[The balance function of the patients with benign paroxysmal positional vertigo during standing]

OBJECTIVE

The purpose of the study was to investigate the balance function of the patients with benign paroxysmal positional vertigo (BPPV) during standing.

METHOD

In this study 41 patients with posterior semicircular canal BPPV (PC BPPV) and 11 patients with horizontal semicircular canal BPPV (HC BPPV) were recruited. Dynamic balance during standing was measured in Sensory Organization Test (SOT). Static balance during standing was measured in modified Clinical Test of Sensory Interaction and Balance (mCTSIB). Data of BPPV patients were compared to that from 44 normal controls.

RESULT

Scores of the patients with PC BPPV were lower than that of the normal controls in the last three test conditions of SOT. Patients with PC BPPV demonstrated greater sway velocity in stance on foam with eyes open and eyes closed in mCTSIB. No postural deficit was observed in neither SOT nor mCTSIB when the patients with HC BPPV were compared to the normal controls.

CONCLUSION

Disorders of the horizontal semicircular canal do not influence postural control. Both dynamic and static posturography can detect the postural imbalance caused by posterior semicircular canal dysfunction.

Surface Coating Constraint Induced Self-Discharging of Silicon Nanoparticles as Anodes for Lithium Ion Batteries

One of the key challenges of Si-based anodes for lithium ion batteries is the large volume change upon lithiation and delithiation, which commonly leads to electrochemi-mechanical degradation and subsequent fast capacity fading. Recent studies have shown that applying nanometer-thick coating layers on Si nanoparticle (SiNPs) enhances cyclability and capacity retention. However, it is far from clear how the coating layer function from the point of view of both surface chemistry and electrochemi-mechanical effect. Herein, we use in situ transmission electron microscopy to investigate the lithiation/delithiation kinetics of SiNPs coated with a conductive polymer, polypyrrole (PPy). We discovered that this coating layer can lead to "self-delithiation" or "self-discharging" at different stages of lithiation. We rationalized that the self-discharging is driven by the internal compressive stress generated inside the lithiated SiNPs due to the constraint effect of the coating layer. We also noticed that the critical size of lithiation-induced fracture of SiNPs is increased from ∼150 nm for bare SiNPs to ∼380 nm for the PPy-coated SiNPs, showing a mechanically protective role of the coating layer. These observations demonstrate both beneficial and detrimental roles of the surface coatings, shedding light on rational design of surface coatings for silicon to retain high-power and high capacity as anode for lithium ion batteries.

Diagnostic Value of Vestibular Evoked Myogenic Potentials in Endolymphatic Hydrops: A Meta-Analysis

In this study, we evaluated the clinical diagnostic value of vestibular evoked myogenic potentials (VEMPs) for endolymphatic hydrops (EH) by systematic review and Meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and area under summary receiver operating characteristic curves (AUC) were calculated. Subgroup analysis and publication bias assessment were also conducted. The pooled sensitivity and the specificity were 49% (95% CI: 46% to 51%) and 95% (95% CI: 94% to 96%), respectively. The pooled positive likelihood ratio was 18.01 (95% CI: 9.45 to 34.29) and the pooled negative likelihood ratio was 0.54 (95% CI: 0.47 to 0.61). AUC was 0.78 and the pooled diagnostic odds ratio of VEMPs was 39.89 (95% CI: 20.13 to 79.03). In conclusion, our present meta-analysis has demonstrated that VEMPs test alone is not sufficient for Meniere’s disease or delayed endolymphatic hydrops diagnosis, but that it might be an important component of a test battery for diagnosing Meniere’s disease or delayed endolymphatic hydrops. Moreover, VEMPs, due to its high specificity and non-invasive nature, might be used as a screening tool for EH.

Restriction-ligation-free (RLF) cloning: a high-throughput cloning method by in vivo homologous recombination of PCR products

In this study, we optimized a restriction-ligation-free (RLF) method to save time and cost of constructing multiple plasmids with the same gene insert, and examined the efficacy of RLF on high-throughput multi-plasmid cloning. This method utilizes the precise DNA repair and recombination systems within Escherichia coli, which allows to bypass the in vitro restriction and ligation enzyme reactions commonly included in routine cloning procedures. A homologous arm is linked to the 5'-end of the forward primer used to amplify both the target gene and vector. A different homologous arm is linked to the 5'-end of the reverse primer. Therefore, genes can be cloned into the vectors by homologous recombination after co-transformation of the amplified target gene and the linearized vector, which bear the same homologous arm on either end. More than twenty-four different plasmids were generated by this method, which uses two simple polymerase chain reaction steps. This method is highly efficient in cloning any gene of interest into any vector at any site without sequence constraints, as no restriction and ligation reactions are required.

Physical Principles of Nanoparticle Cellular Endocytosis

This review article focuses on the physiochemical mechanisms underlying nanoparticle uptake into cells. When nanoparticles are in close vicinity to a cell, the interactions between the nanoparticles and the cell membrane generate forces from different origins. This leads to the membrane wrapping of the nanoparticles followed by cellular uptake. This article discusses how the kinetics, energetics, and forces are related to these interactions and dependent on the size, shape, and stiffness of nanoparticles, the biomechanical properties of the cell membrane, as well as the local environment of the cells. The discussed fundamental principles of the physiochemical causes for nanoparticle-cell interaction may guide new studies of nanoparticle endocytosis and lead to better strategies to design nanoparticle-based approaches for biomedical applications.

BDNF signaling in the rat cerebello-vestibular pathway during vestibular compensation: BDNF signaling in vestibular compensation

Vestibular compensation, which is the behavioral recovery from lesions to the peripheral vestibular system, is attributed to plasticity of the central vestibular system. It has been reported that brain-derived neurotrophic factor (BDNF) is expressed and released in an activity-dependent manner. Upon binding to the tyrosine receptor kinase B (TrkB), BDNF can acutely modulate synaptic transmission and plasticity in the central nervous system. To assess the possible contribution of BDNF to this recovery process, we studied the expression of BDNF, TrkB.FL, TrkB.T1 and KCC2 (K(+) -Cl(-) cotransporter isoform 2) in the bilateral medial vestibular nucleus (MVN) and the flocculus of rats at 4 h, 8 h, 1, 3 and 7 days following unilateral labyrinthectomy (UL) using immunohistochemistry, quantitative real-time PCR and western blotting. Our results have shown that, compared with the sham controls and the contra-lesional side, (a) the expression of BDNF and TrkB.FL increased at 4 h in the ipsi-lesional flocculus after UL; (b) the expression of TrkB.T1 decreased at 4 h and KCC2 decreased at 8 h and 1 day in the ipsi-lesional flocculus after UL; and (c) BDNF and TrkB.FL expression was enhanced and KCC2 expression was reduced in the ipsi-lesional MVN at 8 h after UL. Our data supported the hypothesis that BDNF upregulation may reduce the inhibitory effects of the flocculus and commissural inhibition system by regulating inhibitory GABAergic synaptic transmission in floccular Purkinje cells and Purkinje cell terminals in the MVN. Additionally, KCC2 may be a switch in this process.

Variability of cadmium, lead, and zinc tolerance and accumulation among and between germplasms of the fiber crop Boehmeria nivea with different root-types

Crop germplasms substantially vary in their tolerance for and accumulation of heavy metals, and assessment of this variability plays a significant role in selecting species to use in phytoremediation projects. Here, we examined germplasm-variations in cadmium (Cd), lead (Pb), and zinc (Zn) tolerance and accumulation in ramie (Boehmeria nivea), a fiber crop native to China, which has received little attention. In an 8-week greenhouse test, fourteen germplasms of ramie, among and within deep, middle, and shallow rooted-types, were compared for growth and metal accumulation traits. Results showed that both tolerance and accumulation traits varied across germplasms and rooted-types. The deep rooted-type germplasms produced more biomass and had higher tolerance to metals than the two others. In addition, considerable variations in metal accumulation were observed among plant organs (root, stem, and leaf), rooted-types, germplasms, and metal supply. However, the observed variations in metal tolerance and accumulation among both germplasms and rooted-types were not significant in most cases. In addition to supporting the idea of a certain degree of constitutional metal tolerance for ramie, our results also contribute to deep-rooted germplasms of ramie as a good candidate, rather than middle-/shallow- ones as a least-bad option, for the remediation of multi metal-contaminated soils.

Intratympanic injection in delayed endolymphatic hydrops

CONCLUSIONS

The present study showed that intratympanic dexamethasone injection (ITD) is a promising approach for the treatment of contralateral and ipsilateral delayed endolymphatic hydrops (DEH). Moreover, intratympanic gentamicin injection (ITG), as a chemical labyrinthectomy, is a simple alternative for controlling vertigo in patients with ipsilateral DEH.

OBJECTIVE

This study examined the effect of ITD or ITG on DEH.

METHODS

Fourteen patients with DEH completed the clinical and audio-vestibular evaluation. Among them, 10 cases (ipsilateral type: nine cases, contralateral type: one case) were treated with intratympanic injection. Four patients with ipsilateral DEH underwent ITG, five patients with ipsilateral type and one patient with contralateral type received ITD. All 10 cases were followed up for 8-48 months.

RESULTS

Complete and substantial vertigo control was achieved in four of nine ipsilateral DEH patients treated with ITG. In the other five ipsilateral cases who received ITD, two accomplished complete vertigo control and two had substantial control. In one case, the vertigo was not effectively controlled. One case of contralateral DEH underwent ITD and this case had complete vertigo control. The vertigo intensity, vertigo frequency, vertigo duration and the functional level scale after intratympanic injection was decreased significantly.

Surface-coating regulated lithiation kinetics and degradation in silicon nanowires for lithium ion battery

Silicon (Si)-based materials hold promise as the next-generation anodes for high-energy lithium (Li)-ion batteries. Enormous research efforts have been undertaken to mitigate the chemo-mechanical failure due to the large volume changes of Si during lithiation and delithiation cycles. It has been found that nanostructured Si coated with carbon or other functional materials can lead to significantly improved cyclability. However, the underlying mechanism and comparative performance of different coatings remain poorly understood. Herein, using in situ transmission electron microscopy (TEM) through a nanoscale half-cell battery, in combination with chemo-mechanical simulation, we explored the effect of thin (∼5 nm) alucone and Al2O3 coatings on the lithiation kinetics of Si nanowires (SiNWs). We observed that the alucone coating leads to a "V-shaped" lithiation front of the SiNWs, while the Al2O3 coating yields an "H-shaped" lithiation front. These observations indicate that the difference between the Li surface diffusivity and bulk lithiation rate of the coatings dictates lithiation induced morphological evolution in the nanowires. Our experiments also indicate that the reaction rate in the coating layer can be the limiting step for lithiation and therefore critically influences the rate performance of the battery. Further, the failure mechanism of the Al2O3 coated SiNWs was also explored. Our studies shed light on the design of high capacity, high rate and long cycle life Li-ion batteries.

The role of substrate topography on the cellular uptake of nanoparticles

Improving targeting efficacy has been a central focus of the studies on nanoparticle (NP)-based drug delivery nanocarriers over the past decades. As cells actively sense and respond to the local physical environments, not only the NP design (e.g., size, shape, ligand density, etc.) but also the cell mechanics (e.g., stiffness, spreading, expressed receptors, etc.) affect the cellular uptake efficiency. While much work has been done to elucidate the roles of NP design for cells seeded on a flat tissue culture surface, how the local physical environments of cells mediate uptake of NPs remains unexplored, despite the widely known effect of local physical environments on cellular responses in vitro and disease states in vivo. Here, we report the active responses of human osteosarcoma cells to fibrous substrate topographies and the subsequent changes in the cellular uptake of NPs. Our experiments demonstrate that surface topography modulates cellular uptake efficacy by mediating cell spreading and membrane mechanics. The findings provide a concrete example of the regulative role of the physical environments of cells on cellular uptake of NPs, therefore advancing the rational design of NPs for enhanced drug delivery in targeted cancer therapy.

Ripplocations in van der Waals layers

Dislocations are topological line defects in three-dimensional crystals. Same-sign dislocations repel according to Frank's rule |b1 + b2|(2) > |b1|(2) + |b2|(2). This rule is broken for dislocations in van der Waals (vdW) layers, which possess crystallographic Burgers vector as ordinary dislocations but feature "surface ripples" due to the ease of bending and weak vdW adhesion of the atomic layers. We term these line defects "ripplocations" in accordance to their dual "surface ripple" and "crystallographic dislocation" characters. Unlike conventional ripples on noncrystalline (vacuum, amorphous, or fluid) substrates, ripplocations tend to be very straight, narrow, and crystallographically oriented. The self-energy of surface ripplocations scales sublinearly with |b|, indicating that same-sign ripplocations attract and tend to merge, opposite to conventional dislocations. Using in situ transmission electron microscopy, we directly observed ripplocation generation and motion when few-layer MoS2 films were lithiated or mechanically processed. Being a new subclass of elementary defects, ripplocations are expected to be important in the processing and defect engineering of vdW layers.

Measurement of shear stress-mediated intracellular calcium dynamics in human dermal lymphatic endothelial cells

The shear stress applied to lymphatic endothelial cells (LEC) by lymph flow changes dramatically under normal conditions as well as in response to disease conditions and immune reactions. In general, LEC are known to regulate the contraction frequency and strength of lymphatic pumping in response to shear stress. Intracellular calcium concentration ([Ca(2+)]i) is an important factor that regulates lymphatic contraction characteristics. In this study, we measured changes in the [Ca(2+)]i under different shear stress levels and determined the source of this calcium signal. Briefly, human dermal LEC were cultured in custom-made microchannels for 3 days before loading with 2 µM fura-2 AM, a ratiometric calcium dye to measure [Ca(2+)]i. Step changes in shear stress resulted in a rapid increase in [Ca(2+)]i followed by a gradual return to the basal level and sometimes below the initial baseline (45.2 ± 2.2 nM). The [Ca(2+)]i reached a peak at 126.2 ± 5.6 nM for 10 dyn/cm(2) stimulus, whereas the peak was only 71.8 ± 5.4 nM for 1 dyn/cm(2) stimulus, indicating that the calcium signal depends on the magnitude of shear stress. Removal of the extracellular calcium from the buffer or pharmocological blockade of calcium release-activated calcium (CRAC) channels significantly reduced the peak [Ca(2+)]i, demonstrating a role of extracellular calcium entry. Inhibition of endoplasmic reticulum (ER) calcium pumps showed the importance of intracellular calcium stores in the initiation of this signal. In conclusion, we demonstrated that the shear-mediated calcium signal is dependent on the magnitude of the shear and involves ER store calcium release and extracellular calcium entry.

Stress effects on the initial lithiation of crystalline silicon nanowires: reactive molecular dynamics simulations using ReaxFF

Silicon (Si) has been recognized as a promising anode material for the next-generation high-capacity lithium (Li)-ion batteries because of its high theoretical energy density.

Non-association of MMP-9 -1562C/T polymorphism with preeclampsia risk: evidence from a meta-analysis

Individual genetic association studies examining the relationship between the MMP-9 -1562C/T polymorphism (rs3918242) and preeclampsia risk have yielded inconsistent results.

OBJECTIVE

This study aims to evaluate the association between the MMP-9 -1562C/T polymorphism and preeclampsia risk using meta-analysis.

MATERIALS AND METHODS

Relevant studies were identified by searching PubMed database. Data were extracted and statistical analysis was performed using STATA 12.0 software. A total of six publications involving 871 cases and 845 controls were included in this meta-analysis.

RESULTS

Combined analysis revealed no association between the MMP-9 -1562C/T polymorphism and preeclampsia risk (allelic model: OR = 1.10, 95% CI 0.86-1.41, Pheterogeneity = 0.07; recessive model: OR = 0.38, 95% CI 0.14-1.01, Pheterogeneity = 0.64; dominant model: OR = 1.09, 95% CI 0.70-1.69, Pheterogeneity = 0.01; homozygous model: OR = 0.41, 95% CI 0.15-1.09, Pheterogeneity = 0.67; heterozygous model: OR = 1.36, 95% CI 0.80-2.29, Pheterogeneity = 0.01). Similarly, subgroup analysis by ethnicity showed that MMP-9 -1562C/T polymorphism was not associated with preeclampsia risk in Brazilian (allelic model: OR = 1.37, 95% CI 0.92-2.05, Pheterogeneity = 0.61; recessive model: OR = 0.80, 95% CI 0.18-3.57, Pheterogeneity = 0.58; dominant model: OR = 1.12, 95% CI 0.60-2.10, Pheterogeneity = 0.03; homozygous model: OR 0.87, 95% CI 0.19-3.94, Pheterogeneity = 0.62; heterozygous model: OR = 1.55, 95% CI 0.99-1.75, Pheterogeneity = 0.32).

CONCLUSION

This meta-analysis indicated that MMP-9 -1562C/T polymorphism was not associated with preeclampsia risk. However, large well-designed, multi-center epidemiological studies should be carried out in these and other ethnic populations to confirm our findings.

Bending-induced symmetry breaking of lithiation in germanium nanowires

From signal transduction of living cells to oxidation and corrosion of metals, mechanical stress intimately couples with chemical reactions, regulating these biological and physiochemical processes. The coupled effect is particularly evident in the electrochemical lithiation/delithiation cycling of high-capacity electrodes, such as silicon (Si), where on the one hand lithiation-generated stress mediates lithiation kinetics and on the other the electrochemical reaction rate regulates stress generation and mechanical failure of the electrodes. Here we report for the first time the evidence on the controlled lithiation in germanium nanowires (GeNWs) through external bending. Contrary to the symmetric core-shell lithiation in free-standing GeNWs, we show bending the GeNWs breaks the lithiation symmetry, speeding up lithaition at the tensile side while slowing down at the compressive side of the GeNWs. The bending-induced symmetry breaking of lithiation in GeNWs is further corroborated by chemomechanical modeling. In the light of the coupled effect between lithiation kinetics and mechanical stress in the electrochemical cycling, our findings shed light on strain/stress engineering of durable high-rate electrodes and energy harvesting through mechanical motion.

Effects of isobutyrate supplementation on ruminal microflora, rumen enzyme activities and methane emissions in Simmental steers

The objective of this study was to evaluate the effects of isobutyrate supplementation on rumen microflora, enzyme activities and methane emissions in Simmental steers consuming a corn stover-based diet. Eight ruminally cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment. The treatments were control (without isobutyrate), low isobutyrate (LIB), moderate isobutyrate (MIB) and high isobutyrate (HIB) with 8.4, 16.8 and 25.2 g isobutyrate per steer per day respectively. Isobutyrate was hand-mixed into the concentrate portion. Diet consisted of 60% corn stover and 40% concentrate [dry matter (DM) basis]. Dry matter intake (averaged 9 kg/day) was restricted to a maximum of 90% of ad libitum intake. Population of total bacteria, cellulolytic bacteria and anaerobic fungi were linearly increased, whereas that of protozoa and total methanogens was linearly reduced with increasing isobutyrate supplementation. Real-time PCR quantification of population of Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvens and Fibrobacter succinogenes was linearly increased with increasing isobutyrate supplementation. Activities of carboxymethyl cellulase, xylanase and β-glucosidase were linearly increased, whereas that of protease was linearly reduced. Methane production was linearly decreased with increasing isobutyrate supplementation. Effective degradabilities of cellulose and hemicellulose of corn stover were linearly increased, whereas that of crude protein in diet was linearly decreased with increasing isobutyrate supplementation. The present results indicate that isobutyrate supplemented improved microflora, rumen enzyme activities and methane emissions in steers. It was suggested that the isobutyrate stimulated the digestive micro-organisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum isobutyrate dose was approximately 16.8 g isobutyrate per steer per day.

[Application of nanomaterials in in-vitro diagnostics]

Nanomaterials appear to be promising for a number of applications in in-vitro diagnostics, mainly due to the biocompatibility, specific surface and conduction activity. The use of nanostructures as diagnostic tools has the advantage of very low limit of detection achievable, high sensitivity, strong selectivity and the possibility to fabricate point-of-care diagnostic devices. With the problems of nanotechnology solved, nanomaterials had already put a broad impact in the field of clinical medical examination.

Hexokinase 2 overexpression promotes the proliferation and survival of laryngeal squamous cell carcinoma

Proliferating cancer cells preferentially use anaerobic glycolysis rather than oxidative phosphorylation for energy production. Hexokinase 2 (HK2) is highly expressed in many malignant cells and is necessary for anaerobic glycolysis. The role of HK2 in laryngeal squamous cell carcinoma (LSCC) is unknown. In this study, the expression of HK2 in LSCC was investigated and the effect of inhibiting HK2 expression with small hairpin RNA (shRNA) on tumor growth was investigated. Using immunohistochemistry, HK2 expression was assessed in LSCC tissues. Human laryngeal carcinoma Hep-2 cells were stably transfected with a plasmid expressing HK2 shRNA (pGenesil-1.1-HK2) and were compared to control cells with respect to the cell cycle, cell viability, apoptosis, and their ability to form xenograft tumors. HK2 expression was significantly higher in LSCC than in papilloma or glottis polypus. Tumor samples of higher T, N, and TNM stage often had stronger HK2 staining. HK2 shRNA reduced HK2 mRNA, protein levels, and HK activity in Hep-2 cells. HK2 cells expressing shRNA demonstrated a higher G0-G1 ratio, increased apoptosis, and reduced viability. Xenograft tumors derived from cells expressing HK2 shRNA were smaller and had lower proliferation than those from untransfected or control-plasmid-transfected cells. In conclusion, depletion of HK2 expression resulted in reduced xenograft tumor development likely by reducing proliferation, altering the cell cycle, reducing cell viability and activating apoptosis. These data suggest that HK2 plays an important role in the development of LSCC and represents a potential therapeutic target for LSCC.

Aberrant promoter methylation of the CD4 gene in peripheral blood cells of mastitic dairy cows

Bovine mastitis is the most common and costly disease of dairy cattle. Cluster of differentiation 4 (CD4) is closely related to the immune response in mastitis. We quantified promoter CpG methylation levels of the CD4 gene in Chinese Holsteins with clinical mastitis (CM) and in healthy controls; these levels were quantitatively detected with bisulfite pyrosequencing assays and confirmed by cloning sequencing. We found that the bovine CD4 promoter had 16% more methyl groups in the cows with CM (75.0 ± 5.8%) compared to the controls (59.0 ± 8.5%). The decreased expression level of CD4 in CM cows may be downregulated by the increased DNA methylation levels in the CD4 promoter. Two-dimensional hierarchical clustering analyses showed large differences in promoter CD4 methylation between mastitic and healthy cows; the dendrogram clearly distinguished the cows with clinical mastitis from healthy controls based on methylation levels. The DNA methylation level of the CD4 gene was strongly influenced by mastitis status in all comparisons. We suggest that the DNA methylation level of the CD4 promoter can be used as a molecular marker for clinical mastitis in dairy cows.

Nanovoid formation and annihilation in gallium nanodroplets under lithiation-delithiation cycling

The irreversible chemomechanical degradation is a critical issue in the development of high-capacity electrode materials for the next-generation lithium (Li)-ion batteries. Here we report the self-healing behavior of gallium nanodroplets (GaNDs) under electrochemical cycling at room temperature, observed with in situ transmission electron microscopy (TEM). During lithiation, the GaNDs underwent a liquid-to-solid phase transition, forming a crystalline phase (LixGa) with ~160% volume expansion. Owing to the uneven Li flow during lithiation, the fully lithiated GaNDs exhibited highly distorted morphologies. Upon delithiation, the reverse phase transition occurred, accompanied with the nucleation and growth of a nanosized void. After the GaNDs were fully delithiated, the nanovoid gradually annihilated. Our analysis, along with phase field modeling and experimental measurements of the void growth and annihilation, provides mechanistic insights into the void formation and annihilation mechanism. The GaNDs may function as an effective healing agent in durable composite electrodes for high-performance Li-ion batteries, wherein active components, such as Si, are susceptible to fracture.