Determination of uranium,thorium and potassium contents of rock samples in Yemen

Uranium, thorium and potassium contents in 16 different rock samples from various sites in Republic of Yemen were determined using three different techniques of analysis: γ-spectrometry, Instrumental neutron activation analyses (INAA) and X-ray fluorescence (XRF). The concentration range for thorium, uranium and potassium were found to be from 9,810 ± 272 to 3.6 ± 1.3 ppm, 1,072 ± 40 to 1.2 ± 0.7 ppm and 11 ± 1 to 0.26 ± 0.05%, respectively.     

Low‐level Laser (Light) Therapy Increases Mitochondrial Membrane Potential and ATP Synthesis in C2C12 Myotubes with a Peak Response at 3–6 h

Low‐level laser (light) therapy has been used before exercise to increase muscle performance in both experimental animals and in humans. However, uncertainty exists concerning the optimum time to apply the light before exercise. The mechanism of action is thought to be stimulation of mitochondrial respiration in muscles, and to increase adenosine triphosphate (ATP) needed to perform exercise. The goal of this study was to investigate the time course of the increases in mitochondrial membrane potential (MMP) and ATP in myotubes formed from C2C12 mouse muscle cells and exposed to light‐emitting diode therapy (LEDT). LEDT employed a cluster of LEDs with 20 red (630 ± 10 nm, 25 mW) and 20 near‐infrared (850 ± 10 nm, 50 mW) delivering 28 mW cm² for 90 s (2.5 J cm²) with analysis at 5 min, 3 h, 6 h and 24 h post‐LEDT. LEDT‐6 h had the highest MMP, followed by LEDT‐3 h, LEDT‐24 h, LEDT‐5 min and Control with significant differences. The same order (6 h > 3 h > 24 h > 5 min > Control) was found for ATP with significant differences. A good correlation was found (r = 0.89) between MMP and ATP. These data suggest an optimum time window of 3–6 h for LEDT stimulate muscle cells.     

A novel miniaturized zinc oxide/hydroxylated multiwalled carbon nanotubes as a stir-brush microextractor device for carbamate pesticides analysis

A novel miniaturized “stir-brush microextractor” was prepared using a zinc oxide/hydroxylated multiwalled carbon nanotubes (ZnO/MWCNTs–OH) coated stainless steel brush connected to a small dc motor. The synthesized zinc oxide on each strand of stainless steel had a flower-like nanostructure when observed by a scanning electron microscope (SEM). This structure produced a large surface area before it was coated with the hydroxylated multiwalled carbon nanotubes sorbent. Under optimal conditions, the developed device provided a good linearity for the extraction of carbofuran and carbaryl, in the range of 25–500 ng mL⁻¹ and 50–500 ng mL⁻¹, respectively, with low limits of detection of 17.5 ± 2.0 ng mL⁻¹ and 13.0 ± 1.8 ng mL⁻¹. It also provided a good stir-brush-to-stir-brush reproducibility (% relative standard deviation < 5.6%, n = 6). The device was applied for the extraction and preconcentration of carbamate pesticides in fruit and vegetable samples prior to analysis with a gas chromatograph coupled with a flame ionization detector (GC–FID). Carbofuran was found at 9.24 ± 0.93 ng g⁻¹ and carbaryl was detected at 7.05 ± 0.61 ng g⁻¹ with good recoveries in the range of 73.7 ± 10.0% to 108.4 ± 2.6% for carbofuran and 75.7 ± 10.0% to 111.7 ± 5.7% for carbaryl.     

Quantitative leak test for microholes and microtears in whole gloves and glove pieces

The current leak tests for gloves are qualitative. The developed quantitative leak test uses vacuum pressure to draw measured volumes of water to detect microholes/tears in whole gloves and glove pieces. A modified plastic vacuum desiccator interfaced with a Frazier air permeability tester allowed exposure of disposable unsupported/unlined/powderless Kimtech Blue nitrile to 50 mL of water for glove pieces or to 600 mL within a whole glove at vacua of 8–9 in. (20–23 cm) and 11–12 in. (28–30 cm) water gauge, respectively. Punctures of known dimensions were made before testing in specific glove areas using 21-, 22-, 26-, 30-, and 33-gauge needles (outer/inner diameters in micrometres of 873/514, 794/413, 635/311, 476/127, 318/159 and 238/133, respectively). The length of the punctures varied from 0.13 ± 0.01 to 0.80 ± 0.11 mm. Flow rates of water through the holes/tears ranged from 2.5 ± 0.4 to 106 ± 7 mL/min for glove pieces. For whole gloves, the ranges were from 31 ± 9 to 543 ± 110 mL/min in the palm area; and 0.23 ± 0.06 to 82 ± 18 mL/min in the finger/fingertip area. The method quantified tear lengths as short as 0.13 ± 0.01 mm.     

Sorption of metal ions to untreated,alkali-treated and peroxide-bleached TMP

Knowledge about how different metal ions are bound to pulp fibers is very important for optimal metal management in pulping processes. A column chromatographic method was used to assess the differences in affinity of 14 metal ions to untreated, alkali-treated and peroxide-bleached thermomechanical pulp (TMP). A method of competition between cations in the column chromatographic experiments was used in the sorption experiments, with an excess of each metal ion compared to the total capacity of the pulp studied. The method is very sensitive and even small differences in affinities can be detected. By combining the results from sorption experiments with four different metal ion mixtures the following order of affinity was obtained: Pb²⁺ ≫ Cu²⁺ ≫ Cd²⁺ > Zn²⁺ > Ni²⁺ > Ba²⁺ > Ca²⁺ > Mn²⁺ > Sr²⁺ > Mg²⁺ ≫ Rb⁺ ≈ K⁺ > Na⁺ > Li⁺. All three types of pulps showed the same affinity order. Lead and copper ions were clearly most strongly bound to the pulp fibers. Within the alkali and alkaline earth metal groups the differences in affinity were quite small. The sorption of metal ions to pulp fibers takes place mainly by complexation, where the divalent metal ions are coordinated to functional groups (acid groups) in the fiber phase. Protonation constants and concentrations of acid groups were determined by potentiometric titration. A model with two carboxyl groups and two phenolic hydroxyl groups satisfied best the experimental data. By treatment with alkali and peroxide new acid groups were created and the total binding capacity of hydrogen ions increased from 137 μeq/g for untreated pulp to 187 and 228 μeq/g for alkali-treated and peroxide-treated pulp, respectively.     

Green and highly extraction of phenolic compounds and antioxidant capacity from kinkeliba (Combretum micranthum G. Don) by natural deep eutectic solvents (NADESs) using maceration,ultrasound-assisted extraction and homogenate-assisted extraction

Kinkeliba (C. micranthum) is a tropical plant widely used for its tremendous phytochemicals and biological activities. In the present study, three green carboxylic acid-based natural deep eutectic solvents (NADESs) were used to assess the extraction of phenolic compounds in terms of total phenolic content (TPC), total flavonoid content (TFC), individual phenolic compounds and antioxidant capacity (DPPH and FRAP assays) from dried C. micranthum leaves. For the synthesis of NADESs choline chloride was used as hydrogen bond acceptors (HBA) in combination with lactic acid (ChLa), acetic acid (ChAa) and tartaric acid (ChTa) as hydrogen bond donors (HBDs). The conventional solvents including distilled water, pure methanol and pure ethanol were used for comparison. Three extraction methods including maceration extraction (ME), homogenate-assisted extraction (HAE) and ultrasound-assisted extraction (UAE) were tested to determine the best extraction conditions. The solvents combined with the extraction methods were successfully applied for the recovery of phenolic compounds from C. micranthum leaves. ChLa exhibited the highest performance giving the TPC (21.12 ± 0.13–23.62 ± 0.58 mg GAE/g, followed by ChAc (15.49 ± 0.13–18.85 ± 0.39 mg GAE/g), water (17.08 ± 0.32–18.13 ± 0.13 mg GAE/g), ChTa (14.49 ± 0.26–17.44 ± 0.19 mg GAE/g), methanol (7.46 ± 0.45–11.64 ± 0.32 mg GAE/g) and ethanol (2.88 ± 0.39–4.60 ± 0.39 mg GAE/g), respectively. For TFC, ChLa (4.38 ± 0.09–5.01 ± 0.09 mg ECE/g) was the most prominent solvent, followed by ChAc (2.84 ± 0.04–5.01 ± 0.36 mg ECE/g), methanol (1.93 ± 053–4.85 ± 0.04 mg ECE/g), ethanol (1.49 ± 0.36–4.16 ± 0.04 mg ECE/g), ChTa (1.09 ± 0.04–3.22 ± 0.13 mg ECE/g) and water (1.15 ± 0.04–1.37 ± 0.44 mg ECE/g), respectively. The acidic NADESs especially ChLa and ChAa exhibited the best efficiencies compared to the conventional solvents. Furthermore, UAE and HAE provided good extraction efficiency in a short extraction time (30 min) in terms of the TPC, TFC, individual phenolic compounds and the antioxidant capacity compared to ME which gave a similar yield with 12 h of extraction time. Principal component analysis (PCA) showed that C. micranthum extracts could clearly be discriminated in terms of phytochemical compounds and antioxidant capacity and UAE, HAE or ME combined with ChLa ChAc or ChTa were the best choices to higher extraction efficiency.     

Binding of 6-propyl-2-thiouracil to human serum albumin destabilized by chemical denaturants

We compared the binding affinity of 6-propyl-2-thiouracil (PTU) with native and destabilized human serum albumin (HSA) as a model to assess the binding ability of albumin in patients suffering from chronic liver or renal diseases. Urea (U) and guanidine hydrochloride (Gu·HCl) at a concentration of 3.0 M were used as denaturation agents.Increasing the concentration of PTU from 0.8 × 10⁻⁵ to 1.20 × 10⁻⁴ M in the systems with HSA causes a decrease in fluorescence intensity of the protein excited with both 280 and 295 nm wavelengths. The results indicate that urea and Gu·HCl bind to the carbonyl group and then to the NH-group. To determine binding constants we used the Scatchard plots. The presence of two classes of HSA–PTU binding sites was observed. The binding constants (K_b) are equal to 1.99 × 10⁴ M⁻¹ and 1.50 × 10⁴ M⁻¹ at λ_ex = 280 nm, 5.20 × 10⁴ M⁻¹ and 1.65 × 10⁴ M⁻¹ at λ_ex = 295 nm. At λ_ex = 280 nm the number of drug molecules per protein molecule is a_I = 1.45 and a_II = 1.32 for I and II binding sites, respectively. At λ_ex = 295 nm they are a_I = 0.63 and a_II = 1.54 for the I and II binding sites.The estimation of the binding ability of changed albumin in the uremic and diabetic patients suffering from chronic liver or renal diseases is very important for safety and effective therapy.     

Appraisal of venomous metals in selected crops and vegetables from industrial areas of the Punjab Province

Due to the inadequate water sources, usually sewerage water and industrial effluents are being use for irrigation of the agricultural land around the industrial areas in Pakistan wherein crops and vegetables are cultivated. As untreated effluents contain heavy elements, toxic metals and organic pollutants that may find its way through food chain to general public and may cause health hazards. It is, therefore, mandatory to assess the toxic metals in such crops and vegetables. In this regard, samples of corn, millet, cabbage, spinach and potato were collected within the vicinity of industrial areas of the Faisalabad and Gujranwala regions. The food samples were analyzed using neutron activation analysis (NAA) technique. The highest concentration values of Arsenic (1.9 ± 0.1 μg/g) and Cobalt (0.85 ± 0.01 μg/g) were found in cabbage whereas Manganese (91.6 ± 0.2 μg/g), Antimony (0.15 ± 0.03 μg/g) and Selenium (1.1 ± 0.1 μg/g) were observed in spinach and Chromium (9.63 ± 1.3 μg/g) was found in millet crop. The observed concentrations of all the toxic and heavy metals in crops and vegetables are higher than those reported in the literature.     

Polarity-guided phytochemical extraction,polyphenolic characterization,and multimode biological evaluation of Seriphidium kurramense (Qazilb.) Y. R. Ling

Purpose of studyThe undertaken study aims to assess the polyphenolic profile, and antioxidant, antimicrobial, antiviral, antidiabetic, and cytotoxic potential of Seriphidium kurramense (Qazilb.) Y. R. Ling extracts.MethodsExtracts of aerial parts were prepared by successive extraction (n-hexane {Sk-nH}, ethyl acetate {Sk-EA}, methanol {Sk-M} and aqueous {Sk-Aq}). Chromogenic assays determined the antioxidant profile while HPLC quantified several polyphenols. Agar well diffusion was employed for antimicrobial potential while brine shrimp and hemolytic assays established the biosafety profile.ResultsThe results have shown that maximum extract recovery (17.49% w/w), total phenolics content (24.44 ± 0.15 μg GAE/mgE), and total flavonoids content (6.87 ± 0.25 μg QE/mgE) were recorded in Sk-Aq. RP-HPLC quantified a significant amount of syringic acid (1.43 ± 0.05 µg/mgE), caffeic acid (0.48 ± 0.02 µg/mgE), gentisic acid (6.44 ± 0.01 µg/mgE), and quercetin (4.39 ± 0.01 µg/mgE) in Sk-Aq, while maximum amounts of thymoquinone (0.21 ± 0.02 µg/mgE) and luteolin (3.90 ± 0.03 µg/mgE) along with apigenin (3.72 ± 0.03 µg/mgE) existed in Sk-M and highest quantities of ferulic acid (2.98 ± 0.01 µg/mgE), myricetin (1.04 ± 0.02 µg/mgE) and kaempferol (1.23 ± 0.01 µg/mgE) were found to be present in Sk-EA. A substantial free radical scavenging (85.87 ± 1.00%), total reducing power (211.93 ± 0.97 µg AAE/mgE), and urease inhibition activity (87.99 ± 0.19% at 500 µg/ml) were also recorded in the Sk-Aq. The highest antioxidant capacity (243.5 ± 1.12 µg AAE/mgE), antibacterial, antifungal, and antiviral activity (100% reduction in plaque formation at 400 µg/ml) were observed for Sk-EA. Maximum antibacterial and antifungal activities were revealed against Klebsiella pneumoniae (MIC = 25 ± 0.37 µg/ml), and Candida albicans (MIC = 50 ± 0.19 µg/ml) respectively. The prominent antidiabetic potential was displayed by Sk-nH in terms of α-amylase and α-glucosidase inhibition.ConclusionThe results reported, herein suggest that S. kurramense can be a promising candidate for antioxidant, antibacterial, antifungal, antiviral, and antidiabetic secondary metabolites.     

An examination of the vaporization enthalpies and vapor pressures of pyrazine, pyrimidine, pyridazine, and 1,3,5-triazine

The vaporization enthalpies and liquid vapor pressures from T = 298.15 K to T = 400 K of 1,3,5-triazine, pyrazine, pyrimidine, and pyridazine using pyridines and pyrazines as standards have been measured by correlation-gas chromatography. The vaporization enthalpies of 1,3,5-triazine (38.8 ± 1.9 kJ mol⁻¹) and pyrazine (40.5 ± 1.7 kJ mol⁻¹) obtained by these correlations are in good agreement with current literature values. The value obtained for pyrimidine (41.0 ± 1.9 kJ mol⁻¹) can be compared with a literature value of 50.0 kJ mol⁻¹. Combined with the condensed phase enthalpy of formation in the literature, this results in a gas-phase enthalpy of formation, Δ_f H _m (g, 298.15 K), of 187.6 ± 2.2 kJ mol⁻¹ for pyrimidine, compared to a value of 195.1 ± 2.1 calculated for pyrazine. Vapor pressures also obtained by correlation are used to predict boiling temperatures (BT). Good agreement with experimental BT (±4.2 K) including results for pyrimidine is observed for most compounds with the exception of the pyridazines. The results suggest that compounds containing one or two nitrogen atoms in the ring are suitable standards for correlating various heterocyclic compounds provided the nitrogen atoms are isolated from each other by carbon. Pyridazines do not appear to be evaluated correctly using pyridines and pyrazines as standards.     

Ultra low level deep water <Superscript>137</Superscript>Cs activity in the South Pacific Ocean

We determined ¹³⁷Cs concentrations in deep water samples of the subtropical gyre in the South Pacific collected during the BEAGLE2003 cruise. This was done at an underground facility to achieve extremely low background γ-spectrometry, and we, therefore, obtained reliable values of ¹³⁷Cs activity in the deeper layers. ¹³⁷Cs activity in the layers between 2000 and 4500 m ranged from 7 ± 4 mBq m⁻³ to 25 ± 11 mBq m⁻³. The inventory of ¹³⁷Cs in the water column from 2000 m to the sea bottom was estimated to be 20 ± 8 Bq m⁻² to 94 ± 41 Bq m⁻² in this region.     

A molecular insight into deoiled asphalt’s slurry-phase hydrocracking process

Qilu vacuum residue with Ni + V content of 120 ppm and Ca content of 40 ppm, is hard to process for fixed bed hydrocracking technology. In this work, solvent deasphalting process was used as a pretreatment for processing Qilu vacuum residue, and the yield of deasphalted oil could be up to 48.3 %, with less metal (Ni + V + Ca < 15 ppm) and asphaltene (<0.1 %) in deasphalted oil. The n-butane solvent in solvent deasphalting (SDA) process had higher selectivity for HC class, and correspondingly the relative abundance of HC class of deasphalted oil (DAO) was much higher than that of deasphalted oil (DAO). The abundance of DAO was higher than that of DOA when double bond equivalent (DBE) < 14 or carbon number (CN) < 46, and the relative abundance of SDA1-DOA was higher than that of SDA2-DOA when DBE < 20 or CN < 46. Deoiled asphalt was taken as the feed of slurry-phase hydrocracking (SHC) process, and the conversion ratio of deoiled asphalt in slurry-phase hydrocracking process could be more than 80 % for 240 min reaction. The conversion ratios of SDA1-DOA for SHC1-120 min and SHC1-240 min reactions were 66.92 % and 81.64 % respectively, and the conversion ratios of SDA2-DOA for SHC2-120 min and SHC2-240 min reactions were 70.19 % and 85.71 % respectively. Sulfur species and asphaltene changing rules at molecular level were determined to evaluate DOA’s slurry-phase hydrocracking process.     

Optimization of Direct Blue 71 sorption by organic rich-compost following multilevel multifactor experimental design

Removal of a troublesome textile dye, Direct Blue 71 (DB71) from water by a food waste compost was assessed in the current study. Since compost dye sorption is a multi-factor process influenced by mass, pH, concentration, temperature, contact time, and salinity, the cumulative influence of all parameters on DB71 removal was examined following an optimal multilevel multifactor experimental design. The process had to be presented using both linear and interaction terms, according to the variables analysis: Dye sorption = –0.050Mass + 0.122Conc–0.114pH + 0.132Time – 0.074Temp + 0.056Sal + 0.103Mass × Conc + 0.226 Mass × pH – 0.257Mass × Time – 0.112Mass × Temp – 0.041Mass × Sal + 0.008Conc × pH + 0.100Conc × Time + 0.089Conc × Temp + 0.167Conc × Sal – 0.245pH × Time – 0.231pH × Temp – 0.123pH × Sal + 0.358Tim × Temp + 0.355Tim × Sal – 0.045Temp × Sal (R² = 0.9241)Salinity and pH were positively correlated with concentration, and contact time with temperature and salinity, to get better dye uptake. The optimal conditions for dye removal were the following: solid:liquid ratio 1:375, pH 3.0, initial dye concentration 400 mg L^?1, contact time 240 min, salinity 0.6 M NaCl, temperature 50 °C. At the optimum combination of factors, equilibrium sorption isotherm and sorption kinetics were studied. Kinetic analysis indicated high sorption rate 4.0 mg g^?1 min^?1 while 28% of maximum capacity was reached within the first 10 min of interaction. Sorption isotherm has L2-shape which reflected surface saturation at high solute concentration with low competition with solvent molecules, with a maximum sorption capacity of 95.4 mg g^?1. In column experiments performed at bed depth 5.1–12.8 cm, flow rate 1.0–2.0 mL min^?1 and influent concentration 10–20 mg L^?1, sorption capacity was 19.6 mg g^?1, which represents 21% of the maximum capacity at equilibrium conditions. IR analysis of dye-loaded-compost confirmed the contribution of hydrophobic-hydrophobic forces in the sorption process.     

Synthesis characterization and evaluation of novel triazole based analogs as a acetylcholinesterase and α-glucosidase inhibitors

A series of novel triazole analogs (10a-k) bearing piperidine were synthesized in an aprotic solvent on the most effective pharmacophore with acetylcholinesterase (AChE) and α-glucosidase inhibitory activity. Triazole analogs (10a-k) were obtained in excellent yields (75–90 %) and characterized by EI-MS, IR, ¹³C NMR and ¹H NMR. The newly synthesized triazole analogs (10a-k) showed potent AChE inhibitory activity in the range of K_i = 0.0155 ± 1.25 µM to 0.557 ± 0.50 µM, IC₅₀ = 0.031 ± 0.85 to 0.537 ± 0.76 µM than Eserine (0.04 ± 0.001 µM) having strong electron-withdrawing fluorine group on the pyridine ring was recorded as a most potent inhibitor of AChE while (%) inhibition against α-glucosidase was ranging between 52.36 ± 1.67 to 85.35 ± 1.39. The kinetic study predicted that triazole analogs (10a-k) followed the un-competitive and mixed type of inhibition against AChE. In silico molecular docking was performed at the active site of the AChE co-crystal structure (PDB ID:1NEN). The results of molecular docking corelate will with the experimental findings.     

Measurement of naturally occurring/fallout radioactive elements and assessment of annual effective dose in soil samples collected from four districts of the Punjab Province,Pakistan

Soil samples were collected from different localities of districts Jhelum, Chakwal, Rawalpindi and Attock, Punjab Province, Pakistan with an aim to measure naturally occurring radionuclides, namely ²²⁶Ra, ²³²Th, ⁴⁰K and fallout ¹³⁷Cs radionuclide using a P-type coaxial high purity germanium (HPGe) γ-ray spectrometer. Measured specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K in these soil samples ranged from 26.02 ± 7.11 to 93.54 ± 8.13 Bq kg⁻¹, 29.34 ± 2.58 to 114.41 ± 2.80 Bq kg⁻¹ and 348.15 ± 3.20 to 752.98 ± 4.20 Bq kg⁻¹, respectively. Activity due to ¹³⁷Cs was observed in some locations which ranged from 0.4 ± 0.2 to 7.8 ± 0.3 Bq kg⁻¹. From the measured activity concentrations, radium equivalent activity concentrations were determined followed by calculations of mean absorbed dose rate and mean annual effective dose for the inhabitants of the studied area. The mean radium equivalent activity, internal and external hazard indices values came out to be 179.26 ± 11.93 Bq kg⁻¹, 0.64 ± 0.05 and 0.48 ± 0.03, respectively. Indoors and outdoor average annual effective dose values were found to be 0.42 ± 0.03 and 0.10 ± 0.01 mSv, respectively. Present data have been compared with the published data for other parts of the world and found to be safe for public and environment.     

LC–MS analysis of low molecular weight organic acids derived from root exudation

A sensitive method for quantification of citric, fumaric, malic, malonic, oxalic, trans aconitic, and succinic acid in soil- and root-related samples is presented. The method is based on a novel, fast, and simple esterification procedure and subsequent analysis via liquid chromatography–mass spectrometry. Derivatization comprises in situ generation of HCl, which catalyzes the Fischer esterification with benzyl alcohol. As a key advance, the esterification with the aromate allows reversed-phase separation and improves electrospray ionization efficiency. The method provided procedural detection limits of 1 nM for citric, 47 nM for fumaric, 10 nM for malic, 10 nM for malonic, 16 nM for oxalic, 15 nM for succinic, and 2 nM for aconitic acid utilizing 500 μL of liquid sample. The working range was 3 nM to 10 μM for citric acid, 158 nM to 10 μM for fumaric acid, 34 nM to 10 μM for malic acid, 33 nM to 10 μM for malonic acid, 53 nM to 10 μM for oxalic acid, 48 nM to 10 μM for succinic acid, and 6 nM to 10 μM for aconitic acid. Quantification of the analytes in soil-related samples was performed via external calibration of the entire procedure utilizing ¹³C-labeled oxalic and citric acid as internal standards. The robustness of the method was tested with soil extracts and samples from hydroponic experiments. The latter concerned the regulation of phosphorus solubilization via plant root exudation of citric, malic, and oxalic acid.     

Thermal investigations associated with the behaviour patterns of resting workers of <Emphasis Type="Italic">Bombus atratus</Emphasis> (Hymenoptera: Apidae)

The Neotropical bumblebee Bombus (Fervidobombus) atratus Franklin is widely distributed in South America ranging from tropical and subtropical lowlands to high altitudes in the Andes. Thermal investigations of the Neotropical bumblebee Bombus atratus at rest were performed by means of thermometry. Most social insects are diurnal foragers. When they are inside their nests during the night, they carry out some tasks such as cleaning the nest, brood care or nest thermoregulation. However, forager bees generally pause at night in a sleep-like state. A bumblebee nest was transferred to a brood chamber which was maintained at approximately constant temperature (28 ± 1 °C) to prevent the workers from building the protecting involucrum so that one could mark them at birth. To provide a temperature gradient, two chambers were installed adjacent to the brood chamber, so that the workers had the chance to choose between 3 temperatures: the first one kept at 22 ± 1 °C, the second at 19 ± 1 °C and 28 ± 1 °C. The temperatures of the chambers were recorded continuously by a four channel data logger. Three categories of tasks performed by workers were registered in this investigation: warming brood (task 1), feeding brood (task 2) and foragers (task 3). During the experiment 357 workers were born and 252 (71%) of them showed sleep-like behaviour. The total sleep time in hours according to the work done by the workers was task 1 (240.6 h) > task 3 (236.0 h) > task 2 (227.3 h). The workers who performed tasks 1 and 2 preferred to sleep at the highest temperature (28 ± 1 °C) and the forager workers at 22 ± 1 °C.     

Phenolic composition,antioxidant and enzyme inhibitory activities of Parkia biglobosa (Jacq.) Benth., Tithonia diversifolia (Hemsl) A. Gray,and Crossopteryx febrifuga (Afzel.) Benth

Medicinal plants from Chad grow under special climatic conditions in between the equatorial forest of Central Africa and the desert of North Africa and are understudied. Three medicinal plants from Chad (T. diversifolia, P. Biglobosa and C. Febrifuga) were evaluated for their phenolic composition, antioxidant and enzyme inhibition activities. The total phenolic composition varied from 203.19 ± 0.58 mg GAE/g DW in the ethyl acetate extract of P. biglobosa, to 56.41 ± 0.89 mg GAE/g DW in the methanol extract of C. febrifuga while the total flavonoid content varied from 51.85 ± 0.91 mg QE/g DW in the methanol extract of P. biglobosa to 08.56 ± 0.25 mg QE/g DW in the methanol extract of C. febrifuga. HPLC-DAD revealed that rutin, gallic acid and protocatechuic acid were the most abundant phenolics in T. diversifolia, P. Biglobosa and C. Febrifuga respectively. The antioxidant activity assayed by five different methods revealed very good activity especially in the DPPH^?, ABTS^?+ and CUPRAC assays where the extracts were more active than the standard compounds used. Good inhibition was exhibited against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with methanol (IC₅₀: 15.63 ± 0.72 µg/mL), ethyl acetate (IC₅₀: 16.20 ± 0.67 µg/mL) extracts of P. biglobosa, and methanol (IC₅₀: 21.53 ± 0.65 µg/mL) and ethyl acetate (IC₅₀: 30.81 ± 0.48 µg/mL) extracts of T. diversifolia showing higher inhibition than galantamine (IC₅₀: 42.20 ± 0.44 µg/mL) against BChE. Equally, good inhibition was shown on α-amylase and α-glucosidase. On the α-glucosidase, the ethyl acetate (IC₅₀ = 12.47 ± 0.61 µg/mL) and methanol extracts (IC₅₀ = 16.51 ± 0.18 µg/mL) of P. biglobosa showed higher activity compared to the standard acarbose (IC₅₀ = 17.35 ± 0.71 µg/mL) and on α-amylase, the ethyl acetate (IC₅₀ = 13.50 ± 0.90 µg/mL) and methanol (IC₅₀ = 18.12 ± 0.33 µg/mL) extracts of P. biglobosa showed higher activity compared to acarbose (IC₅₀ = 23.84 ± 0.25 µg/mL). The results indicate that these plants are good sources of antioxidant phenolics and can be used to manage oxidative stress linked illnesses such as Alzheimer’s disease and diabetes.     

Re-examination of 7,7′-dimethyl-7-germanorbornadiene photocleavage in solution and in organic glasses

Dimethylgermylene and its Ge=Ge doubly bonded dimer, tetramethyldigermene, have been characterized directly in solution by 308-nm laser flash photolysis in n-hexane solution, as well as 254-nm photolysis in hydrocarbon glasses at t = 77 K. An absorption band maximum of λ _max ≈ 430 nm and molar absorption coefficient of ε ≈ 2,700 M⁻¹ cm⁻¹ have been shown to be attributable to low-temperature glasses, while the absorption band maximum of λ _max ≈ 480 nm and molar absorption coefficient of ε ≈ 2,400 M⁻¹ cm⁻¹ have been shown to be related to dimethylgermylene in n-hexane solution. The molar absorption coefficient of tetramethyldigermene (λ _max ≈ 380 nm) was determined to be ε ≈ 84,000 M⁻¹ cm⁻¹. The germylene is formed via (formal) cheletropic photocycloreversion of 7,7′-dimethylgerma-1,4,5,6-tetraphenyl-2,3-benzo-norbornadiene. Tetramethyldigermene and 1,2,3,4-tetraphenylnaphthalene in the triplet state were formed, together with dimethylgermylene. We attempted to explain the various contradictory interpretations of experimental data existing in the literature on this reaction.     

Phytochemical,antioxidant, enzyme inhibitory,thrombolytic, antibacterial,antiviral and in silico studies of Acacia jacquemontii leaves

The main objective of this work was to gain insight into biological propensities, and bioactive phytochemicals of Acacia jacquemontii Benth, a wild plant providing medicinal components, as well as to establish a link between its phytochemical profile and biological activities. Phytochemical profiling revealed the presence of a higher amount of total phenolic (271.44 ± 4.41 mg GAE/g) and flavonoid contents (216.47 ± 5.82 mg QE/g) in methanolic extract (MEAJ), and as compared to n-hexane fraction (HEAJ) and stronger biological activities of MEAJ were possibly linked to the higher bioactive contents. The freshly collected plant leaves showed a strong antioxidant potential (total antioxidant capacity 1.03 ± 0.19 mmol TE/g), which was found even stronger in dried methanolic extract (TAC; 4.36 ± 1.12 mmol TE/g), moreover, MEAJ also showed strong antioxidant potential when investigated by different antioxidant assays (DPPH; 154.04 ± 2.47, ABTS; 122.36 ± 0.80, FRAP; 453.18 ± 5.9, CUPRAC; 1389.97 ± 5.32 mg TE/g). The MEAJ showed good tyrosinase inhibition activity (71.69 %), compared with 83 % inhibition by kojic acid. Ten major compounds identified by GC–MS were docked and eight legends showed lower binding energies (-6 to ?7.8 kcal/mol) compared with kojic acid (-5.9 kcal/mol), which shows the possible role of these compounds in the anti-tyrosinase activity of the extract, and the ADMET analysis predicted the drug-likeness and safety profile of the studied compounds. The thrombolytic effect of MEAJ was 56.41 ± 0.75 to 57.15 ± 1.41 % which was comparable with streptokinase (82.44 ± 1.15 to 84.14 ± 0.95 %). Antibacterial activity of MEAJ was also good (MEAJ; 0.5–2.0 mg/mL, and co-amoxiclav; 5.0–12.5 µg/mL), and the highest activity was observed against Bacillus subtilis (MEAJ; 0.5 mg/mL, co-amoxiclav; 5.0 µg/mL). The antiviral activity of MEAJ was highly strong (HA titer; 00 to 08) against all the tested strains. It can be concluded that A. jacquemontii is a prospective source of phytochemicals with strong biological activities, and their usage in formulations of natural products and pharmaceuticals is recommended, however, further research may address the discovery and development of novel drugs for the pharmaceutical industry.