Search

Ferroelectricity in two-dimensional (2D) systems generally arises from phonons and has been widely investigated. On the contrary, electronic ferroelectricity in 2D systems has been rarely studied. Using first-principles calculations, the ferroelectric behavior of the buckled blue SiSe monolayer under strain are explored. It is found that the direction of the out-of-plane ferroelectric polarization can be reversed by applying an in-plane strain. And such polarization switching is realized without undergoing geometric inversion. Besides, the strain-triggered polarization reversal emerges in both biaxial and uniaxial strain cases, indicating it is an intrinsic feature of such a system. Further analysis shows that the polarization switching is the result of the reversal of the magnitudes of the positive and negative charge center vectors. And the variation of buckling is found to play an important role, which results in the switch. Moreover, a non-monotonic variation of band gap with strain is revealed. Our findings throws light on the investigation of novel electronic ferroelectric systems. [ABSTRACT FROM AUTHOR]

Different from the honeycomb monolayer (like graphene), the single-layer boron chalcogenide B2X3 (X = S, Se, Te) exhibits a kagome lattice. Using the first-principles calculations, the existence of sliding ferroelectricity in van der Waals kagome-B2X3 bilayers is demonstrated. The sliding ferroelectricity results from the breaking of the inversion symmetry by interlayer sliding. In addition, there are multiple stable states in a unit cell for kagome-lattice bilayers. The bandgap is found to vary with sliding distance. By choosing specific pathways, not only the out-of-plane polarization but also the in-plane polarization can be reversed by interlayer sliding. Such a simultaneous reversal for both in-plane and out-of-plane polarizations by sliding would be useful for applications in various devices. These behaviors are found in all the three configurations (X = S, Se, Te), suggesting they are the intrinsic features of such systems and may throw light on the development of future devices. [ABSTRACT FROM AUTHOR]

BACKGROUND: With improving living standards, the incidence of cervical spondylotic myelopathy (CSM) has become increasingly high. OBJECTIVE: The study aims to explore the effect of diversified health-promoting models on rehabilitation exercises in patients with CSM after an operation. METHOD: This was a randomized controlled trial, wherein 107 patients with CSM treated by neurosurgery were selected as the subjects. Of those, 52 patients in the control group adopted the conventional health-promoting model, while the remaining 55 patients in the intervention group adopted diversified health-promoting models. The effect of rehabilitation exercises in the two groups was evaluated according to the self-efficacy rehabilitation outcome scale, grip strength measurement of the affected limb, and Barthel index. RESULTS: At Day 3 post-operation and before discharge, the self-efficacy management of rehabilitation exercises in the intervention group was better than that of the control group (P < 0.05). The grip strength measurement of the affected limb, Japanese Orthopedic Association score of the cervical vertebra, and Barthel index of the two groups at Day 3 post-operation were lower than before the intervention and were not statistically significant (P > 0.05). However, these three items before discharge were improved when compared with those of before intervention and were statistically significant (P < 0.05). CONCLUSION: Postoperative rehabilitation exercises guided by the diversified health-promoting models for patients with CSM can improve the patients' self-efficacy management ability in rehabilitation exercises, help improve grip strength, and promote the recovery of cervical vertebra function, thereby improving the patients' quality of life. [ABSTRACT FROM AUTHOR]

The article focuses on the application of Enhanced Recovery After Surgery (ERAS) protocols in the surgical management of cervical spondylosis to improve patient outcomes. Topics include the role of preoperative education and nutritional optimization, the use of minimally invasive techniques and anesthetic protocols during surgery, and the importance of early mobilization in the postoperative phase to enhance recovery and minimize complications.

By using modified Levins and Petraitis formulae, this paper determined the niche breadth and niche overlap of the phytoplankton's dominant species in Dianshan Lake of East China, and analyzed the relationships between the niche breadth and niche overlap and the density and dominance of the dominant species. The niche breadth and niche overlap of the dominant species differed in different periods, and different dominant species had different adaptive capacity to the environmental factors. Based on their niche breadth in different seasons, the dominant species in the Lake could be classified into four groups, among which, Chroomonas acuta and Chlorella vulgaris had broader niche, more quantity, wider distribution, and better use of environmental resources. During cyanobacterial blooms, the niche overlap among Cyanophyta species was comparatively higher, Microcystis aeruginosa had broader niche breadth, but other species showed lower niche breadth. Correlation analysis showed that the dominance of the dominant species in different seasons had significant correlation with their niche breadth, and the dominant species density had significant correlation with their niche overlap. [ABSTRACT FROM AUTHOR]

Objective: To explore the feasibility of passage, cryopreservation, and recovery of osteoclasts in order to develop new techniques facilitating osteoclast research., Methods: Passage of osteoclasts: adult male SD rat(SPF grade, weight of 250 g) was sacrificed and the abdominal aorta was exposed for blood draw. Monocytes isolated from peripheral circulation was treated with RANKL and M-CSF for 2 weeks. After formation of osteoclasts, they were trypsinized with pipetting, centrifuged, re-suspended with α-MEM containing RANKL and M-CSF, and cultured in 6 well-plates and 35 mm culture dishes. Freezing of osteoclasts: trypsinized osteoclasts were centrifuged and resuspended with DMSO, FBS, α-MEM (1:2:7), and were stored in liquid nitrogen(-196 °C). Recovery of osteoclasts: frozen osteoclasts were taken out of liquid nitrogen tank and thawed quickly at 37 °C in water bath. After wash with PBS, the cells were resuspended with α-MEM containing RANKL and M-CSF, and were cultured in 6 well dishes and 35 mm culture dishes. Meanwhile, cells were checked with inverted phase contrast microscope and observed in the live cell station for real time imaging. TRAP staining was performed 3 days after plating., Results: Trypsinization together with pipetting and shaking can detach the adherent osteoclasts, and the resuspended cells can be used for passage and storage in liquid nitrogen. The passaged cells became fully attached to the culture dishes in 2 hours, and the multinucleated feature could be clearly seen. The osteoclasts recovered from liquid nitrogen could completely spread out for 2 to 3 hours so that the multinucleated cells were clearly seen. These cells were still TRAP positive., Conclusions: Although osteoclasts strongly adhere to the bottom of culture dishes, a large majority of the osteoclasts can be detached after appropriate digestion with trypsin, pipetting and shaking. These cells can be used for passage and cryopreservation. After recovering from liquid nitrogen, these cells still preserve the viability and the feature of osteoclasts. The results provide a new and powerful tool for future study of osteoclast biology., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.

Objective: To explore the association of insulin resistance and β cell function with lipid metabolism in middle-aged and elderly Hui and Han populations., Methods: A total of 1000 subjects age over 40 years were recruited from five urban communities in Yinchuan and Wuzhong cities of Ningxia. The composition ratio between Hui and Han nationality was 1:2. A questionnaire-based survey was performed. Physical examinations were carried out to measure the height, body mass, waistline, and hipline. The levels of triglyceride (TG), total cholesterol (TC), blood uric acid (BUA), fasting blood glucose and insulin were measured. The boby mass index (BMI), waist-hip ratio (WHR), and secretion related index including insulin resistance index (IR), insulin sensitivity index (IAI), and beta cell function index (HBCI) were calculated., Results: The BMI, WHR, IAI, HBCI, and the prevalence rate of diabetes in Hui nationality were significantly higher than those in Han nationality (P<0.01). The levels of BUA, fasting blood glucose, TC, and IR in Han nationality were significantly lower than those in Hui nationality (P<0.01). In Hui populations, TG, BMI, WHR, and BUA were positively correlated with IR (r=0.234, r=0.193, r=0.143, and r=0.129, respectively; P<0.01) and were negatively correlated with IAI (r=-0.234, r=-0.193, r=-0.143, r=-0.129, respectively; P<0.01), whereas TC was negatively correlated with HBCI (r=-0.169, P<0.01). In Han populations, TC, TG, BMI, WHR, and BUA were positively correlated with IR (r=0.140, r=0.257, r=0.288, r=0.163, r=0.104, P<0.01) and negatively correlated with IAI (r=-0.140, r=-0.257, r=-0.288, r=-0.163, and r=-0.104, P<0.01), whereas BMI was negatively correlated with HBCI (r=-0.111, P<0.01). After the influential factors such as gender, nationality, and age were adjusted, the TC, TG, BMI, WHR, BUA levels were positively correlated with IR (r=0.109, r=0.256, r=0.253, r=0.139, and r=0.142, P<0.01) and negatively correlated with IAI (r=-0.109, r=-0.256, r=-0.253, r=-0.139, and r=-0.142, P<0.01). TC and BMI were negatively correlated with HBCI (r=-0.113, r=-0.086, P<0.01). TG and BMI were independently associated with IR and IAI (r=0.218, r=0.182, r=-0.218, r=-0.182), while TC and BMI were independently associated with HBCI (r=-0.113, r=-0.086)., Conclusions: The distributions of TC, TG, BMI, WHR, BUA, IR, IAI, and HBCI differ between Han and Hui populations. The development of insulin resistance is closely related with the increased levels of TC, TG, BMI, WHR, and BUA. However, the HBCI increases with the increased level of TC and BMI. TG and BMI may be related with insulin resistance. Also, TC and BMI may affect the secretion function of β cells.

By using modified Levins and Petraitis formulae, this paper determined the niche breadth and niche overlap of the phytoplankton's dominant species in Dianshan Lake of East China, and analyzed the relationships between the niche breadth and niche overlap and the density and dominance of the dominant species. The niche breadth and niche overlap of the dominant species differed in different periods, and different dominant species had different adaptive capacity to the environmental factors. Based on their niche breadth in different seasons, the dominant species in the Lake could be classified into four groups, among which, Chroomonas acuta and Chlorella vulgaris had broader niche, more quantity, wider distribution, and better use of environmental resources. During cyanobacterial blooms, the niche overlap among Cyanophyta species was comparatively higher, Microcystis aeruginosa had broader niche breadth, but other species showed lower niche breadth. Correlation analysis showed that the dominance of the dominant species in different seasons had significant correlation with their niche breadth, and the dominant species density had significant correlation with their niche overlap.

Based on the investigation data of phytoplankton in Dianshan Lake from May to October in 2009, the characteristics of phytoplankton community and the dominant species succession are studied. The results show that Cyanophyta and Chlorophta are the main taxa. Cyanophyta is dominant in cell abundance and Chlorophta is dominant in species variety. From the flat distribution, the species variety and density of Cyanophyta are higher in west and southwest. The peak of cell density reaches 23.40 x 10(7) cells x L(-1) in September due to the occurrence of cyanobacterial bloom, Cyanophyta account for 90.3 percents, with significant differences in each point (ANOVA, P < 0.05). An obvious succession of phytoplankton species is found, Microcystis of Cyanophyta become the dominant taxa and then conglutinated together to form water bloom. Temperature and pH are the main factors that affect the cyanobacterial bloom, and wind direction is an important reason for the horizontal distribution of the bloom-forming Microcystis. The phytoplankton diversity index is poor in central and western sites, diversity index decreases during cyanobacterial bloom and the community structures are simple.

To understand the relationship between the spatial-temporal variations of phytoplankton primary productivity and its environmental factors in Dianshan Lake, monthly survey was carried out from April, 2009 to March, 2010, with the method of white and black bottles. The result shows that seasonal variation of primary productivity (calculated according to carbon, following the same) is summer [0.95 g x (m3 x d)(-1)] > winter [0.83 g x (m3 x d)(-1)] > spring [0.77 g x (m3 x d)(-1)] > autumn [0.62 g x (m3 x d)(-1). From the flat distribution, primary productivity is higher in northern and southern parts than that in east and west, with no significant differences in each point (p > 0.05). From the vertical distribution, phytoplankton light availability is an important limiting factor. Primary production of 0. 3 m underwater is higher than that of 0.5 m. However, primary production of 0.3 m level in summer is lower because of light inhibition. Seasonal changes in primary productivity may be due to phytoplankton community structure and replacement of the dominant species. There are significantly positive correlation between Chlorophyll a (Chl-a) and phytoplankton density with primary productivity (p < 0.01), and Chl-a has better correlation with primary productivity. Phytoplankton biomass shows a positive reaction to its productivity and may preliminary provide a reference for the number of phytoplankton.