Physical Mechanism of the Transverse Instability in Radiation Pressure Ion Acceleration

The transverse stability of the target is crucial for obtaining high quality ion beams using the laser radiation pressure acceleration (RPA) mechanism. In this Letter, a theoretical model and supporting two-dimensional (2D) particle-in-cell (PIC) simulations are presented to clarify the physical mechanism of the transverse instability observed in the RPA process. It is shown that the density ripples of the target foil are mainly induced by the coupling between the transverse oscillating electrons and the quasistatic ions, a mechanism similar to the oscillating two stream instability in the inertial confinement fusion research. The predictions of the mode structure and the growth rates from the theory agree well with the results obtained from the PIC simulations in various regimes, indicating the model contains the essence of the underlying physics of the transverse breakup of the target.

Adolescent and Young Adult Cancer Survivors' Perspectives on Their Internet Use for Seeking Information on Healthy Eating and Exercise

PURPOSE

To explore adolescent and young adult (AYA) cancer survivors' internet use in seeking healthy lifestyle behavior (HLB) information on diet and exercise.

METHODS

Twenty-five AYA cancer survivors participated in focus groups or interviews. Data were analyzed using qualitative content analysis.

RESULTS

Most survivors (92%) sought HLB information from internet sources. Key issues included the following: (1) too much information available, (2) information not meeting survivors' unique needs, and (3) concerns about trustworthiness of information.

CONCLUSION

Although AYA cancer survivors use the internet to seek HLB information, internet resources could be modified to better meet the needs of AYA cancer survivors.

[Effects of microporous polysaccharide on foreign body reaction induced by subcutaneously imbedding expanded polytetrafluoroethylene in mice]

Objective: To observe the effects of early applying of microporous polysaccharide on foreign body reaction induced by subcutaneously imbedding expanded polytetrafluoroethylene (e-PTFE) in mice. Methods: Ten wide type adult C57BL/6J mice were collected and made a full-thickness skin incision on both sides of their back. The two incisions on the back of each mouse were divided into two groups according the random number table, with 10 incisions in each group. A tube-shaped e-PTFE was imbedded into each incision in microporous polysaccharide group, and then 0.03 g microporous polysaccharide was evenly sprayed in the cavity. Whereas, a tube-shaped e-PTFE was imbedded into each incision in control group without other treatment. The incisions in two groups were performed with conventional full-thickness suture. On post operation day (POD) 14, the e-PTFE surrounded with fibrous capsule in each incision of two groups was taken out, and then fibrous capsule tissue was harvested. The thickness of fibrous capsule was observed and measured with HE staining. Collagen fiber distribution in fibrous capsule tissue was observed with Masson staining to calculate the collagen fiber index. Neovascularization and macrophage infiltration in fibrous capsule tissue were observed respectively with immunohistochemical staining, and the numbers of new vessels and macrophages were counted. Data were processed with t test. Results: On POD 14, the thickness of fibrous capsule surrounding e-PTFE imbedded into the incision of microporous polysaccharide group was (127±19) μm, which was significantly thinner than that of control group [(250±35) μm, t=4.13, P<0.05]. On POD 14, the collagen fiber index of fibrous capsule tissue surrounding e-PTFE imbedded into the incision of microporous polysaccharide group was 0.500±0.003, which was significantly higher than that of control group (0.488±0.004, t=5.00, P<0.05). On POD 14, the number of new vessels in fibrous capsule tissue surrounding e-PTFE imbedded into the incision of microporous polysaccharide group was 19±3 per 400 fold visual field, which was significantly more than that of control group (11±3 per 400 fold visual field, t=2.05, P<0.05). On POD 14, the number of macrophages in fibrous capsule tissue surrounding e-PTFE imbedded into the incision of microporous polysaccharide group was 64±5 per 400 fold visual field, which was close to that of control group (66±7 per 400 fold visual field, t=0.78, P>0.05). Conclusions: Topically applying microporous polysaccharide can reduce the formation of fibrous capsule after subcutaneous imbedding of e-PTFE in mice, and it can improve the collagen deposition and angiogenesis but not impact on macrophage infiltration.

Barriers to follow-up care among survivors of adolescent and young adult cancer

PURPOSE

Though the need for risk-based follow-up care for survivors of adolescent and young adult (AYA) cancer has been documented, survivors often report forgoing recommended care due to cost. We sought to understand whether additional barriers to follow-up care exist for AYA survivors.

METHODS

We recruited survivors who were diagnosed with cancer between the ages of 15 and 39 using the Utah Cancer Registry (UCR). Overall, 28 survivors participated in 6 focus groups held between March and May 2015 in Salt Lake City and St. George, UT. Focus group discussions focused on the reasons survivors may or may not attend recommended medical visits after completing therapy.

RESULTS

Survivors reported myriad barriers to follow-up medical visits, including lack of clear provider recommendation, fear of recurrent cancer diagnosis, wishing to move on with life, competing life responsibilities due to work and children, and not perceiving the need for a visit due to lack of symptoms.

CONCLUSIONS

Though cost likely plays a major part in follow-up care adherence for survivors of AYA cancer, in our focus groups, participants indicated there were many other psychosocial and logistic barriers to care. Such factors play an important role in the day-to-day lives of survivors and are critical in medical decision-making.

IMPLICATIONS FOR CANCER SURVIVORS

Several factors impede follow-up care adherence for survivors of AYA cancer that are amenable to interventions, including clearer provider recommendations, flexible appointment times, and childcare availability in clinics.

A multisite evaluation of summer camps for children with cancer and their siblings

Summer camps for pediatric cancer patients and their families are ubiquitous. However, there is relatively little research, particularly studies including more than one camp, documenting outcomes associated with children's participation in summer camp. The current cross-sectional study used a standardized measure to examine the role of demographic, illness, and camp factors in predicting children's oncology camp-related outcomes. In total, 2,114 children at 19 camps participated. Campers were asked to complete the pediatric camp outcome measure, which assesses camp-specific self-esteem, emotional, physical, and social functioning. Campers reported high levels of emotional, physical, social, and self-esteem functioning. There were differences in functioning based on demographic and illness characteristics, including gender, whether campers/siblings were on or off active cancer treatment, age, and number of prior years attending camp. Results indicated that summer camps can be beneficial for pediatric oncology patients and their siblings, regardless of demographic factors (e.g., gender, treatment status) and camp factors (e.g., whether camp sessions included patients only, siblings only, or both). Future work could advance the oncology summer camp literature by examining other outcomes linked to summer camp attendance, using longitudinal designs, and including comparison groups.

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.

Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe

A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.

A systematic review of interventions to improve adherence to melanoma preventive behaviors for individuals at elevated risk

BACKGROUND AND OBJECTIVES

To examine the effectiveness of behavioral interventions for melanoma prevention targeted to individuals at elevated risk due to personal and/or family history.

METHODS

Through literature searches in 5 search databases (through July 2014), 20 articles describing 14 unique interventions focused on melanoma prevention among individuals at elevated risk for the disease were identified. Interventions targeting only patients undergoing active treatment for melanoma were excluded.

RESULTS

The average study quality was moderate. The majority of interventions (6 out of 9, 66% of studies) led to improvements in one or more photoprotective behaviors, particularly for improvements in use of protective clothing (3 out of 5, 60% of studies), and frequency and/or thoroughness of skin self-examinations (9 out of 12, 75%). Fewer interventions (5 out of 14, 36%) targeted uptake of total body skin examinations (60% led to improvements). Also, fewer interventions targeted all three preventive behaviors (5 out of 14, 36%).

CONCLUSIONS

Findings suggest that future interventions should aim to improve adherence across multiple preventive behaviors, over a longer time period (past 8months post-intervention), and target high-risk children. Studies should include adequate sample sizes to investigate moderators and mediators of intervention effectiveness. Interventions may be strengthened by new techniques, such as incorporating family members (e.g., to improve thoroughness of skin self-examinations) and eHealth technology.

Commentary: Writing and Evaluating Qualitative Research Reports

OBJECTIVE

To provide an overview of qualitative methods, particularly for reviewers and authors who may be less familiar with qualitative research.

METHODS

A question and answer format is used to address considerations for writing and evaluating qualitative research.

RESULTS AND CONCLUSIONS

When producing qualitative research, individuals are encouraged to address the qualitative research considerations raised and to explicitly identify the systematic strategies used to ensure rigor in study design and methods, analysis, and presentation of findings. Increasing capacity for review and publication of qualitative research within pediatric psychology will advance the field's ability to gain a better understanding of the specific needs of pediatric populations, tailor interventions more effectively, and promote optimal health.

Emergent Kondo Lattice Behavior in Iron-Based Superconductors AFe_{2}As_{2} (A=K, Rb, Cs)

Here, we experimentally study the origin of d-electron heavy fermion (HF) behavior in iron-based superconductors (FeSCs) AFe_{2}As_{2} (A=K, Rb, Cs). Nuclear magnetic resonance on ^{75}As reveals a universal coherent-incoherent crossover with a characteristic temperature T^{*}. Below T^{*}, a so-called "Knight shift anomaly" is first observed in FeSCs, which exhibits a scaling behavior similar to f-electron HF materials. Furthermore, the scaling rule also regulates the manifestation of magnetic fluctuation. These results undoubtedly support an emergent Kondo lattice scenario for the d-electron HF behavior, which qualifies the AFe_{2}As_{2} (A=K, Rb, Cs) as d-electron HF superconductors.

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.

Discussion of photoprotection, screening, and risk behaviors with children and grandchildren after melanoma genetic testing

The purpose of the current study was to examine changes in frequency of discussion about melanoma preventive behaviors among adults who received melanoma genetic test reporting and counseling and their children and grandchildren, correspondence of frequency of discussion with intentions, and content of discussions. Participants received CDKN2A/p16 testing and counseling (N = 24, 46 % p16-positive). Discussions about preventive behaviors were assessed before testing and 1 and 6 months post-testing. Intentions to discuss preventive behaviors and perceived preparedness to discuss risk were assessed post-testing. Open-ended questions assessed content of reported discussions. Discussion of preventive behaviors declined following test reporting, with more rapid decline reported by noncarriers. There was a large gap between the percentage of participants who intended to discuss preventive behaviors and who then reported discussions 1 and 6 months after counseling. Participants felt prepared to discuss melanoma risk but also suggested resources to facilitate discussions. Genetic test reporting and counseling alone did not sustain discussions about preventive behaviors for a hereditary cancer with children and grandchildren. The gap between intentions to have discussions and reported discussions has implications for augmentation of counseling to support at-risk families' discussions about preventive behaviors.

An Assessment to Inform Pediatric Cancer Provider Development and Delivery of Survivor Care Plans

Current guidelines recommend all pediatric cancer survivors receive a survivor care plan (SCP) for optimal health management, yet clinical delivery of SCPs varies. We evaluated oncology providers' familiarity with and preferences for delivering SCPs to inform the implementation of a future SCP program at our institution. From November 2013 to April 2014, oncology providers from the Primary Children's Hospital in Salt Lake City, UT, completed a survey (n=41) and a 45-min focus group (n=18). Participants reported their familiarity with and training in SCP guidelines, opinions on SCPs, and barriers to delivering SCPs. As a secondary analysis, we examined differences in survey responses between physicians and nurses with Fisher's exact tests. Focus group transcripts and open-ended survey responses were content analyzed. Participants reported high familiarity with late effects of cancer treatment (87.8%) and follow-up care that cancer survivors should receive (82.5%). Few providers had delivered an SCP (oncologists 35.3% and nurses 5.0%; p=0.03). Barriers to providing SCPs included lack of knowledge (66.7%), SCP delivery is not expected in their clinic (53.9%), and no champion (48.7%). In qualitative comments, providers expressed that patient age variation complicated SCP delivery. Participants supported testing an SCP intervention program (95.1%) and felt this should be a team-based approach. Strategies for optimal delivery of SCPs are needed. Participants supported testing an SCP program to improve the quality of patient care. Team-based approaches, including nurses and physicians, that incorporate provider training on and support for SCP delivery are needed to improve pediatric cancer care.

Barriers and Facilitators of Healthy Diet and Exercise Among Adolescent and Young Adult Cancer Survivors: Implications for Behavioral Interventions

PURPOSE

This study uses qualitative methods to identify barriers to and facilitators of exercise and healthy eating among adolescent and young adult (AYA) cancer survivors (survivors currently aged 18-39 years and diagnosed with cancer anytime in their lives), as reported by survivors and their primary supporters.

METHODS

Survivors (M(age) = 27.6 years, SD = 6.6 years) had completed active cancer therapy. Survivors and supporters (i.e., nominated by survivors as someone who was a main source of support) attended separate focus group sessions (five survivor focus groups, five supporter focus groups) and were asked to complete a self-reported questionnaire assessing demographic and cancer history and engagement in exercise and healthy eating.

RESULTS

In total, 25 survivors and 19 supporters participated. The three overarching themes identified were barriers to exercise and healthy eating (e.g., lack of resources, negative thoughts and feelings, negative social and environmental influences), facilitators of exercise and healthy eating (e.g., cognitive motivators, tools for health behavior implementation, social relationships), and intervention implications (e.g., informational needs, desire for social support).

CONCLUSION

AYA cancer survivors and their supporters identified barriers to and facilitators of healthy lifestyle behaviors, which should be considered when designing interventions to improve the long-term health of survivors.

First Principles Study on the Electronic Structure and Interface Stability of Hybrid Silicene/Fluorosilicene Nanoribbons

The interface stability of hybrid silicene/fluorosilicene nanoribbons (SFNRs) has been investigated by using density functional theory calculations, where fluorosilicene is the fully fluorinated silicene. It is found that the diffusion of F atoms at the zigzag and armchair interfaces of SFNRs is endothermic, and the corresponding minimum energy barriers are respectively 1.66 and 1.56 eV, which are remarkably higher than the minimum diffusion energy barrier of one F atom and two F atoms on pristine silicene 1.00 and 1.29 eV, respectively. Therefore, the thermal stability of SFNRs can be significantly enhanced by increasing the F diffusion barriers through silicene/fluorosilicene interface engineering. In addition, the electronic and magnetic properties of SFNRs are also investigated. It is found that the armchair SFNRs are nonmagnetic semiconductors, and the band gap of armchair SFNRs presents oscillatory behavior when the width of silicene part changing. For the zigzag SFNRs, the antiferromagnetic semiconducting state is the most stable one. This work provides fundamental insights for the applications of SFNRs in electronic devices.

Coexistence of superconductivity and antiferromagnetism in (Li0.8Fe0.2)OHFeSe

Iron selenide superconductors exhibit a number of unique characteristics that are helpful for understanding the mechanism of superconductivity in high-Tc iron-based superconductors more generally. However, in the case of AxFe2Se2 (A = K, Rb, Cs), the presence of an intergrown antiferromagnetic insulating phase makes the study of the underlying physics problematic. Moreover, FeSe-based systems intercalated with alkali metal ions, NH3 molecules or organic molecules are extremely sensitive to air, which prevents the further investigation of their physical properties. It is therefore desirable to find a stable and easily accessible FeSe-based superconductor to study its physical properties in detail. Here, we report the synthesis of an air-stable material, (Li0.8Fe0.2)OHFeSe, which remains superconducting at temperatures up to ~40 K, by means of a novel hydrothermal method. The crystal structure is unambiguously determined by a combination of X-ray and neutron powder diffraction and nuclear magnetic resonance. Moreover, antiferromagnetic order is shown to coexist with superconductivity. This synthetic route opens a path for exploring superconductivity in other related systems, and confirms the appeal of iron selenides as a platform for understanding superconductivity in iron pnictides more broadly.

A meta-analysis of body mass index of adolescent and adult survivors of pediatric acute lymphoblastic leukemia

PURPOSE

We conducted a meta-analysis of existing studies to examine body mass index (BMI) of adolescent and adult survivors of pediatric acute lymphoblastic leukemia (ALL) compared to individuals without cancer.

METHODS

Studies were identified and reviewed using specific inclusion criteria. The effect size was odds ratio (OR) of the prevalence of overweight/obese BMI (≥ 25 kg/m(2)) in ALL survivors versus comparison groups. Study data were coded and validated. Fixed-effects (FE) and random-effects (RE) estimates of the effect size were estimated.

RESULTS

A total of 9 studies met our inclusion criteria. Survivors were more likely to be overweight/obese compared to comparison groups (FE OR = 1.12, 95% CI 1.06-1.18 and RE OR = 1.28, 95% CI 1.07-1.53). When limited to studies from North American samples, female survivors were overweight/obese more often than the comparison groups (FE OR = 1.30, 95% CI 1.19-1.43).

CONCLUSIONS

Adolescent and adult survivors of pediatric ALL, especially female survivors, may be at a higher risk of being overweight/obese compared to individuals without cancer. However, few studies provided detailed information on patient and treatment factors (e.g., cranial radiation) that can impact BMI. Standardized reporting of study content is vital for providing robust information on the risk of developing late effects among cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

Adolescent and adult survivors of pediatric ALL require additional weight management resources such as targeted counseling for physical activity and dietician support both early in treatment and after the end of their therapy. Female survivors may need additional guidance to develop healthy eating practices and to participate in exercise programs.

Antiepileptic drug nonadherence predicts pediatric epilepsy seizure outcomes

OBJECTIVE

The aim of the study was to determine sociodemographic, biological epilepsy-specific, and adherence predictors of long-term pediatric seizure outcomes.

METHODS

This study is a prospective, longitudinal, observational study of antiepileptic drug (AED) adherence and seizure outcomes in children with newly diagnosed epilepsy. Patients were recruited from April 2006 to March 2009 and followed for 2 years. Objective, electronic monitors were used to assess AED adherence. Medical chart reviews assessed medical variables and seizure outcomes.

RESULTS

Participants (n = 109) were 7.3 ± 2.9 years of age, and 62% male. Four adherence trajectory groups were identified: severe early nonadherence (n = 10), variable nonadherence (n = 16), moderate nonadherence (n = 40), and high adherence (n = 43). Two seizure probability trajectory groups were identified: high seizure (n = 28) and low seizure probability (n = 81). Participants with recognizable syndromes were less likely to be a member of the high seizure probability group (b = -2.372; odds ratio [OR] = 0.093; 95% confidence interval [CI]OR = 0.015, 0.595); those with the presence of epileptiform discharges on EEG were more likely to be in the high seizure probability group (b = 1.649; OR = 5.203; 95% CIOR = 1.422, 19.037). Adherence trajectory group status was a significant predictor of seizure trajectory group status (partial max-rescaled R(2) = 0.13).

CONCLUSIONS

Adherence trajectories and 2 biological epilepsy-specific variables explain a similar proportion of the variability in longitudinal seizure outcomes. The relationship between AED nonadherence and seizure outcomes is not linear. Early adherence interventions could change the course of seizure outcomes, particularly if variability in adherence was minimized postdiagnosis.

Practice-Based Approach to Assessing and Treating Non-Adherence in Pediatric Regimens

With advances in medical care, youth with chronic illness have the potential for higher quality of life; however, these treatments often come with cost (i.e., burden, financial) that can result in non-adherence. Pediatric non-adherence, on average, is approximately 50% across chronic health conditions. Research has identified effective, evidence-based assessment measures and intervention strategies to promote regimen adherence in youth. Yet, these measures and strategies typically are designed for clinical trials and thus may not be feasible or practical in typical clinic settings. As the field of adherence assessment and intervention expands, it will be important to devise evidence-based tools that are pragmatic and can be translated easily into practice. To guide this future direction, the goals of this paper are to review evidence-based adherence assessment and intervention strategies that can be used with youth and families in clinical practice, to illustrate the complexities of addressing adherence concerns in routine practice, and to discuss the challenges of disseminating and implementing evidence-based strategies in the real world.

Health care provider-delivered adherence promotion interventions: a meta-analysis

BACKGROUND AND OBJECTIVE

Improving medical regimen adherence is essential for maximizing the therapeutic potential of treatments for pediatric chronic illness. Health care providers are uniquely positioned to deliver adherence promotion interventions. However, no studies have summarized the effectiveness of health care provider-delivered adherence interventions. The objective of this study was to describe the effectiveness of health care provider-delivered adherence promotion interventions in improving adherence among children who have chronic illness. Data sources include PubMed, PsycINFO, CINAHL, and Scopus. Studies were included if they were randomized-controlled trials of pediatric interventions aiming to increase adherence to the primary regimen for a chronic illness and at least 1 health care provider delivered the intervention.

RESULTS

A total of 35 randomized-controlled studies including 4616 children were included. Greater improvements in adherence were observed immediately after health care provider-delivered interventions (d = 0.49; 95% confidence interval, 0.32 to 0.66) than at longer-term follow-up (d = 0.32; 95% confidence interval, 0.10 to 0.54). Treatment effect sizes differed across the adherence behaviors measured. There was significant heterogeneity in treatment effects; however, no moderators of treatment effectiveness were identified. This meta-analysis focused on the published literature. In addition, the majority of studies involved children who had asthma and younger children.

CONCLUSIONS

Health care provider-delivered interventions for children who have chronic illness can be effective in improving adherence. Gains in adherence are highest immediately after intervention. Future interventions and studies should include multiple methods of assessing adherence, include active comparators, and address long-term maintenance of adherence gains.

Connexin43 hemichannels mediate small molecule exchange between chondrocytes and matrix in biomechanically-stimulated temporomandibular joint cartilage

OBJECTIVE

Connexin (Cx) 43 hemichannels play a role in mechanotransduction. This study was undertaken in order to determine if Cx43 hemichannels were activated in rat temporomandibular joint (TMJ) chondrocytes under mechanical stimulation.

METHODS

Sprague-Dawley rats were stimulated dental-mechanically. Cx43 expression in rat TMJ cartilage was determined with immunohistochemistry and real-time PCR, and Cx43 hemichannel opening was evaluated by the extra- and intracellular levels of prostaglandin E2 (PGE2). Both primary rat chondrocytes and ATDC5 cells were treated with fluid flow shear stress (FFSS) to induce hemichannel opening. The Cx43 expression level was then determined by real-time PCR or Western blotting, and the extent of Cx43 hemichannel opening was evaluated by measuring both PGE2 release and cellular dye uptake.

RESULTS

Cx43 expression and intra- and extracellular PGE2 levels were increased in mechanically-stimulated rat TMJ cartilage compared to the unstimulated control. The FFSS treatment increased Cx43 expression and induced Cx43 hemichannel opening in primary rat chondrocytes and ATDC5 cells indicated by enhanced PGE2 release and dye uptake. Furthermore, the Cx43 hemichannel opening could be blocked by the addition of 18β-glycyrrhetinic acid, a Cx channel inhibitor, Cx43-targeting siRNA, or by withdrawal of FFSS stimulation. The migration of cytosolic Cx43 protein to the plasma membrane in ATDC5 cells was still significant after 8 h post 2-h FFSS treatment, and the Cx43 protein level was still high at 48 h, which returned to control levels at 72 h after treatment.

CONCLUSION

Cx43 hemichannels are activated and mediate small molecule exchange between TMJ chondrocytes and matrix under mechanical stimulation.