Current advances in biomaterials for inner ear cell regeneration

Inner ear cell regeneration from stem/progenitor cells provides potential therapeutic strategies for the restoration of sensorineural hearing loss (SNHL), however, the efficiency of regeneration is low and the functions of differentiated cells are not yet mature. Biomaterials have been used in inner ear cell regeneration to construct a more physiologically relevant 3D culture system which mimics the stem cell microenvironment and facilitates cellular interactions. Currently, these biomaterials include hydrogel, conductive materials, magneto-responsive materials, photo-responsive materials, etc. We analyzed the characteristics and described the advantages and limitations of these materials. Furthermore, we reviewed the mechanisms by which biomaterials with different physicochemical properties act on the inner ear cell regeneration and depicted the current status of the material selection based on their characteristics to achieve the reconstruction of the auditory circuits. The application of biomaterials in inner ear cell regeneration offers promising opportunities for the reconstruction of the auditory circuits and the restoration of hearing, yet biomaterials should be strategically explored and combined according to the obstacles to be solved in the inner ear cell regeneration research.

[Research on the establishment of standard limits for perfluorooctanoic acid and perfluorooctane sulfonate in the "Standards for Drinking Water Quality（GB5749-2022）"in China]

Perfluorinated compounds, especially Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are widely detected in water environments in China. Considering the potential health risks of drinking water exposure routes, PFOA and PFOS have been added to the water quality reference index of the newly issued "Standards for Drinking Water Quality (GB5749-2022)", with limit values of 40 and 80 ng/L, respectively. This study analyzed and discussed the relevant technical contents for determining the limits of the hygiene standard, including the environmental existence level and exposure status of PFOA and PFOS, health effects, derivation of safety reference values, and determination of hygiene standard limits. It also proposed prospects for the future direction of formulating drinking water standards.

[Research on the determination of the limit value of perchlorate in the "Standards for Drinking Water Quality（GB5749-2022）" in China]

Perchlorate is an environmental pollutant that has been a focus of attention in recent years. It has been detected in many environmental water bodies and drinking water in China, with a high level of presence in some areas of the Yangtze River Basin. The human body may ingest perchlorate through exposure pathways such as drinking water and food, and its main health effect is to affect the thyroid's absorption of iodine. The "Standards for Drinking Water Quality" (GB5749-2022) includes perchlorate as an expanded indicator of water quality, with a limit value of 0.07 mg/L. This article analyzes the technical content related to the determination of hygiene standard limits for perchlorate in drinking water, including the environmental presence level and exposure status of perchlorate, main health effects, derivation of safety reference values, and determination of hygiene standard limits.

[Effect of CKIP-1 on hepatocyte apoptosis in nonalcoholic fatty liver disease]

Objective: To explore the effect and underlying mechanism of casein kinase 2 interacting protein-1 (CKIP-1) on hepatocyte apoptosis in nonalcoholic fatty liver disease (NAFLD). Methods: Experimental study. An NAFLD cell model was established by inducing human hepatoma cell line, HepG₂ cells, with oleic acid (OA). Flag-CKIP-1 expression vector and shRNA-CKIP-1 were transfected into HepG₂ cells. Flow cytometry was used to detect the effect of CKIP-1 on the activity and apoptosis of NAFLD hepatocytes. The levels of apoptosis-related proteins were detected by Western blot. CKIP-1 knockout mice in C57BL/6 back-ground were fed with either standard or high-fat diet for 8 weeks. Apoptosis-related signal proteins in NAFLD hepatocytes were detected by immunohistochemistry. Results: After CKIP-1 was transfected into HepG₂ cells, the degree of OA induced cell liposis was significantly reduced (P<0.05). Annexin V-FITC/PI flow cytometry showed that CKIP-1 reduced the apoptosis of steatotic hepatocytes. Overexpression of CKIP-1 could significantly inhibit the expression of caspase-3 and caspase-9 and increase the expression of Bcl-2/Bax (P<0.05). Knockdown of CKIP-1 could increase the expression of caspase-3 and caspase-9 (P<0.05). CKIP-1 knockout could further increase the expression of caspase-3 and caspase-9 in NAFLD mice (P<0.01,P<0.05), and further decrease the expression of Bcl-2/Bax (P<0.05). Conclusion: CKIP-1 inhibited the apoptosis of steatotic hepatocytes by up-regulating the expression of apoptosis inhibitor gene, Bcl-2/Bax, and affecting the proteases, caspase-3 and caspase-9.

Betatron radiation and emittance growth in plasma wakefield accelerators

Beam-driven plasma wakefield acceleration (PWFA) has demonstrated significant progress during the past two decades of research. The new Facility for Advanced Accelerator Experimental Tests (FACET) II, currently under construction, will provide 10 GeV electron beams with unprecedented parameters for the next generation of PWFA experiments. In the context of the FACET II facility, we present simulation results on expected betatron radiation and its potential application to diagnose emittance preservation and hosing instability in the upcoming PWFA experiments. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Producing multi-coloured bunches through beam-induced ionization injection in plasma wakefield accelerator

This paper discusses the properties of electron beams formed in plasma wakefield accelerators through ionization injection. In particular, the potential for generating a beam composed of co-located multi-colour beamlets is demonstrated in the case where the ionization is initiated by the evolving charge field of the drive beam itself. The physics of the processes of ionization and injection are explored through OSIRIS simulations. Experimental evidence showing similar features are presented from the data obtained in the E217 experiment at the FACET facility of the SLAC National Laboratory. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Multicentre comparative study of Z-shape elevating-pulling reduction and skull traction reduction for treatment of lower cervical locked facets

PURPOSE

The aim of this study was to assess the clinical efficacy and safety of Z-shape elevating-pulling reduction as compared to that of conventional skull traction in the treatment of lower cervical locked facet.

METHODS

Patients with cervical locked facet (n = 63) were retrospectively enrolled from four medical centers and divided into two groups according to the pre-operative reduction method used: Z-shape elevating-pulling reduction (Z-shape elevating group; n = 20) or traditional skull traction reduction (skull traction group; n = 43).

RESULTS

The success rates, efficacy of reduction, and safety were compared between the two groups. The success rates were significantly better in the Z-shape elevating group than in the skull traction group: 87.5% (7/8) vs. 35.3% (6/17) for unilateral locked facet reduction (P = 0.03) and 100% (12/12) vs. 69.2% (18/26) for bilateral locked facet reduction (P = 0.04). There was no obvious change in American Spinal Injury Association (ASIA) grade after the reduction in either group. Combined surgery was necessary in 5% in the Z-shape elevating group vs. 27.9% in the skull traction group. Imaging showed that the segment angle and horizontal displacement were significantly improved after surgery in both groups, with no significant difference between the groups. Follow-up with radiography showed good recovery of the cervical spine sequence; all internal fixation sites were stable, with no loosening, prolapse, or breakage of internal fixators.

CONCLUSIONS

Halo vest-assisted Z-shape elevating-pulling reduction appears to be a simple, safe, and effective technique for pre-operative reduction of lower cervical locked facets.

Measurement of Transverse Wakefields Induced by a Misaligned Positron Bunch in a Hollow Channel Plasma Accelerator

Hollow channel plasma wakefield acceleration is a proposed method to provide high acceleration gradients for electrons and positrons alike: a key to future lepton colliders. However, beams which are misaligned from the channel axis induce strong transverse wakefields, deflecting beams and reducing the collider luminosity. This undesirable consequence sets a tight constraint on the alignment accuracy of the beam propagating through the channel. Direct measurements of beam misalignment-induced transverse wakefields are therefore essential for designing mitigation strategies. We present the first quantitative measurements of transverse wakefields in a hollow plasma channel, induced by an off-axis 20 GeV positron bunch, and measured with another 20 GeV lower charge trailing positron probe bunch. The measurements are largely consistent with theory.

Acceleration of a trailing positron bunch in a plasma wakefield accelerator

High gradients of energy gain and high energy efficiency are necessary parameters for compact, cost-efficient and high-energy particle colliders. Plasma Wakefield Accelerators (PWFA) offer both, making them attractive candidates for next-generation colliders. In these devices, a charge-density plasma wave is excited by an ultra-relativistic bunch of charged particles (the drive bunch). The energy in the wave can be extracted by a second bunch (the trailing bunch), as this bunch propagates in the wake of the drive bunch. While a trailing electron bunch was accelerated in a plasma with more than a gigaelectronvolt of energy gain, accelerating a trailing positron bunch in a plasma is much more challenging as the plasma response can be asymmetric for positrons and electrons. We report the demonstration of the energy gain by a distinct trailing positron bunch in a plasma wakefield accelerator, spanning nonlinear to quasi-linear regimes, and unveil the beam loading process underlying the accelerator energy efficiency. A positron bunch is used to drive the plasma wake in the experiment, though the quasi-linear wake structure could as easily be formed by an electron bunch or a laser driver. The results thus mark the first acceleration of a distinct positron bunch in plasma-based particle accelerators.

Phylogenetic analysis of the Mongolian gerbil (Meriones unguiculatus) from China based on mitochondrial genome

Meriones unguiculatus (Gerbillinae, Rodentia) is widely used as an animal model of human disease. Here, we provide the first report of the complete mitochondrial genome sequence of M. unguiculatus (GenBank accession Nos. KF425526 and NC_023263). The sequence contained the conserved vertebrate pattern of 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and 1 major noncoding region. We identified one extended termination-associated sequence and one conserved sequence block in the non-coding region. The putative origin of replication for the light strand (O_L) was 35 bp long. The O_L stem and adjacent sequences were highly conserved, but the loop region differed from those of other rodent species. Base composition and codon usage of the 13 protein-coding genes in M. unguiculatus were compared with those of 23 rodent species with previously sequenced mitochondrial genomes. An A+T content of 63.0% was present in M. unguiculatus; this is similar to the Murinae average (62.4 ± 0.8%) and falls between the average for Mus musculus (63.1 ± 0.1%) and Rattus sp (61.7 ± 0.4%). The AT and GC skew values of M. unguiculatus were 0.035 and -0.28, respectively, similar to those of Cricetinae species (0.057 ± 0.05 and -0.31 ± 0.05). The codon families exhibited similar abundance in all 24 species. Analysis of phylogenetic relationships with 23 other rodent species using neighbor-joining and maximum likelihood protocols and the 12 protein-coding regions on the H strand showed that M. unguiculatus should be classified as genus Meriones, sub-family Gerbillinae, family Muridae.

Self-mapping the longitudinal field structure of a nonlinear plasma accelerator cavity

The preservation of emittance of the accelerating beam is the next challenge for plasma-based accelerators envisioned for future light sources and colliders. The field structure of a highly nonlinear plasma wake is potentially suitable for this purpose but has not been yet measured. Here we show that the longitudinal variation of the fields in a nonlinear plasma wakefield accelerator cavity produced by a relativistic electron bunch can be mapped using the bunch itself as a probe. We find that, for much of the cavity that is devoid of plasma electrons, the transverse force is constant longitudinally to within ±3% (r.m.s.). Moreover, comparison of experimental data and simulations has resulted in mapping of the longitudinal electric field of the unloaded wake up to 83 GV m(-1) to a similar degree of accuracy. These results bode well for high-gradient, high-efficiency acceleration of electron bunches while preserving their emittance in such a cavity.

Nanoscale Electron Bunching in Laser-Triggered Ionization Injection in Plasma Accelerators

Ionization injection is attractive as a controllable injection scheme for generating high quality electron beams using plasma-based wakefield acceleration. Because of the phase-dependent tunneling ionization rate and the trapping dynamics within a nonlinear wake, the discrete injection of electrons within the wake is nonlinearly mapped to a discrete final phase space structure of the beam at the location where the electrons are trapped. This phenomenon is theoretically analyzed and examined by three-dimensional particle-in-cell simulations which show that three-dimensional effects limit the wave number of the modulation to between >2k_{0} and about 5k_{0}, where k_{0} is the wave number of the injection laser. Such a nanoscale bunched beam can be diagnosed by and used to generate coherent transition radiation and may find use in generating high-power ultraviolet radiation upon passage through a resonant undulator.

Physics of Phase Space Matching for Staging Plasma and Traditional Accelerator Components Using Longitudinally Tailored Plasma Profiles

Phase space matching between two plasma-based accelerator (PBA) stages and between a PBA and a traditional accelerator component is a critical issue for emittance preservation. The drastic differences of the transverse focusing strengths as the beam propagates between stages and components may lead to a catastrophic emittance growth even when there is a small energy spread. We propose using the linear focusing forces from nonlinear wakes in longitudinally tailored plasma density profiles to control phase space matching between sections with negligible emittance growth. Several profiles are considered and theoretical analysis and particle-in-cell simulations show how these structures may work in four different scenarios. Good agreement between theory and simulation is obtained, and it is found that the adiabatic approximation misses important physics even for long profiles.

Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield

Electrical breakdown sets a limit on the kinetic energy that particles in a conventional radio-frequency accelerator can reach. New accelerator concepts must be developed to achieve higher energies and to make future particle colliders more compact and affordable. The plasma wakefield accelerator (PWFA) embodies one such concept, in which the electric field of a plasma wake excited by a bunch of charged particles (such as electrons) is used to accelerate a trailing bunch of particles. To apply plasma acceleration to electron-positron colliders, it is imperative that both the electrons and their antimatter counterpart, the positrons, are efficiently accelerated at high fields using plasmas. Although substantial progress has recently been reported on high-field, high-efficiency acceleration of electrons in a PWFA powered by an electron bunch, such an electron-driven wake is unsuitable for the acceleration and focusing of a positron bunch. Here we demonstrate a new regime of PWFAs where particles in the front of a single positron bunch transfer their energy to a substantial number of those in the rear of the same bunch by exciting a wakefield in the plasma. In the process, the accelerating field is altered--'self-loaded'--so that about a billion positrons gain five gigaelectronvolts of energy with a narrow energy spread over a distance of just 1.3 metres. They extract about 30 per cent of the wake's energy and form a spectrally distinct bunch with a root-mean-square energy spread as low as 1.8 per cent. This ability to transfer energy efficiently from the front to the rear within a single positron bunch makes the PWFA scheme very attractive as an energy booster to an electron-positron collider.

Facilitatory and inhibitory effects of Kinesio tape: Fact or fad?

OBJECTIVES

Kinesio tape (KT) is a commonly used intervention in sports. It claims to be able to alter the muscle activity, in terms of both facilitation and inhibition, by certain application methods. This study compared the neuromuscular activity of the wrist extensor muscles and maximal grip strength with facilitatory, inhibitory KT, and tapeless condition in healthy adults who were ignorant about KT. Potential placebo effects were eliminated by deception.

DESIGN

Randomized deceptive trial.

METHODS

33 participants performed maximal grip assessment in a randomly assigned order of three taping conditions: true facilitatory KT, inhibitory KT, and no tape. The participants were blindfolded during the evaluation. Under the pretense of applying a series of adhesive muscle sensors, KT was applied to their wrist extensor muscles of the dominant forearm in the first two conditions. Within-subject comparisons of normalized root mean square of the wrist extensors electromyographic activity and maximal grip strength were conducted across three taping conditions.

RESULTS

31 out of 33 enlisted participants were confirmed to be ignorant about KT. No significant differences were found in the maximum grip strength (p=0.394), electromyographic activity (p=0.276), and self-perceived performance (p=0.825) between facilitatory KT, inhibitory KT, and tapeless conditions.

CONCLUSIONS

Neither facilitatory nor inhibitory effects were observed between different application techniques of KT in healthy participants. Clinically, alternative method should be used for muscle activity modulation.

Phase-space dynamics of ionization injection in plasma-based accelerators

The evolution of beam phase space in ionization injection into plasma wakefields is studied using theory and particle-in-cell simulations. The injection process involves both longitudinal and transverse phase mixing, leading initially to a rapid emittance growth followed by oscillation, decay, and a slow growth to saturation. An analytic theory for this evolution is presented and verified through particle-in-cell simulations. This theory includes the effects of injection distance (time), acceleration distance, wakefield structure, and nonlinear space charge forces, and it also shows how ultralow emittance beams can be produced using ionization injection methods.

Beam loading by distributed injection of electrons in a plasma wakefield accelerator

We show through experiments and supporting simulations that propagation of a highly relativistic and dense electron bunch through a plasma can lead to distributed injection of electrons, which depletes the accelerating field, i.e., beam loads the wake. The source of the injected electrons is ionization of the second electron of rubidium (Rb II) within the wake. This injection of excess charge is large enough to severely beam load the wake, and thereby reduce the transformer ratio T. The reduction of the average T with increasing beam loading is quantified for the first time by measuring the ratio of peak energy gain and loss of electrons while changing the beam emittance. Simulations show that beam loading by Rb II electrons contributes to the reduction of the peak accelerating field from its weakly loaded value of 43  GV/m to a strongly loaded value of 26  GV/m.