Investigating the minimum detectable activity concentration and contributing factors in airborne gamma-ray spectrometry

In this study,the theory of minimum detectable activity concentration(MDAC)for airborne gamma-ray spectrometry(AGS)was derived,and the relationship between the MDAC and the intrinsic effi-ciency of a scintillation counter,volume,and energy res-olution of scintillation crystals,and flight altitude of an aircraft was investigated.To verify this theory,experi-mental devices based on NaI and CeBr 3 scintillation counters were prepared,and the potassium,uranium,and thorium contents in calibration pads obtained via the stripping ratio method and theory were compared.The MDACs of AGS under different conditions were calculated and analyzed using the proposed theory and the Monte Carlo method.The relative errors found via a comparison of the experimental and theoretical results were less than 4%.The theory of MDAC can guide the work of AGS in probing areas with low radioactivity.

The Activity Concentrations, Radiation Contamination, and Hazards from Wastes and Soil Samples in Nasirabad Industrial Area, Chattogram, Bangladesh

Soils and other solid wastes from industrial areas of Nasirabad, Chattogram are usually dumped or used for land development. Information about the radioactivity level presented on these soil and wastes enables one to assess any possible radiological hazard to humankind by the use of such materials. A total of 37 (31 soils and 6 solid waste) samples near from different types of industries along four kilometre range were collected. The presence and activity concentrations of naturally occurred radioactive materials (NORM) and anthropogenic radionuclides in the samples were estimated using HPGe detector of 40% relative efficiency. The activity concentration of 226Ra, 232Th and 40K were found to be ranging from 8 ± 2 to 131 ± 18.33 with an average of 21 Bq·kg-1, 10 ± 2.69 to 133 ± 15.96 with an average of 40 Bq·kg-1 and 81 ± 22.68 to 930 ± 260.40 with an average of 449 Bq·kg-1 respectively. Besides this, some hazard indices like, the radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), and the activity concentration index (Iy) were calculated to assess the radiation hazard in this region. The averages of calculated hazard indices were within the normal limits, except the activity concentration index, which shows elevated values. The outcomes of this study could serve as important baseline radiological data for future epidemiological studies and environmental monitoring initiatives in the study area.

Effect of thyroid hormone on serum NO concentration and iNOS activity of intestinal mucosa in septic rats

Objective To investigate the effect of exogenous thyroid hormone on serum NO and iNOS activity of intestinal mucosa in septic rats. Methods Septic model was established by cecal ligation puncture (CLP) in male SD rats. Triiodothyronine ( T3 ) was administered intraperitoneally to correct the low T3 syndrome of septic rats. Blood was collected to examine serum NO and thyroid hormone concentration. Intestinal mucosa iNOS activity was assayed using immunochemical stain. Results Mortality rate in the prevention group was significantly lower than the septic group (Log rank = 3. 85, P 【 0.05). Serum NO concentration was significantly lower in the prevention group (F=19.6,F【0.01). The degree of inflammatory injury of intestinal mucosa was much milder in the prevention group than in the septic group (x2 = 5.303,P【0. 05). Mucosa iNOS activity was also significantly lower in the prevention group (x2 = 4. 876, P【0. 01). Conclusion Thyroid hormone protects the intestinal mucosa barrier inhibiting the expression of

Study and Simulated the Natural Radioactivity (NORM) U-238, Th-232 and K-40 of Igneous and Sedimentary Rocks of Al-Atawilah (Al-Baha) in Saudi Arabia

In this work, gamma-ray spectroscopy based on semiconductor hyper pure germanium (HPGe) detector was used to evaluate the activity concentrations of the natural radionuclides (U-238 (Ra-226), Th-232 and K-40) and the fallout nuclide (Cs-137) for thirty samples of igneous and sedimentary rocks of Al-Atawilah (Al-Baha). The mean values of the activity concentrations of U-238 (Ra-226), Th-232, K-40 and Cs-137 in the igneous samples are found as (11.0, 11.50, 1172.71, 1.47) Bq/Kg respectively. In the sedimentary rocks, the mean values of the activity concentrations of the natural radionuclides (U-238 (Ra-226), Th-232 and K-40) and the fallout nuclide (Cs-137) equal to (12.04, 13.18, 1131.36, 1.60) Bq/Kg respectively. The averages of radiological hazards (Raeq, Hex and Iγ) were calculated and found to be within the UNSCEAR permissible limit values (370 Bq/kg for Raeq, and 1 for Hex and Iγ), except for a slight increase of average value of Iγ in the igneous rock samples (1.36). The results indicate that the dose rate values depend on the kind of rocks (high in some igneous rock samples, and most of sedimentary rock samples have low dose rate). The activities of naturalnuclides were predicted and simulated in T time using a written MATLAB R2020a script based on the average activity concentrations and respective half-lives of U-238 and Th-232 series, and K-40, this is to evaluate the future effects of natural radionuclides on the population and estimate the human inputs in the future.

Determination of Natural Radioactivity of the <i>Hibiscus sabdariffa</i>Linn (Roselle) Used in Côte d’Ivoire (Ivory Coast)

In this work, ten medicinal and nutritional leaves samples of Hibiscus sabdariffa Linn imported from Mali and Burkina Faso in Côte d’Ivoire and sold on the market were collected. The analysis of these plants using High Purity Germanium detector (HPGE) gamma spectrometry showed the activity concentrations of 226Ra, 232Th, and 40K varied respectively in the range of (1.74 - 0.11) × 10−3 Bq/kg, (6.72 - 0.61) × 10−4 Bq/kg and (4.65 - 0.54) × 10−3 Bq/kg1 in the leaves of H. sabdariffa. The Average Annual Committed Effective Dose (AACED) values from leaves this plant varied from 251.492 × 10−6 to 68.133 × 10−6 mSv/y. These values found are below 0.30 mSv/y, the world average value for an individual. These results show that there is no radiological risk in consuming “bissap” leaves.

Cd──Sb合金熔体作用浓度计算模型

According to the Cd-Sb alloy phase diagram, resistivity, heat capacity, partial molar entropy and viscosity,the structural units of this alloy melt have been determined as Cd and Sb atoms as well as Cd3Sb2, Cd4Sb3 and CdSb compounds.Based on these structural units and the coexistence theory of metallic melt structure involing compound formation,a calculating model of mass action concentrations has been deduced.The calculated mass action concentrations Ncd are in good agreement with measured activities acd. The Gibbs standard free energy of formatioin for above three compunds have been obtained too.

Apply X-Ray Fluorescence and γ-Ray Spectroscopy to Analyze Igneous and Sedimentary Environmental Samples of Al-Atawilah (Al-Baha), Saudi Arabia

Igneous and sedimentary rocks contain an amount of natural radioactivity (NORM). U-238, Th-232 and their decay products, and K-40 are important sources of gamma-radiation. Knowledge of the radionuclide content of rocks is necessary to estimate the exposure of the population to the radiation. Many types of rocks are used in building and industries, thus the radiation detection is important, it provides a baseline map of levels of the radioactivity in the study region. The purpose of this study is to evaluate the activity concentrations of the natural radionuclides (U-238 (Ra-226), Th-232 and K-40) and the fallout nuclide (Cs-137) (if found) in thirty samples of igneous and sedimentary rocks of Al-Atawilah (Al-Baha). The samples were collected and prepared during 2018/2019, and analyzed with a good experimental instrument (High energy resolution γ-ray spectroscopy with HPGe detector), also these rock samples were analyzed with X-ray fluorescence to subdivided these rocks based on the major oxides proportions contained of each sample. The mean activity concentrations of naturally radionuclides were found in the igneous rock samples varied depending on the type of the igneous rock. For sedimentary rock samples, the activity concentrations were found high for quartz sandstone sample, which may be due to its high proportion of SiO2 and K2O. The estimated mean values of absorbed dose rate are within the permissible limit value. The findings indicate high dose level values in granite (rhyolite) and most of diorite (andesite) igneous rock samples while gabbro (basalt) igneous rock samples (except for one sample) record low levels of dose rate. All sedimentary rock samples have low dose rate (except for the quartz sand-stone sample).

Image Quality Assessment Using NEMA Standards for Lu-177 Radionuclide

A lutetium 177 (177Lu) radiopharmaceutical has been used as a theragnostic agent in molecular radiotherapies. This study aimed to produce images simulating those obtained in a total body imaging study with hot lesions to assess and investigate the image quality of the Hawkeye SPECT/CT images from Lu-177. The NEMA image quality phantom (PTW) with spheres (inner diameters of 10, 13, 17, 22, 28 and 37 mm) and lung insert was used. The measured volume in the background of the current phantom setting was 9482 mL. The five smaller spheres were filled with an activity concentration of 0.461 MBq/mL and the biggest sphere was filled with water. The phantom was placed on the couch and scanned at four hot sphere-to-background concentrations, which are no background, 16:1, 8:1 and 4:1. The images obtained from the scans were imported onto the OXIRIS image analysis tool. Regions of interest (ROIs) were drawn on each sphere of the reconstructed SPECT image. Image contrast and background variability ratios for hot spheres were used as measures of image quality. In addition, the accuracy of corrections were determined from the uniform background and cold lung insert regions. The 37 mm cold sphere had the highest percent contrast, whiles the 10 mm hot sphere had the least for the various hot sphere to background ratios. The background variability for each hot sphere was also determined. The average lung residual error was calculated to be 23.13% for the 16:1 and 22.57% for both the 8:1 and 4:1 hot sphere to background ratio. The results show that the scanner has very good overall performance.

Quality Assurance in SPECT/CT for Radionuclide Therapy with Lutetium-177

This study was done to quality assure the Hawkeye SPECT/CT at the St. Olav’s hospital and create a clinical method for doing individual dosimetry with 177Lu-octreotate in targeted radionuclide therapy for neuroendocrine tumors. Various quality control parameters were performed on Infinia Hawkeye SPECT/CT. A calibration dose of 160% ± 2% MBq was ordered and first calibrated for all the dose calibrators. The uniformity test was obtained using a 40 MBq Tc-99m point source positioned 2.5 m away from the two detectors. A 200 MBq Tc-99m was diluted in 70 ml of water, dispersed in six syringes for the registration test. A Lu-177 point source was placed in front of the detectors, one at a time, to check the energy peaks. The Jaczczak phantom with a hollow sphere set (volumes: 0.5, 1, 2, 4, 8, and 16) ml with an additional 60 ml sphere was used for the 3D sensitivity and recovery with Lu-177. Total activity of 945.3 MBq was added to 160 ml of water yielding an activity concentration of 5.908 MBq/ml in the spheres. The phantom was then scanned at various time intervals. A cylindrical phantom with a volume of 6283 ml was also used to obtain the cross-calibration measurement (cps/MBq). Total activity of 995.6 MBq was added and the phantom was scanned at days 0, 6, 13 and 23. The dose calibration factor was changed from 762 to 760 to achieve correct doses. The 2D mean sensitivity factor was 5.56 cps/MBq. Uniformities for both detectors were approved after iteration calibration of the PM tubes. The X-ray to SPECT registration was found to be accurate and within specifications. The energy peak test revealed off-centered 208 keV energy peaks for the two detectors. Quality assurance of imaging devices using radiation is essential for radiation protection and ensures a high-quality image.

Radiological Hazard Assessment of Raw Granites from Ranyah, KSA

The assessment of radiological hazard due to external and internal indoor exposure was investigated for 26 raw granites collected from different granite quarries in Ranyah (KSA). The activity concentrations of 226Ra, 232Th and 40K were measured by high-resolution gamma spectrometry. Four granites were classified as “anomalous” due to their relatively high radioactivity. The averages and ranges of their activity concentrations were 667 (305 - 1120), 320 (161 - 491) and 586 (282 - 893) Bq·kg-1, respectively. The corresponding ones for all remaining 22 granites were 45 (18 - 77), 39 (16 - 73) and 1178 (954 - 1531) Bq·kg-1, respectively. In accordance with new European Basic Safety Standards (BSS) directives requiring a uniform reference level for indoor external exposure to gamma rays of 1 mSv·y-1, all 22 granites may be used as bulk or ornamental building materials without any restrictions. Three anomalous granites should be subjected to control to be used as bulk materials. One anomalous granite was categorized as hazardous having an activity concentration index higher than 6. All four anomalous granites exceeded the level of newly adopted reference level of 300 Bq·m-3 for radon indoor exposure in case of poor ventilation. Two of them exceeded even for adequate ventilation. ·

Investigation of the Radiological Risk of Farmlands and the Transfer Factor from Soil to Crops in Jalingo and Wukari L.G.A of Taraba State, Nigeria

The activity concentrations of radionuclides, absorbed dose rate, excess lifetime cancer risk, and soil-to-plant transfer factor have been evaluated in soil and crop samples from Jalingo and Wukari Local Government Area of Taraba State, Nigeria. The activity concentrations were determined with the aid of High Purity Germanium detector. The absorbed dose and excess lifetime cancer risk were evaluated and forecasted for 60 years using the ResRad off-site model. The average activity concentration of 40K, 232Th, and 238U in the soil samples were 633.13, 141.15, and 71.20 Bq·kg-1 respectively, for the Jalingo study area, and while that of the Wukari study area was;199.21, 87.23, and 25.37 Bq·kg-1 respectively. The average soil-to-plant transfer factors for 40K, 232Th, and 238U were 0.51, 0.10, and 0.27 respectively for the Jalingo study area while that of Wukari are 0.40, 0.57, and 0.74 respectively. The mean annual effective dose equivalent for the study area is higher than the world average of 0.07 mS·vy-1. The excess lifetime cancer risk for the study areas has values that are higher than the safety limit. The ResRed model showed that direct radiation from the crops is the major contributor to excess cancer risk among other pathways. The radiological hazard indices reveal health risks to farmers, especially in the Jalingo area.

Simultaneous nitrogen and phosphorus removal under low dissolved oxygen conditions

A full-scale test was operated by using low dissolved oxygen activated sludge process to enhance biological nitrogen and phosphorus removal. When the influent concentrations of CODCr, TN and TP varied in a range of 352.9 mg/L-1338.2 mg/L, 34.4 mg/L-96.3 mg/L, and 2.21 mg/L-24.0 mg/L, the average removal efficiencies were 94.9%, 86.7% and 93.0%, respectively. During the test period of two months, effluent meas of CODCr,, BOD5, NH3-N, TN and TP were below 50 mg/L, 25 mg/L, 10 mg/L and 1.0 mg/L respectively. The low dissolved oxygen activated sludge process has a simple flow sheet, fewer facilities and high N and P removal efficiency. It is very convenient to retrofit the conventional activated sludge process with the above process.

Nitrogen and phosphorus removal under intermittent aeration conditions

A practice wastewater treatment plant was operated using intermittent aeration activated sludge process to enhance biological nitrogen and phosphorus removal. When the influent concentrations of COD Cr , BOD 5, TN, TP, NH 3\|N, TKN, and SS varied in a range of 207.5—1640 mg/L, 61.8—637 mg/L, 28.5—75.6 mg/L, 4.38—20.2 mg/L, 13.6—31.9 mg/L, 28.5—75.6 mg/L, and 111—1208 mg/L, the effluent means were less than 50 mg/L, 20 mg/L, 5 mg/L, 1.0 mg/L, 5 mg/L, 10 mg/L, and 20 mg/L, respectively. Based on a long time of operating results, this process is very suitable for nutrient biological removal for treating the municipal wastewater those water characteristics are similar as that of the Songjiang Municipal Waste Water Treatment Plant(SJMWTP).

Variations in leaf functional traits and physiological characteristics of Abies georgei var.smithii along the altitude gradient in the Southeastern Tibetan Plateau

Variations in leaf functional traits of Abies georgei var. smithii at 3700, 3900, 4100, 4300, and 4390 m altitude were investigated in 15 typical plots in the Southeastern Tibetan Plateau. In each plot, three seedlings were selected, of which functional leaves in current-year sunny branches were chosen for the measurement of morphological, photosynthetic, and physiological and biochemical characteristics, and their variations were analyzed. Results showed that significant variations existed among the leaf functional traits of A. georgei var. smithii along the altitudinal gradient, as well as their physiological adaption indicators. Leaf area decreased, while the mass per area and thickness of leaf increased at an altitude above 4,100 m. The maxima of pigment, total nitrogen concentration, net photosynthesis rate during light-saturated, and when water use efficiency appeared at 4100 m altitude. In addition, A. georgei var. smithii seedlings regulated the activities of superoxide dismutase and ascorbate peroxidase to resist abiotic stress under 4100 m altitude. Meanwhile, malondialdehyde concentration and the dark respiration rate rapidly increased, which indicates that A. georgei var. smithii seedlingssuffered from heavy abiotic stress from 4100 m to 4390 m altitude. Basing on variations in leaf functional traits along the altitude gradient, we inferred that 4100 m altitude was the suitable region for A. georgei var. smithii growth in the Sygera Mountain. Moreover, the harsh environment was the main limiting factor for A. georgei var. smithii population expansion to high altitude.

Phosphorus diffusion and activation in fluorine co-implanted germanium after excimer laser annealing

The diffusion and the activation of phosphorus in phosphorus and fluorine co-implanted Ge after being annealed by excimer laser are investigated.The results prove that the fluorine element plays an important role in suppressing phosphorus diffusion and enhancing phosphorus activation.Moreover,the rapid thermal annealing process is utilized to evaluate and verify the role of fluorine element.During the initial annealing of co-implanted Ge,it is easier to form high bonding energy FnVm clusters which can stabilize the excess vacancies,resulting in the reduced vacancy-assisted diffusion of phosphorus.The maximum activation concentration of about 4.4 ×10^(20) cm^(-3) with a reduced diffusion length and dopant loss is achieved in co-implanted Ge that is annealed at a tailored laser fluence of 175 mJ/cm^(2).The combination of excimer laser annealing and co-implantation technique provides a reference and guideline for high level n-type doping in Ge and is beneficial to its applications in the scaled Ge MOSFET technology and other devices.

Effects of harvesting intensities and techniques on re-growth dynamics and quality of Terminalia bellerica fruits in central India

Terminalia bellericaRoxb. （Belleric myrobalan） is one of the important multipurpose trees in central India. The fruits of the tree are highly valued for medicinal uses, with the greatest demand coming from the pharmaceutical industry. This has resulted in overexploitation and present harvesting practices have led to a significant decline in natural regeneration for this tree species. Our study was conducted from 2006 to 2009 in Chhattisgarh （India） to standardize suitable harvesting practices for sustainable management for this valuable species. Experiments were conducted at four different sites located in Dhamtari, Sarguja, and Rai-garh forest divisions of the state, covering both protected and open forest in a complete randomized block design （RCBD）. At each site, linear transects of 200 m× 100 m （2 ha） were randomly selected to sample the initial population and study the effects of two harvesting methods （tradi-tional and nondestructive） and four harvesting intensities （60%, 70%, 80%, and 90%） on the sustainability ofT. bellerica. Fruits were collected and analyzed for their tannin and gallic acid content. Significant increase in tannin and gallic acid content was found with the maturity of fruits （September to December）. This is the first study to experimentally assess the consequences of harvesting ofT. bellericafruits in central India. Our findings reveal that harvesting intensity, time, and method are key factors for maintaining the population. Nondestructive harvesting meth-ods were found to be superior to traditional harvesting in terms of regen-eration, recruitment, and concentration of active ingredients. When the fruits were harvested through non-destructive means at maturity, the population of species increased. The study concludes that 70% harvest of T. bellerica fruits through non-destructive means maintains the sustain-ability and provides quality raw material for the pharmaceutical industry.

Synthesis and biological evaluation of dihydrotriazine derivatives as potential antibacterial agents

A series of 1,4-dihydro-1,3,5-triazine derivatives were designed and synthesized and their antibacterial and antifungal activities were evaluated. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains（including multidrug-resistant clinical isolates） and Gramnegative bacterial strains, with minimum inhibitory concentrations（MICs） in the range of 2.1–181.2 mmol/L. Compounds 7a and 7c presented the most potent inhibitory activities against Grampositive bacteria（e.g., Staphylococcus aureus 4220）, Gram-negative bacteria（e.g., Escherichia coli 1924）,and the fungus Candida albicans 7535, with MICs of 2.1 or 4.1 mmol/L. Especially, compound 7a was the most potent, with an MIC of 2.1 mmol/L against four multidrug-resistant, Gram-positive bacterial strains.The cytotoxic activity of the compound 7a, 7c and 7f was assessed in HepG2 cells, and the results suggest that 1,4-dihydro-1,3,5-triazine derivatives bearing a 6-benzyloxynaphthalen moiety are interesting scaffolds for the development of novel antibacterial agents.