Evaluating the impact of extraction and cleanup parameters on the yield of total petroleum hydrocarbons in soil

Interlaboratory comparisons for the analysis of mineral oil in polluted soil using the GC–FID method indicate that extraction and cleanup conditions have significant effects on the analytical results. In this investigation a ruggedness test was performed on the extraction and cleanup method for the determination of total petroleum hydrocarbons in soil. A two-level Plackett–Burman design was utilized to study the effect of 11 different method parameters on the extraction recovery of total petroleum hydrocarbons (TPH) in soil. Both qualitative and quantitative factors were investigated. The results indicate that total petroleum hydrocarbons can be relatively reliably monitored through strict implementation of the ISO and CEN draft standards. However, variation in certain method parameters readily affects the validity of the results. The most critical factors affecting TPH recovery were the solvent and co-solvent used for extraction, the extraction time, adsorbent and its weight and sample TPH concentration. Because adaptation of the draft standards especially with respect to these factors easily leads to TPH recoveries higher than 200% or lower than 70%, the validity of the adapted method should always be verified. A proper estimate of the expanded uncertainty should also be appended to TPH results, because only then can the reliability of the results be guaranteed and further justification is gained to support the end-use of the data. This also supports the credibility of the analytical services and prevents the data end-users from drawing misleading conclusions concerning the environmental risks and potential remediation requirements.     

1,3,4-Oxadiazole-containing hybrids as potential anticancer agents: Recent developments,mechanism of action and structure-activity relationships

Chemotherapy is an important therapeutic approach for the treatment of cancer. Currently, many anticancer drugs are available in the market that plays an important role in cancer treatment, but concerns such as, drug resistance and side effects create an urgent need for the development of new anti-tumor drugs with high potency and less side effects. Heterocycles are of great interest due to their fascinating anticancer activity. Among them, 1,3,4-oxadiazoles showed attracting anti-tumor activity and its derivatives are under clinical trials for the treatment of cancer. Hybridization of 1,3,4-oxadiazole moiety with other heterocyclic pharmacophoresis a promising approach to overcome various disadvantages of current anticancer drugs such as drug resistance, toxicity, and other side effects. Thus, 1,3,4-oxadiazole-heterocycle hybrids occupy a significant position in the discovery of anti-tumor drugs. Among the reported oxadiazole-based hybrids reviewed here, compounds 45i, 59j, and 62x showed the highest anticancer activity with IC₅₀ values in the nanomolar range. This review summarizes the recent developments in the anticancer potential, structure–activity relationships, and mechanisms of actions of 1,3,4-oxadiazole-heterocycle hybrids.     

Variations of antioxidant characteristics and mineral contents in pulp and peel of different apple (Malus domestica Borkh.) cultivars from Pakistan

Variations of phenolics, antioxidant activity, and mineral contents in peel and pulp of five apple (Malus domestica Borkh.) cultivars from Pakistan, namely Red Delicious, Golden Delicious, Kashmiri Amri, Kala Kulu and Sky Spur were appraised. The mean extract yield of antioxidant components obtained with 80:20 methanol-water (v/v), was found to be 22.1 g/100 g for peel and 14.2 g/100 g for pulp on a dry weight basis. The amounts of total phenolics and total flavonoids in peel and pulp of different cultivars of apple ranged from 1,907.5-2,587.9 mg gallic acid equivalent/100 g DW and 1,214.3-1,816.4 mg catechin equivalent/100 g DW and 1,185.2-1,475.5 mg GAE/100 g DW and 711.8-999.3 mg CE/100 g DW, respectively. The inhibition of linoleic acid peroxidation and DPPH scavenging activity of the extracts varied from 71.7-84.9 and 66.6-80.8% in peel, and 43.9-52.8 and 42.9-51.1% in pulp, respectively. Reducing power of the tested fruit part extracts at concentration 12.5 mg/mL ranged from 2.54-2.89 and 1.37-1.73, respectively. With regard to minerals analysis, both fruit parts showed the amount of K to be the highest, followed by Mg, Ca, Fe, Na and Zn. The results revealed that peel of the tested apple cultivars in this study had superior antioxidant capacity and mineral concentration than the pulp, indicating significant variations between the parts tested. Thus, consumption of apple fruits along with peel might be recommended to gaining better nutritive benefits.     

A Comprehensive Review on the Techniques for Extraction of Bioactive Compounds from Medicinal Cannabis

Cannabis is well-known for its numerous therapeutic activities, as demonstrated in pre-clinical and clinical studies primarily due to its bioactive compounds. The Cannabis industry is rapidly growing; therefore, product development and extraction methods have become crucial aspects of Cannabis research. The evaluation of the current extraction methods implemented in the Cannabis industry and scientific literature to produce consistent, reliable, and potent medicinal Cannabis extracts is prudent. Furthermore, these processes must be subjected to higher levels of scientific stringency, as Cannabis has been increasingly used for various ailments, and the Cannabis industry is receiving acceptance in different countries. We comprehensively analysed the current literature and drew a critical summary of the extraction methods implemented thus far to recover bioactive compounds from medicinal Cannabis. Moreover, this review outlines the major bioactive compounds in Cannabis, discusses critical factors affecting extraction yields, and proposes future considerations for the effective extraction of bioactive compounds from Cannabis. Overall, research on medicinal marijuana is limited, with most reports on the industrial hemp variety of Cannabis or pure isolates. We also propose the development of sustainable Cannabis extraction methods through the implementation of mathematical prediction models in future studies.     

Thermophysical property determination of high temperature alloys by thermal analysis

Differential scanning calorimetric measurements to determine solidus and liquidus temperatures and latent heat of fusion of two high temperature materials, PWA1484 and an experimental gamma titanium aluminide alloy, are presented. The solidus and liquidus temperatures of PWA1484 are 1340 and 1404°C. The solidus and liquidus temperatures of the titanium aluminide alloy are 1453 and 1522°C. Solidus and liquidus temperatures determined from actual heating and cooling curves, which were measured using imbedded thermocouples and analyzed by a pseudo-differential thermal analysis technique are found to be in good agreement with the differential scanning calorimetric measurements. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hot luminescence study of the intramolecular thermal bath of aromatics

We report a hot luminescence study of the vibrational relaxation in the S₁ state of anthracene and perylene in various solid matrices at 4.2 K. A set of relaxational data is evaluated and presented. The need of an external thermal bath at the initial stage of relaxation of these molecules is discussed. Some problems of distinction of resonant secondary emission components are illustrated by the mixed crystal spectra. A novel approach to the separation of scattering and hot luminescence in strongly inhomogeneous spectra at resonant excitation is introduced.     

Homeomorphisms of the Heisenberg group preserving BMO

We provide a new geometric proof of Reimann’s theorem characterizing quasiconformal mappings as the ones preserving functions of bounded mean oscillation. While our proof is new already in the Euclidean spaces, it is applicable in Heisenberg groups as well as in more general stratified nilpotent Carnot groups.     

An efficient strategy for the synthesis of 1-chloroethyl phosphates and phosphoramidates

[reaction: see text] A versatile, efficient, and simple method for the preparation of various 1-chloroethyl phosphates and phosphoramidates is described. The protected chlorophosphates or phosphoramidates are synthesized to the vinyl derivative under mild conditions, followed by conversion to the chloroethylidene phosphate or phosphoramidate by dry HCl gas, resulting in good to excellent yields. 1-Chloroethyl phosphates and phosphoramidates are excellent building blocks for the synthesis of novel ethylidene-linked phosphate prodrugs.