Many rodents are nocturnal. However, even rodents that are active during the day tend to prefer darker areas. Most rats, for example, have adapted to be accustomed to spending daylight hours largely sheltered from light sources. This makes lighting control in habitats used for rodent research an important variable to be considered. However, lighting control encompasses more than just light intensity. Things like the duration of exposure, pigmentation of the animal, age, species, and sex of the animal are just some of the other factors that need to be considered. Additionally, many rodents used in research applications are albino, which makes them more susceptible to light than other varieties. Because of this, albino rodents have been used in establishing baselines for illumination levels.
So what light levels are appropriate for housing rodents? According to the US National Research Council’s Guide for the Care and Use of Laboratory Animals, the light experience of each animal can affect its light sensitivity, but in normal cases light intensity at the cage level should be between 12 and 30 foot candles (130-325 lux). The normal fluorescent bulbs in our Rodent Incubators produce light intensity between 80-100 foot candles (860-1080 lux) at the cage, which is quite strong. A glass door in the incubator (with no timed light control) could allow the room lighting to provide the correct illumination, but we wanted to provide a better option for researchers looking for less intense, and timed, lighting within the chamber. Powers Scientific now offers dimmable light covers on our Rodent Incubators. These light covers are plastic bulb sleeves with graded black striping to block some of the light emitted. The striping changes in density around the cover so that as the covers are rotated around the bulb, more or less of the light is blocked depending on the direction you twist it. With the light covers mounted, light intensity inside the chamber is reduced to 10-40 foot candles (105-430 lux), depending on how the covers are oriented. With these light covers, our chambers are capable of providing low-intensity lighting conditions for many applications. Read More
“Complexity that works is built up out of modules that work perfectly, layered one over the other.”
– Kevin Kelly
Living creatures are almost incomprehensibly complex. Take the human body, which is made up of trillions of cells creating thousands of different parts. Our mass of interconnected systems, and indeed the complex biological systems of many members of the animal kingdom, have slowly built up over the course of millions of years as life forms have grown in complexity and adapted to become more specialized. One of the reasons that these forms of life have been able to become so elaborate is that their cells are capable of determining their location and orientation within the body. This ability for cells to know where they are in the body leads to an evolutionary advantage: it allows for the creation of elaborate, non-symmetrical systems.
While the details of living organisms have changed massively in the past half-billion years, one thing common to most of them hasn’t changed very much at all: the genetics that control the process of orienting cells in consistent directions within the body. In March 2016, Scientific American ran an article discussing how scientists are experimenting to determine how these genes work. These “polarity genes” originally evolved five hundred million years ago and haven’t changed much in the interim. They cause certain proteins in cells to work a lot like magnets. Within each cell, these proteins push each other apart to opposite ends of the cell. Between the cells, the same proteins that repel each other within a cell experience an attraction, pulling the opposite protein from adjacent cells towards them. The ultimate effect of this is that, locally, the cells become oriented with all the proteins of one type lined up on one side of the cell, and all proteins of the other type lined up on the opposite side. This effectively creates a sort of compass for the cells and allows the establishment of a common directionality. Read More
One of the classic images of pediatric medicine in the United States is the image of a physician giving a vaccination shot. Like many other classic images of twentieth-century life in the US, this one is unsurprisingly immortalized in a Norman Rockwell painting. However, over the last few decades, it has become much more difficult for small practices to provide the vaccination services that they have historically been relied upon to give.
The cost to administer vaccines has risen sharply over that time period. In 1986, the cost of the five vaccines recommended for all children from birth to age 18 was $215. In 2014, the cost of those same five vaccines (adjusted for inflation) was $937: more than a four-fold increase! In addition, eight new recommended vaccinations were added in the intervening 28 years, requiring an additional $1,255 of medicine to fully vaccinate a child. Given this large increase in costs, maximizing the effectiveness of each batch of vaccines by minimizing the waste is very valuable, especially to small family-practice doctors and pediatricians. Storing vaccines properly is critical to making sure that the maximum amount of vaccine can be delivered effectively. Read More
For thousands of years, humans have struggled against infectious diseases transmitted by mosquitos. Records describing the symptoms of malaria can be traced back to 2700 B.C. in China. Other mosquito-borne diseases, such as yellow fever, dengue, and West Nile virus are a perennial threat to the health and safety of people all over the world.
One mosquito-borne illness that has rapidly gained notoriety recently is the Zika virus. This disease was first documented in monkeys in Uganda in 1947, and then in humans in 1952. However, recent large outbreaks of the disease in French Polynesia (in 2013) and Brazil (in 2015) have drastically heightened public awareness of the virus. In January, the CDC issued a level 2 alert for travel to Mexico, Central America, South America and the Caribbean due to Zika virus outbreaks, warning travelers to “practice enhanced precautions” and take steps to protect themselves from mosquito bites. Read More
Last week, the New York Times reported that two-thirds of the world is facing severe water shortages at least once a year. A large chunk of the affected population is in India and China, but areas of the United States like Texas, Florida, and California are included in the impact area. California, specifically, has experienced a well-publicized drought for the last several years.
California has been under drought conditions since 2011. Their water infrastructure relies heavily on snowpack. During the winter months, snow accumulates in the Sierra Nevada Mountains, and when that snow melts in the dry summer months the melt-water fills their reservoirs. However, snowpack has been severely reduced recently, with March 2015 totals measuring only 19% of average. The paucity of water in the reservoirs has led to increased reliance on groundwater, which has stressed the aquifers’ supply, reducing the overall water supply even further. Read More