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Frequent freezing injury greatly influences winter wheat production; thus, effective prevention and a command of agricultural production are vital. The freezing injury monitoring method integrated with '3S' (geographic information systems (GIS), global positioning system (GPS) and remote sensing (RS)) technology has an unparalleled advantage. Using HuanJing (HJ)-1A/1B satellite images of a winter wheat field in Shanxi Province, China plus a field survey, crop types and winter wheat planting area were identified through repeated visual interpretations of image information and spatial analyses conducted in GIS. Six vegetation indices were extracted from processed HJ-1A/1B satellite images to determine whether the winter wheat suffered from freezing injury and its degree of severity and recovery, using change vector analysis (CVA), the freeze injury representative vegetation index and the combination of the two methods, respectively. Accuracy of the freezing damage classification results was verified by determining the impact of freezing damage on yield and quantitative analysis. The CVA and the change of normalized difference vegetation index (ΔNDVI) monitoring results were different so a comprehensive analysis of the combination of CVA and ΔNDVI was performed. The area with serious freezing injury covered 0.9% of the total study area, followed by the area of no freezing injury (3.5%), moderate freezing injury (10.2%) and light freezing injury (85.4%). Of the moderate and serious freezing injury areas, 0.2% did not recover; 1.2% of the no freezing injury and light freezing injury areas showed optimal recovery, 15.6% of the light freezing injury and moderate freezing injury areas showed poor recovery, and the remaining areas exhibited general recovery. [ABSTRACT FROM AUTHOR]

A physical model is developed with the volume of fluid (VOF) method to track the free interface in the meltpool to understand the meltpool evolution, fluid flowing and the behaviour in gas and liquid interface. The model is characterized with a combined heat source model consisting of a parabolic rotating and a cylindrical distribution, and a stochastic distributed model of powder bed with powder particle size. The heat source is only loaded in the unit interface between metallic and gas phase in the laser-powder interaction zone. The simulation is carried out only in first and second laser scanning track due to the reduction in computing time. Simulation results exhibits the fluid flowing and surface morphology in the meltpool is determined significantly by different laser parameters such as laser power and scanning velocity. The simulated meltpool geometry has good agreement with the experimental ones. The meltpool geometry of the first track changes from the approximate circle, ellipse to 'comet' due to the heat accumulation during continuous laser scanning. The meltpool geometry of the second track becomes much larger, its temperature is higher and the fluid flowing is faster than that of the first track. The melt metal flows violently in the initial position due to the high flowing velocity in a limit melt space. The second track has enough space for metal flowing and it is easy to obtain a smooth surface morphology than the first track; thus, a long enough meltpool helps to get a steady fluid and smooth surface morphology. The temperature of the meltpool at beam centre fluctuates during laser scanning process, which depend on the determined effects of the interaction between thermal conduction and violent fluid flowing or the interaction between heat accumulation and violent fluid flowing. The information about temperature distribution and fluid flowing in the meltpool provided by the simulation helps to analyse and understand the formation mechanism of the meltpool geometry, surface morphology and meltpool evolution as well, benefiting to further control the laser powder bed fusion (LPBF) processing of Ti6Al4V alloy powder. [ABSTRACT FROM AUTHOR]

A simple electrochemical method for the determination of cyanuric acid (CA) has been developed based on a CuGeO3 nanowire modified glassy carbon electrode. The dense CuGeO3 nanowire film can be formed on the surface of the glassy carbon electrode. The roles of scan rate, CA concentration, and electrolytes with different pH values on the electrochemical responses of CA have also been analyzed. The intensities of two anodic peaks vary linearly with the increase of the scan rate from 25 to 200 mVs-1. The intensity of the electrochemical CV peak increases with the increase of the acidity of the electrolytes. The two anodic peak currents are linear with the CA concentration in the range of 0.005-2 mM. The linear correlation coefficient is 0.984 and 0.980 for the cyclic voltammogram peaks (cvp) cvp1 and cvp2, respectively. The detection limit is 4.3 μM and 2.1 μM for cvp1 and cvp2, respectively. The proposed electrochemical method is convenient and effective sensing of CA. [ABSTRACT FROM AUTHOR]

The electrochemical responses of ascorbic acid have been investigated by cyclic voltammetry on the CuGeO3/20wt% polyaniline nanowire modified glassy carbon electrode at room temperature. The results show that the modified electrode exhibits good analytical performance for the electrochemical detection of ascorbic acid in neutral solution. The intensities of the anodic cyclic voltammogram (CV) peaks increase linearly with the increase of the ascorbic acid concentration from 0.001 to 2 mM and scan rate from 25 to 200 mVs-1. CuGeO3/20wt% polyaniline nanowire modified glassy carbon electrode exhibits good reproducibility, stability, low detection limit of 0.61 µM and 0.26 µM for cvp1 and cvp2, respectively, which is better than those at other modified electrodes. [ABSTRACT FROM AUTHOR]

Objective Controlled twitch mouth pressure (Tw Pmo) via the use of a two-way non-rebreathing valve is a new method to assess diaphragm contractility. The optimal trigger threshold was confirmed. Design We sought to determine the optimal trigger threshold for 17 healthy subjects (29±4 years) and 17 COPD patients (64±10 years). The Tw Pmo, twitch oesophageal pressure (Tw Pes) and twitch transdiaphragmatic pressure (Tw Pdi) in response to phrenic nerve stimulation were measured using an inspiratory pressure trigger at -1, -2, -3, -4, -5 and -6cmH2O. Results The lung volume did not change during triggering at different trigger thresholds using a two-way non-rebreathing valve. The highest correlation between Tw Pmo and Tw Pes in healthy subjects and COPD patients occurred for a -2cmH2O trigger threshold (r=0.939 and r=0.869, P<0.0001). The narrowest limits of agreement for Tw Pmo and Tw Pes both occurred at -2cmH2O in healthy subjects, with a bias (range) of -0.4cmH2O (-1.85 to 1.41), and in COPD patients, with a bias (range) of 0.16cmH2O (-1.36-1.67). Conclusions We conclude that the measurement of Tw Pmo using a two-way non-rebreathing valve is of clinical value to investigate the suspected diaphragm contractility. The highest trigger threshold for clinical applications was -2cmH2O. [ABSTRACT FROM AUTHOR]

A stimulator that analogs the needle puncture has been designed to deliver quantitative mechanical stimulus to a small area of muscle. A friction coupler is designed to transmit the driving force from motor to a needle which is used to deliver stimulus. Rotation of the needle may be stopped but the friction will be maintained between the needle and the tissue when this friction moment comes to the driving moment of the coupler. Experiments were done on 6 hindlimb muscles in 2 cats and the results show the value of the stimulator in probing the mechanisms of acupuncture.

Peripheral nerve injury may result in many kinds of sensory disorders such as hyperalgesia, dysesthesia, causalgia, etc. This paper mainly reviews the changes in morphology and physiological function occuring in the chronic painful peripheral neuropathy of two kinds of animal models which are now generally used to study the mechanisms of chronic neuropathic pain.

A peripheral neuropathy with hyperalgesia and allodynia was produced by loosely tying constrictive ligature around the left sciatic nerve of rats, i.v. injection of anisodamine 20 mg/Kg abolished both neuropathic hyperalgesia responses to noxious radiant heat and ectopic discharges generated from the injured region of the nerve. Anisodanime applied either systemically or locally to the damaged area of the nerve not only ceased the spontaneous ectopic discharges recorded from A beta to C fibers but also blocked the afferent ectopic discharge elicited by K+ channel blocker, noradrenaline, Ca2+ or antidromic stimulation of sciatic nerve proximal to the injured nerve area. The experiments indicated that anisodamine probably possessed a calcium channel blocker-like activity and produced selective block of the new channels in the injured area. It is suggested that anisodamine may be a candidate therapeutic agent in relieving hyperalgesia and allodynia following nerve injury.

Changes in ectopic discharges from axons in an injured nerve were examined while agents that interact with ion channels were applied to the site of the nerve injury. Tetraethylammonium (TEA) greatly facilitated spontaneous ectopic discharges or evoked ectopic firing in previously silent axons. Tetrodotoxin, an Na+ channel blocker, completely blocked spontaneous discharges. Verapamil, La3+, and Mn2+, agents that interact with Ca2+ channels, blocked spontaneous discharges and depressed the responses evoked by TEA, noradrenaline and high concentration of K+. Increasing Ca2+ levels facilitated ectopic discharges and this effect was blocked by La3+ and Mn2+. Normal axons (from uninjured nerves) were insensitive to all the effects seen in the axons from the injured nerve. These results suggest that following nerve injury the membrane of the regenerating sprout contains new ion channels, particularly Ca2+ channels, and that these channels are responsible for the generation of ectopic discharges.

Using intracellular microelectrode technique and microcomputer analyzing system, the effects of m-nisoldipine (m-Nis) and nisoldipine (Nis) on spontaneous electric activity of human atrial tissue were studied. APA and Vmax were remarkably decreased by m-Nis (0.25 and 1.25 mumol.L-1) and Nis (0.25 mumol.L-1). RPF was also greatly decreased as a result of inhibition in VDD. The inhibitory effects of m-Nis on transmembrane potentials were less than those of Nis at equal concentration (0.25 mumol.L-1). Neither MDP nor APD90 was affected by m-Nis and Nis.

A peripheral neuropathy was produced in adult rats by placing loosely constrained ligature around the common sciatic nerve. At the ligature region of the nerve, demyelination developed. The postoperative behavior of these rats indicated that hyperalgesia and allodynia were produced. The electrical activity pattern of the damaged fibers was remarkably different from those of normal nerves: there were some abnormal spontaneous afferent firings from the injured fibers; multi-impulse responses of C-fiber to single shock was recorded; a lasting firing was elicited after the injured region was gently pressed or by oil drops at 40 degrees C; an antidromic electric stimulus to the injured region, stimulations of L5 sympathetic ganglion or systemic administration of noradrenaline, all caused an increase in on-going spontaneous discharges of the injured fibers or brought the silent fibers into firing. Stimulation of the dorsal roots of the sciatic nerve produced no effect on their activities or caused a pause of the on-going discharges of them. Phentolamine, an alpha receptor blocker, ceased the abnormal firing, but did not affect the normal fiber firings. It is hypothesized that noradrenaline released by the sympathetic nerve would be an important factor responsible for both hyperalgesia and allodynia following injury of peripheral nerve.

The hypothesis of Meridian-Cortex-Viscera Interrelationship maintains: 1. Meridian channel system is an independent system connected with the nerves to the cortex; 2. It acts through the nerves; 3. The nervous action is realized by humoral agents. This article gives preliminary-experimental supports for the above criteria.

The p.d. of the rat seminiferous tubules was 4.75 +/- 1.39 mV (lumen negative) at 35 degrees C and varied linearly with temperatures from 26 to 40 degrees C. A depolarization of the seminiferous tubules was found in the rats administered with gossypol at the dosage of 30 mg/kg body weight for 3 weeks, the p.d. lowered to 3.63 +/- 0.79 mV at 35 degrees C and was independent of the changes of seminiferous tubules temperature. In the 5-week-gossypol-treatment group, the tracer penetrated not only the myoid cell layer, but also went beyond the tight junction complexes between Sertoli cells. The lanthanum appeared in the cleft surrounding spermatogonia. In the 8-week-gossypol-treatment group, the lanthanum was found in the adluminal compartment. It indicates that gossypol can cause a dysfunction of the Sertoli cells and blood-testis barrier and disturb a good physiological environment for the developing spermatocytes.

In this article, seventy nociceptive units of dorsal horn and five preganglionic sympathetic units of spinal cord in forty-four anesthetized cats immobilized with Flaxedil were studied. The results observed were: 1. Electrophoretic administration of noradrenaline (NA) induced a remarkable depression of both evoked and spontaneous discharges of nociceptive units. Similar effects could be produced by electric stimulation of noradrenergic Al nuclei or injection of amphetamine or hand pressing of "Zusanli" (one form of acupuncture) respectively. 2. The effect of 5-hydroxytryptamine (5-HT on evoked nociceptive discharge was similar to NA, but on spontaneous discharge of nociceptive units was excitement. 3. Effects of the above-mentioned factors on the nociceptive discharges of preganglionic sympathetic neurons were similar to the nociceptive units too. 4. On the contrary, the activity of inhibited neuron by noxious stimulation was augmented by administration of NA, amphetamine, the stimulation of Al nuclei and the deep muscle. It is suggested that the noradrenergic nuclei in lower brain stem may play an important role in descending inhibitory circuits of nociceptive spinal reflex.