Studies in science - Latest news on science

study suggests: Low-salt diets may not be beneficial for all

Posted by saikat manna
A large worldwide study has found that, contrary to popular thought, low-salt diets may not be beneficial and may actually increase the risk of cardiovascular disease (CVD) and death compared to average salt consumption.

In fact, the study suggests that the only people who need to worry about reducing sodium in their diet are those with hypertension (high blood pressure) and have high salt consumption.
The study, involving more than 130,000 people from 49 countries, was led by investigators of the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences.
They looked specifically at whether the relationship between sodium (salt) intake and death, heart disease and stroke differs in people with high blood pressure compared to those with normal blood pressure.
The researchers showed that regardless of whether people have high blood pressure, low-sodium intake is associated with more heart attacks, strokes, and deaths compared to average intake.
"These are extremely important findings for those who are suffering from high blood pressure," said Andrew Mente, lead author of the study, a principal investigator of PHRI and an associate professor of clinical epidemiology and biostatistics at McMaster's Michael G. DeGroote School of Medicine.
"While our data highlights the importance of reducing high salt intake in people with hypertension, it does not support reducing salt intake to low levels.
"Our findings are important because they show that lowering sodium is best targeted at those with hypertension who also consume high sodium diets."
Current intake of sodium in Canada is typically between 3.5 and 4 grams per day and some guidelines have recommended that the entire population lower sodium intake to below 2.3 grams per day, a level that fewer than five per cent of Canadians and people around the world consume.
Previous studies have shown that low-sodium, compared to average sodium intake, is related to increased cardiovascular risk and mortality, even though low sodium intake is associated with lower blood pressure.
This new study shows that the risks associated with low-sodium intake -- less than three grams per day -- are consistent regardless of a patient's hypertension status.
Further, the findings show that while there is a limit below which sodium intake may be unsafe, the harm associated with high sodium consumption appears to be confined to only those with hypertension.
Only about 10 per cent of the population in the global study had both hypertension and high sodium consumption (greater than 6 grams per day).
Mente said that this suggests that the majority of individuals in Canada and most countries are consuming the right amount of salt.
He added that targeted salt reduction in those who are most susceptible because of hypertension and high salt consumption may be preferable to a population-wide approach to reducing sodium intake in most countries except those where the average sodium intake is very high, such as parts of central Asia or China.
He added that what is now generally recommended as a healthy daily ceiling for sodium consumption appears to be set too low, regardless of a person's blood pressure level.
"Low sodium intake reduces blood pressure modestly, compared to average intake, but low sodium intake also has other effects, including adverse elevations of certain hormones which may outweigh any benefits. The key question is not whether blood pressure is lower with very low salt intake, instead it is whether it improves health," Mente said
Dr. Martin O'Donnell, a co-author on the study and an associate clinical professor at McMaster University and National University of Ireland Galway, said: "This study adds to our understanding of the relationship between salt intake and health, and questions the appropriateness of current guidelines that recommend low sodium intake in the entire population."
"An approach that recommends salt in moderation, particularly focused on those with hypertension, appears more in-line with current evidence." The study was funded from more than 50 sources, including the PHRI, the Heart and Stroke Foundation of Canada and the Canadian Institutes of Health Research.
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The above post is reprinted from materials provided by McMaster UniversityNote: Materials may be edited for content and length.

Gram Staining Procedure Of Bacteria

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Gram staining: this technique was development by Danish physician, Hans Christian Gram, in 1884; which is very useful in taxonomic grouping of bacteria. The basic distinction between gram+ and gram-bacteria is in the difference of cell wall structure, along with some other characteristics. The crystal violet, iodine, ethyl alcohol (95%) and safranin are used for staining. First, the cell are stained
with crystal violet, then with gram iodine and finely washed in 95%ethanol which differentiate two  i.e., Gram+ and the other one which loses stain i.e., Gram-. The slides are washed with distilled water, followed by counter-stain with safranin for 30sec. and finely the slide are again washed with distilled water. Gram+ bacteria remain dark violet or purple coloured, but gram- bacteria become red (pink). This grouping does not depend on the shape of bacteria e.g., the bacillus shaped  bacteria like Bacillus subtails is gram+, while the other rod-shaped bacteria like coxiella burnetii is gram-. The coccus-shaped bacteria such as Escherichia coli is gram-, but sporosarcina is gram+. The detailed flow chart of the gram staining procedure is giving bellow:
groups : one which retains stain becomes dark-violet or purple coloured


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Vegetative body mycelia and consist of septate much branched hyphae. Spore on germination develop into monokaryotic or primary mycelium, either + or- typ. The primary mycelium is short lived and it soon transform into diakaryotic or secondary mycelium by the fusion of two cell of different monokaryotic mycelium following clamp connection. The hyphae of the diakaryotic mycelia interlace
twist together to form thick hyphal cord, called rhizomorph which bear the fruit bodies.


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Neem fruits
In developing countries, the losses of crops due to pest, plant disease and competition from weeds is great. In households, pest and insects such as mosquitoes, cockroaches, mice etc pose risks such as the destruction of furniture, clothing and to the causation of various diseases, most seriously; malaria. Pesticides/insectides produced to kill these pests in order to prevent these damages, also tend to have adverse effects on humans in various ways, most especially those produced from synthetic materials. These adverse effects of headache, dizziness, catarrh worth investigating. The insecticides range from agricultural to household pesticides. Every category has its own effect, both on the targeted pest/insect and the environment in which it lives.Neem has attracted worldwide attention in recent decades mainly due to


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Rauwolfia serpentina is a small erect glabrous shrub about1 to 3 feet in height, bearing white or pinkish flowers. It grows fairly wild in the United Provinces, also in Bihar and Eastern and Western Ghats. It is called ‘Sarpa-gandha’ in Sanskrit and ‘Chota Chand’ in Hindi.The roots, the leaves and the juice have been

Aloe vera plants products/benefits/uses/medicinal value (juice, gel, skin, cancer, burns)

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Aloe Vera, also known as the ‘plant of immortality’ by the ancient Egyptians, was used for its healing properties since time immemorial. The scientific epithet ‘vera’ means true and genuine. Aloe Vera plants are commonly found in the African regions and belong to the family of Liliaceae, known for its succulent or fleshy leaves. Aloe vera is a stemless or very short-stemmed succulent plant growing to 60–100 cm (24–39 in) tall, spreading by offsets. The leaves are thick and fleshy, green to grey-green, with some varieties showing white flecks on their upper and lower stem surfaces. The margin of the leaf is serrated and has small white teeth. The flowers are produced in summer on a spike up to 90 cm (35 in) tall, each flower being pendulous, with a yellow tubular corolla 2–3 cm (0.8–1.2 in) long. Like other Aloe species, Aloe vera forms arbuscular mycorrhiza, asymbiosis that allows the plant better access to mineral nutrients in soil. Aloe Vera leaf looks unique; lanceolate, it doesn’t have any stems and the edges of leaves have tiny spikes.

Medicinal uses of Rauwolfia

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Rauvolfia serpentina, or 'snakeroot' or 'sarpagandha' is a species of flowering plant in the family Apocynaceae. It is a evergreen trees and shrubs. The genus is named to honor Leonhard Rauwolf. The approximately 85 species in the genus can mainly be found in tropical regions. Rauvolfia caffra is the South African quinine tree. Rauwolfia serpentina is a small erect glabrous shrub about 1 to 3 feet in height, bearing white or pinkish flowers. It grows fairly wild in the United Provinces, also in Bihar and Eastern and Western Ghats. It is called ‘Sarpa-gandha’ in Sanskrit and ‘Chota Chand’ in Hindi. The roots, the leaves and the juice have been considered of medicinal importance from the very early times and have attracted the attention of the practitioners of the indigenous system of medicine. It has been used as an anthelmintic, as an antidote against snake bite and bites of other poisonous insects, in diarrhoea, dysentery, cholera and also as an ecbolic. In recent years interest has been stimulated in this drug, because of its well marked hypnotic and sedative properties.

Atmosphere layers of earth

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The atmosphere of the Earth serves as a key factor in sustaining the planetary ecosystem. The thin layer of gases that envelops the Earth is held in place by the planet's gravity. Dry air consists of 78% nitrogen, 21% oxygen, 1% argon and other inert gases, such as carbon dioxide. The remaining gases are often referred to as trace gases,
among which are the greenhouse gases such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Filtered air includes trace amounts of many other chemical compounds. Air also contains a variable amount of water vapor and suspensions of water droplets and ice crystals seen as clouds. Many natural substances may be present in tiny amounts in an unfiltered air sample, including dust, pollen and spores, sea spray, volcanic ash, and meteoroids. Various industrial pollutants also may be present, such as chlorine (elementary or in compounds), fluorine compounds, elemental mercury, and sulphur compounds such as sulphur dioxide [SO2].

capsicum frutescens medicinal uses

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Shrubby perennial plants; branches angular. Leaves broadly ovate, acuminate, usually wrinkled, more or less pubescent. Pedicels slender, usually 2 or more together. Calyx embracing the base of the fruit, usually cup shape. Corolla white or greenish white. Fruit red, ovoid, obtuse or oblong, acuminate.

Algae as a fuel /biofuel

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Algae are a very large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelp (large brown alga), that may grow up to 50 meters in length. Most are photosynthetic and "simple" because they lack many of the distinct cell organelles and cell types found in land plants. The largest and most complex marine forms are called seaweeds. The lipid, or oily part of the algae biomass can then be extracted and converted into biodiesel through a process similar to that used for any other vegetable oil, or converted in a refinery into "drop-in" replacements for petroleum-based fuels. The algae's carbohydrate content can be fermented into bioethanol and biobutanol.