Objective To establish a sourceless efficiency calibration method by coupling Monte Carlo simulation with analytical calculation. Methods Monte Carlo simulation was used to calculate the point-to-point detection efficiency of specific detectors to establish a detection efficiency grid. The detection efficiency of point source, disc, cylindrical, beaker, spherical, U-tube and Marlin cup samples was analyzed using numerical integration method after detection efficiency grid interpolation. Results The above coupling method was used for sourceless efficiency calibration. Within the energy range of 0.2–3 MeV, the relative deviation of calibration between coupling method and Monte Carlo simulation was mostly less than 10%, the maximum relative deviation was 18.06%, and the computation time was reduced by at least 86%. The above coupling method was used for sourceless efficiency calibration of an HPGe detector manufactured by ORTEC for point source detection, which was in good agreement with the experimental calibration, and the relative deviations were less than 10%. Conclusion This method can be generalized and used in the sourceless efficiency calibration of HPGe, LaBr₃, and NaI detectors.

Objective:The Chinese pediatric mesh-type reference phantoms were developed and applied in the dose assessment of X-ray radiography.Methods:The 5- and 10-year-old Chinese pediatric mesh-type reference phantoms were developed based on the CT data. Based on the phantoms, the Monte Carlo method was applied to simulate the X-ray radiography to calculate the organ dose conversion coefficient and the effective dose conversion coefficient in different radiography conditions.Results:The 5- and 10-year-old Chinese pediatric mesh-type reference phantoms were developed, and the physical parameters were consistent with the national standard. The differences of the organ mass between the established phantoms and reference data were within 2%. The database of the pediatric chest posteroanterior projection and abdominal anteroposterior projection, tube voltage 60-90 kVp, total filtration 2.5~4 mmAl were simulated, and the difference between the effective dose conversion factor and the literature result was within 3%.Conclusions:The established Chinese pediatric mesh-type reference phantoms can be applied in the studies of radiation protection and clinical medicine and their result can provide an important reference for the dose assessment of the pediatric X-ray radiography.

Objective:To measure the microdosimetric spectrum of carbon ion beam and calculate the relative biological effect (RBE) distribution, so as to provide reference for radiotherapy microdosimetric research.Methods:A silicon on insulator (SOI) microdosimeter was used to measure the microdosimetric spectrum of 12C ion beam, at 260 MeV/u, provided by Lanzhou Heavy Ion Accelerator National Laboratory. The measured pulse amplitude spectrum was converted to obtain the dose distribution. The microdosimetric spectra and RBE values at different polymethyl methacrylate depths were measured by the combination of different thickness PMMA. Results:The microdosimetric spectra of 12C ion beam at 260 MeV/u were measured at different PMMA depths, and the relationship between dose line energy yD and RBE and different PMMA depths was also obtained. The measurement result showed that the RBE value reached a peak of 2.6 at the PMMA depth of 116.5 mm, and decreased rapidly after the Bragg peak. However, the RBE value was still 1.3 at the trailing point, which was about twice as much as the entrance of the flat zone. Conclusions:This paper provides basic data for carbon ion beam microdosimetric spectroscopy through measurement. The RBE value of 12C ion beam gradually rises and reaches a peak with the increase of PMMA depth. After the Bragg peak position, it drops rapidly, but the biological effect at the tail cannot be ignored. At the same time, it reflects the dose fraction caused by different line energy intervals, and provides a reference for assessing the risk of heavy ion therapy for secondary cancer.

Objective To simulate and analyze the CT examination doses to typical patients based on Chinese reference human phantom, and to develop an online software for assessing the organ absorbed dose and effective dose to the examinees undergoing CT examination in order to provide a tool for rapid assessment of radiation dose from CT examination. Methods Based on the Monte Carlo simulation, a GE LightSpeed 16 CT scanner was modeled. The organ doses to Chinese adult male, female and 1 year-old child male from single axial scan were calculated based on the Chinese reference phantoms and an organ dose database was established. A web-based CT dose assessment software was developed to read the data from the organ dose database according to the CT scanning parameters entered by the user and to calculate the organ absorbed dose and effective dose rapidly. Results A new CT dose assessment software was developed, which can be used to assess organ doses to Chinese adult male, female and 1-year-old male for different CT scanner, voltage, current, collimator width and other CT parameters. The organ doses calculated in this work were compared with simulation data in two relevant studies. Dose differences for the organs completely included in the scan range were small, with relative differences less than 15％ and 25％, respectively. Conclusions The CT dose assessment software provides a powerful tool for the simple and rapid assessment of radiation dose to the examinees undergoing CT examinations.

OBJECTIVETo compare the efficacy difference between's flying acupuncture combined with conventional treatment and conventional treatment alone on acute cerebral infarction hemiplegia.

METHODSA total of 120 patients were randomly divided into an observation group and a control group, 60 cases in each one. The control group was treated with conventional treatment, including anti-platelet aggregation, lipid-lowering, formula of traditional Chinese medicine which could promote circulation and remove stasis, neurotrophic medication and symptomatic treatment; mannitol was used for cerebral infarction with large area or increased intracranial pressure. Based on the conventional treatment applied in the control group, the observation group was treated with flying acupuncture at the affected Jianyu (LI 15), Quchi (LI 11), Shousanli (LI 10), Waiguan (TE 5), Hegu (LI 4), Huantiao (GB 30), Biguan (ST 31), Futu (ST 32), Zusanli (ST 36), etc. The treatment was given once a day, six days per week, for totally 2 weeks. The simplified Fugl-Meyer score, National Institute of Health Stroke Scale (NIHSS) and ADL-Bathel index (BI) score were evaluated before and after treatment in the two groups.

RESULTSAfter the treatment, the simplified Fugl-Meyer and BI were significantly increased in both groups (all<0.05), which was significantly higher in the observation group (both<0.05); after the treatment, the NIHSS was significantly lowered in both groups (both<0.05), which was significantly lower in the observation group (<0.05).

CONCLUSION 's flying acupuncture combined with conventional treatment were effective for acute cerebral infarction hemiplegia, which have better efficacy than conventional treatment on improving motor function, neurological deficit and daily living ability, and the pain is mild.

Objective To evaluate the efficacy of salvage radiotherapy for supraclavicular lymph node metastasis ( SLNM) after initial treatment in patients with esophageal cancer. Methods A total of 117 patients with SLNM after radical resection for esophageal cancer were enrolled as subjects from 2006 to 2012. All patients received three?dimensional radiotherapy with 1. 8?2. 0 Gy per cycle, 5 cycles a week. The survival rates were calculated using the Kaplan?Meier method and analyzed using the log?rank test. The Cox model was used for multivariate analysis. Results The follow?up rate was 100%. In all the patients, the 1?and 3?year overall survival (OS) rates were 38. 5% and 14. 1%, respectively. The 1?and 3?year OS rates were significantly higher in patients treated with salvage radiotherapy or radiochemotherapy ( n=100) than in patients without any salvage treatment (n=17)(42% vs. 18%,P=0. 008;17% vs. 0%, P=0. 008). The patients treated with radiochemotherapy ( n=32) had significantly higher 1?and 3?year OS rates than those treated with radiotherapy alone (n=68)(59% vs. 34%, 36% vs. 11%, P=0. 002) or without any salvage treatment (n=17)(59% vs. 18%, 36% vs. 0%, P=0. 002). Patients without visceral metastasis (n=80) had significantly higher 1?and 3?year OS rates than those with visceral metastasis ( n=37) ( 44% vs. 27%, P=0. 002;22% vs. 0%,P=0. 002) . Patients with supraclavicular doses of ≥60 Gy in salvage radiotherapy ( n=75) had significantly higher 1?and 3?year OS rates than those with supraclavicular doses of<60 Gy in salvage radiotherapy ( n=25) ( 75% vs. 25%,P=0. 000;24% vs. 8%,P=0. 000) . The multivariate analysis using the Cox model showed that supraclavicular doses of ≥60 Gy, mediastinal metastasis, visceral metastasis, and salvage treatment method were independent factors for survival ( P=0. 001,0. 015,0. 009, 0. 025) . Conclusions Salvage radiotherapy can improve the survival of patients with SLNM in esophageal cancer. Salvage radiotherapy or radiochemotherapy is highly recommended for patients with SLNM alone. A radiation dose of ≥60 Gy in salvage radiotherapy improves survival in patients.

Objective To study the effects ofShenqi YizhiGranules (SQYZ) on learning and memory and content of Aβ1-42 of cerebral tissue in 5XFAD mice with Alzheimer’s disease; To discuss its mechanism on improving learning and memory ability of 5XFAD mice.Methods Four-month-old C57BL?6 wild type mice were randomly divided into NS control group and SQYZ control group, and the 5XFAD mice were randomly divided into model group, SQYZ group and huperzine-A (HupA) group, 15 mice in each group. Each group were given same volume for gavage for 60 d. After treatment, the learning and memory ability were evaluated by nesting test, passive avoidance and Morris water maze test. The senile plaques and content of Aβ1-42, ionized calcium binding adapter molecule 1 and glial fibrillary acidic protein in cerebral cortex and hippocampus were detected by immunohistochemical staining and immunofluorescence, respectively.Results Compared with NS control group, the score of nesting test in model group significantly decreased; the step-through latency in passive avoidance was shortened and the escape latentcy in Morris water maze test was prolonged; the quantity of senile plaques and content of Aβ1-42 increased in cerebral cortex and hippocampus; the activation of glial cells significantly increased. In the SQYZ group, the above-mentioned indexes reached or approached the level of wild type control mice. The difference between SQYZ group and model group was statistically significant (P<0.05,P<0.01).Conclusion SQYZ improved learning and memory ability in 5XFAD mice, which may be related to reduction of senile plaques, inhibition of over activation in glial cells and reduction of content of Aβ1-42 in cerebral cortex and hippocampus.

Objective To explore the effects of luteolin on cognition function in pentylenetetrazol (PTZ)-induced epileptic rats and related mechanism.Methods Fifty male SD rats were randomly divided into a normal control group(n=8), a model group(n=12), and groups of 25, 50 mg/kg luteolin(both ofn=11), as well as 100 mg/kg luteolin group(n=8). Those rats were given different doses of luteolin (25, 50 and 100 mg/kg, daily, intragastric administration) for 36 consecutive days. Similarly, rats of the normal control group and the model group were given 0.5% sodium carboxymethyl cellulose suspension liquid via intragastric administration. Thirty minutes later, a model of epilepsy was induced using PTZ (40 mg/kg, daily) via intraperitoneal injection except the control group. Learning and memory of rats were evaluated by Morris water maze and novel objective recognition trials(including escape latency and recognition index). The levels of CaM and CaMPK were determined by ELISA methods, and expression of Ras proteins in the hippocampus were detected by Western Blot.Results Compared with the model group, luteolin treatment groups significantly shorten the escape latency(28.51 ± 3.84 s, 19.77 ± 5.41 s, 14.86 ± 2.76 svs. 37.08 ± 5.18 s) in the Morris water maze, and increased recognition index(18.77% ± 2.02%, 25.06% ± 4.32%, 31.92% ± 2.65%vs. 13.87% ± 2.14%) in the novel objection trial(P<0.05 orP<0.01). Meanwhile, CaM(140.33 ± 13.52 ng/L, 124.26 ± 9.97 ng/L, 113.52 ± 11.57 ng/Lvs. 158.36 ± 10.68 ng/L) and CaMPK(8.25 ± 1.37 ng/ml, 7.69 ± 0.84 ng/ml, 6.74 ± 0.93 ng/mlvs. 9.87 ± 1.02 ng/ml) were significantly decreased(P<0.05 orP<0.01). What’s more, the expression of Ras proteins(0.99 ± 0.08, 0.76 ± 0.07, 0.52 ± 0.07vs. 1.58 ± 0.12) was obviously decreased compared with the model group(P<0.05 orP<0.01).Conclusion Luteolin could effectively improve the cognition dysfunction of epileptic rats, and the mechanism might be relevant to regulate the CaM-CaMPK signaling pathway via down-regulation of CaM, CaMPK, as well as Ras protein.

As an important material in pharmaceutical and chemical industry, β-alanine was mainly produced by chemical methods. L-aspartate-α-decarboxylase could catalyze the α-decarboxylation from L-aspartate to β-alanine. Determinations for specific activities of PanDs from Escherichia coli, Corynebacterium glutamicum and Bacillus subtilis were performed in this study (0.98 U/mg, 7.52 U/mg and 8.4 U/mg respectively). The optimal temperature and pH of PanDs from C. glutamicum and B. subtilis were 65 degrees C, pH 6.5 and 60 degrees C, pH 6.5 respectively. According to our research, PanD from B. subtilis could be more appropriate for industrial application because of the higher activity and thermostability when compared to PanDs from E. coli and C. glutamicum which had been the most studied. We also analyzed and discussed the special post-translation self-cleavage phenomenon and the mechanism based inactivation.
Bacillus subtilis ; enzymology ; Bacterial Proteins ; genetics ; metabolism ; Corynebacterium glutamicum ; enzymology ; Escherichia coli ; enzymology ; Glutamate Decarboxylase ; genetics ; metabolism ; Industrial Microbiology ; Temperature ; beta-Alanine

Photosynthetic CO(2) fixation is the ultimate source of organic carbon on earth and thus is essential for crop production and carbon sequestration. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the first step of photosynthetic CO(2) fixation. However, the extreme low carboxylation efficiency of Rubisco makes it the most attractive target for improving photosynthetic efficiency. Extensive studies have focused on re-engineering a more efficient enzyme, but the effort has been impeded by the limited understanding of its structure-function relationships and the lack of an efficient selection system towards its activity. To address the unsuccessful molecular engineering of Rubisco, we developed an Escherichia coli-based activity-directed selection system which links the growth of host cell solely to the Rubisco activity therein. A Synechococcus sp. PCC7002 Rubisco mutant with E49V and D82G substitutions in the small subunit was selected from a total of 15,000 mutants by one round of evolution. This mutant showed an 85% increase in specific carboxylation activity and a 45% improvement in catalytic efficiency towards CO(2). The small-subunit E49V mutation was speculated to influence holoenzyme catalysis through interaction with the large-subunit Q225. This interaction is conserved among various Rubisco from higher plants and Chlamydomonas reinhardtii. Knowledge of these might provide clues for engineering Rubisco from higher plants, with the potential of increasing the crop yield.
Amino Acid Substitution ; Bacterial Proteins ; chemistry ; genetics ; Carbon Dioxide ; chemistry ; Directed Molecular Evolution ; Escherichia coli ; growth & development ; Ribulose-Bisphosphate Carboxylase ; chemistry ; genetics ; Synechococcus ; enzymology