Md Mizanur Rahman Masud

University of the Ryukyus

Widespread contamination of arsenic (As) has become a global public health concern. Exposure to As causes respiratory complications. Asthma, a major respiratory complication, is increasing worldwide. However, the effect of chronic As exposure on the risk of asthma remains to be clarified. This study aims to examine the associations between As expos...

Various methodologies, sensitivities, and types of interference affect the quantification of plant hydrogen peroxide (H2O2) concentration. Modified ferrous oxidation xylenol orange (eFOX) assay and titanium sulfate (Ti(SO4)2 assay are relatively accessible methods. However, their correlation is unknown, for example whether we can get the same resul...

Humans and other organisms are adversely affected by cyanobacterial blooming. This study aims to investigate the long-term effects of light intensities and different temperatures on Phormidium ambiguum and Pseudanabaena foetida. Enough P. ambiguum and P. foetida cells were acclimated for 24 days at 30 °C, 20 °C, and 10 °C in separate incubators. Th...

Dams and weirs impede the continuity of rivers and transit of migratory fish. To overcome this obstacle, fishways are installed worldwide; however, management after installation is important. The Miyanaka Intake Dam has three fish ladders with different flow velocities and discharges and has been under adaptive management since 2012. Fish catch sur...

In vegetation management, understanding the condition of submerged plants is usually based on long-term growth monitoring. Reactive oxygen species (ROS) accumulate in organelles under environmental stress and are highly likely to be indicators of a plant’s condition. However, this depends on the period of exposure to environmental stress, as enviro...

We measured diurnal variations in oxidative stress conditions of cyanobacteria utilizing field observations and laboratory experiments in order to evaluate photoinhibition effects. On clear summer days, transparent bottles filled with surface water were set up at several depths and were collected every three hours together with the measurement of t...

Microcystis aeruginosa toxicity is an increasing problem for human and animal health. Therefore, this study is designed to evaluate the long-term effect of light intensities in different temperatures to eradicate M. aeruginosa. M. aeruginosa was acclimated at 30°C and 20°C in two incubators for 24 days. After 24 days of acclimatization, the first s...

The Miyanaka Intake Dam fishway underwent improvements in 2012, and we established a new rock-ramp fishway called the Seseragi Fishway, cognizant of its utility as a passage and a habitat for bottom-dwelling and small fish with weak swimming ability. However, the fishway is occasionally submerged by floods, causing sediment accumulation that leads...

In 2012, the fishway in the Miyanaka Intake Dam in Niigata Prefecture, Japan, was reconstructed and divided into three fishways (ice-harbor-, stair-, and rock-ramp-type) with different flow velocities and water depths. We conducted an adaptive monitoring survey in these fishways from 2012 to 2020, and 33 fish types were found, including migratory,...

The feasible condition for submerged macrophyte growth is hard to understand as many environmental factors contribute to establishing macrophyte distribution with different intensities generating excess reactive oxygen species (ROS). Among various kinds of ROS, hydrogen peroxide (H2O2) is relatively stable and can be measured accurately. Thus, for...

Temperature and light intensity have a significant impact on cyanobacteria. This study conducted laboratory experiments to evaluate the combined effect of different temperatures and diurnal light intensities on cyanobacteria. The sufficient Microcystis aeruginosa and Phormidium ambiguum cells were transferred into three incubators at 30°C, 20°C, an...

This study conducted laboratory experiments to evaluate the combined effect of different temperatures and diurnal light intensities on cyanobacteria. After 23 days of incubation of sufficient Microcystis aeruginosa cells at 30°C, 20°C, and 10°C temperatures, the light intensities were changed diurnally hourly by 100 µmol m − 2 s − 1 starting from 6...

Diurnal variations in oxidative stress conditions of cyanobacteria using laboratory experiments were conducted for assessing photoinhibition effects. The sufficient Microcystis aeruginosa cells were made in three sets at 30°C, 20°C, and 10°C for 23 days. The diurnal light changing exposure was performed after 23 days starting at 6:00 and continuing...

The feasible condition for submerged macrophytes to grow is hard to understand as many environmental factors contribute to establish their distribution with different intensities. Hydrogen peroxide (H2O2) is one of reactive oxidative species (ROS) was investigated to assess the possibility as an indicator to evaluate the submerged macrophyte specie...

Riparian vegetation is frequently exposed to abiotic stress, which generates reactive oxygen species (ROS) caused by strong differences in a river’s hydrological conditions. Among different ROS, hydrogen peroxide (H2O2) is relatively steady and can be measured appropriately. Thus, the quantification of plant H2O2 can be used as a stress indicator f...

The migration of fish is influenced by the unique environmental characteristics of the destination and migratory habitat preferences. There are three fishways in Miyanaka Intake Dam. The rock-ramp fishway was newly established in 2012, creating an environment with different flow velocities and water depths. The purpose of this study was to investig...

Diurnal variations of the oxidative stress condition of cyanobacteria were measured by field observations and laboratory experiments. In the field experiment, on clear summer days, transparent bottles, filled with surface water, were set up near the water surface, and several depths to 1 m deep. One bottle from each depth was collected every three...

Riparian vegetation is frequently exposed to abiotic stress generating reactive oxygen species (ROS) caused by strong differences in the hydrological conditions of the river. The current study examined the colonization by riparian vegetation communities across the elevation gradient of riparian zones, through quantification of environmental stress...

Chronic exposure to arsenic via drinking water is a serious public health issue in many countries. Arsenic causes not only cancers but also non-malignant diseases, including asthma. We have previously reported that arsenic exposure increases the risk of Th2-mediated allergic asthma. The serum level of periostin, an extracellular matrix protein acti...

The effect of combined stresses, photoinhibition, and nutrient depletion on the oxidative stress of cyanobacteria was measured in laboratory experiments to develop the biomass prediction model. Phormidium ambiguum was exposed to various photosynthetically active radiation (PAR) intensities and phosphorous (P) concentrations with fixed nitrogen conc...

Submerged macrophytes are subjected to a vast array of stresses in natural waters. Since each stress factor has a different mechanism of affecting the plants, it is often difficult to evaluate the total level of stress acting on the macrophytes. Therefore, using environmental factors to devise a common index for assessing the magnitude of the stres...

The effect of combined stresses, photoinhibition and nutrient depletion, on the oxidative stress of cyanobacteria was measured in laboratory experiments, to develop the biomass prediction model. Phormidium ambiguum was exposed to various photosynthetically active radiation (PAR) intensities and phosphorous concentrations with fixed nitrogen concent...

Limited information is available regarding the effects of arsenic exposure on immune function. We have recently reported that chronic exposure to As was associated asthma, as determined by spirometry and respiratory symptoms. Because T helper 2 (Th2)-driven immune responses are implicated in the pathogenesis of allergic diseases, including asthma,...

Riparian vegetation is constantly subjected to environmental stresses and reactive oxygen species are generated in the plant tissue due to the stress. The study examined the effect of elevation on riparian vegetation along the Hii River in Japan by quantifying the environmental stresses, using foliar hydrogen peroxide (H 2O2) concentration. In the...

An unsafe level of manganese (Mn) was detected in the drinking water in some arsenic (As)-contaminated areas in Bangladesh. Mn is an essential trace element; however, the intake of a higher level of Mn through the drinking water is associated with the development of toxicity in humans. This study was designed to evaluate the effects of As and Mn co...

Background: Arsenic poisoning is a public health problem worldwide. A few studies have reported the effects of arsenic exposure on adult cognitive function, but with limitations in the subject selection and exposure markers. Moreover, information regarding the association between arsenic exposure and biomarker of cognitive impairment is scarce. O...

Groundwater particularly drinking water contamination with metals has created an environmental disaster in Bangladesh. Manganese (Mn), an essential trace element, plays a key role in the development and function of the brain. Excess Mn exposure is reported to be associated with complex neurological disorders. Here, we have found a notably large ext...

Arsenic (As) toxicity and diabetes mellitus (DM) are emerging public health concerns worldwide. Although exposure to high levels of As has been associated with DM, whether there is also an association between low and moderate As exposure and DM remains unclear. We explored the dose-dependent association between As exposure levels and hyperglycemia,...

Career Objective: To work for an educational and research organization that aims to conduct basic researches that can improve the ways of life of people around the world and where in I can put my experience, education and skills as a dynamic researcher.

Arsenic is one of the most dominating global environmental toxicants. Specific pattern of respiratory illness caused by chronic exposure has not yet been clearly understood. Asthma is a very common pattern of respiratory illness causing increased morbidity and mortality worldwide. This study has been designed to evaluate the association between ars...

Arsenic poisoning is a major threat to the public health in many countries, including Bangladesh. Chronic arsenic exposure is associated with cognitive impairment, peripheral neuropathy, Alzheimer's diseases, dementia, and many other forms of neurological disorders. Underlying mechanism of arsenic-induced neurological disorders remains to be clarif...

It is about association between arsenic exposure and respiratory complication especially asthma.

Groundwater contaminated by arsenic in Bangladesh is one of the largest mass poisoning of population in the history. Growing evidence suggest that chronic arsenic exposure is associated with non-malignant airway obstructive (AO) diseases, however, arsenic exposure-related specific pattern of AO diseases has not yet been clearly understood. Asthma a...

The physiological condition of aquatic plants, growth and survival rates, and colony formation are all affected by a biotic stresses in nature. However, in eco hydraulics, other factors than dynamic process often do not be considered in a flume experiment or field observation, as there is not any suitable method to identify other stressors effect q...