in AI5 is the shortest active center responsible for the neurotoxicity of A[3 from molecule to behavior; and HNG protects spatial learning and memory in rats against Aβ-indnced insults; and prob- ably involves the activation of tyrosine kinases and sub- sequent beneficial modulation of STAT3 and caspase3.