Thermo-catalytic decomposition of polystyrene waste: Comparative analysis using different kinetic models.

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin-1, 10°Cmin-1, 15°Cmin-1 and 20°Cmin-1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats-Redfern) and model free methods (Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats-Redfern, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman models were found in the ranges 105-148.48 kJmol-1, 99.41-140.52 kJmol-1, 103.67-149.15 kJmol-1 and 99.93-141.25 kJmol-1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.

Overexpression of the Stress-Inducible SsMAX2 Promotes Drought and Salt Resistance via the Regulation of Redox Homeostasis in Arabidopsis.

Recent studies have demonstrated that strigolactones (SLs) also participate in the regulation of stress adaptation; however, the regulatory mechanism remains elusive. In this study, the homolog of More Axillary Branches 2, which encodes a key component in SL signaling, in the perennial oil plant Sapium sebiferum was identified and functionally characterized in Arabidopsis. The results showed that the expression of SsMAX2 in S. sebiferum seedlings was stress-responsive, and SsMAX2 overexpression (OE) in Arabidopsis significantly promoted resistance to drought, osmotic, and salt stresses. Moreover, SsMAX2 OE lines exhibited decreased chlorophyll degradation, increased soluble sugar and proline accumulation, and lower water loss ratio in response to the stresses. Importantly, anthocyanin biosynthesis and the activities of several antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX), were enhanced in the SsMAX2 OE lines, which further led to a significant reduction in hydrogen peroxide levels. Additionally, the SsMAX2 OE lines exhibited higher expression level of several abscisic acid (ABA) biosynthesis genes, suggesting potential interactions between SL and ABA in the regulation of stress adaptation. Overall, we provide physiological and biochemical evidence demonstrating the pivotal role of SsMAX2 in the regulation of osmotic, drought, and salt stress resistance and show that MAX2 can be a genetic target to improve stress tolerance.

Comparative transcriptome analysis reveals the regulatory networks of cytokinin in promoting the floral feminization in the oil plant Sapium sebiferum.

BACKGROUND: Sapium sebiferum, whose seeds contain high level of fatty acids, has been considered as one of the most important oil plants. However, the high male to female flower ratio limited the seed yield improvement and its industrial potentials. Thus, the study of the sex determination in S. sebiferum is of significant importance in increasing the seed yield. RESULTS: In this study, we demonstrated that in S. sebiferum, cytokinin (CK) had strong feminization effects on the floral development. Exogenous application with 6-benzylaminopurine (6-BA) or thidiazuron (TDZ) significantly induced the development of female flowers and increased the fruit number. Interestingly, the feminization effects of cytokinin were also detected on the androecious genotype of S. sebiferum which only produce male flowers. To further investigate the mechanism underlying the role of cytokinin in the flower development and sex differentiation, we performed the comparative transcriptome analysis of the floral buds of the androecious plants subjected to 6-BA. The results showed that there were separately 129, 352 and 642 genes differentially expressed at 6 h, 12 h and 24 h after 6-BA treatment. Functional analysis of the differentially expressed genes (DEGs) showed that many genes are related to the hormonal biosynthesis and signaling, nutrients translocation and cell cycle. Moreover, there were twenty one flowering-related genes identified to be differentially regulated by 6-BA treatment. Specifically, the gynoecium development-related genes SPATULA (SPT), KANADI 2 (KAN2), JAGGED (JAG) and Cytochrome P450 78A9 (CYP79A9) were significantly up-regulated, whereas the expression of PISTILLATA (PI), TATA Box Associated Factor II 59 (TAFII59) and MYB Domain Protein 108 (MYB108) that were important for male organ development was down-regulated in response to 6-BA treatment, demonstrating that cytokinin could directly target the floral organ identity genes to regulate the flower sex. CONCLUSIONS: Our work demonstrated that cytokinin is a potential regulator in female flower development in S. sebiferum. The transcriptome analysis of the floral sex transition from androecious to monoecious in response to cytokinin treatment on the androecious S. sebiferum provided valuable information related to the mechanism of sex determination in the perennial woody plants.

Exogenous Melatonin Confers Cadmium Tolerance by Counterbalancing the Hydrogen Peroxide Homeostasis in Wheat Seedlings.

Melatonin has emerged as a research highlight regarding its important role in regulating plant growth and the adaptation to the environmental stresses. In this study, we investigated how melatonin prevented the cadmium toxicity to wheat seedlings. The results demonstrated that cadmium induced the expression of melatonin biosynthesis-related genes and cause a significant increase of endogenous melatonin level. Melatonin treatment drastically alleviated the cadmium toxicity, resulting in increased plant height, biomass accumulation, and root growth. Cadmium and senescence treatment significantly increased the endogenous level of hydrogen peroxide, which was strictly counterbalanced by melatonin. Furthermore, melatonin treatment caused a significant increase of GSH (reduced glutathione) content and the GSH/GSSG (oxidized glutathione) ratio. The activities of two key antioxidant enzymes, ascorbate peroxidase (APX) and superoxide dismutase (SOD), but not catalase (CAT) and peroxidase (POD), were specifically improved by melatonin. Additionally, melatonin not only promoted the primary root growth, but also drastically enhanced the capacity of the seedling roots to degrade the exogenous hydrogen peroxide. These results suggested that melatonin played a key role in maintaining the hydrogen peroxide homeostasis, via regulation of the antioxidant systems. Conclusively, this study revealed a crucial protective role of melatonin in the regulation of cadmium resistance in wheat.

Nanoparticles decorated with a Schiff's base for the microextraction of Cd, Pb, Ni, and Co in environmental samples.

In this paper, we report a new liquid-liquid microextraction procedure called "nanoparticles decorated with a Schiff's base for the microextraction of Cd, Pb, Ni, and Co in environmental samples". The developed procedure was utilized for the extraction of Cd, Pb, Ni, and Co in environmental samples. The Schiff's base was formed by reacting salicylaldehyde with 3-aminopropyltriethoxysilane-functionalized iron oxide nanoparticles. Analyte extraction was conducted in a capillary column system loaded with modified nanoparticles and triton X-114 as dispersion medium. 1-Butyl-3-methylimidazolium hexafluorophosphate was employed as an extraction solvent. Acidified methanol in ultrasonic bath was used as desorption solvent, and elemental determination was carried out with flame atomic absorption spectrometer. Characterization of modified nanoparticles was performed with FTIR spectroscopy and transmission electron microscopy. Solution pH, nanoparticles amount, dispersant concentration, ionic liquid, and temperature were optimized for the extraction. Detection limits obtained for Cd, Pb, Ni, and Co were 0.183, 0.201, 0.241, and 0.192 µg L(-1), respectively, and enhancement factors were 79.1, 86.4, 95.7, and 82.0, respectively. The reproducibility of the developed procedure was in the range of 3.98-5.10%. Validation was checked by applying the developed procedure on certified reference water samples. The microextraction based on nanoparticles decorated with Schiff's base was successfully applied for the extraction of Cd, Pb, Ni, and Co in real environmental water samples.

A new dispersive liquid-liquid microextraction using ionic liquid based microemulsion coupled with cloud point extraction for determination of copper in serum and water samples.

A simple and rapid dispersive liquid-liquid microextraction procedure based on ionic liquid assisted microemulsion (IL-µE-DLLME) combined with cloud point extraction has been developed for preconcentration copper (Cu(2+)) in drinking water and serum samples of adolescent female hepatitits C (HCV) patients. In this method a ternary system was developed to form microemulsion (µE) by phase inversion method (PIM), using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and nonionic surfactant, TX-100 (as a stabilizer in aqueous media). The Ionic liquid microemulsion (IL-µE) was evaluated through visual assessment, optical light microscope and spectrophotometrically. The Cu(2+) in real water and aqueous acid digested serum samples were complexed with 8-hydroxyquinoline (oxine) and extracted into IL-µE medium. The phase separation of stable IL-µE was carried out by the micellar cloud point extraction approach. The influence of of different parameters such as pH, oxine concentration, centrifugation time and rate were investigated. At optimized experimental conditions, the limit of detection and enhancement factor were found to be 0.132 µg/L and 70 respectively, with relative standard deviation <5%. In order to validate the developed method, certified reference materials (SLRS-4 Riverine water) and human serum (Sero-M10181) were analyzed. The resulting data indicated a non-significant difference in obtained and certified values of Cu(2+). The developed procedure was successfully applied for the preconcentration and determination of trace levels of Cu(2+) in environmental and biological samples.

Occupational and environmental lead exposure to adolescent workers in battery recycling workshops.

Lead (Pb), as other environmental neurotoxicant substances, has the capability to interfere with many biochemical events present in cells throughout the body. In the present study, the environmental and occupational exposure to Pb has been assessed by analyzing the scalp hair samples of male adolescents aged 12-15 years, who have worked for the last 12-36 months in Pb battery recycling workshops (BRWs). For comparative purposes, gender and age-matched subjects living in the vicinity of recycling workshops as well as in areas without industrial activity were used as controls. The scalp hair samples were oxidized by acid in a microwave oven prior to determination of Pb by electrothermal atomic absorption spectrometry. The results indicated that both workers and nonworking exposed subjects had higher levels of Pb than nonexposed controls. The contents of Pb in scalp hair of adolescent workers in the present study were compared with those reported in other studies.

Estimation of calcium, magnesium, cadmium, and lead in biological samples from paralyzed quality control and production steel mill workers.

The determination of trace and toxic metals in the biological samples of human beings is an important clinical screening procedure. The aim of the present study was to compare the level of essential trace and toxic elements cadmium (Cd), calcium (Ca), lead (Pb), and magnesium (Mg) in biological samples (whole blood, urine, and scalp hair) of male paralyzed production (PPW) and quality control workers (PQW) of a steel mill, age ranged (35-55 years). For comparison purposes, healthy age-matched exposed referent subjects (EC), working in steel mill and control subjects (NEC), who were not working in industries and lived far away from the industrial areas, were selected as control subjects. The concentrations of electrolytes and toxic elements in biological samples were measured by atomic absorption spectrometry after microwave-assisted acid digestion. The validity and accuracy of the methodology were checked using certified reference materials. The results of this study showed that the mean values of Cd and Pb were significantly higher in scalp hair, blood, and urine samples of PPW and PQW as compared to NEC and EC (p < 0.001), whereas the concentrations of Ca and Mg were found to be lower in the scalp hair and blood but higher in the urine samples of PPW and PQW. The results show the need for immediate improvements in workplace, ventilation, and industrial hygiene practices.

Arsenic content in smokeless tobacco products consumed by the population of Pakistan: related health risk.

Extensive investigation has shown that smokeless tobacco (SLT) may cause inflammation of the oral cavity. In this study, the concentration of arsenic (As) was determined in SLT products (gutkha, mainpuri, and dry and moist snuff). Scalp hair samples of males aged 20-30 years who consumed different types of SLT products available in Pakistan were analyzed for As contents. Total As in different SLT products and in scalp hair was determined by electrothermal atomic absorption spectrometry after microwave-assisted extraction. The validity of the methodology was tested by simultaneously analyzing certified reference materials and spike recovery studies. The range of As concentrations in moist snuff, dry snuff, gutkha, and mainpuri were 0.574-1.53, 0.642-1.07, 0.246-0.622, and 0.419-0.874 µg/g, respectively. We estimated that a daily intake of 10 g of all SLT products could contribute 2.0-12.2% of the provisional maximum tolerable daily intake for As in adults. The As concentration in scalp hair of SLT consumers was higher than that of referents who had not consumed any type of tobacco products.

Determination of total selenium in pharmaceutical and herbal supplements by hydride generation and graphite furnace atomic absorption spectrometry.

The total selenium (Se) was determined in herbal and pharmaceutical supplements used for liver diseases. The total Se contents were determined in different pharmaceutical and herbal supplements by hydride generation atomic absorption spectrometry (HGAAS) and graphite furnace atomic absorption spectrometry (GFAAS) after microwave-assisted acid digestion. The accuracy of the techniques was evaluated by using certified reference material and the standard addition method. The recoveries of total Se were 99.4 and 99.0% for HGAAS and GFAAS, respectively. The precision of the techniques expressed as RSD were 2.34 and 4.54% for HGAAS and GFAAS measurements, respectively. The LOD values for HGAAS and GFAAS were 0.025 and 0.052 pglg, respectively. The concentrations of Se in pharmaceutical and herbal supplements were found in the range of 19.2-53.8 and 25.0-42.5 pg/g, respectively, corresponding to 35-76% and 45-76% of the total recommended dose of Se for adults.

Evaluation of status of arsenic, cadmium, lead and zinc levels in biological samples of normal and arthritis patients of age groups (46 - 60) and (61 - 75) years.

BACKGROUND: Arthritis is a chronic inflammatory disease resulting in inflammation of diarthrodial joints (particularly joints of hands, wrists, feet, knees, ankles, and shoulders), manifested by swelling and functional impairment. This study was designed to evaluate the levels of the toxic elements arsenic (As), cadmium (Cd), and lead (Pb) and correlate those with the essential trace element zinc (Zn) in biological samples (scalp hair, blood, and urine) of arthritis patients, in two age groups (46 - 60 and 61 - 75) of both genders. For comparison purposes all three biological samples were collected from gender- and age-matched non-arthritic subjects as referents. METHODS: The As, Cd, and Pb in biological samples were analysed by electrothermal atomic absorption spectrometry, prior to microwave assisted acid digestion. The level of Zn was determined by flame atomic absorption spectrometry. The validity and accuracy of the methodology was checked by using Certified Reference Materials (CRM) from the Community Bureau of Reference (BCR) of the Commission of the European Community and with those values obtained by conventional wet acid digestion method on the same CRMs. RESULTS: The results of this study showed that the mean values of As, Cd, and Pb were higher in blood, scalp hair, and urine samples of arthritis patients as compared to those values obtained in age-matched referent subjects. The concentration of Zn was lower in the biological samples of rheumatoid arthritis patients of both genders with respect to non-arthritic subjects. The urinary levels of the elements studied were found to be higher in the arthritis patients than in the age-matched healthy referents (p < 0.001). CONCLUSIONS: An inverse correlation was observed between Zn and toxic elements in biological samples of arthritis patients (r = 0.612 - 0.754). Intake of certain antioxidant micronutrients, particularly a zinc supplement, may protect against the development of rheumatoid arthritis.

Distribution of copper, iron, and zinc in biological samples of Pakistani hypertensive patients and referent subjects of different age groups.

BACKGROUND: The abnormal metabolism of metal ions plays an important role in health and disease conditions, and studies about them have been attracting significant interest. The aim of our study was to assess the trace metals (copper (Cu), iron (Fe), and zinc (Zn)) in biological samples (scalp hair, blood, urine) of 387 hypertensive males and females, age range 30 - 60 years, from an urban population and 439 non-hypertensive subjects of same age group and residential areas. METHODS: The element concentrations were measured by means of an atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet acid digestion method, using certified reference materials. The overall recoveries of all elements were found in the range of 95.2 - 98.7 % of certified values. RESULTS: The results indicated significantly lower levels of Cu, Fe, and Zn in the biological samples (blood and scalp hair) of hypertensive patients when compared to referents of both genders while the levels of these elements was found to be high in urine samples of hypertensive patients as compared to referents. CONCLUSIONS: The deficiency of Cu, Fe, and Zn may be synergistic with risk factors associated with hypertension. These data present guidance to clinicians and other professionals who will be investigating the deficiency of essential micronutrients in biological samples (scalp hair, serum, and blood) of hypertensive patients.

Simultaneously evaluate the toxic levels of fluoride and arsenic species in underground water of Tharparkar and possible contaminant sources: a multivariate study.

The present study investigated total arsenic (tAs), inorganic arsenic (iAs) species and fluoride ion (F(-)) contamination in underground water of Mithi and Nangarparkar subdistricts of Tharparkar, Pakistan. Statistical parameters, principal component analysis, cluster analysis, sodium absorption ratio and saturation indices (SI) were used to detect interrelation and sources of concentration of tAs, iAs species (As(3+) and As(5+)), F(-) and others physicochemical parameters. The concentration of As(3+) was measured by cloud point extraction using ammonium pyrrolidinedithiocarbamate (APDC) as complexing reagent, while inorganic arsenic (iAs) was determined by solid phase extraction, using titanium dioxide. The positive correlation was observed between F(-) contents with As species and other major ions, found in the underground water of the study area. The resulted data indicated that underground water samples of two areas of Tharparkar were severely contaminated with arsenic (0.100-3.83 mg/L) and fluoride ion (13.8-49.3mg/L), which were exceeded the World Health Organization provisional guideline values, 0.01 mg/L and 1.5mg/L, respectively. The SI of fluorite and calcite in the underground water samples showed that most of the samples were oversaturated with respect to calcite and fluorite.

Simultaneous preconcentration of toxic elements in artificial saliva extract of smokeless tobacco product, mainpuri by cloud point extraction method.

It has been extensively investigated that smokeless tobacco chewing can lead mainly to inflammation of oral cavity. In present study, the total and artificial saliva extracted toxic elements, arsenic, cadmium, nickel and lead were estimated in smokeless tobacco product, mainpuri. Cloud point extraction has been used for the preconcentration of arsenic, cadmium, nickel and lead in artificial saliva extract, using complexing reagent, ammonium pyrrolidinedithiocarbamate. Total and extractable toxic elements were measured by electrothermal atomic absorption spectrometry. The chemical variables of cloud point extraction were optimized. The validity of methodology was tested by simultaneously analyzing certified reference material (Virginia tobacco leaves) and spike recovery test. The artificial saliva extractable levels of arsenic, cadmium, nickel and lead ranged from 15-22, 45-70, 35-58, and 18-32%, respectively, of total elemental contents in mainpuri samples. It was estimated that intake of 10g of different brands of mainpuri contributing the 5.88, 55.0, 45.0 and 40.3% of the provisional maximum tolerable daily intake for arsenic, cadmium, nickel and lead, respectively for adults of ~60kg.

Cloud point extraction and flame atomic absorption spectrometric determination of cadmium and nickel in drinking and wastewater samples.

A simple method for the preconcentration of cadmium (Cd) and nickel (Ni) in drinking and wastewater samples was developed. Cloud point extraction has been used for the preconcentration of both metals, after formation of complexes with 8-hydroxyquinoline (8-HQ) and extraction with the surfactant octylphenoxypolyethoxyethanol (Triton X-114). Dilution of the surfactant-rich phase with acidified ethanol was performed after phase separation, and the Cd and Ni contents were measured by flame atomic absorption spectrometry. The experimental variables, such as pH, amounts of reagents (8-HQ and Triton X-114), temperature, incubation time, and sample volume, were optimized. After optimization of the complexation and extraction conditions, enhancement factors of 80 and 61, with LOD values of 0.22 and 0.52 microg/L, were obtained for Cd and Ni, respectively. The proposed method was applied satisfactorily for the determination of both elements in drinking and wastewater samples.

Identification and characterization of the karrikins signaling gene SsSMAX1 in Sapium sebiferum.

SUPPRESSOR OF MAX2 LIKE 1 (SMAX1) is a member of the SUPPRESSOR of MAX2 1­LIKE family of genes and is known as a target protein of KARRIKIN INSENSITIVE2 (KAI2)-MORE AXILLARY BRANCHES2 (MAX2), which mediates karrikin signaling in Arabidopsis. SMAX1 plays a significant role in seed germination, hypocotyl elongation, and root hair development in Arabidopsis. SMAX1 has not yet been identified and characterized in woody plants. This study identified and characterized SsSMAX1 in Sapium sebiferum and found that SsSMAX1 was highly expressed in the seed, hypocotyl, and root tips of S. sebiferum. SsSMAX1 was functionally characterized by ectopic expression in Arabidopsis. SsSMAX1 overexpression lines of Arabidopsis showed significantly delayed seed germination and produced seedlings with longer hypocotyl and roots than wild-type and Atsmax1 functional mutants. SsSMAX1 overexpression lines of Arabidopsis also had broader and longer leaves and petioles than wild-type and Atsmax1, suggesting that SsSMAX1 is functionally conserved. This study characterizes the SMAX1 gene in a woody and commercially valuable bioenergy plant, Sapium sebiferum. The results of this study are beneficial to future research on the molecular biology of woody plants.

Chromosomal-level genome and multi-omics dataset provides new insights into leaf pigmentation in Acer palmatum.

Acer palmatum (A. palmatum), a deciduous shrub or small arbour which belongs to Acer of Aceraceae, is an excellent greening species as well as a beautiful ornamental plant. In this study, a high-quality chromosome-level reference genome for A. palmatum was constructed using Oxford Nanopore sequencing and Hi-C technology. The assembly genome was ∼745.78 Mb long with a contig N50 length of 3.20 Mb, and 95.30 % (710.71 Mb) of the assembly was anchored into 13 pseudochromosomes. A total of 28,559 protein-coding genes were obtained, ∼90.02 % (25,710) of which could be functionally annotated. The genomic evolutionary analysis revealed that A. palmatum is most closely related to A. yangbiense and A. truncatum, and underwent only an ancient gamma whole-genome duplication event. Despite lacking a recent independent WGD, 25,795 (90.32 %) genes of A. palmatum were duplicated, and the unique/expanded gene families were linked with genes involved in plant-pathogen interaction and several metabolic pathways, which might underpin adaptability. A combined genomic, transcriptomic, and metabolomic analysis related to the biosynthesis of anthocyanin in leaves during the different season were characterized. The results indicate that the dark-purple colouration of the leaves in spring was caused by a high amount of anthocyanins, especially delphinidin and its derivatives; and the red colouration of the leaves in autumn by a high amount of cyanidin 3-O-glucoside. In conclusion, these valuable multi-omic resources offer important foundations to explore the molecular regulation mechanism in leaf colouration and also provide a platform for the scientific and efficient utilization of A. palmatum.

Evaluation of status of zinc, copper, and iron levels in biological samples of normal and arthritis patients in age groups 46-60 and 61-75 years.

BACKGROUND: A great number of studies have investigated the possible role of trace elements in the etiology and pathogenesis of rheumatoid arthritis (RA). METHODS: The aim of the study was to evaluate copper (Cu), iron (Fe), and zinc (Zn) levels in three biological samples (scalp hair, blood, and urine) in patients with rheumatoid arthritis (RA) in two groups, age ranges 46 - 60 and 61-75 years, of both genders compared to age-matched healthy individuals. A microwave assisted wet acid digestion procedure was developed as a sample pretreatment for the determination of Cu, Fe, and Zn in biological samples. The digests of all biological samples were analysed for Cu, Fe, and Zn by flame atomic absorption spectrometry (FAAS) using an air/acetylene flame. The proposed method was validated by analyzing certified reference samples of hair, blood, and urine. RESULTS: The results indicated significantly lower levels of Fe, Cu, and Zn in the biological samples (blood and scalp hair) of male and female rheumatoid arthritis patients as compared to control subjects of both genders (p < 0.01). CONCLUSIONS: These data present guidance to clinicians and other professional investigating deficiency of essential trace metals in biological samples (scalp hair and blood) of RA patients.

Evaluation of calcium, magnesium, potassium, and sodium in biological samples (scalp hair, serum, blood, and urine) of Pakistani referents and arthritis patients of different age groups.

BACKGROUND: Rheumatoid Arthritis is a chronic inflammatory disease resulting in joint inflammation (particularly joints of hands, wrists, feet, knees, ankles, and shoulder) that is manifested by swelling and functional impairment. METHODS: This study was designed to compare the levels of calcium (Ca), magnesium (mg), potassium (K), and sodium (Na) in four biological samples (scalp hair, serum, blood, and urine) of patients with rheumatoid arthritis (RA) as compared to referent subjects of both genders who do have not arthritis problems. All patients and referents were divided in two age groups, (46-60) and (61-75) years. A microwave assisted wet acid digestion procedure was used for acid digestion of biological samples. The digests of all biological samples were analysed for Ca, Mg, K, and Na by flame atomic absorption spectrometry (FAAS). The proposed method was validated by using conventional wet digestion of the same sub samples and certified reference samples of hair, serum, blood, and urine. RESULTS: The results indicated significantly lower levels of Ca, Mg, and K in the biological samples (blood, serum, and scalp hair) of male and female rheumatoid arthritis patients when compared to referents of both genders, whereas the levels of Na were found to be high in blood and urine samples of patients as compared to nonrheumatic referents. CONCLUSIONS: These data represent a guide for clinicians and other professionals who will be investigating the deficiency of essential micronutrients in biological samples (scalp hair, serum, and blood) of rheumatoid arthritis patients.

Interaction between selenium and arsenic in biological samples of psoriasis patients.

BACKGROUND: Psoriasis is a noncontagious, chronic skin disease affecting 1 in 50 people worldwide. METHODS: The aim of present study was to compare the levels of arsenic (As) and selenium (Se) in samples of whole blood, urine, and scalp hair of 418 psoriasis patients of both genders aged 25 - 55 years. All psoriatic patients lived in the vicinity of a cement factory, and were categorized as mild, moderate, and severe. For comparison purposes, 395 healthy age-matched referent/control subjects, residents of industrial and non-industrial areas, were selected. The concentrations of essential trace and toxic elements were measured by electrothermal atomic absorption spectroscopy after microwave-assisted acid digestion. The validity and accuracy of methodology was checked by using certified reference materials (CRMs) and the conventional wet acid digestion method on the same CRMs and real samples. RESULTS: The observed mean values of As were significantly higher in scalp hair, blood, and urine samples of patients with mild and severe psoriasis as compared to the controls (p = 0.01 - 0.001), while the concentrations of Se were lower in the scalp hair and blood, but higher in the urine samples of psoriasis patients of all categories. CONCLUSIONS: The deficiency of Se in psoriatic patients may undoubtedly be caused by the toxic element exposures via dust produced by the cement factory.