99mTc-labeling of a dithiocarbamate-DWAY fragment using [99mTcN]2+ core for the preparation of potential 5HT1A receptor imaging agents

1-(2-methoxy phenyl) piperazine fragment of WAY100635 or its phenolic analogue, derived from DWAY is used to design the desired structure of 5HT_1A receptor imaging agents. In this study a DWAY analogue was labeled with ^99mTc-nitrido ([^99mTcN]²⁺) core via dithiocarbamate. 2-(piperazin-1-yl) phenol dithiocarbamate was synthesized by the reaction of 2-(piperazin-1-yl) phenol with an equivalent amount of carbon disulfide in KOH solution then radiolabeled with ^99mTc-nitrido core. The final complex was characterized by HPLC and its radiochemical purity was more than 90 %. In vitro stability studies have shown the complex was stable at least 4 h after labeling at room temperature. The n-octanol/water partition coefficient experiment demonstrated log p = 1.34 for ^99mTcN–OHPP–DTC. Biodistribution results showed that radio tracer had moderate brain uptake (0.39 ± 0.03 %ID/g at 15 min and 0.29 ± 0.02 %ID/g at 120 min) and good retention, suggesting that this complex may lead to a further development of a radiotracer with specific binding to 5-HT_1A receptor.     

Optical single-particle detection in nanoholes towards simple parallel detection of molecular binding events

A novel scheme for the optical detection of a few or even single gold nanoparticle labels is introduced. It utilizes sub-wavelength holes in a chromium layer on a glass substrate, where a bioaffinity reaction could take place and the outcome (regarding particle label binding) can be monitored using optical means. Experiments in combination with simulations demonstrate that the presence of particles in such a chromium hole can be simply detected by using the color information of images by a charge couple device (CCD) camera without the need for additional spectroscopy setups. The presence of gold nanoparticles leads to a detectable red-shift in the images of the respective nanohole, which is the sensing principle of the sensor.     

Polymerization of Acrylonitrile Initiated by the Redox System Peroxydisulfate-Cyclohexanol in the Presence of Silver Ion Catalyst

The kinetics of the polymerization of acrylonitrile initiated by the redox system peroxydisulfate-cyclohexanol catalyzed by silver ion has been studied. The rate of polymerization was found to be directly proportional to the first power of monomer concentration and the square roots of peroxydisulfate, cyclohexanol, and silver ion concentrations. The effect of temperature has been investigated in the range of 35 to 60°C and the overall activation energy was found to be 4.6 kcal/mol from the Arrhenius plot. A plausible kinetic scheme has been proposed to account for the observations.     

Evaluation of radon induced lung cancer risk in occupants of the old and new dwellings of the Dera Ismail Khan City,Pakistan

In order to carry out indoor radon measurement in new and old buildings of the Dera Ismail Khan city, CR-39 based radon detectors were installed in bed rooms and sitting rooms/TV lounges in 25 (each) old and new houses and were exposed to indoor radon for 90 days. After processing, mean weighted average indoor radon concentrations in old and new houses were found to be 275 ± 33 and 86 ± 18 Bq m^?3 whereas mean annual effective doses expected to be received by the occupants were 6.86 ± 0.79 and 2.1 ± 0.43 mSv year^?1, respectively. From the measured weighted average indoor radon concentration, excess relative risk factor was calculated using the risk model of BEIR VI for the age group of 35 and 55 years. Average excess lung cancer risk was found to be 1.63 ± 0.19 and 1.35 ± 0.16 and 0.5 ± 0.10 and 0.4 ± 0.08 for old and new houses, respectively.     

Rate Coefficients of C1 and C2 Criegee Intermediate Reactions with Formic and Acetic Acid Near the Collision Limit: Direct Kinetics Measurements and Atmospheric Implications

Rate coefficients are directly determined for the reactions of the Criegee intermediates (CI) CH₂OO and CH₃CHOO with the two simplest carboxylic acids, formic acid (HCOOH) and acetic acid (CH₃COOH), employing two complementary techniques: multiplexed photoionization mass spectrometry and cavity‐enhanced broadband ultraviolet absorption spectroscopy. The measured rate coefficients are in excess of 1×10^?10 cm³ s^?1, several orders of magnitude larger than those suggested from many previous alkene ozonolysis experiments and assumed in atmospheric modeling studies. These results suggest that the reaction with carboxylic acids is a substantially more important loss process for CIs than is presently assumed. Implementing these rate coefficients in global atmospheric models shows that reactions between CI and organic acids make a substantial contribution to removal of these acids in terrestrial equatorial areas and in other regions where high CI concentrations occur such as high northern latitudes, and implies that sources of acids in these areas are larger than previously recognized.     

A Targeted Review of Current Progress,Challenges and Future Perspective of g-C3N4 based Hybrid Photocatalyst Toward Multidimensional Applications

The increasing demand for searching highly efficient and robust technologies in the context of sustainable energy production totally rely onto the cost-effective energy efficient production technologies. Solar power technology in this regard will perceived to be extensively employed in a variety of ways in the future ahead, in terms of the combustion of petroleum-based pollutants, CO₂ reduction, heterogeneous photocatalysis, as well as the formation of unlimited and sustainable hydrogen gas production. Semiconductor-based photocatalysis is regarded as potentially sustainable solution in this context. g-C₃N₄ is classified as non-metallic semiconductor to overcome this energy demand and enviromental challenges, because of its superior electronic configuration, which has a median band energy of around 2.7 eV, strong photocatalytic stability, and higher light performance. The photocatalytic performance of g-C₃N₄ is perceived to be inadequate, owing to its small surface area along with high rate of charge recombination. However, various synthetic strategies were applied in order to incorporate g-C₃N₄ with different guest materials to increase photocatalytic performance. After these fabrication approaches, the photocatalytic activity was enhanced owing to generation of photoinduced electrons and holes, by improving light absorption ability, and boosting surface area, which provides more space for photocatalytic reaction. In this review, various metals, non-metals, metals oxide, sulfides, and ferrites have been integrated with g-C₃N₄ to form mono, bimetallic, heterojunction, Z-scheme, and S-scheme-based materials for boosting performance. Also, different varieties of g-C₃N₄ were utilized for different aspects of photocatalytic application i. e., water reduction, water oxidation, CO₂ reduction, and photodegradation of dye pollutants, etc. As a consequence, we have assembled a summary of the latest g-C₃N₄ based materials, their uses in solar energy adaption, and proper management of the environment. This research will further well explain the detail of the mechanism of all these photocatalytic processes for the next steps, as well as the age number of new insights in order to overcome the current challenges.     

Hydrodynamic Characteristics and Adsorption Particularity of Nanobiological Feedstock Along the Bed Height in a Novel Chromatography Column

Expanded bed adsorption (EBA) is a practical method for the separation of nanoparticulates. In order to analysis the local hydrodynamic and adsorption behavior of nanoparticle (NP)-based biological feedstock, a modified Nano Biotechnology Group EBA column with a 26-mm inner diameter was used to withdraw liquid from different axial positions of the column. Fabricated egg albumin (EA) NPs with an average size of 70 nm were employed as a model system and viral size/charge mimic to assess the relationship between hydrodynamic and adsorption performance of NPs at the different column regions. The effects of influential factors, including flow velocity and initial concentration of NPs, on NP hydrodynamic behavior and adsorption kinetics along the bed height were investigated. NP hydrodynamic studies confirmed that non-uniform behavior dominated the system and a decreasing trend of liquid mixing/dispersion with increase of bed height was observed in this column. The results demonstrated an increase in the mixing/dispersion at certain bed heights with the increase in both the velocity and feed initial concentration. Breakthrough curves were measured at various column points to determine the adsorption performance [dynamic binding capacity (DBC) and yield] in different bed positions/zones. Yield and DBC of NPs were improved along the bed height, whereas liquid velocity had the opposite effect. Increasing the initial concentration of NPs enhanced only the DBC. Separation of EA NPs under optimal conditions was 87 %, which is an excellent result for a one-pass frontal chromatography method.

     

One-pot access to indolo[2,3-b]quinolines by electrophile-triggered cross-amination/Friedel-Crafts alkylation of indoles with 1-(2-tosylaminophenyl)ketones

Activation of C2 and C3 of indoles by molecular iodine (I(2)) and base followed by in situ reaction with 1-(2-tosylaminophenyl)ketones or 2-tosylaminobenzaldehyde can afford highly substituted indolo(2,3-b)quinolines in moderate to excellent yields (up to 99%). The reaction provides a metal-free selective difunctionalization of indoles. The synthetic potential of the protocol has been illustrated by the synthesis of neocryptolepine and its 11-methyl analogue.     

Variation in antioxidant attributes at three ripening stages of guava (Psidium guajava L.) fruit from different geographical regions of Pakistan

The present investigation was carried out to appraise the levels of total phenols and vitamin C as well as antioxidant potential at three different ripening stages (un-ripe, semi-ripe and fully-ripe) of guava (Psidium guajava L.) fruit collected from three different geographical regions of Pakistan (Islamabad, Faisalabad and Bhakkar). The antioxidant potential of guava fruit extracts was assessed by means of different in-vitro antioxidant assays, namely inhibition of peroxidation in linoleic acid system, reducing power and radical scavenging capability. Overall, fruit at the un-ripe stage (G1) exhibited the highest levels of TPC, TFC, reducing power and DPPH radical scavenging activity, followed by the semi-ripe (G2) and fully-ripe (G3) stages. On the other hand, vitamin C content increased as the fruit maturity progressed, with highest value seen at the fully-ripe stage (G3) followed by the semi-ripe (G2) and un-ripe stage (G1). The concentration of vitamin C in fruits varied as: Faisalabad (136.4-247.9 mg 100 g?1), Islamabad (89.7-149.7 mg 100 g?1) and Bhakkar (73.1-129.5 mg 100 g?1). The results showed that different stages of maturation and geographical locations had profound effects on the antioxidant activity and vitamin C contents of guava fruit.