Stepped-up development of accelerator mass spectrometry method for the detection of ^(60)Fe with the HI-13 tandem accelerator

The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.

Role of insulin in pancreatic microcirculatory oxygen profile and bioenergetics

BACKGROUND The pancreatic islet microcirculation adapts its metabolism to cope with limited oxygen availability and nutrient delivery.In diabetes,the balance between oxygen delivery and consumption is impaired.Insulin has been proven to exert complex actions promoting the maintenance of homeostasis of the pancreas under glucotoxicity.AIM To test the hypothesis that insulin administration can improve the integrated pancreatic microcirculatory oxygen profile and bioenergetics.METHODS The pancreatic microcirculatory partial oxygen pressure(PO_(2)),relative hemoglobin(rHb)and hemoglobin oxygen saturation(SO_(2))were evaluated in nondiabetic,type 1 diabetes mellitus(T1DM),and insulin-treated mice.A threedimensional framework was generated to visualize the microcirculatory oxygen profile.Ultrastructural changes in the microvasculature were examined using transmission electron microscopy.An Extracellular Flux Analyzer was used to detect the real-time changes in bioenergetics by measuring the oxygen consumption rate and extracellular acidification rate in islet microvascular endothelial cells(IMECs).RESULTS Significantly lower PO_(2),rHb,and SO_(2) values were observed in T1DM mice than in nondiabetic controls.Insulin administration ameliorated the streptozotocin-induced decreases in these microcirculatory oxygen parameters and improved the mitochondrial ultrastructural abnormalities in IMECs.Bioenergetic profiling revealed that the IMECs did not have spare respiratory capacity.Insulin-treated IMECs exhibited significantly greater basal respiration than glucotoxicity-exposed IMECs(P<0.05).An energy map revealed increased energetic metabolism in insulin-treated IMECs,with significantly increased ATP production,non-mitochondrial respiration,and oxidative metabolism(all P<0.05).Significant negative correlations were revealed between microcirculatory SO_(2) and bioenergetic parameters.CONCLUSION Glucotoxicity deteriorates the integrated pancreatic microcirculatory oxygen profile and bioenergetics,but this deterioration can be reversed by insulin administration.

Global trend and future landscape of intestinal microcirculation research from 2000 to 2021:A scientometric study

BACKGROUND The intestinal microcirculation functions in food absorption and metabolic substance exchanges.Accumulating evidence indicates that intestinal microcirculatory dysfunction is a significant source of multiple gastrointestinal diseases.To date,there has not been a scientometric analysis of intestinal microcirculatory research.AIM To investigate the current status,development trends,and frontiers of intestinal microcirculatory research based on bibliometric analysis.METHODS VOSviewer and CiteSpace 6.1.R2 were used to identify the overall characteristics and knowledge map of intestinal microcirculatory research based on the core literature published from 2000 to 2021 in the Web of Science database.The characteristics of each article,country of origin,institution,journal,cocitations,and other information were analyzed and visualized.RESULTS There were 1364 publications enrolled in the bibliometric analysis,exhibiting an upward trend from 2000 to 2021 with increased participation worldwide.The United States and Dalhousie University took the lead among countries and institutions,respectively.Shock was the most prolific journal,and Nature Reviews Microbiology Clinical had the most citations.The topical hotspots and frontiers in intestinal microcirculatory research were centered on the pathological processes of functional impairment of intestinal microvessels,diverse intestinal illnesses,and clinical treatment.CONCLUSION Our study highlights insights into trends of the published research on the intestinal microcirculation and offers serviceable guidance to researchers by summarizing the prolific areas in intestinal disease research to date.

Changes in intraocular pressure and central corneal thickness during pregnancy:a systematic review and Meta-analysis

AIM：To conduct a Meta-analysis for investigating the variations in intraocular pressure（IOP）and central corneal thickness（CCT）during normal pregnancy.METHODS：We searched for clinical trials published up to November 2015 without language or region restrictions in Pub Med,EMBASE,Web of Science,the Cochrane Central Register of Controlled Trials,Ovid,EBSCO,Elsevier,the Chinese Biomedicine Database,Wan Fang,CNKI,CQVIP and Google Scholar.Studies of the ocular changes observed in pregnant women were selected.The main outcomes were assessed by changes in IOP and CCT.RESULTS：Fifteen studies were included.In subgroup analyses,IOP was significantly decreased during the second MD=-1.53,95%CI（-2.19,-0.87）;P〈0.00001,and third MD=-2.91,95%CI（-3.74,-2.08）;P〈0.00001 trimesters of pregnancy.CCT was increased during the second MD=10.12,95%CI（2.01,18.22）;P=0.01,trimester of pregnancy;moreover,during the third trimester of pregnancy,the CCT displayed an increasing trend,but the difference was not significant MD=5.98,95%CI（-1.11,13.07）;P=0.1.CONCLUSION：A decrease in IOP is accompanied by an increase in CCT in the second and third trimesters of a normal pregnancy in women.

Inflammatory Changes in Paravertebral Sympathetic Ganglia in Two Rat Pain Models

Injury to peripheral nerves can lead to neuropathic pain, along with well-studied effects on sensory neurons, including hyperexcitability, abnormal spontaneous activity, and neuroinflammation in the sensory ganglia. Neuropathic pain can be enhanced by sympathetic activity. Peripheral nerve injury may also damage sympathetic axons or expose them to an inflammatory environment. In this study, we examined the lumbar sympathetic ganglion responses to two rat pain models： ligation of the L5 spinal nerve, and local inflammation of the L5 dorsal root ganglion （DRG）, which does not involve axotomy. Both models resulted in neuroinflammatory changes in the sympathetic ganglia, as indicated by macrophage responses, satellite glia activation, and increased numbers of T cells, along with very modest increases in sympathetic neuron excitability （but not spontaneous activity） measured in ex vivo recordings. The spinal nerve ligation model generally caused larger responses than DRG inflammation. Plasticity of the sympathetic system should be recognized in studies of sympathetic effects on pain.

A low-temperature sol-gel route for the synthesis of bioactive calcium silicates

Received 14 August 2012 Received in revised form 19 November 2012 Accepted 28 November 2012 Available online 7 February 2013

Removal of residual nitrate ion from bioactive calcium silicate through soaking

Bioactive calcium silicates prepared by sol–gel routes mainly use calcium nitrate as the calcium precursor. However, the toxic nitrate ions are usually removed by calcination（i.e. 550 8C or over）, which poses great challenge for the in situ preparation of inorganic/polymer composites, as polymer moieties could not survive such temperatures. In this study, we prepared 70Si30Ca（70 mol% Si O_2 and 30 mol%Ca O） bioactive glass at low temperatures where polymer could survive（i.e. 200 8C and 350 8C）, and proposed to remove the residual nitrate ions through soaking. Deionized water and simulated body fluid（SBF） were employed as the soaking medium. The results showed that the residual nitrate ions could be removed as quickly as 0.5 h while maintain the bioactivity of the samples. This technique may open the possibility of preparing sol–gel derived bioactive glass/polymer hybrids in situ with reduced potential toxicity.

Formation of six-coordinated silicon in calcium phosphosilicate xerogels assisted by polyols at low temperature and pressure

Silicon is usually found to be four-coordinated when neighbored with oxygen. Six-coordinated silicon is only seen in samples at very specific composition or made at high temperature/pressure. In this study, we managed to synthesize calcium phosphosilicate xerogels containing six-coordinated silicon with the help of polyols by sol-gel method, without the need of treatment at high temperature or high pressure. Both phosphorus precursors and polyols were found to be essential for the formation of six-coordinated silicon species; in the absence of either species, only normal four-coordinated silicon was observed under otherwise identical conditions. Samples containing six-coordinated silicon sites were found to release silicon species faster than those without six-coordinated silicon sites upon dissolved in water, suggesting that six-coordinated silicon species have higher reactivity toward hydrolysis.

Poly(1,8-octanediol citrate)/bioactive glass composite with improved mechanical performance and bioactivity for bone regeneration

Poly（1,8-octanediol-co-citrate） （POC） represents a new promising biocompatible and biodegradable polyester that has been extensively investigated for soft tissue engineering. However, the poor mechanical performance and poor bioactivity limit its application in bone regeneration. In this study, a series of POC/bioactive glasses （BG） composites were developed using 45S5 Bioglass^Θ and a phytic acid- derived bioactive glass （referred as PSC）. The results indicated that calcium in BG could enhance the crosslinking of the POC/BG composites by forming calcium dicarboxylate bridges and thus improve their mechanical performances. When PSC were used, the composites exhibited significantly better mechanical properties compared to composites with 45S5 Bioglass^Θ. For example, by incorporating 70wt% PSC, the compressive strength of POC/PSC composites could be improved to approximately 50 MPa and modulus 1.3-h 0.1 GPa. Furthermore, all these POC/PSC composites showed good in vitro bioactivity and cellular biocompatibility. Histology results in femoral condyle defects of Sprague-Dawley rats indicated that the POC/PSC samples integrated well with surrounding tissues and stimulated bone regeneration. The improved mechanical properties and bioactivity of POC/PSC composites make them promising for potential application in bone regeneration.