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Fragment yields for Z ≥ 5 from projectile fragmentation using primary beams of 36,40Ar at 50 MeV/nucleon on 64Ni target have been measured in RIBLL fragment separator. We compare the fragment cross sections with the predictions of the empirical EPAX parametrization of fragmentation cross-sections and Statistical Abration-Ablation model (SAA) by considering the RIBLL separator transmission rate. Isotope yield ratios between these two reactions were calculated and isoscaling parameters α and β are extracted, their dependences on fragment atomic number Z and neutron number N were presented. [ABSTRACT FROM AUTHOR]

Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter phase. In this work, we investigated the directed flow and elliptic flow for proton-neutron bremsstrahlung hard photons in intermediate energy heavy-ion collisions. The positive directed flow and negative elliptic flow of directed photons are illustrated and they seem to be anti-correlated to the free proton's flow. Also we calculated the two-photon correlation functions from which the information of photon source was extracted, and while two-photon azimuthal correlations are presented as a good method to extract the elliptic flow parameter v2 of direct hard photons. [ABSTRACT FROM AUTHOR]

An experiment of 22Mg and 20Ne beams bombarding on a 12C target at an energy of 60~70 A MeV has been performed at the RIKEN projectile fragment separator (RIPS) in the RIKEN Ring Cyclotron Facility to study the two-proton correlated emission from 22Mg and 20Ne excited states. The two-protons momentum correlation functions have been obtained for 22Mg and 20Ne, respectively. The trajectories of the 22Mg decayed products (20Ne + p + p) were also measured to get the angular correlations between the two protons in Center of Mass of decaying system by relativistic-kinematics reconstruction. The results exhibit that 22Mg has the features of 2He cluster decay mechanism. [ABSTRACT FROM AUTHOR]

Experiments of 23Al and 22Mg radioactive beams bombarding a 12C target at an energy of 60 ~70 A MeV have been performed at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility to study the two-proton emission from 23Al and 22Mg excited states, respectively. The trajectorie of the decay products, namely 21Na + p + p from 23Al and 20Ne + p + p from 22Mg, are clean identified. The relative momentum and opening angle between two protons in the rest frame of three body decay channels are obtained by relativistic-kinematics reconstruction. The results demonstrate that there are some di-proton emission components from 2He cluster for the excited 23Al and 22Mg. [ABSTRACT FROM AUTHOR]

The 18Ne(α,p)21Na reaction is thought to be one of the key breakout reactions from the hot CNO cycles to the rp process in type I x-ray bursts. In this work, the resonant properties of the compound nucleus 22Mg have been investigated by measuring the resonant elastic scattering of 21Na + p. An 89-MeV 21Na radioactive beam delivered from the CNS Radioactive Ion Beam Separator bombarded an 8.8 mg/cm² thick polyethylene (CH2)n target. The 21Na beam intensity was about 2 × 105 pps, with a purity of about 70% on target. The recoiled protons were measured at the center-of-mass scattering angles of θc.m. ≈ 175.2°, 152.2°, and 150.5° by three sets of ΔE-E telescopes, respectively. The excitation function was obtained with the thick-target method over energies Ex(22Mg) = 5.5-9.2 MeV. In total, 23 states above the proton-threshold in 22Mg were observed, and their resonant parameters were determined via an R-matrix analysis of the excitation functions. We have made several new Jα assignments and confirmed some tentative assignments made in previous work. The thermonuclear 18Ne(α,p)21Na rate has been recalculated based on our recommended spin-parity assignments. The astrophysical impact of our new rate has been investigated through one-zone postprocessing x-ray burst calculations. We find that the 18Ne(α,p)21Na rate significantly affects the peak nuclear energy generation rate, reaction fluxes, and onset temperature of this breakout reaction in these astrophysical phenomena. [ABSTRACT FROM AUTHOR]

The 18Ne(a,p)21Na reaction provides a pathway for breakout from the hot CNO cycles to the rp process in type-I x-ray bursts. To better determine this astrophysical reaction rate, the resonance parameters of the compound nucleus 22Mg have been investigated by measuring the resonant elastic scattering of 21Na+p. An 89 MeV 21Na radioactive ion beam was produced at the CNS Radioactive Ion Beam Separator and bombarded an 8.8 mg/cm2 thick polyethylene target. The recoiled protons were measured at scattering angles of θc.m.~175° and 152¯ by three θE-E silicon telescopes. The excitation function was obtained with a thick-target method over energies Ex(22Mg) = 5.5-9.2 MeV. The resonance parameters have been determined through an R-matrix analysis. For the first time, the Jπ values for ten states above the a threshold in 22Mg have been experimentally determined in a single consistent measurement. We have made three new Jπ assignments and confirmed seven of the ten tentative assignments in the previous work. The 18Ne(a,p)21Na reaction rate has been recalculated, and the astrophysical impact of our new rate has been investigated through one-zone postprocessing x-ray burst calculations. We find that the 18Ne(a,p)21Na rate significantly affects the peak nuclear energy generation rate and the onset temperature of this breakout reaction in these phenomena. [ABSTRACT FROM AUTHOR]

The breakup reactions of 31Cl + 12C at 44A MeV are investigated experimentally. The longitudinal momentum distribution of 30S after one-proton removal from 31Cl has been obtained. By assuming core plus a valence proton structure, the momentum distribution is studied using the few-body Glauber model. The calculation shows that the width of momentum distribution for a valence proton with l = 2 is consistent with the experimental data, which indicates a dominant d-wave component for the valence proton in 31Cl. [ABSTRACT FROM AUTHOR]

We have measured the interaction cross-sections (σI) for light neutron-rich nuclei (14Be, 14,15B) at ∼50A MeV at the Radioactive Ion Beam Line in Lanzhou (RIBLL) in IMP with a new scheme. In this scheme, a carbon reaction target was installed at the intermediate focusing point at RIBLL. This scheme allowed us to identify particles before and after the reaction target unambiguously. However, this scheme might suffer a large loss of transmission efficiency in the second half of RIBLL. We checked this effect by changing the emittance of the RI beams. The results showed that a correction of the transmission efficiency is needed to deduce σI. We performed a Monte Carlo type simulation and tried to deduce σI for the above nuclei. Finally, we obtained reasonable σI although their error bars were fairly large. The results were compared with calculations by an energy-dependent semi-empirical formula. [Copyright &y& Elsevier]

Objective: To investigate the impact of intermittent senescent cell clearance on the proliferation and differentiation of dental pulp stem cells (DPSC) in long-term, large-scale expansion, and to explore strategies for maintaining the youthful state of DPSC in vitro . Methods: Human-derived dental pulp stem cells were isolated from healthy permanent teeth extracted for orthodontic or impeding eruption reasons, provided by the Department of Oral and Maxillofacial Surgery at West China Hospital of Stomatology, Sichuan University. Long-term, large-scale in vitro expansion of DPSC was conducted. The study compared young DPSC (passage 5) with aged DPSC (passage 25) using cellular senescence-associated β-galactosidase staining, colony formation assay, and Alizarin Red S staining for osteogenic differentiation induction. To assess the differences between the two cell populations in terms of senescence and amplification and differentiation ability. Medicine screening for the most effective senolytic was compared among 5 common senolytics [Navitoclax (ABT-263), curcumin, dasatinib, fisetin, and quercetin]. The clearance efficacy was compared using cellular senescence-associated β-galactosidase staining to reflect the changes in senescent cell ratio. The senolytic with the highest efficacy was chosen for further experiments. The passage at which the proportion of senescent cells significantly increased was identified, and the selected senolytic was administered three times at three-generation intervals from that passage to remove senescent cells. Both the control and senolytic-treated groups were estimated by fluorescence cellular senescence-associated β-galactosidase staining, real-time fluorescence quantitative PCR (RT-qPCR), colony formation assay, wound healing assay, and Alizarin Red S staining for osteogenic differentiation induction. Subcutaneous heterotopic osteogenesis was performed in nude mice and the grafts were analyzed by HE staining and alkaline phosphatase (ALP) immunohistochemical staining. Results: The proportion of senescent cells increased as the expansion extended, leading to decreased proliferation and osteogenic differentiation ability of senescent DPSC compared to young DPSC ( P <0.05). Senescent DPSC exhibited altered mRNA expression levels of senescence-related genes, including p21, p16INK4a, IL-6, and Ki67 ( P <0.001). Among the five senolytics, ABT-263 had the biggest decreases in the proportion of senescent cells. After intermittent ABT-263 treatment during expansion, the proportion of senescent cells in the senolytic-treated group [(6.72±2.34)%] was significantly lower than that in the control group [(31.82±0.57)%] ( P <0.001). RT-qPCR confirmed that compared with the control group, mRNA expressions of p21, p16 INK4a , and IL-6 in the senolytic-treated group were significantly decreased ( P <0.05), while mRNA expressions of Ki67 were significantly increased ( P <0.01). Furthermore, the cell healing ability and osteogenic differentiation ability of the senolytic-treated group were higher than those of the control group ( P <0.05). In vivo experimental results indicated that the relative new bone area [(2.36±0.48)%] after DPSC transplantation in the senolytic-treated group was greater than that in the control group [(1.00±0.46)%] ( P <0.05), and the expression of ALP was higher than that in the control group ( P <0.01). Conclusions: ABT-263 can effectively eliminate senescent cells in long-term large-scale DPSC expansion. Continuous treatment with ABT-263 during cultivation can maintain the proliferation and differentiation ability of DPSC both in vivo and in vitro .

Periodontitis is an oral infectious disease that occurs in the tooth supporting tissues, which damages the soft and hard tissues of the periodontium and eventually results in tooth mobility and loss. Traditional clinical treatment can effectively control the periodontal infection and inflammation. However, as the therapeutic effect depending on the local condition of periodontal defect and the systemic factors of patients, it's hard to achieve satisfactory and stable periodontal tissue regeneration for damaged periodontal tissues. Recently, as a promising therapeutic strategy in periodontal regeneration, mesenchymal stem cells (MSC) play an important role in modern regenerative medicine. Combined with the clinical translational researches of MSC in periodontal tissue engineering and the research results of our group in the past decade, it is summarized and explained the mechanism of MSC promoting periodontal regeneration, the preclinical and the clinical transformation researches as well as the future application prospects of MSC in periodontal regeneration therapy in this paper.

Researches on pulp regeneration based on odontogenic stem cells have made a breakthrough and some results have been applied clinically in recent years. It is demonstrated that exosomes secreted by stem cells play a significant role in tissue regeneration. Compared with stem cells, exosomes exhibit more advantages such as wider sources, more immediate effects, and less immune rejections, which are expected to be exploited in the pulp regeneration by cell-homing. In this review, the conventional dental pulp tissue engineering and exosomes-based dental pulp regeneration method are discussed, the new strategy for dental pulp regeneration by using exosomes is analyzed and proposed.

Objective: To investigate the efficacy and safety of mechanical thrombectory with a tri-axial system of the solitaire AB stent through a Navien delivery catheter to treatment acute vertebrobasilar artery occlusion. Methods: The clinical data of 16 consecutive patients with acute ischemic stroke of vertebrobasilar artery occlusion treated with the Solitaire AB device from March 2016 to March 2018 in Department of Neurosurgery, the First Affiliated Hospital, Medical College of Shihezi University, were extracted and then retrospectively analyzed.Recanalization rate as well as complications after treatment were analysized. Also, neurological functions of the patients before and after operation 1 weeks, measured by National Institute of Health stroke scale (NIHSS) score were compared via t test and the clinical outcomes were assessed by modified Rankin score (mRS) at 90 days after operation. Results: There were 10 male and 6 female patients with a median age of 59 years (ranging from 45 to 78 years).Fourteen patients resulted in successfully recanalization, and 2 cases failed both of whose onset to sheath mean time were 8.5 hours.The NIHSS score at 7 days was 13±7, which was significantly decreased compared to the admission NIHSS score 24±4 ( P= 0.000).No symptomatic intracranial hemorrhage case was found after operation.At 90 days, 8 patients achieved good outcome (mRS 0 to 2), one patient died (mRS 6),two patients moderately seriously disabled (mRS 4).Three patients resulted in moderate outcome (mRS 3).In 3 cases of death,2 patients died due to failure in recanalization,another patient died of severe pulmonary infection. Conclusion: The results suggest that this technique of a tri-axial system used of the Solitaire AB stent through a Navien delivery catheter can effectively retrieve clots from the occlusive artery and improves functional outcome in patients with acute ischemic stroke of vertebrobasilar artery.

The loss of periodontal support tissues might cause movement or finally loss of the teeth affected, impair furthermore the pronunciation and mastication functions, and even result in a series of physiological and psychological problems. Tissue engineering, as a technology to remodel missing tissues or organs and functional reconstruction, has achieved gratifying progress in regeneration of periodontal tissues. However, conventional construction methods have some deficiencies for functional periodontal reconstruction. In recent years, with the progress of tissue engineering technology, a series of new techniques and methods, such as cell sheet technology, decellular technology, electrospinning technology and three-dimensional printing, has been applied in tissue engineering bringing new hope for the regeneration of periodontal tissues. In this review article, the recent progress achieved in the field of periodontal tissue engineering and application of modern technology are summarized to make a brief exposition and to explore the future development of periodontal regeneration.

Stem cell based generation of functional tissue modules is becoming a hotspot in the field of tissue regeneration. These functional tissue modules, which can be prepared through a variety of ways, including self-organization of stem cells, cell sheets, electrospinning and bio-printing, can serve as the basic unit and be assembled to form larger tissues and organs. This new technology can be a break-through to address current issues in tissue regeneration and further promote the translational use of regenerated tissues/organs. Construction of functional tooth modules is still in its early stage, where the stem cell source, preparing method and strategy of translational use are not clearly defined yet. How to construct the functional tissue module through the existing technology still needs further study. Here, we would like to share our current understanding and thoughts on constructing strategies and potential clinical application of functional tooth modules including dental pulp, periodontal tissue and tooth root, and hope it could shed new lights on the regeneration of tooth.