Stability of Low Crested and Submerged Breakwaters with Single Layer Armouring

The stability of single layer armour units on low crested and submerged breakwaters has been investigated in 2D hydraulic model tests. Armour unit movements including settlements, rocking and displacements have been determined. The effect of freeboard, packing density and wave steepness on the armour layer stability on crest, front and rear slope has been investigated. Armour units were mostly displaced in the most upper part of the seaward slope and at the seaward side of the crest. Damage on the crest was progressing towards the rear slope. About 40% to 50% larger armour units are required on the seaward slope and crest of low crested structures （as compared to conventional high crested breakwaters）. About 35% larger armour units are required on the rear slope. Larger armour units are not required on submerged breakwaters if the water depth on the crest exceeds 40% of design wave height.

Responses of Primary Afferent Fibers to Acupuncture-Like Peripheral Stimulation at Different Frequencies:Characterization by Single-Unit Recording in Rats

The pain-relieving effect of acupuncture is known to involve primary afferent nerves(PANs) via their roles in signal transmission to the CNS.Using single-unit recording in rats,we characterized the generation and transmission of electrical signals in Aβ and Aδ fibers induced by acupuncture-like stimuli.Acupuncture-like signals were elicited in PANs using three techniques:manual acupuncture(MAc),emulated acupuncture(EAc),and electro-acupuncture(EA)-like peripheral electrical stimulation(PES).The discharges evoked by MAc and EAc were mostly in a burst pattern with average intra-burst and inter-burst firing rates of 90 Hz and 2 Hz,respectively.The frequency of discharges in PANs was correlated with the frequency of PES.The highest discharge frequency was 246 Hz in Aβ fibers and 180 Hz in Aδ fibers.Therefore,EA in a dense-disperse mode(at alternating frequency between 2 Hz and 15 Hz or between 2 Hz and 100 Hz) best mimics MAc.Frequencies of EA output>250 Hz appear to be obsolete for pain relief.

Is there a primitive reflex residue underlying Marcus Gunn Syndrome? Rat electrophysiology

AIM: To make an electrophysiological demonstration of a possible jaw muscle afferents-oculomotor neural pathway that was proposed by our previous works on rats, which substantiates an early "release hypothesis" on pathogenesis of human Marcus Gunn Syndrome(MGS). METHODS: Extracellular unit discharge recording was applied and both orthodromic and spontaneous unitary firing were recorded in the oculomotor nucleus(III), and the complex of pre-oculomotor interstitial nucleus of Cajal and Darkschewitsch nucleus(INC/DN), following electric stimulation of the ipsilateral masseter nerve(MN) in rats. RESULTS: Extracellular orthodromic unit discharges, with latencies of 3.7±1.3 and 4.7±2.9 ms, were recorded unilaterally in the III, and the INC/DN neurons, respectively. Spontaneous unit discharges were also recorded mostly in the INC/DN and less frequently in the III. Train stimulation could prompt either facilitation or inhibition on those spontaneous unit discharges. The inhibition pattern of train stimulation on the spontaneous discharging was rather different in the III and INC/DN. A slow inhibitory pattern in which spontaneous firing rate decreased further and further following repeated train stimulation was observed in the III. While, some high spontaneous firing rate units, responding promptly to the train stimuli with a short-term inhibition and recovered quickly when stimuli are off, were recorded in the INC/DN. However, orthodromic unit discharge was not recorded in the III and INC/DN in a considerable number of experiment animals. CONCLUSION: A residual neuronal circuit might exist in mammals for the primitive jaw-eyelid reflex observed in amphibians, which might not be well-developed in all experimental mammals in current study. Nonetheless, this pathway can be still considered as a neuroanatomic substrate for development of MGS in some cases among all MGS with different kind of etiology.

Fast time-division color electroholography using a multiple-graphics processing unit cluster system with a single spatial light modulator

We demonstrate fast time-division color etectroholography using a multiple-graphics-processing-unit （GPU） cluster system with a spatial light modulator and a controller to switch the color of the reconstructing light. The controller comprises a universal serial bus module to drive the liquid crystal optical shutters. By using the controller, the computer-generated hologram （CGH） display node of the multiple-GPU cluster system synchronizes the display of the CGH with the color switching of the reconstructing light. Fast time-division color electroholography at 20 fps is realized for a three-dimensional object comprising 21,000 points per color when 13 GPUs are used in a multiple-GPU cluster system.

Photoinduced RAFT Step-Growth Polymerization toward Degradable Living Polymer Networks

The application of reversible degenerative radical polymerization(RDRP)in the construction of polymer networks(PNs)provides a facile and convenient way to fabricate 3D objects with the ability to be posttransformed.However,the polymerization mechanism mainly relies on chain-growth polymerization,which limits its wide application for various polymeric materials with different functionalities.

Response properties of the electrosensory neurons in hindbrain of the white sturgeon,Acipenser transmontanus

Objective The passive electrosense is a primitive sensory modality in the Chondrostei, which include sturgeon and paddlefish. Using electroreceptors, these fish detect the weak electric fields from other animals or geoelectric sources, and use this information for prey detection or other behaviors. The primary afferent fibers innervating the electroreceptors project to a single hindbrain target called the dorsal octavolateral nucleus （DON）, where the electrosensory information is first processed. Here, we investigated the electrophysiological properties of DON neurons. Methods Extracellular recording was used to investigate the response properties of DON neurons to dipole electric fields with different amplitudes and frequencies in the white sturgeon, Acipenser transmontanus. Results The DON neurons showed regular spontaneous activity and could be classified into two types： neurons with a low spontaneous rate （〈10 Hz） and those with a high spon- taneous rate （〉10 Hz）. In response to sinusoidal electric field stimuli, DON neurons showed sinusoidally-modulated and phase-locked firing. In addition, neurons showed opposite phase responses corresponding to the different directions of the dipole. Conclusion The response properties of DON neurons match the electrosensory biological function in sturgeon, as they match the characteristics of the electric fields of its prey.

Effects of pallidal neurotensin on haloperidol-induced parkinsonian catalepsy: behavioral and electrophysiological studies

Objective The globus pallidus plays a critical role in movement regulation. Previous studies have indicated that the globus pallidus receives neurotensinergic innervation from the striatum, and systemic administration of a neurotensin analog could produce antiparkinsonian effects. The present study aimed to investigate the effects of pallidal neurotensin on haloperidol-induced parkinsonian symptoms. Methods Behavioral experiments and electrophysiological recordings were performed in the present study. Results Bilateral infusions of neurotensin into the globus pallidus reversed haloperidolinduced parkinsonian catalepsy in rats. Electrophysiological recordings showed that microinjection of neurotensin induced excitation of pallidal neurons in the presence of systemic haloperidol administration. The neurotensin type-1 receptor antagonist SR48692 blocked both the behavioral and the electrophysiological effects induced by neurotensin. Conclusion Activation of pallidal neurotensin receptors may be involved in neurotensin-induced antiparkinsonian effects.

Precise Pentamers with Diverse Monomer Sequences and Their Thermal Properties

Sequenced-defined oligomer has been emerged as one of the hot topics in polymer chemistry due to its capability of precisely controlling both chain length and monomer sequence.Recent efforts have focused on development of synthetic methodologies using state-ofthe-art chemistry tools.However,investigating the impact of minor changes in monomer sequence on physical properties of these materials is still underdeveloped.Herein,four sequenced pentamers are synthesized by a reversible addition-fragmentation chain transfer(RAFT)single unit monomer insertion technique,in which a base pentamer possesses a relatively rigid backbone comprising of five cyclic monomer units.One of the cyclic units in this base pentamer is replaced by an acyclic monomer at different locations(the 1st,3rd and 5th unit)to produce three modified pentamers,which leads to a significant decrease of glass transition temperature(Tg)compared to the base pentamer.Meanwhile,the modified pentamers with identical primary structures but distinct monomer sequences also present different Tg values depending on the position of the acyclic monomer unit.The middle(3rd)position of the acyclic unit causes profound decrease of Tg due to its increased molecular flexibility.These synthetic pentamers have been demonstrated to be excellent oligomeric plasticizers to modulate thermal transitions of bulk polymer materials.

Modulation of firing activity by endogenous GABA_A receptors in the globus pallidus of MPTP-treated parkinsonian mice

The globus pallidus in rodents,equivalent to the external segment of the globus pallidus in primates,plays an important role in movement regulation.Previous studies have shown abundant γ-aminobutyric acid（GABA）ergic innervation and GABAA receptors in the globus pallidus.In this study,we investigated the effects of endogenous GABAA receptors on the spontaneous firing activity of pallidal neurons in both normal and MPTP-treated mice using multi-barrel electrodes extracellular recordings in vivo.We found that in normal mice,pressure ejection of 0.1 mmol/L gabazine,a specific GABA A receptor antagonist,increased the spontaneous firing rate of globus pallidus neurons by 27.6 ± 5.6%.Furthermore,in MPTP mice（14 days after MPTP treatment）,0.1 mmol/L gabazine increased the firing rates by 51.0 ± 7.9%,significantly greater than in normal mice.These results suggest that endogenous GABAA receptors modulate the activity of globus pallidus neurons.The present findings may provide a rationale for investigations into the potential role of GABAA receptors in Parkinson’s disease.