Monday, September 18, 2017

8th ASCASS Conference in Kathmandu, Nepal

Asian Society for Colloid and Surface Science, ASCASS, established on 2004, is going to organize its 8th conference in Kathmandu, Nepal on September 25-28, 2019. Earlier, ASCASS organized its 7th Asian Conference on Colloid and Interface Science on 8-11 August 2017 in Berjaya Times Square Hotel, Kuala Lumpur, MALAYSIA.  The current president of ASCASS is Professor Toyoko Imae from National Taiwan University, Taiwan.

It is a matter of pride to all Nepalese that an important conference is going to be held in Kathmandu. The blogger likes to thank Dr. Lok Kumar Shrestha, a preeminent Nepali researcher (currently in National Institute for Materials Science, Japan), for his great effort as a key role player in attracting such conference in Nepal. For sure, this conference will entice many researchers in the beautiful city of Kathmandu which will ultimately help in substantial discussions in the field of Colloids and Interface Science. There is no question that the tourism industry in Nepal will flourish. 


Friday, July 28, 2017

New Imaging Technique in Surface Chemistry

As being a surface chemist, I keep on tracking the signs of progress made so far in the Surface Chemistry field. Recently, I found good news about the imaging tool in surface chemistry. Here is the story:
Researchers at Ecole Polytechnique Fédérale de Lausanne (EPFL) Laboratory for Fundamental BioPhotonics (LBP) have developed a microscope that can track, in real time, 3D spatial changes in the molecular structure and chemistry of confined systems, such as curved surfaces and pores to understand the geological, catalytic, biological and chemical processes which are driven by surface chemical heterogeneities, electrostatic fields and flow. They predict that this may enable the further development of new materials and microtechnology.
“An optical imaging tool to visualize surface chemistry in real time has been developed. This system basically images the interfacial chemistry in the microscopically confined geometry of a simple glass micro-capillary. The glass is covered with hydroxyl (-OH) groups that can lose a proton, a much-studied chemical reaction that is important in geology, chemistry, and technology. A 100-micron long capillary displayed a remarkable spread in surface OH bond dissociation constant of a factor of a billion.”
The developed microscope was used to image the surface chemical structure of the inside of a glass microcapillary. Surface potential maps were designed from the millisecond images, and the chemical reaction constant of each 188nm-wide pixel was evaluated. Amazingly, this very simple system which is used in many devices displayed a stunning spread in surface heterogeneity. The researchers' findings have been published in Science. It is believed that this method will be a plus point in understanding fundamental (electro)chemical, geological and catalytic processes and for building new devices.
Second-harmonic imaging
Imaging of surface potential and chemical process at the surface.
Image: taken from Google (28th July, 2017)
Sylvie Roke, director of the Julia Jacobi Chair of Photomedicine at EPFL, has developed a unique set of optical tools to study water and aqueous interfaces on the nanoscale. She uses second-harmonic and sum-frequency generation, which are optical processes in which two photons of a certain color are converted into a new color. "The second-harmonic process involves 1000 nm femtosecond photons i.e., 0.00000000000001-second bursts of light -- being converted into 500 nm photons, and this occurs only at interfaces," says Roke. "It is therefore ideal for interfacial microscopy. Unfortunately, the process is very inefficient. But by using a number of optical tricks, such as wide field imaging and light shaping, we were able to enhance both the imaging throughput and the resolution, bringing the time to record an image down from minutes to 250 milliseconds."
Surprising surface chemistry
The researchers then imaged the deprotonation reaction of the inner silica capillary/water interface in real time. Silica is one of the most abundant minerals on earth, and its interaction with water shapes our climate and environment. Although many researchers have characterized the properties of the silica/water interface, there is no consensus on its chemical reactivity. Roke continues: "Our data shows why there is a remarkable spread in surface reactivity, even on a very small portion of a capillary. Our data will help in the development of theoretical models that are more effective at capturing this surprising complexity. In addition, our imaging method can be used for a wide variety of processes, such as for analyzing the real-time functioning of a fuel cell, or for seeing which structural facet of a mineral is most chemically active. We could also gain more insight into nanochannels and both artificial and natural pores.
References
 1. Carlos Macias-Romero, Igor Nahalka, Halil I. Okur, Sylvie Roke. Optical imaging of surface chemistry and dynamics in confinementScience, July 2017 DOI: 10.1126/science.aal4346
2. Science Daily, July 28, 2017 Issue (www.sciencedialy.com)

Friday, June 16, 2017

Pregnant Women and Coffee


“Coffee, for many of us, is a daily fix. But few would relate to it as being a life changer” – this is what BBC (27th Feb, 2013 issue) writes by narrating a story of Nepali farmer whose life was changed by farming coffee instead of regular maize and paddy cultivation. Nepalese coffee is different from other countries. People mainly produce Arabica type of coffee which is organic. But, what about intake of coffee by Nepalese women? Frankly, in Nepal tea is preferred than coffee. Most of the people in the rural area take milk-added-tea which is considered more harmful than black tea. Let’s know something about caffeine, a key component in coffee and its effect on the pregnant women.

Caffeine is a natural component of coffee, tea, and cocoa products. It is added to many soft drinks and to certain prescription and over-the-counter medications. Caffeine's pharmacologic effects include central nervous system stimulation, bronchodilation, and higher blood pressure, most likely through antagonism of adenosine receptors in the brain, heart, lungs, and blood vessels. Based on a recent survey by the U.S. Department of Agriculture, coffee, soft drinks, and tea (in that order) are the major sources of caffeine among adults. Average caffeine intake is estimated to be 164 mg per day among women 18–34 years and 125 mg per day among pregnant women. In a prospective cohort study conducted in Connecticut during 1988–1992, caffeine consumption during the first month of pregnancy was reported by 60% of study participants, with 16% consuming 150 mg or more of caffeine per day.

Caffeine is teratogenic in animal studies when administered at high concentrations. There is no evidence to support a teratogenic effect of caffeine in humans. Current epidemiologic evidence is not adequate to assess the possibility of a small change in risk of congenital anomalies resulting from maternal caffeine consumption.

Picture from Google on 16th June 2017 
Marilyn Brown has published a review paper in epidemiology journal by evaluating methodological aspects of epidemiologic studies of maternal caffeine exposure and risk of congenital anomalies1. He has reported that there is no evidence that caffeine intake causes a large increase in the risk of various types of congenital anomalies, but there is greater uncertainty about small elevations in risk. Given the relatively high prevalence of maternal caffeine exposure, even a small increase in the risk of congenital anomalies would have an important effect on public health. 

Large study populations and improved exposure assessment methods would be necessary to rule out small risks for specific categories of congenital anomalies after maternal exposure to caffeine.
In the United States, some 60 percent of women continue to drink caffeinated coffee during their first month of pregnancy.  About 16 percent of pregnant mothers consume 150 mg of caffeine or more per day. But the question is, Is this harmful to your unborn baby? Three things to know.  One, caffeine can freely cross the placenta.  Two, 90 percent of a mother’s caffeine level reaches the developing fetus.  Three, the half-life of caffeine is much longer in the fetus than in the adult2.
Some studies have shown a correlation between prenatal caffeine consumption and decreased birth weight.  But are there longer-term consequences? Researchers in Florida studied mice that had were exposed to physiologically relevant doses of caffeine in utero.  They found that caffeine significantly altered the expression of genes in embryonic hearts.  Pathways related to cardiovascular development and diseases were significantly affected by caffeine. The researchers stress that “the long-term effects of caffeine on human cardiac function are unclear.”  They recommend further studies “to evaluate the safety of caffeine exposure during human pregnancy.”

References
1.         Browne, M. L., Maternal exposure to caffeine and risk of congenital anomalies: a systematic review. Epidemiology 2006, 17 (3), 324-331.
2.         Fang, X.; Mei, W.; Barbazuk, W. B.; Rivkees, S. A.; Wendler, C. C., Caffeine exposure alters cardiac gene expression in embryonic cardiomyocytes. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 2014.