Heavy metal transport with adsorption for instantaneous and exponential attenuation of concentration.

Heavy metal pollutant is a serious problem in environmental pollution, and it is very difficult to eradicate once it enters the soil. As heavy metal adsorption has been proven to occur, the heavy metal's behaviour can be modeled as a transport equation with adsorption. Previous adsorption term mostly due to the concentration alone, while in here, the desorption effect given by the rate of change of the concentration is also included. Also, the heavy metals are frequently considered to enter the soil after being dumped into the soil for a certain period of time. But, quick dumping onto the soil can introduce heavy metal instantaneously. Heavy metals entering the soil through leaching or when their concentration in the soil is influenced by chemical reactions, can all lead to the exponential decay of heavy metals entering the soil. Based on two-dimensional advection diffusion equation (ADE) with the new adsorption term, analytical solutions are obtained for the cases of instantaneous and exponential attenuation of heavy metals emission to soil by the method of Laplace transform. The results highlight the significant influence of emission type on the peak concentrations. If heavy metals are instantaneously enter the soil, the peak occurs in the range of 1-3 m radius from the point of emission on the first day, while for exponential attenuation the peak occurs close to the point of emission. Furthermore, there exists a correlation between retardation factors and heavy metal concentrations, where a decrease in retardation factors leads to an increase in heavy metal concentration. It is essential to investigate both types of heavy metals emission to provide valuable information for proper pollution management, effective environmental regulations and enforcement.

Intravenous thrombolysis for multi-ethnic Asians with acute ischaemia stroke in Malaysian public primary stroke centres versus acute stroke ready hospitals: Comparison of real-world clinical outcomes.

INTRODUCTION: Intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator is beneficial in acute ischaemic stroke (AIS). We aim to compare the realworld clinical outcomes and service efficiency of IVT in Malaysian primary stroke centres (PSCs) versus acute stroke ready hospitals (ASRHs). MATERIALS AND METHODS: We conducted a multi-centre cohort study involving 5 PSCs and 7 ASRHs in Malaysia. Through review of medical records of AIS patients who received IVT from 01 January 2014 to 30 June 2021, real-world data was extracted for analysis. Univariate and multivariate regression models were employed to evaluate the role of PSCs versus ASRHs in post-IVT outcomes and complications. Statistical significance was set at p<0.05. RESULTS: A total of 313 multi-ethnic Asians, namely 231 from PSCs and 82 from ASRHs, were included. Both groups were comparable in baseline demographic, clinical, and stroke characteristics. The efficiency of IVT delivery (door-toneedle time), functional outcomes (mRS at 3 months post- IVT), and rates of adverse events (intracranial haemorrhages and mortality) following IVT were comparable between the 2 groups. Notably, 46.8% and 48.8% of patients in PSCs and ASRHs group respectively (p=0.752) achieved favourable functional outcome (mRS≤1 at 3 months post-IVT). Regression analyses demonstrated that post-IVT functional outcomes and adverse events were independent of the role of PSCs or ASRHs. CONCLUSION: Our study provides real-world evidence which suggests that IVT can be equally safe, effective, and efficiently delivered in ASRHs. This may encourage the establishment of more ASRHs to extend the benefits of IVT to a greater proportion of stroke populations and enhance the regional stroke care.

Genotoxicity following Organophosphate Pesticides Exposure among Orang Asli Children Living in an Agricultural Island in Kuala Langat, Selangor, Malaysia.

BACKGROUND: Agriculture is an important sector for the Malaysian economy. The use of pesticides in agriculture is crucial due to its function in keeping the crops from harmful insects. Children living near agricultural fields are at risk of pesticide poisoning. OBJECTIVE: To evaluate the genotoxic risk among children who exposed to pesticides and measure DNA damage due to pesticides exposure. METHODS: In a cross-sectional study 180 Orang Asli Mah Meri children aged between 7 and 12 years were studied. They were all living in an agricultural island in Kuala Langat, Selangor, Malaysia. The data for this study were collected via modified validated questionnaire and food frequency questionnaire, which consisted of 131 food items. 6 urinary organophosphate metabolites were used as biomarkers for pesticides exposure. For genotoxic risk or genetic damage assessment, the level of DNA damage from exfoliated buccal mucosa cells was measured using the comet assay electrophoresis method. RESULTS: Out of 180 respondents, 84 (46.7%) showed positive traces of organophosphate metabolites in their urine. Children with detectable urinary pesticide had a longer tail length (median 43.5; IQR 30.9 to 68.1 µm) than those with undetectable urinary pesticides (median 24.7; IQR 9.5 to 48.1 µm). There was a significant association between the extent of DNA damage and the children's age, length of residence in the area, pesticides detection, and frequency of apple consumption. CONCLUSION: The organophosphate genotoxicity among children is associated with the amount of exposure (detectability of urinary pesticide) and length of residence in (exposure) the study area.

Spot urine potassium as a potential screening test for aldosterone breakthrough.

BACKGROUND AND AIMS: Treatment with angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) may suppress aldosterone production only in the initial phase of treatment and subsequently lead to a rising level of aldosterone to baseline or higher. This phenomenon is described as aldosterone breakthrough. Apart from serial plasma aldosterone levels, there are no other test to identify this condition. The purpose of this study was to evaluate the role of spot urine potassium as a potential screening test for aldosterone breakthrough. MATERIALS AND METHODS: This was a cross sectional study involving 94 patients who were on an ACEI or ARB for a minimum duration of 40 weeks. An aldosterone cut off value of 102 pg/ml was used to define aldosterone breakthrough based on a previous study. Patients with primary hyperaldosteronism, conditions giving rise to secondary hyperaldosteronism and those who were on drugs which could interfere with the renin-angiotensin-aldosterone system were excluded. The study patients had their blood sample analysed for renal profile, renin, aldosterone and urine sample analysed for urine potassium. RESULTS: Incidence of aldosterone breakthrough in this study was 23.4%. The median urine potassium was 62.0 mmol/L in the aldosterone breakthrough group compared to the non-breakthrough group which was 38.5 mmol/L. The urine potassium showed statistically significant difference between both groups (p=0.016). The correlation coefficient was 0.284; statistically significant (p=0.006) as the sample size was large (n=94). CONCLUSION: A raised urinary potassium after initiating treatment ith ACEI or ARB is a potential screening test for aldosterone breakthrough.

Effect of iodized oil supplementation on thyroid hormone levels and mental performance among Orang Asli schoolchildren and pregnant mothers in an endemic goitre area in Peninsular Malaysia.

Although endemic goitre is no longer a major public health problem in Malaysia, iodine deficiency still remains a significant problem in a few remote settlements. The aim of this study was to determine the effectiveness of iodized oil intervention in the prevention of endemic goitre among the indigenous people in Malaysia. A pretest and post-test controlled trial was conducted among primary schoolchildren and pregnant mothers in Lasah, Sungai Siput and Perak. Legap Post and Yum Post were selected as the intervention areas, while Perwor Post and Poi Post were taken as controls. The variables studied included thyroid hormone concentrations, thyroid volume, urinary iodine excretions and mental performance. A baseline and two follow-up visits were conducted in both intervention and control areas. Intervention subjects were given iodized oil in the form of capsules which were taken orally (Laboratoire Guerbet, Paris, France). There was a significant increase in serum thyroxine hormone (T4) concentrations (p<0.0001) and a significant decrease in thyroid stimulating hormone (TSH) concentrations (p<0.05) in the schoolchildren following the intervention, however, pregnant mothers did not show any significant changes in T4 and TSH concentrations. Thyroid size was significantly reduced in both groups (p<0.05). Urinary iodine excretions showed a significant increase in both groups following the intervention (p<0.01). However, mental performance in schoolchildren was not affected. In conclusion, iodized oil (oral) is effective in reducing thyroid size, as well as improving the supply of iodine among schoolchildren and pregnant mothers in endemic goitre areas; however, its long-term effects need to be monitored closely. This method can be considered as an alternative while awaiting national coverage for the salt iodization program.

The effects of superstructure fit and loading on individual implant units: Part 2. The effects of loading a superstructure with varying degrees of fit.

This study investigated force transmission in an implant supported bridge with varying degrees of fit. The project utilised an in vitro model of five implant fixtures mounted linearly and rigidly. These supported a well-fitting cast gold superstructure via implant abutments fitted with strain gauges so as to function as force transducers. Gaps of 10-110 microns were created at the middle and one terminal abutment and loads of 50N applied over the cantilever and 230N between the terminal abutments. Force distribution was uneven, compression, tension and torque observed, and loading of the cantilever noted to generate large forces.

The effects of superstructure fit and loading on individual implant units: Part I. The effects of tightening the gold screws and placement of a superstructure with varying degrees of fit.

This in vitro study investigated forces associated with the assembly of rigidly mounted Nobelpharma implants and a 'passively' fitting cast gold superstructure. The effects of modifying the fit by 10-110 micrometers were also investigated. Measurements were made using linear resistance strain gauges mounted longitudinally on the abutments. Tightening the gold screws produced high compressive strains. These were unevenly distributed, and inconsistent. Tensile strains were produced by gaps as small as 10 micrometers between the superstructure and an abutment while the ability of a torque of 10 N-cm in the gold screw to close the gaps was dependent on their dimensions and locations.

Nutritional status of women and children in Malaysian rural populations.

This study was conducted to investigate the nutritional status of the rural population in Malaysia, especially women and children. A total of 262 women aged 18 and over and 183 children aged 2-6 years were selected using multistage cluster sampling from four locations in rural areas. It was found that the prevalence of malnutrition among children 2-6 years old ranged between 25.5% in the Malays Felda settlement scheme to 80% in the Orang Asli settlement. Malnutrition was associated with worm infestations, bottle feeding and early weaning. More than 30% of Orang Asli women were malnourished compared to less than 15% of Malay Felda settlement women. On the other hand, Malay women in the land settlement scheme had a higher risk of developing overweight and diabetes. Goitre was found among 11.5% of children; however, no cretinism was found. Breast feeding was still a common practice among rural mothers, but inadequate health education tended to reduce the duration of breast feeding and increased early weaning. Upgrading women's status in the rural areas will ultimately improve the nutritional and health status of the children and community as a whole.

Periodontal status of teeth in contact with denture in removable partial denture wearers.

The aims of the study were to determine the periodontal status of the teeth in contact with removable partial dentures (RPDs) and to compare them with other teeth in the opposing arch not related to any prosthesis. The periodontal status was also assessed in relation to the age of the dentures. Four hundred and twenty-seven patients treated with RPDs from 1981 to 1986 were recalled for examination. Prior to prosthetic treatment they were given periodontal treatment and fillings when required. Initially all were given oral hygiene instructions and motivation. They were reviewed regularly only on a short-term basis. Eighteen patients were suitable for the present study comprising of eight males and 10 females whose mean age was 41 years. The RPDs were in use from 1.5 to 8 years (mean 4.6 years). The following parameters were assessed: Plaque index (P1I), Gingival index (GI), loss of attachment (LA) and tooth mobility. The wearing of RPDs resulted in higher P1I, GI and LA compared to the controls and these differences were statistically significant. There was an increased frequency of higher P1I, GI and LA with the increase in denture age. Minor changes in tooth mobility were observed. It was concluded that the wearing of RPDs was detrimental to periodontal health in patients whose oral hygiene was less than adequate.

Other dental treatment needs in patients who requested removable partial dentures.

The aims of this study were to determine the dental and periodontal status and the associated treatment needs, other than that for prosthetic care, in patients who requested removable partial dentures. Forty-six patients who had never worn removable partial dentures before were examined for plaque index, tooth status, gingival index, loss of periodontal attachment and tooth mobility. Prior to prosthetic treatment, 15% of the teeth needed conservative treatment and 1% needed extractions. From the periodontal point of view, 65% of the teeth needed some form of related therapy, and 2% of the teeth were at risk of extraction due to advanced mobility.

Sulfate reduction relative to methane production in high-rate anaerobic digestion: technical aspects.

The effect of different substrates and different levels of sulfate and sulfide on methane production relative to sulfate reduction in high-rate anaerobic digestion was evaluated. Reactors could be acclimated so that sulfate up to a concentration of 5 g of sulfate S per liter did not significantly affect methanogenesis. Higher levels gave inhibition because of salt toxicity. Sulfate reduction was optimal at a relatively low level of sulfate, i.e., 0.5 g of sulfate S per liter, but was also not significantly affected by higher levels. Both acetoclastic and hydrogenotrophic methane-producing bacteria adapted to much higher levels of free H(2)S than the values reported in the literature (50% inhibition occurred only at free H(2)S levels of more than 1,000 mg/liter). High levels of free H(2)S affected the sulfate-reducing bacteria only slightly. Formate and acetate supported the sulfate-reducing bacteria very poorly. In the high-rate reactors studied, intensive H(2)S formation occurred only when H(2) gas or an H(2) precursor such as ethanol was supplied.

Sulfate reduction relative to methane production in high-rate anaerobic digestion: microbiological aspects.

In the high-rate anaerobic reactors studied (ca. 10 g of chemical oxygen demand [COD] removed per liter of reactor per day), the sulfate-reducing bacteria (SRB) were poor competitors of methane-producing bacteria (MPB), scavenging only on the order of 10 to 20% of the total electron flow. The relatively noncompetitive nature of the SRB in this type of reactor is in sharp contrast to the tendency of the SRB to dominate in natural environments and in other types of anaerobic digesters. Various factors such as the feedback inhibition of H(2)S on the SRB, iron limitation, the origin of the SRB inocula, biokinetics, and thermodynamics were investigated. The outcome of the SRB-MPB competition under the reactor conditions studied appeared to be particularly determined by two factors. The SRB, as predicted by the V(max)-K(m) kinetics, competed most effectively at low substrate levels (<0.5 g of COD per liter). The MPB, however, appeared to colonize and adhere much more effectively to the polyurethane carrier matrix present in the reactor, thus compensating for the apparent lower growth rates. Even if the reactor was initially allowed to be predominantly colonized by SRB, the MPB could regain dominance.