Alkil benzen’den türetilmiş amfifillerin, asfalten çökelmesini geciktirici özellikleri sebebiyle, asfalt endüstrisinde kullanıldığı bilinmektedir, ancak bu konuda yapılmış çalışmalar kısıtlıdır. ...Çalışma kapsamında, deterjan endüstrisinde kullanılan lineer alkil benzen sülfonik asit (LABSA) sürfaktanının bitüm ile kullanımı, penetrasyon ve yumuşama noktası deneyi ile dinamik kayma reometresi kullanılarak incelenmiştir. Farklı LABSA içerikleri ile üretilmiş numunelerin penetrasyon indeksi ve kompleks kayma modül değerleri göz önünde bulundurularak sıcaklık hassasiyeti ve viskoelastik davranışları araştırılmıştır. Ayrıca, numunelerin kısa dönem ve uzun dönem yaşlanma sonrasındaki performansları da incelenerek LABSA içeriğinin yaşlanmaya karşı etkileri irdelenmiştir. Elde edilen sonuçlara göre, LABSA kullanımının sıcaklık hassasiyetini belirgin özellikte azalttığı ve bitüme elastik davranış kazandırdığı görülmektedir. Bitüm ağırlığının %2’si oranında LABSA kullanımı, sıcaklık hassasiyeti ve elastik performans açısından en uygun sonuçları vermektedir. Bununla birlikte, LABSA modifikasyonunun bitümün yaşlanmaya karşı direncini arttırmaktadır.
Svrha je uvođenja graničnih vrijednosti profesionalne izloženosti (engl. occupational exposure limits, krat. OELs) upravljanje rizikom ne bi li se zaštitilo zdravlje i dobrobit radnika od štetnih ...agensa kojima su izloženi na radnome mjestu. U ovom smo pregledu izdvojili granične koncentracije benzena, toluena, etilbenzena, ksilena (BTEX) i stirena u zraku i, analizirajući 49 članaka objavljenih u zemljama (jugo) zapadne Azije od 1980. do 2021., pronađenih sustavnom pretragom literature, ocijenili profesionalnu izloženost tim spojevima. Granične vrijednosti za BTEX i stiren uvedene su samo u Iranu i Turskoj, i na sličnim su razinama kao one koje vrijede u europskim zemljama I SAD-u. Analiziranih 49 članaka obuhvaćaju istraživanja izloženosti u šest zemalja, ali se većina (njih 40) odnosi na Iran. Prosječna profesionalna izloženost benzenu u radnika u industrijama povezanima s naftom viša je od preporučene granične vrijednosti, a profesionalna izloženost ostalim spojevima niža je od lokalnih graničnih vrijednosti (tamo gdje su uvedene). Trenutačno nema dovoljno podataka o razinama profesionalne izloženosti BTEX-u i stirenu u zemljama (jugo)zapadne Azije, stoga je u njima potrebno regulirati granične vrijednosti i primjenjivati ih. Osim toga, potrebno je provoditi sustavna istraživanja ne bi li se utvrdile stvarne razine profesionalne izloženosti, odgovori na koncentracije onečišćivala i gospodarske i tehničke mogućnosti industrija tih zemalja da riješe trenutačne probleme.
Biodegradation can achieve complete and cost-effective elimination of aromatic pollutants through harnessing diverse microbial metabolic processes. Aromatics biodegradation plays an important role in ...environmental cleanup and has been extensively studied since the inception of biodegradation. These studies, however, are diverse and scattered; there is an imperative need to consolidate, summarize, and review the current status of aromatics biodegradation. The first part of this review briefly discusses the catabolic mechanisms and describes the current status of aromatics biodegradation. Emphasis is placed on monocyclic, polycyclic, and chlorinated aromatic hydrocarbons because they are the most prevalent aromatic contaminants in the environment. Among monocyclic aromatic hydrocarbons, benzene, toluene, ethylbenzene, and xylene; phenylacetic acid; and structurally related aromatic compounds are highlighted. In addition, biofilms and their applications in biodegradation of aromatic compounds are briefly discussed. In recent years, various biomolecular approaches have been applied to design and understand microorganisms for enhanced biodegradation. In the second part of this review, biomolecular approaches, their applications in aromatics biodegradation, and associated biosafety issues are discussed. Particular attention is given to the applications of metabolic engineering, protein engineering, and “omics” technologies in aromatics biodegradation.
The aim of introducing occupational exposure limits (OELs) is to use them as a risk management tool in order to protect workers’ health and well-being against harmful agents at the workplace. In this ...review we identify OELs for benzene, toluene, ethylbenzene, xylene (BTEX), and styrene concentrations in air and assess occupational exposure to these compounds through a systematic literature search of publications published in West Asian countries from 1980 to 2021. OELs for BTEX and styrene have been set in Iran and Turkey to levels similar to those in European countries and the US. The search yielded 49 full-text articles that cover studies of exposure assessment in six countries, but most (n=40) regard Iran. Average occupational exposure to benzene of workers in oil-related industries is higher than recommended OEL, while average occupational exposure to other compounds is lower than local OELs (where they exist). Currently, information about levels of occupational exposure to BTEX and styrene is insufficient in West Asian countries, which should be remedied through OEL regulation and application. Furthermore, coherent research is also needed to determine actual levels of occupational exposure, dose-responses, and the economic and technical capacity of local industries to address current issues.
A new class of materials was prepared from aniline-containing oligomers that are covalently linked to the nucleobases of duplex DNA. Oligomers composed of repeating aniline (PANI) or 4-aminobiphenyl ...(PAB) units having the properties of conducting polymers conjoined to the DNA were prepared by the reaction of horseradish peroxidase and H2O2 with DNA having the appropriate monomers aligned within the major groove. These oligomers exhibit the spectral and chemical properties typical of para-linked polyanilines. This method of preparation enables utilization of the unique self-recognizing properties and sequence programmability of DNA to create tailored oligomers. This ability was demonstrated experimentally by preparation of PAB oligomers from alternating benzene and aniline monomers. Conjoined conducting polymers carrying the sequence information of DNA may have applicability as nanowires.
Celem pracy jest charakterystyka czasowego i przestrzennego rozkładu zanieczyszczeń komunikacyjnych (NO2, PM10, O3, C6H6) na trzech stacjach monitoringu jakości powietrza na obszarze Warszawy. ...Analizowany okres to 2011–2013. Uzyskano wyższe stężenia na stacji Komunikacyjna niż na stacjach referencyjnych: Targówek i Ursynów. Wzrost stężeń zanieczyszczeń komunikacyjnych był obserwowany w godzinach szczytu: porannego o 7–11 oraz popołudniowego o 15–20 spowodowanego wzrostem natężenia ruchu drogowego na badanym obszarze. Określono również związek między wartościami stężenia analizowanych zanieczyszczeń i warunkami meteorologicznymi.
Nuclear xenobiotic receptor CAR activates transcription of the
CYP2B6 gene by directly binding to the distal enhancer PB responsive enhancer module (PBREM). This CAR-mediated activation is synergized ...by transcription factors early growth response 1 (EGR1) and hepatocyte-enriched nuclear factor 4α (HNF4α) that bind to the proximal element OA response element KI (OARE
KI) Inoue, K., & Negishi, M. (2008). Nuclear receptor CAR requires early growth response 1 to activate the human cytochrome P450 2B6 gene. J. Biol. Chem. 283, 10425–10432. Two additional EGR1 binding sites have now been found just downstream from PBREM. Internal deletion of EGR1 sites within the context of the −1.8
kb
CYP2B6 promoter, which contains both PBREM and OARE
KI, revealed that the distal and proximal EGR1 sites are essential for EGR1 to synergize CAR-mediated transcription. Chromatin conformation capture 3C assays demonstrated that ERG1 may loop the distal PBREM towards the proximal OARE
KI so that together, CAR and HNF4α synergistically activate the
CYP2B6 promoter.
Objective: The objective of the present study was to investigate the possible effects of grape seed extract (GSE) against benzene-induced toxicity in Swiss albino mice.
Methods: The animals were ...randomly divided into six groups each containing six mice. Group I, treated with distilled water; Group II and III orally treated with 50 mg/kg and 150 mg/kg body weight GSE, respectively. Group IV, orally treated with 250 mg/kg body weight benzene by using feeding cannula; Group V, orally treated with 50 mg/kg body weight GSE + 250 mg/kg body weight benzene; Group VI, orally treated with 150 mg/kg body weight GSE + 250 mg/kg of body weight benzene for 50 consecutive days. At the end of experimental period all mice were sacrificed; blood, liver and kidney tissues were removed after post-mortem examination. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), creatinine levels were analyzed from serum. Malondialdehyde (MDA) and reduced glutathione (GSH) levels were analyzed from isolated tissues. And also histopathological examinations of liver and kidney tissues were investigated.
Results: Serum AST, ALT, ALP, BUN and creatinine levels were slightly increased in Group IV compared with the other tested groups (p<.05). Benzene-induced toxicity caused a significant decrease in GSH levels and a significant rise in MDA levels of liver and kidney tissues. Oral treatment with GSE significantly ameliorated the indices of hepatotoxicity, nephrotoxicity and lipid peroxidation induced by benzene. Both doses of GSE provided significant protection and the strongest effects were observed at the dose level of 150 mg/kg.
Conclusion: Consequently, it was found that GSE has a significant positive effect in benzeneinduced toxicity, and its GSE effect is dose dependent.
Mısır sapları yenilenebilir doğal kaynaklardan olup hâlihazırda endüstriyel kullanımı oldukça sınırlıdır. Bu
çalışmanın amacı mısır saplarının bir kısım kimyasal özelliklerini (holoselüloz, ...α-selüloz, lignin ve kül miktarları, alkolbenzen,
sıcak ve soğuk su ve seyreltik alkali (% 1 NaOH) çözünürlükleri) belirlemek ve orta yoğunlukta lif levha (MDF)
üretimi için uygunluğunu değerlendirmektir. Bu çalışmada, farklı oranlarda (% 0'dan % 100 kadar) mısır sapları (Zea mays
indurata Sturt.) ve karaçam (Pinus nigra) lifleri kullanılarak MDF'ler üretilmiştir. Üretilen levhaların yoğunlukları 0.6,
0.7 ve 0.8 g $cm^ {-3}$ tür. Üretilen levhaların fiziksel ve mekanik özellikleri belirlenmiştir. Yapılan kimyasal analizler mısır
saplarının holoselüloz, α-selüloz ve lignin miktarlarının diğer tarımsal artıklar ve odun ile kıyaslanabilir olduğunu
göstermiştir. Mısır sapları yapraklı/iğne yapraklı ağaçlara nazaran daha fazla kül miktarına sahiptir. Mekanik test sonuçları
ise 0.6 g $cm^ {-3}$ yoğunlukta üretilen levhalar hariç, diğer levhaların standartlarda belirtilen minimum değerlerin altına
düşmeden, sadece mısır sapları kullanılarak MDF üretilebileceği görülmüştür. Diğer taraftan karışımdaki mısır sapları
miktarının azalması ile daha iyi özelliklere sahip levhalar üretilebileceği belirlenmiştir.
Corn stalk is a renewable natural resource that currently has limited industrial utilization. The objective of this
study was to examine some chemical properties of corn stalk (holocellulose, α-cellulose, lignin and ash content, alcoholbenzene,
hot and cold water solubility, and solubility in dilute alkali 1% NaOH) and to evaluate its suitability for
medium-density fiberboard (MDF) production. Panels were produced using mixtures of corn stalk (Zea mays indurata
Sturt.) and pine (Turkish Pinus nigra) fibers in various proportions (from 0% to 100%). The panels produced had density
levels of 0.6, 0.7, and 0.8 g $cm^ {-3}$. The physical and mechanical properties of the manufactured panels were tested. Chemical
analysis shows that the holocellulose, α-cellulose, and lignin content of corn stalk was similar to that of wood and some
other crop residues. The ash content of corn stalk was higher than that of soft- and hardwoods. Mechanical test results
indicate that the panels produced utilizing solely corn stalk met the required standards, except the panels with a density
of 0.6 g $cm^ {-3}$. Increasing the pine fiber ratio in the panel mixture improved panel properties.
The electrotopological state (E‐state) index was employed to characterize the structures of 51 substituted benzenes. Eleven E‐state indices of the compounds were calculated by the computer program ...developed in our laboratory. The method for variable selection and modeling based on prediction (VSMP) was used to select an optimal combination of the variables from 11 E‐state descriptors. Then the optimal descriptors were employed to model the relationship between the relative biodegradability of the substituted benzenes and their molecular structures. A novel 5‐descriptor linear model was developed and the model has a high quality with the correlation coefficient and the root mean square error in estimation step being 0.9378 and 0.35, respectively, and these in leave‐one‐out cross‐validation procedure being 0.9210 and 0.39, respectively.
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