Knowledge Update

Washington, Oct 4 (IANS) After collecting some key samples on the Red Planet for the past four years, NASA's Curiosity rover is driving toward uphill destinations as part of its two-year mission extension that commenced from October 1.

The destinations include a ridge capped with material rich in the iron-oxide mineral hematite, about two-and-half km ahead and an exposure of clay-rich bedrock beyond that.

These are key exploration sites on lower Mount Sharp where Curiosity is currently investigating evidence of ancient, water-rich environments that contrast with the harsh, dry conditions on the surface of Mars today.

"We continue to reach higher and younger layers on Mount Sharp. Even after four years of exploring near and on the mountain, it still has the potential to completely surprise us," said Indian-origin project scientist Ashwin Vasavada from NASA's Jet Propulsion Laboratory, Pasadena, California.

Curiosity has taken more than 180,000 images since landing on Mars in August 2012. 

Newly available vistas include the rover's latest self-portrait from the colour camera at the end of its arm and a scenic panorama from the colour camera at the top of the mast.

"Curiosity's assignment is the ongoing study of ancient habitability and the potential for life," said Curiosity Programme Scientist Michael Meyer from NASA.

This latest drill site -- the 14th for Curiosity -- is in a geological layer about 600 feet thick called the Murray formation. 

Curiosity has climbed nearly half of this formation's thickness so far and found it consists primarily of mudstone, formed from mud that accumulated at the bottom of ancient lakes. 

The findings indicate that the lake environment was enduring, not fleeting. 

For roughly the first half of the new two-year mission extension, the rover team anticipates investigating the upper half of the Murray formation.

"We will see whether that record of lakes continues further," Vasavada said. 

The "Hematite Unit" and "Clay Unit" above the Murray formation were identified from Mars orbiter observations before Curiosity's landing. 

"The Hematite and the Clay units likely indicate different environments from the conditions recorded in older rock beneath them and different from each other. It will be interesting to see whether either or both were habitable environments," added Vasavada.

The mission is also monitoring the modern environment of Mars, including natural radiation levels.

New York, Oct 4 (IANS) US researchers have identified 41 genes that may cause gum disease, paving the way for developing compounds that can be used in targeted treatment of severe periodontitis before loss of teeth and supportive bone occurs.

Periodontal disease is inflammation of the tissue around the teeth, often causing shrinkage of the gums and loosening of the teeth.

In the study, the team "reverse-engineered" the gene expression data to build a map of the genetic interactions that lead to periodontitis and identify individual genes that appear to have the most influence on the disease.

"Our approach narrows down the list of potentially interesting regulatory genes involved in periodontitis," said Panos N Papapanou, Professor at Columbia University Medical Center (CUMC) in New York.

"This allows us to focus on the handful of genes that represent the most important players in the process rather than the whole transcriptome," Papapanou added.

The researchers examined RNA from healthy and diseased gum tissues of 120 patients with periodontitis. 

Many of the genes identified by Papapanou and his team are implicated in immune and inflammatory pathways, confirming laboratory and clinical observations of the development of periodontal disease.

"Now it's important to do the downstream work of validating these master regulator genes in the lab before we can test these genes in experimental models," Papapanou noted in the paper published in the Journal of Dental Research.

Beijing, Oct 2 (IANS) China will have 240 million people aged 60 or above by 2020.

By 2020, senior citizens will make up 17 per cent of the population, Xinhua news agency on Sunday quoted Liu Qian, deputy head of the National Health and Family Planning Commission, as saying.

Liu said there were more than 260 million chronically ill patients in the country. These illnesses were to blame for over 86 per cent of deaths in China.

Liu said the per capita annual spending on health was estimated at around $472 last year.

​New York, Oct 2 (IANS) Using a food additive, a team of researchers has created environment-friendly plastic solar cells that can be manufactured at room temperature.

The efficient, semi-printed solar cells have implications for large-scale commercial production, said the researchers from North Carolina State University and the Chinese Academy of Sciences.

Two of the key advantages are that these cells can be mass produced in the open air environment and that the process doesn't pose health or environmental hazards, said Long Ye, post-doctoral research scholar in physics at NC State.

Ye and his colleagues developed a semi-printed plastic solar cell that utilised o-methylanisole (o-MA) as the solvent. 

O-MA is a commonly used flavouring agent in foods and is non-toxic to humans.

Plastic solar cells are popular because they are lightweight, flexible, transparent and inexpensive to manufacture. 

Unfortunately, the halogen-containing solvents used in their manufacture are an obstacle to large-scale commercialisation. 

These solvents are key to making sure that the solar cell's morphology, or structure, maximises its energy efficiency. However, they are environmentally hazardous. 

"Hopefully, this work can help pave the way for printing solar cells in ambient air (room temperature)," Ye added in a paper that appeared in the journal Chemistry of Materials.

​London, Oct 2 (IANS) Excessive sugar consumption -- specifically the sugar fructose such as in soda -- has been linked to a rise in metabolic disease worldwide, a study has found.

Some investigators contend that commonly consumed amounts of sugar do not contribute to this epidemic. While others are convinced that excessive sugar ingestion is a major cause.

"There is still significant controversy as to whether sugar consumption is a major contributor to the development of diabetes," said senior author Mark Herman, Assistant Professor at Duke University.

However, "the study reveals a specific mechanism by which consuming fructose in large amounts, such as in soda, can cause problems", Herman added.

Insulin is a key hormone that regulates blood glucose after eating. Insulin resistance, when the body's metabolic tissues stop responding normally to insulin, is one of the earliest detectable changes in the progression to diabetes.

The likely cause of insulin resistance may not be the build-up of fat in the liver, as commonly believed, but may be caused by excess sugar in the liver that activates a molecular factor known as carbohydrate-responsive element-binding protein, or ChREBP.

ChREBP may then contribute to the development of both fatty liver and increased glucose production, the researchers said.

The ChREBP protein is found in several metabolic organs in mice, humans and other mammals.

"We found that no matter how much insulin the pancreas made, it couldn't override the processes started by this protein, ChREBP, to stimulate glucose production. This would ultimately cause blood sugar and insulin levels to increase, which over time can lead to insulin resistance elsewhere in the body," Herman explained.

To test their hypothesis, researchers studied mice that were genetically altered so their liver insulin signalling pathways were maximally activated -- in other words, their livers should not have been able to produce any glucose.

The researchers found that even in these mice, eating fructose triggered ChREBP-related processes in the liver, causing it to make more and more glucose, despite insulin signals telling it to stop.

Previous studies have reported that high fructose diets can cause multiple metabolic problems in humans and animals, including insulin resistance and fatty liver disease.

The finding could also help scientists one day diagnose metabolic disorders earlier on, potentially allowing patients to make changes to their diets and lifestyles sooner to prevent more serious complications.

The study published in the Journal of Clinical Investigation.

Sydney, Oct 2 (IANS) Researchers have found three-dimensional prints of a 400 million year old fish fossil that can reveal the possible evolutionary origins of human teeth.

The printed fish fossil was found around Lake Burrinjuck in southeast Australia, by researchers from The Australian National University (ANU) and Queensland Museum in Australia.

The team digitally dissected the jaws of a fossil Buchanosteus -- an armoured fish from the extinct placoderm group -- and used the 3-D prints to learn how the jaws moved and whether the fish had teeth.

"We are conducting further research on the internal tissue structure of tooth-like denticles in the mouth of the fish fossil, to determine whether they represent a transitional stage in the evolution of teeth," said Gavin Young, palaeontologist at The Australian National University (ANU).

In the study, the team used high-resolution CT scan to investigate the internal structure of very fragile fossil skulls and braincases that have been acid-etched from limestone rock.

"It's great that we are able to use recent technology, such as micro-CT scanning and 3-D printing, to examine some of the earliest known evidence of tooth-like structures in the most primitive jawed fishes," noted Carole Burrow from Queensland Museum.

The study helped determine when and how teeth -- a characteristic feature of all animal species with jaws, including humans -- had originated in evolutionary history.

The results were published in the journal Biology Letters.

​London, Oct 2 (IANS) Family history and environment of the residential area are responsible for the differences between individual immune systems, a study has found.

The study published in the journal Trends in Immunology, discusses what shapes our immune system and how it might be applied.

The study has shown that air quality, food, stress levels, sleep patterns, and lifestyle choices had a strong combined effect on immune responses.

"Diversity isn't just programmed into our genes -- it emerges from how our genes respond to the environment," said Adrian Liston, researcher at the Translational Immunology Laboratory, Belgium.

Long-term infections are responsible for most of the differences between individual immune systems. 

These interactions slowly change the cellular makeup of immune system and make it more sensitive to that specific virus but also easier for other infections to slip past its defences. 

"People without these infections don't experience these cellular changes and even with the occasional cold or fever, their immune systems stay relatively stable over time. The exception is when a person is elderly," Liston added.

Researchers have shown that ageing changes how our immune system responds to threats. 

According to the study, as one gets older an organ called the thymus gradually stops producing T cells, which are made to help to fight off infection. Without new T cells, older people are more likely to get sick and less likely to respond to vaccines.

Beyond T cells, ageing also seems to broadly change the way our immune systems react. 

"A lot of diseases that we associated with ageing have an inflammatory component, which suggests there is likely immune involvement," said Michelle Linterman, researcher at the Babraham Institute, Britain.

"Understanding how the immune system changes with age is going to be hugely important for treating age-related diseases in the future," Linterman added. 

Washington, Oct 1 (IANS) Homeopathic teething tablets and gels may pose a health risk to infants and children, the US Food and Drug Administration (FDA) has warned.

Consumers should stop using these products and dispose of any in their possession, FDA recommended on Friday. 

Homeopathic teething tablets and gels are distributed by CVS, Hyland's, and possibly others, and are sold in retail stores and online, the US drug regulator said in a statement.

Following the FDA's warning, CVS announced a voluntary withdrawal of all brands of homeopathic teething products sold in its retail stores and online at CVS.com.

"Consumers should seek medical care immediately if their child experiences seizures, difficulty breathing, lethargy, excessive sleepiness, muscle weakness, skin flushing, constipation, difficulty urinating, or agitation after using homeopathic teething tablets or gels," FDA said.

"Teething can be managed without prescription or over-the-counter remedies," said Janet Woodcock, Director of the FDA's Center for Drug Evaluation and Research. 

"We recommend parents and caregivers not give homeopathic teething tablets and gels to children and seek advice from their health care professional for safe alternatives," Woodcock noted.

The FDA is analysing adverse events reported to the agency regarding homeopathic teething tablets and gels, including seizures in infants and children who were given these products, since a 2010 safety alert about homeopathic teething tablets. 

The FDA is currently investigating this issue, including testing product samples.

​Toronto, Oct 1 (IANS) Researchers in Canada have developed two caffeine-based chemical compounds that show promise in preventing the ravages of Parkinson's disease.

Parkinson's disease attacks the nervous system, causing uncontrolled shakes, muscle stiffness, and slow, imprecise movement, chiefly in middle-aged and elderly people. 

It is caused by the loss of brain cells (neurons) that produce dopamine, an essential neurotransmitter that allows neurons to "talk" to each other.

The team from University of Saskatchewan focused on a protein called Alpha-synuclein (AS), which is involved in dopamine regulation.

In Parkinson's sufferers, AS gets misfolded into a compact structure associated with the death of dopamine-producing neurons. 

"Many of the current therapeutic compounds focus on boosting the dopamine output of surviving cells, but this is effective only as long as there are still enough cells to do the job," said one of the lead researchers Jeremy Lee from University of Saskatchewan College of Medicine.

"Our approach aims to protect dopamine-producing cells by preventing AS from mis-folding in the first place," Lee noted.

Although the chemistry was challenging, Lee explained the team synthesised 30 different "bifunctional dimer" drugs, that is, molecules that link two different substances known to have an effect on dopamine-producing cells. 

They started with a caffeine "scaffold," guided by literature that shows the stimulant has a protective effect against Parkinson's.

From this base, they added other compounds with known effects -- nicotine, the diabetes drug metformin, and aminoindan, a research chemical similar to the Parkinson's drug rasagiline.

Using a yeast model of Parkinson's disease, Lee and his team discovered two of the compounds prevented the AS protein from clumping, effectively allowing the cells to grow normally.

"Our results suggest these novel bifunctional dimers show promise in preventing the progression of Parkinson's disease," Lee said.

The findings were published in the journal ACS Chemical Neuroscience.

Singapore, Sep 30 (IANS) Oral administration of a compound derived from neem -- a medicinal plant native to the Indian sub-continent -- can significantly reduce the size of prostate tumour by up to 70 per cent as well as suppress its spread by half, a study led by an Indian-origin scientist has found.

Prostate cancer -- the most commonly diagnosed cancers worldwide -- occurs in a man's prostate -- a small walnut-shaped gland that produces seminal fluid. Current therapies available for metastatic prostate cancer are only marginally effective. 

The study revealed that nimbolide -- a bioactive terpenoid compound derived from neem plant -- can significantly suppress cell invasion and migration of prostate cancer cells, suggesting its ability to reduce tumour metastasis or spread.

"The study demonstrated that nimbolide can inhibit tumour cell viability -- a cellular process that directly affects the ability of a cell to proliferate, grow, divide, or repair damaged cell components -- and induce programmed cell death in prostate cancer cells," said Gautam Sethi, Associate Professor at the National University of Singapore (NUS). 

The findings showed that oral administration of nimbolide for 12 weeks can reduce the size of prostate cancer tumour by as much as 70 per cent and decreased its spread by about 50 per cent, without exhibiting any adverse effects.

Nimbolide directly targets glutathione reductase -- an enzyme which is responsible for maintaining the antioxidant system that regulates the STAT3 gene in the body. 

This activation of the STAT3 gene has been reported to contribute to prostate tumour growth and metastasis, explained the researchers. 

"We have found that nimbolide can substantially inhibit STAT3 activation and thereby abrogating the growth and metastasis of prostate tumour," Sethi added.

The results of the study were published in the journal Antioxidants & Redox Signaling.