The effect of walking speed on the foot inter-segment kinematics, ground reaction forces and lower limb joint moments

Background: Normative foot kinematic and kinetic data with different walking speeds will benefit rehabilitation programs and improving gait performance. The purpose of this study was to analyze foot kinematics and kinetics differences between slow walking (SW), normal walking (NW) and fast walking (FW) of healthy subjects. Methods: A total of 10 healthy male subjects participated in this study; they were asked to carry out walks at a self-selected speed. After measuring and averaging the results of NW, the subjects were asked to perform a 25% slower and 25% faster walk, respectively. Temporal-spatial parameters, kinematics of the tibia (TB), hindfoot (HF), forefoot (FF) and hallux (HX), and ground reaction forces (GRFs) were recorded while the subjects walked at averaged speeds of 1.01 m/s (SW), 1.34 m/s (NW), and 1.68 m/s (FW). Results: Hindfoot relative to tibia (HF/TB) and forefoot relative to hindfoot (FF/HF) dorsiflexion (DF) increased in FW, while hallux relative to forefoot (HX/FF) DF decreased. Increased peak eversion (EV) and peak external rotation (ER) in HF/TB were observed in FW with decreased peak supination (SP) in FF/HF. GRFs were increased significantly with walking speed. The peak values of the knee and ankle moments in the sagittal and frontal planes significantly increased during FW compared with SW and NW. Discussion: Limited HF/TB and FF/HF motion of SW was likely compensated for increased HX/FF DF. Although small angle variation in HF/TB EV and FF/HF SP during FW may have profound effects for foot kinetics. Higher HF/TB ER contributed to the FF push- offthe ground while the center of mass (COM) progresses forward in FW, therefore accompanied by higher FF/HF abduction in FW. Increased peak vertical GRF in FW may affected by decreased stance duration time, the biomechanical mechanism maybe the change in vertical COM height and increase leg stiffness. Walking speed changes accompanied with modulated sagittal plane ankle moments to alter the braking GRF during loading response. The findings of foot kinematics, GRFs, and lower limb joint moments among healthy males may set a reference to distinguish abnormal and pathological gait patterns. © 2018 Sun et al

Distribution and biology of prowfish (Zaprora silenus) in the northeast Pacific

The prowfish (Zaprora silenus) is an infrequent component of bottom trawl catches collected on stock assessment surveys. Based on presence or absence in over 40,000 trawl catches taken throughout Alaskan waters southward to southern California, prowfish are most frequently encountered in the Gulf of Alaska and the Aleutian Islands at the edge of the continental shelf. Based on data from two trawl surveys, relative abundance indicated by catch per swept area reaches a maximum between 100 m and 200 m depth and is much higher in the Aleutian Islands than in the Gulf of Alaska. Females weigh 3.7% more than males of the same length. Weight-length functions are W (g) = 0.0164 L2.92 (males) and W = 0.0170 L2.92 (females). Length at age does not differ between sexes and is described by L = 89.3(1 – e–0.181(t+0.554)), where L is total length in cm and t is age in years. Females reached 50% maturity at a length of 57.0 cm and an age of 5.1 years. Prowfish diet is almost entirely composed of gelatinous zooplankton, primarily scyphozoa and salps

Effect of precursor pH on AuNP/MWCNT nanocomposites synthesized by plasma-induced non-equilibrium electrochemistry

In recent years, plasma-induced non-equilibrium electrochemistry (PiNE) has been increasingly used for the synthesis of nanomaterials. In this study, we investigated the effect of solution pH on the formation of AuNP/MWCNT nanocomposites synthesized by PiNE. It is found that resulting nanocomposite morphology can be manipulated by the solution pH with pH 2 giving the most uniformly distributed AuNP along the MWCNT surface during the nanocomposite formation. The detailed mechanisms of AuNP/MWCNT nanocomposites formation under different pH have been discussed. For selected AuNP/MWCNT, we further evaluated the photothermal conversion performance under a blue laser (wavelength 445 nm) and the material biocompatibility using HeLa cells. The promising photothermal capability and biocompatibility of the composite sample point to their potential future applications such as solar thermal conversion and healthcare technology

The structure of a magnitude-frequency relation for debris flows conditioned by earthquake shock

Debris flow is a major secondary geological process associated with the 2008 M7.9 Wenchuan Earthquake area, causing the loss of around 200 lives as well as extensive property damage. Based on data developed over the past 21 years (1998–2018) of continuous monitoring of debris flow events in Sichuan, the temporal and spatial aspects of debris flows have been analyzed, including magnitude and frequency. The 21-year study period is divided into three time-intervals: 1998–2007 (pre-earthquake), 2008–2013 (short-term post-earthquake), and 2014–2018 (long-term post-earthquake). Distribution maps are plotted to compare debris flow distribution density in the three periods and to visualize debris flow development throughout Sichuan Province from 1998 to 2018. Many large-scale debris flows occur in groups immediately following the earthquake (2008–2013). After 2014, the magnitude and frequency of debris flows begin to decrease and gradually returned near to the pre-earthquake level as the damaged landscape recovered. The effect of rainfall is investigated by analyzing a 21-year record of precipitation; Following the earthquake the threshold rainfall values for debris flow triggering decrease only to recover to pre-earthquake levels as the landscape heals. Magnitude-frequency (M-F) relations for debris flows of the three periods were developed, and the distribution can be well fitted by a power-law function. Finally, the work done by debris flow was defined by multiplying the magnitude by frequency. At the regional scale, the work peaks in the three time periods have been determined and it is found that the peaks corresponded with the larger debris flow sizes. The concept of offset is introduced to describe the shift of the work peak in relation to the probability peak and is termed the Wolman-Miller offset. It is concluded that with a greater offset in the short-term post-earthquake period, more work has been done by larger events and that the greater proportion of the volume being mobilized by larger events occurring more frequently is a key process in the landscape returning to a pre-earthquake (equilibrium) state. The recovery of an earthquake-damaged landscape represents a transient period of high hazard that should be considered in any hazard assessment of earthquake-triggered landslides (in addition to co-seismic landslides)

Active control of magnetoresistance of organic spin valves using ferroelectricity

Organic spintronic devices have been appealing because of the long spin life time of the charge carriers in the organic materials and their low cost, flexibility and chemical diversity. In previous studies, the control of resistance of organic spin valves is generally achieved by the alignment of the magnetization directions of the two ferromagnetic electrodes, generating magnetoresistance.1 Here we employ a new knob to tune the resistance of organic spin valves by adding a thin ferroelectric interfacial layer between the ferromagnetic electrode and the organic spacer. We show that the resistance can be controlled by not only the spin alignment of the two ferromagnetic electrodes, but also by the electric polarization of the interfacial ferroelectric layer: the MR of the spin valve depends strongly on the history of the bias voltage which is correlated with the polarization of the ferroelectric layer; the MR even changes sign when the electric polarization of the ferroelectric layer is reversed. This new tunability can be understood in terms of the change of relative energy level alignment between ferromagnetic electrode and the organic spacer caused by the electric dipole moment of the ferroelectric layer. These findings enable active control of resistance using both electric and magnetic fields, opening up possibility for multi-state organic spin valves and shed light on the mechanism of the spin transport in organic spin valves

Review of the mathematical foundations of data fusion techniques in surface metrology

The recent proliferation of engineered surfaces, including freeform and structured surfaces, is challenging current metrology techniques. Measurement using multiple sensors has been proposed to achieve enhanced benefits, mainly in terms of spatial frequency bandwidth, which a single sensor cannot provide. When using data from different sensors, a process of data fusion is required and there is much active research in this area. In this paper, current data fusion methods and applications are reviewed, with a focus on the mathematical foundations of the subject. Common research questions in the fusion of surface metrology data are raised and potential fusion algorithms are discussed

The RN/CFT Correspondence Revisited

We reconsidered the quantum gravity description of the near horizon extremal Reissner-Nordstr{\o}m black hole in the viewpoint of the AdS$_2$/CFT$_1$ correspondence. We found that, for pure electric case, the right moving central charge of dual 1D CFT is $6 Q^2$ which is different from the previous result $6 Q^3$ of left moving sector obtained by warped AdS$_3$/CFT$_2$ description. We discussed the discrepancy in these two approaches and examined novel properties of our result.Comment: revtex4, 16 pages, sign mistakes corrected, references include

The Reproducibility of Lists of Differentially Expressed Genes in Microarray Studies

Reproducibility is a fundamental requirement in scientific experiments and clinical contexts. Recent publications raise concerns about the reliability of microarray technology because of the apparent lack of agreement between lists of differentially expressed genes (DEGs). In this study we demonstrate that (1) such discordance may stem from ranking and selecting DEGs solely by statistical significance (P) derived from widely used simple t-tests; (2) when fold change (FC) is used as the ranking criterion, the lists become much more reproducible, especially when fewer genes are selected; and (3) the instability of short DEG lists based on P cutoffs is an expected mathematical consequence of the high variability of the t-values. We recommend the use of FC ranking plus a non-stringent P cutoff as a baseline practice in order to generate more reproducible DEG lists. The FC criterion enhances reproducibility while the P criterion balances sensitivity and specificity