scholarly journals Biodegradation Studies of Benzene, Toluene, Ethylbenzene and Xylene (BTEX) Compounds by Gliocladium sp. and Aspergillus terreus

2020 ◽  
Vol 24 (6) ◽  
pp. 1063-1069
Author(s):  
N. Usman ◽  
H.I. Atta ◽  
M.B. Tijjani
Keyword(s):  
Room Temperature ◽  
Aspergillus Terreus ◽  
Mineral Salts ◽  
Standard Curve ◽  
Significant Difference ◽  
Petroleum Contaminated Soil ◽  
Benzene Toluene ◽  
Monoaromatic Hydrocarbons ◽  
The Mean ◽  
Btex Compounds

Benzene, toluene, ethylbenzene and xylene (BTEX) are monoaromatic hydrocarbons found frequently in petroleum and its derivatives; and they are among the most important pollutants of soil and groundwater. This study focused on harnessing the enzymatic capabilities of filamentous fungi Gliocladium sp. and Aspergillus terreus, dwelling in a petroleum-contaminated soil to degrade benzene, toluene, ethylbenzene and xylene (BTEX) compounds. The biodegradation experiment was carried out using the fungi individually and in consortium in a batch culture containing mineral salts medium supplemented with 1% v/v BTEX. The experiments were carried out in triplicates at room temperature on a rotary shaker (180rpm) for twenty five days and aliquots were taken on a five day interval to determine the hydrocarbon utilizing fungal (HUF) count and residual BTEX in order to monitor the rate of biodegradation. The hydrocarbon utilizing fungal counts were determined by direct counting using a Neubauer  Haemocytometer while, the residual BTEX was determined using absorbance values measured using a spectrophotometer and the corresponding concentrations determined from a standard curve. The highest percentage degradation of BTEX was observed with Aspergillus terreus (89.1%) while, the least was observed with Gliocladium sp. (84.4%). The growth peak was attained on the 15th day in all treatments after which the HUF counts declined. Statistical analysis showed no significant difference (P>0.05) in the mean amounts of BTEX degraded and hydrocarbon-utilizing fungal counts between the treatments. The strains of Gliocladium sp. and Aspergillus terreus used in this study showed high ability for BTEX degradation thus, they are potential candidates for bioremediation of soils contaminated with monoaromatic hydrocarbons. Keywords: Biodegradation, BTEX, Gliocladium sp., Aspergillus terreus, Monoaromatic hydrocarbons

scholarly journals Monitoring Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) Levels in Mixed-Use Residential-Commercial Buildings in Shiraz, Iran: Assessing the Carcinogenicity and Non-Carcinogenicity Risk of Their Inhabitants

2022 ◽  
Vol 19 (2) ◽  
pp. 723
Author(s):  
Zahra Baberi ◽  
Abooalfazl Azhdarpoor ◽  
Mohammad Hoseini ◽  
Mohammadali Baghapour ◽  
Zahra Derakhshan ◽  
...  
Keyword(s):  
Indoor Air ◽  
Residential Buildings ◽  
Hazard Quotient ◽  
Lifetime Cancer Risk ◽  
Mixed Use ◽  
Residential Units ◽  
Benzene Toluene ◽  
The Mean ◽  
Health Application ◽  
Btex Compounds

The aim of this study is to investigate the concentration of Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) compounds in the indoor air of residential-commercial complexes and to compare it with other residential buildings (control) as well as to assess the carcinogenicity and non-carcinogenicity risk of these pollutants. BTEX concentration was investigated in the indoor air of 30 ground floor restaurants, 30 upper residential units of the complexes, 20 adjacent residential units (control), and their corridors. The mean BTEX concentration measured in the upper residential units was reported higher than in the control residential units, though they were not significantly different. The lifetime cancer risk (LTCR) value calculated for benzene in the upper residential units was lower than 10−4 and higher than 10−6 across all ages, indicating a carcinogenicity risk. Furthermore, the mean hazard quotient (HQ) for all compounds was obtained lower than 1, suggesting no concern about the non-carcinogenicity risk of these compounds in the studied region. Nevertheless, considering the sources of benzene production in the indoor air as well as the carcinogenicity of these pollutants and the risk they pose in human health, application towards the reduction of the sources and concentration of benzene in the indoor air are necessary.

Variability and temperature dependence of the velocity of retrograde particle transport in myelinated axons

1981 ◽  
Vol 59 (8) ◽  
pp. 857-863 ◽  
Author(s):  
Richard S. Smith ◽  
Paul D. Cooper
Keyword(s):  
Temperature Dependence ◽  
Particle Velocity ◽  
Coefficient Of Variation ◽  
Room Temperature ◽  
Common Mechanism ◽  
Morphological Evidence ◽  
Myelinated Axons ◽  
Wide Range ◽  
Significant Difference ◽  
The Mean

The velocity of the retrograde transport of optically detectable particles was studied in isolated myelinated axons from Xenopus laevis at room temperature and with varying temperature. At room temperature (22–23.1 °C) the mean particle velocity was significantly different in some axons of the same animal. Results pooled from a number of axons did not indicate any significant difference in the average particle velocity in different animals. At room temperature, even though the mean particle velocity might differ between axons, the coefficient of variation of particle velocity in separate fibers tended to remain constant.The temperature dependence of mean particle velocity (V) could be adequately described by the relationship V = 0.26 exp 0.073T – 0.33, where V is in micrometres per second and T is degrees Celsius. Throughout the temperature range at which transport took place (approximately 5–35 °C) the coefficient of variation of particle velocity remained approximately constant at 0.40. All particles ceased their motion abruptly, and to some extent reversibly, at 37 °C. On morphological evidence, none of the effects of temperature appeared to be related to microtubule depolymerization.The results indicate that retrogradely transported particles with a wide range of velocities respond homogeneously to temperature changes. This supports the view that a common mechanism may underlie the motion of all the particles. No evidence was obtained that the differences between axons at room temperature could be attributed to the presence in separate axons of dissimilar proportions of faster and slower particles. Nor was the velocity–temperature characteristic in the region of room temperature sufficiently steep to explain the differences between axons. It is suggested that axons may differ in general mechanical or chemical properties so that the motion of all particles is affected uniformly.

Risk assessment of BTEX in the groundwater of Songyuan region of Songhua River in China

2015 ◽  
Vol 16 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Zhuo Zhang ◽  
Yanguo Teng ◽  
Guanlin Guo ◽  
Fasheng Li ◽  
Chao Zhang
Keyword(s):  
River Basin ◽  
Human Health Risk ◽  
Shallow Groundwater ◽  
Threshold Level ◽  
Risk Level ◽  
Songhua River ◽  
Songhua River Basin ◽  
Benzene Toluene ◽  
The Mean ◽  
Btex Compounds

BTEX compounds (benzene, toluene, ethylbenzene and xylenes (m-, p-xylene and o-xylene)) in shallow groundwater were investigated in 16 monitoring wells of the Songyuan region (Songhua River basin). Mean concentrations of benzene, toluene, ethylbenzene, and xylenes were found to be 1.53 μg/L, 1.76 μg/L, 2.11 μg/L and 0.30 μg/L, respectively. Ecological and human health risk assessments were conducted to evaluate potential adverse effects of the BTEX compounds in terms of toxicity. Toluene posed a severe ecological risk, xylenes a moderate risk, while benzene and ethylbenzene were both considered to be a low risk. The mean cancer risk for benzene was estimated to be 1.14 × 10−6, which is higher than the acceptable risk level of 1.0 × 10−6. The mean non-carcinogenic risks for benzene, toluene, ethylbenzene, and xylenes were lower than the standard threshold level of 1.0, both individually and cumulatively. In terms of a screening assessment, these results indicate that BTEX in groundwater may pose a threat to the ecosystem and residents in the Songyuan region of the Songhua River basin. This information will be useful for the further evaluation and risk management of groundwater in this area.

scholarly journals Prospective comparison of chilled versus room temperature saline irrigation in alcohol-assisted photorefractive keratectomy

2013 ◽  
Vol 5 (2) ◽  
pp. 154-160 ◽  
Author(s):  
Marcus C Neuffer ◽  
YM Khalifa ◽  
M Moshirfar ◽  
MD Mifflin
Keyword(s):  
Ocular Surface ◽  
Room Temperature ◽  
Photorefractive Keratectomy ◽  
Spherical Equivalent ◽  
Saline Irrigation ◽  
Prospective Comparison ◽  
Significant Difference ◽  
Manifest Refraction ◽  
The Mean ◽  
Contralateral Eye

Introduction: Chilled saline is commonly used to irrigate the ocular surface after photorefractive keratectomy (PRK) and is often considered by the patients to be uncomfortable. Room temperature (non-chilled) saline may be a safe and less painful alternative. Objectives: To compare pain and visual outcomes after irrigating the ocular surface with chilled saline versus room temperature saline in alcohol assisted PRK. Materials and methods: In this prospective, single-masked, randomized, contralateral eye study, myopic eyes were treated with PRK. Immediately after laser ablation one eye was irrigated with chilled saline and the other with non-chilled saline. Primary outcomes measured were pain, haze, uncorrected (UCVA) and best-corrected (BCVA) visual acuities, and manifest refraction. Results: Each group comprised of 40 eyes. There was no significant difference in pain between the groups at any point during five days after surgery. At 6 months the mean UCVA was -0.08 logMAR ± .077 [SD] (20/17) and -0.07 ± .074 logMAR (20/17) in the chilled and non-chilled groups respectively (p =.35). Both groups achieved 95% UCVA of 20/20 or better. The manifest refraction spherical equivalent (MRSE) was -0.05 ± 0.21 D and -0.025 ± 0.27 D respectively (p = .79). There were no lines lost of BCVA and no haze observed. Similar outcomes were observed with regard to pain and vision in both groups. Conclusion: The use of room temperature saline irrigation during PRK appears to be safe and effective. Nepal J Ophthalmol 2013; 5(10): 154-160 DOI: http://dx.doi.org/10.3126/nepjoph.v5i2.8706

Immunoreactive Aldolase C in Cerebrospinal Fluid of Patients with Neurological Disorders

1980 ◽  
Vol 17 (3) ◽  
pp. 110-113 ◽  
Author(s):  
V J C Willson ◽  
J G Graham ◽  
I N F McQueen ◽  
R J Thompson
Keyword(s):  
Cerebrospinal Fluid ◽  
Neurological Disorders ◽  
Gel Filtration ◽  
Elution Profile ◽  
Standard Curve ◽  
Aldolase C ◽  
Human Cerebrospinal Fluid ◽  
Significant Difference ◽  
Brain Extracts ◽  
The Mean

Nervous-system specific aldolase C has been detected in human cerebrospinal fluid (CSF) by radioimmunoassay. Measurement of 138 samples of CSF showed a mean level of 92 ± 28 ng/ml. There was no correlation between the level of CSF aldolase C and the CSF total protein, albumin, IgG, or IgA levels. Aldolase C immunoreactivity present in concentrated CSF diluted out in parallel with the standard curve in the assay and showed an elution profile on ion-exchange and gel filtration chromatography similar to that of aldolase present in whole human brain extracts. Addition of known quantities of purified aldolase C4 to CSF gave quantitative recovery on subsequent radioimmunoassay. Measurement of aldolase C in the CSF of 66 patients with neurological disorders showed several patients with levels considerably in excess of 120 ng/ml, but there was no statistically significant difference in the mean levels between groups of patients with different diseases.

scholarly journals Effect of preheating on the cytotoxicity of bulk-fill composite resins

2020 ◽  
Vol 14 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Mohammad Esmaeel Ebrahimi Chaharom ◽  
Mahmoud Bahari ◽  
Leila Safyari ◽  
Hossein Safarvand ◽  
Hajar Shafaei ◽  
...  
Keyword(s):  
Room Temperature ◽  
Composite Resin ◽  
Human Fibroblasts ◽  
Composite Resins ◽  
Significance Level ◽  
Significant Difference ◽  
Different Types ◽  
The Mean ◽  
Post Hoc ◽  
Cylindrical Samples

Background . Due to the effect of pre-heating on the degree of conversion of composite resins and the possible effect on cytotoxicity, the effect of pre-heating of bulk-fill composite resins was investigated on cytotoxicity in this study. Methods. In this study, three different types of composite resin were used, including Tetric N-Ceram Bulk-Fil, Xtrafil, and Xtrabase. From each composite resin, 10 cylindrical samples (5 mm in diameter and 4 mm in height) were prepared, with five samples preheated to 68°C, and the other five samples polymerized at room temperature (25°C). Twenty-four hours after polymerization, cytotoxicity was assessed by MTT assay on human fibroblasts. Statistical analysis of data was carried out with two-way ANOVA and Sidak Post-Hoc. The significance level of the test was determined at 0.05. Results. There was no statistically significant difference between the mean percentage of cytotoxicity in terms of pre-heating (P>0.05), but the cytotoxicity of the studied composite resins was significantly different (P<0.001). The cytotoxicity of Tetric N-Ceram Bulk-fil composite resin was higher than that of the two other composite resins. Conclusion. Pre-heating of bulk-fill composite resin did not affect their cytotoxicity. In addition, the cytotoxicity of different bulk-fill composite resins was not the same.

scholarly journals Evaluation of 18 artificial tears based on viscosity and pH

2020 ◽  
Vol 2 (2) ◽  
pp. 96-111
Author(s):  
Fatin Amalina Che Arif ◽  
Mohd Radzi Hilmi ◽  
Khairidzan Mohd Kamal ◽  
Mohd Hafidz Ithnin
Keyword(s):  
Physical Properties ◽  
Room Temperature ◽  
High Viscosity ◽  
P Value ◽  
Limited Data ◽  
Artificial Tears ◽  
Artificial Tear ◽  
Significant Difference ◽  
The Mean ◽  
Level Of Significance

Introduction: Different polymers used in artificial tear formulations influence their physical properties, such as viscosity and pH, hence affecting their bioavailability. There is limited data available from manufacturers specifying the physical properties of artificial tears, even though these data can contribute to their efficacyand effectiveness. Purpose: The aim of this study was to evaluate 18 artificial tears available in the Malaysian market based on their physical properties. Methodology: Viscosity and pH of 18 artificial tears were evaluated using rheometer and compact pH-meter, respectively, at standard room temperature (25°C). The amount of fluid used for both tests of each artificial tear was standardised using micropipette. The Kruskal-Wallis test was employed to compare the viscosity median between the three groups (low, medium, and high viscosity) of artificial tears, while the independent t-test was used to compare the pH between preservative and non-preservative artificial tears. A p-value of 0.05 was set as the level of significance. Results: The mean viscosity for all 18 artificial tears was 12.05 cP ± 10.21 within a range of 0.55 cP to 34.49 cP. There was a significant difference observed in viscosity between low- (n = 7), median- (n = 8), and high- (n = 3) viscosity groups, χ2(2) = 14.474, p = 0.001. The mean pH for all 18 artificial tears was 7.21 ± 0.43, with a range of 6.19 to 7.85. pH for preservative artificial tears was slightly alkaline compared to non-preservative artificial tears (7.26 ± 0.47 vs 7.14 ± 0.38, respectively). Conclusion: Rheological findings indicated that different formulations of artificial tears have different viscosities, with most artificial tears falling within the recommended values. There was no difference in terms of pH between preservative and non-preservative artificial tears.

scholarly journals Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and o-Xylene in Sediment-Free Iron-Reducing Enrichment Cultures

2005 ◽  
Vol 71 (6) ◽  
pp. 3355-3358 ◽  
Author(s):  
Michael K. Jahn ◽  
Stefan B. Haderlein ◽  
Rainer U. Meckenstock
Keyword(s):  
Electron Acceptor ◽  
Ferric Oxide ◽  
Aromatic Compounds ◽  
Anaerobic Degradation ◽  
Disulfonic Acid ◽  
Free Iron ◽  
Enrichment Cultures ◽  
Benzene Toluene ◽  
Monoaromatic Hydrocarbons ◽  
Btex Compounds

ABSTRACT Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX) are widespread contaminants in groundwater. We examined the anaerobic degradation of BTEX compounds with amorphous ferric oxide as electron acceptor. Successful enrichment cultures were obtained for all BTEX substrates both in the presence and absence of AQDS (9,10-anthraquinone-2,6-disulfonic acid). The electron balances showed a complete anaerobic oxidation of the aromatic compounds to CO2. This is the first report on the anaerobic degradation of o-xylene and ethylbenzene in sediment-free iron-reducing enrichment cultures.

Vowel Recognition Threshold as a Function of Temporal Segmentations

1970 ◽  
Vol 13 (4) ◽  
pp. 715-724 ◽  
Author(s):  
Richard L. Powell ◽  
Oscar Tosi
Keyword(s):  
Normal Hearing ◽  
Recognition Threshold ◽  
Vowel Sound ◽  
Significant Difference ◽  
The Mean ◽  
Vowel Recognition ◽  
Temporal Segment

Vowels were segmented into 15 different temporal segments taken from the middle of the vowel and ranging from 4 to 60 msecs, then presented to 6 subjects with normal hearing. The mean temporal-segment recognition threshold of 15 msecs with a range from 9.3 msecs for the /u/ to 27.2 milliseconds for the /a/. Misidenti-fication of vowels was most often confused with the vowel sound adjacent to it on the vowel-hump diagram. There was no significant difference between the cardinal and noncardinal vowels.

Left Ventricular Dysfunction and Blood Glycohemoglobin Levels in Young Diabetics

1991 ◽  
Vol 30 (05) ◽  
pp. 183-188
Author(s):  
A. Aydrner ◽  
A. Oto ◽  
E. Oram ◽  
O. Gedik ◽  
C. F. Bekdik ◽  
...  
Keyword(s):  
Ejection Fraction ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Left Ventricular ◽  
Diabetic Patients ◽  
Filling Fraction ◽  
Time To Peak ◽  
Significant Difference ◽  
The Mean ◽  
Hba1c Levels

Left ventricular function including regional wall motion (RWM) was evaluated by 99mTc first-pass and equilibrium gated blood pool ventriculography and glycohemoglobin (HbA1c) blood levels determined by a quantitative column technique in 25 young patients with insulin-dependent diabetes mellitus without clinical evidence of heart disease, and in healthy controls matched for age and sex. Phase analysis revealed abnormal RWM in 19 of 21 diabetic patients. The mean left ventricular global ejection fraction, the mean regional ejection fraction and the mean 1/3 filling fraction were lower and the time to peak ejection, the time to peak filling and the time to peak ejection /cardiac cycle were longer in diabetics than in controls. We found high HbA1c levels in all diabetics. There was no significant difference between patients with and without retinopathy and with and without peripheral neuropathy in terms of left ventricular function and HbA1c levels.

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