The Effect of Increasing the Amount of Indium Alloying Material on the Efficiency of Sacrificial Aluminium Anodes

Al-Zn-In alloys having 4.2% zinc content and various indium content in the range of 0.02–0.2% were tested with respect to the most important electrochemical properties of sacrificial anodes in a cathodic protection, i.e., the current capacity and potential of the operating anode. The distribution of In and Zn in the tested alloys was mapped by means of the EDX technique, which demonstrated that these elements dissolve well in the alloy matrix and are evenly distributed within it. The current capacity of such alloys was determined by means of the method of determining the mass loss during the dissolution by a current of known charge. The results obtained demonstrate that the current capacity of Al-Zn-In alloy decreases with the increase in the In content, which results in an increased consumption of anode material and shorter lifetime of anodes. With 0.02% In content, the capacity amounted to approx. 2500 Ah/kg, whereas the alloy with 0.2% In had as much as 30% lower capacity amounting to approx. 1750 Ah/kg. Microscopic examination for the morphology and surface profile of the samples after their exposure demonstrated that a higher indium content in the alloy results in a more uneven general corrosion pattern during the dissolution of such alloy, and the cavities (pits) appearing on the alloy surface are larger and deeper. As the indium content is increased from 0.02% to 0.05%, the Al-Zn-In alloy potential decreases by about 50 mV to −1100 mV vs. Ag/AgCl electrode, which is advantageous in terms of using this alloy as a sacrificial anode. When the indium content is further increased from 0.05% to 0.2%, the potential of the alloy is no longer changed to a more negative one. The results obtained from all these tests demonstrate that alloys containing up to 0.05% of In additive are practically applicable for cathodic protection.     

Safety of 5 kHz tACS

BackgroundSinusoidal transcranial alternating current stimulation (tACS) at 5 kHz applied for 10 min at 1 mA intensity over the hand area of the primary motor cortex (M1) results in sustained changes in cortical excitability as previously demonstrated.ObjectiveHere we have assessed safety aspects of this stimulation method by measuring neuron-specific enolase (NSE) levels, examining electroencephalogram (EEG) traces and analyzing anatomical data by using magnetic resonance imaging (MRI).MethodsAltogether 18 healthy volunteers participated in the study. tACS was applied at 5 kHz for a duration of 10 min over the left M1 at an intensity of 1 mA.ResultsAfter stimulation no significant changes were detected in NSE levels, no structural alterations were observed in the anatomical scans and no pathological changes were found in the EEG recordings.ConclusionsOur data imply that the application of tACS is safe at least within these parameters and with these applied protocols.     

The effects of consecutive sessions of anodal transcranial direct current stimulation over the primary motor cortex on hand function in healthy older adults

BackgroundWith advancing age, changes in the central nervous system may lead to motor functional deficits. Non-invasive brain stimulation techniques are suggested to help modifying brain function.ObjectivesThe aim of the current study was to investigate the effect of using multi session anodal transcranial Direct Current Stimulation (a-tDCS) over the primary motor cortex (M1) on the hand function in healthy older adults.MethodIn this randomized, double-blinded, sham-controlled study 32 participants received active or sham a-tDCS (1 mA, 20 min, for five consecutive days) and performed the Purdue Pegboard Test (PPT) on the first day before tDCS application, immediately (T1), 30 min (T2), and one week after the last session (5th day) (T3) of the stimulation.ResultsThere was a significant improvement for PPT (p < 0.05) in a-tDCS group at all post-test values except for PPT for left hand (PPTL) at T1. Compared to the sham group, the results indicated significant improvement in all PPT subtests (P < 0.05), except for PPTL at T1, PPT for both hands at T2 and PPT assembly at T3 in a-tDCS group.ConclusionThe current findings suggest a-tDCS can be considered as a promising stand-alone technique in the intervention of the age-related decline of manual dexterity for improving hand function.     

Sequential acquisition of cacophony calcium currents,sodium channels and voltage‐dependent potassium currents affects spike shape and dendrite growth during postembryonic maturation of an identified Drosophila motoneuron

During metamorphosis the CNS undergoes profound changes to accommodate the switch from larval to adult behaviors. In Drosophila and other holometabolous insects, adult neurons differentiate either from respecified larval neurons, newly born neurons, or are born embryonically but remain developmentally arrested until differentiation during pupal life. This study addresses the latter in the identified Drosophila flight motoneuron 5. In situ patch‐clamp recordings, intracellular dye fills and immunocytochemistry address the interplay between dendritic shape, excitability and ionic current development. During pupal life, changes in excitability and spike shape correspond to a stereotyped, progressive appearance of voltage‐gated ion channels. High‐voltage‐activated calcium current is the first current to appear at pupal stage P4, prior to the onset of dendrite growth. This is followed by voltage‐gated sodium as well as transient potassium channel expression, when first dendrites grow, and sodium‐dependent action potentials can be evoked by somatic current injection. Sustained potassium current appears later than transient potassium current. During the early stages of rapid dendritic growth, sodium‐dependent action potentials are broadened by a calcium component. Narrowing of spike shape coincides with sequential increases in transient and sustained potassium currents during stages when dendritic growth ceases. Targeted RNAi knockdown of pupal calcium current significantly reduces dendritic growth. These data indicate that the stereotyped sequential acquisition of different voltage‐gated ion channels affects spike shape and excitability such that activity‐dependent calcium influx serves as a partner of genetic programs during critical stages of motoneuron dendrite growth.     

县区级妇幼保健机构运行现状与思考

对张掖市6所县区级妇幼保健机构运行情况进行调查,结合近几年业务发展和公共卫生项目执行情况进行分析,进一步探讨县区级妇幼保健机构的定位与发展.公共卫生工作和能力建设必须齐抓共管,互相促进,共同发展,既要坚持基层妇幼保健机构的公益性不放松,又要把基础医疗和临床保健工作做精做强,为妇女儿童提供全面的基本医疗服务和保健服务,同时政府要加大对基层保健机构的投入,解决基础设备落后、编制不足和人才短缺的问题.     

Finite Element Modeling of Cutaneous Electrical Stimulation for Sensory Feedback

It is currently difficult for the amputee to perceive environmental information such as tactile pressure on the fingertip of the present upper limb prostheses. Sensory feedback induced by cutaneous electrical stimulation can be used to transmit tactile information from hand prostheses to sensory nerve of intact upper arm, thus producing the corresponding perceptions in human brain. In order to have a deeper understanding on the distribution of stimulation current within the limb, and find a better placement of the stimulating and reference electrodes, we constructed a three-dimensional upper-limb model to systematically study the effect of electrode placement on current distribution based on finite element analysis. In these simulations, the reference electrode is positioned at four different locations around and on the axial direction of the arm. The results show that with the increase of distance between reference electrode and stimulating electrode, the current density increases in the skin layer of the upper limb. When the reference electrode is on the opposite side of stimulating electrode around the arm, the current is more concentrated in the skin layer, which is in line with recent findings in psychophysiological experiments. But better spatial selectivity could be achieved when the reference electrode is closer to the stimulating electrode around the arm, and it is more obvious in comparison with that on the axial direction. These findings will provide insights for the design of electrode array used for evoking cutaneous sensory afferents.