Category Archives: Life Science

Modeling Weight Loss Over the Long Term

Researchers at the National Institutes of Health have created a mathematical model of what happens when people of varying weights, diets and exercise habits try to change their weight. The findings challenge the commonly held belief that eating 3,500 fewer calories, or burning them off exercising, will result in a pound of weight loss.

Instead, the researchers’ computer simulations indicate that this assumption overestimates weight loss because it fails to account for how metabolism changes. The computer simulations show how these metabolic changes can significantly differ among people.

However, the computer simulation of metabolism is meant as a research tool and not as a weight-loss guide for the public. The computer program can run simulations for changes in calories or exercise that would never be recommended for healthy weight loss. The researchers hope to use the knowledge gained from developing the model and from clinical trials in people to refine the tool for everyone.

“This research helps us understand why one person may lose weight faster or slower than another, even when they eat the same diet and do the same exercise,” said Kevin Hall, Ph.D., an obesity researcher and physicist at the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases. “Our computer simulations can then be used to help design personalized weight management programs to address individual needs and goals.”

The online simulation tool based on the model enables researchers to accurately predict how body weight will change and how long it will likely take to reach weight goals based on a starting weight and estimated physical activity. The tool simulates how factors such as diet and exercise can alter metabolism over time and thereby lead to changes of weight and body fat.

The team found that people’s bodies adapt slowly to changes in dietary intake. They also found heavier people can expect greater weight change with the same change in diet, though reaching a stable body weight will take them longer than people with less fat.

The model also points to a potential simplified method to approximate weight loss in an average overweight person. An adult who has a body mass index (a measure of a person’s weight in relation to his or her height) between 25 and 29.9 is considered overweight. One example: For every pound you want to lose, permanently cut 10 calories from your current intake per day. At that rate, it will take about one year to achieve half of the total weight loss, and almost all of the weight loss will have occurred by three years. This calculation shows how long it takes to achieve a weight-loss goal for a single permanent change of diet or exercise.

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Fossil or Mystery Monster Found In Kentucky Seems to Defy All Known Groups of Organisms

Around 450 million years ago, shallow seas covered the Cincinnati region and harbored one very large and now very mysterious organism. Despite its size, no one has ever found a fossil of this “monster” until its discovery by an amateur paleontologist last year.

UC Paleontologist David Meyer, left and Carlton Brett, right, flank Ron Fine, who discovered the large fossil spread out on the table.

The fossilized specimen, a roughly elliptical shape with multiple lobes, totaling almost seven feet in length, will be unveiled at the North-Central Section 46th Annual Meeting of the Geological Society of America, April 24, in Dayton, Ohio.

Fine is a member of the Dry Dredgers, an association of amateur paleontologists based at the University of Cincinnati. The club, celebrating its 70th anniversary this month, has a long history of collaborating with academic paleontologists.

“I knew right away that I had found an unusual fossil,” Fine said. “Imagine a saguaro cactus with flattened branches and horizontal stripes in place of the usual vertical stripes. That’s the best description I can give.”

The layer of rock in which he found the specimen near Covington, Kentucky, is known to produce a lot of nodules or concretions in a soft, clay-rich rock known as shale. “While those nodules can take on some fascinating, sculpted forms, I could tell instantly that this was not one of them,” Fine said. “There was an ‘organic’ form to these shapes. They were streamlined.”

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The Secret Life of Plankton

Fun video with great shots of exotic ocean life that forms the base of the food chain in the ocean from TED Education.

How do Plants Grow Into the Sunlight?

Plants are extremely competitive in gaining access to sunlight. A plant’s primary weapon in this fight is the ability to grow towards the light, getting just the amount it needs and shadowing its competition. Now, scientists have determined precisely how leaves tell stems to grow when a plant is caught in a shady place.

Hole in the Wall trail, Olympic National Park, Washington, USA by John Hunter

The researchers discovered that a protein known as phytochrome interacting factor 7 (PIF7) serves as the key messenger between a plant’s cellular light sensors and the production of auxins, hormones that stimulate stem growth.

“We knew how leaves sensed light and that auxins drove growth, but we didn’t understand the pathway that connected these two fundamental systems,” says Joanne Chory, professor and director of the Salk’s Plant Biology Laboratory and a Howard Hughes Medical Institute investigator (HHMI provides huge amounts of funding for scientific research). “Now that we know PIF7 is the relay, we have a new tool to develop crops that optimize field space and thus produce more food or feedstock for biofuels and biorenewable chemicals.”

Plants gather intelligence about their light situation—including whether they are surrounded by other light-thieving plants—through photosensitive molecules in their leaves. These sensors determine whether a plant is in full sunlight or in the shade of other plants, based on the wavelength of red light striking the leaves. This is pretty cool; I love to learn about the brilliant strategies that have evolved.

If a sun-loving plant, such as thale cress (Arabidopsis thaliana), the species Chory studies, finds itself in a shady place, the sensors will tell cells in the stem to elongate, causing the plant to grow upwards towards sunlight.

When a plant remains in the shade for a prolonged period, however, it may flower early and produce fewer seeds in a last ditch effort to help its offspring spread to sunnier real estate. In agriculture, this response, known as shade avoidance syndrome, results in loss of crop yield due to closely planted rows of plants that block each other’s light.

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Dangerous Drug-Resistant Strains of TB are a Growing Threat

Drug-resistant strains of TB are out of control

The fight against new, antibiotic-resistant strains of tuberculosis has already been lost in some parts of the world, according to a senior World Health Organisation expert.
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Dr Paul Nunn, head of the WHO’s global TB response team, is leading the efforts against multi-drug resistant TB (MDR-TB). Nunn said that, while TB is preventable and curable, a combination of bad management and misdiagnosis was leaving pharmaceutical companies struggling to keep up. Meanwhile, the disease kills millions every year.

“It occurs basically when the health system screws up,” said Nunn. “Treating TB requires a carefully followed regime of medication over six months. In places where health services are fragmented or underfunded, or patients poor and health professionals ill-trained, that treatment can fall short, which can in turn lead to patients developing drug-resistant strains. It’s been estimated that an undiagnosed TB-infected person can infect 10 others a year.

We tend to do a poor job of dealing with systemic effects of poorly functioning systems. Direct present threats get out attention. And we are decent at directing brain power and resources to find solutions. We are not very good at dealing with failures that put us in much worse shape in the long term. For small threats we can wait until it becomes a present threat and then deal with it. There are costs to doing this (economic and personal) but it can be done.

Some problems though become enormously complicated to deal with once they become obvious. Global climate change, for example. And often, even once they are obvious, we won’t act until the costs (economic and in human lives) are very large. It is possible that once we decide to get serious about dealing with some of these issues that the costs (economic and in human lives) will be catastrophic.

The failure to use anti-biotics medicine properly is a very serious threat to become one of these catastrophic societal failures. While tuberculosis failures may be larger in poorer countries, rich countries are failing probably much more critically in the misuse of anti-biotics (I would guess, without having much evidence at my fingertips to back up my opinion. I believe the evidence exists I am just not an expert). These failures have huge costs for all of humanity but we are risking many premature deaths because we systemically fail to deal with issues until the consequences are immediate.

Is Dirt Healthier Than Broccoli?

That dirt I ate as a kid is maybe why I have been relatively healthy. Ok, probably that hasn’t been the most important factor. But it may be that some dirt and germs (kids licking their dirty hands and the ice cream melts on it, etc.) is actually more important for their long term health than finishing off the broccoli (of course, a healthy diet requires eating a bunch of vegetables, more than most kids eat).

The hygiene hypothesis has become a popular explanation for the boom in asthma, allergies and other health problems. Boiled down to one sentence the hypothesis is that exposure to germs early in life creates a healthy immune system and too little exposure results in a hypersensitive immune system (that is not as effective and leads to things like allergies).

A recent closed science paper, Microbial Exposure During Early Life Has Persistent Effects on Natural Killer T Cell Function, found mice exposed to more germs early on where healthier:

Exposure to microbes during early childhood is associated with protection from immune-mediated diseases such as inflammatory bowel disease (IBD) and asthma. Here, we show that, in germ-free (GF) mice, invariant natural killer T (iNKT) cells accumulate in the colonic lamina propria and lung, resulting in increased morbidity in models of IBD and allergic asthma compared to specific pathogen-free (SPF) mice. This was associated with increased intestinal and pulmonary expression of the chemokine ligand CXCL16, which was associated with increased mucosal iNKT cells. Colonization of neonatal—but not adult—GF mice with a conventional microbiota protected the animals from mucosal iNKT accumulation and related pathology. These results indicate that age-sensitive contact with commensal microbes is critical for establishing mucosal iNKT cell tolerance to later environmental exposures.

The microscopic battles waged in our bodies every day and over our lifetimes are amazing.

Lean Science: Using Cheap Robots to Aid Research

Fun video showing how scientists use Lego Mindstorm robots to aid research into creating artificial bones. Lego Mindstorm robots are useful at a very reasonable price.

The webcast also includes this practical quote from Michelle Oyen, lecturer in the Department of Engineering at Cambridge University: “without your bones you would be a pile of goo lying on the floor.”

The thinking discussed in the webcast echos the lean manufacturing principles discussed in the Curious Cat Management Improvement Blog: finding good solutions to aid people in doing their jobs. The type of custom solutions they discuss here are great.

This type of use of technology is great. One of the problems we often see with technology solutions though is when they are imposed on the workplace in a way that doesn’t aid people. There is a big difference between what Toyota does (using robots to make people’s jobs easier) and what others do in trying to copy Toyota (using robots to eliminate jobs). Lean manufacturing stressed the importance of using brainpower people bring to work every day. You want to use technology to enable people. These scientists understand that. Unfortunately many managers don’t.

Photosynthesis: Science Explained

Another very good webcast on a science topic from Crash Course. It is packed with info, thankfully you can pause and rewind as much as you need. Well normally you can, YouTube decided to not let me do that just now 🙁

Science Continues to Explore Causes of Weight Gain

Science is amazing when it explains very cool ideas. It is also very interesting (if a bit frustrating) when the scientific inquiry process is ongoing and open to debate. Weight gain is one such area that is of great concern and large amount of study but some issues are still unclear. I have discussed this before. I think that calories in compared to calories consumed is a good first approximation. I believe it makes sense that the efficiency of our bodies at capturing the calories and turning them into weight gain could be affected by things other than the total calories in. It might be the type of calories or it might be other factors (bacteria or chemical present)…

What’s Really Making Us Fat?

Researchers in a relatively new field are looking at the role of industrial chemicals and non-caloric aspects of foods — called obesogens — in weight gain. Scientists conducting this research believe that these substances that are now prevalent in our food supply may be altering the way our bodies store fat and regulate our metabolism. But not everyone agrees. Many scientists, nutritionists, and doctors are still firm believers in the energy balance model. A debate has ensued, leaving a rather unclear picture as to what’s really at work behind our nation’s spike in obesity.
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A widely reported study that came out in January in The American Journal of Clinical Nutrition (AJCN) would seem to dispute this finding: it confirms the belief in the energy balance model, and has been cited as proof by many researchers working in the field. I asked an author of the study, Dr. George Bray, professor of medicine at Louisiana State University, about the myriad of additives and industrial ingredients in our food that were not accounted for in this study. “It doesn’t make any difference,” he said in a telephone interview. “Calories count. If you can show me that it doesn’t work, I’d love to see it. Or anybody else who says it doesn’t — there ain’t no data the other way around.”

It seems to me that it certainly makes sense to reduce calories if you need to lose weight. And it sure seems the strongest evidence is for calories being the most important factor.

I also believe exercise is good, for overall health. It also seems more and more evidence is being found about how difficult it is to lose weight which reinforces the importance of preventing the weight gain in the first place.

Exploring Eukaryotic Cells

This webcast is packed with information on the makeup and function of eukaryotic cells, which are the type of cells found in animals. It is part of a interesting series of science webcasts by Crash Course. The webcast style might be a bit too hyperactive and flippant for some but the content is quite interesting and the videos they are are of similar style and quality so if you like this one you can subscribe to their channel. They offer quite a few webcasts on science but they also offer webcasts on history.