Molecular Rotor Measures Viscosity of Live Cells

Anant Babu Marahatta
Tohoku University
Japan (ananta037@gmail.com)

Introduction:
Viscosity is one of the major parameters determining the diffusion rate of species in condensed media. In bio-systems, changes in viscosity have been linked to disease and malfunction at the cellular level. These perturbations are caused by changes in mobility of chemicals within the cell, influencing signaling and transport and the efficiency of bimolecular processes.

Observation:

Fluorescence measurements of 1 made in methanol/glycerol mixtures of different viscosities shows that the fluorescence quantum yield increases dramatically with increasing solvent viscosity.The observed increase in fluorescence intensity is consistent with the restricted rotation of the phenyl group in the medium of high viscosity. The rates of radiative and nonradiative decays have been calculated from the measured fluorescence lifetimes and quantum yields. From these results, it has been concluded that, for 1, the nonradiative decay rate increases with decreasing viscosity, and the radiative decay rate remains approximately constant. Thus 1 is truly a molecular rotor which displays both fluorescence intensity and lifetime sensitivity to viscosity of the environment.

For detail, readers are requested to go through J.AM.CHEM.SOC. 2008,130, 6672-6673 if interested.

We must learn “How to love nation” from Japanese devotement

Anant Marahatta
Tohoku Univ.
Japan (ananta037@gmail.com)

After the scary and massive catastrophe on March, 2011 in northeastern Japan, several consequences raised in the world. Germany has already announced to shut down all the nuclear power plants within a decade; China has stopped to increase the number of power plants until the full safety measures are installed into already existed plants and the world’s super power USA has also checked the safety precautions in all the power plants including the biggest one located in the danger zone at California. Experts have already warned the US government and asked for installing safety measures especially in thhe California based reactors.

The victimized country, Japan, has already suspended around 40 reactors out of 50 for close inspection. It has decided to build 20m high seawalls around the reactors located in the danger zones to block them from giant tsunami. The biggest nuclear energy crisis forces to reduce the office hours of world’s largest manufacturers like Sony, Canon, Toyota, Honda, Toshiba and several others. Almost all the companies, universities and many research institutes, supermarket complexes, food-chain stores etc. are asked to minimize the electricity consumption. For it, all Japanese are doing their best by even removing their kitchen wares etc. Most of the chain stores and restaurants are using the play cards holding “Let’s do our level best. Never give up, Tohoku. Let’s build new Japan” at their main entrance. This is a very praiseworthy dedication of the citizens towards their nation.

Since the northeastern part of Japan has been jolting by several aftershocks. Almost every day, the skyscrapers are shaken 3-4 times in an average. After the strongest 9 M tremor on March 11, more than 5 jolts are already categorized into the strong range. They all cross 6 M in strength. The local and central government announce the tsunami warnings immediately after the strong earthquakes. But every Japanese is ready to challenge this horrified situation and gives his/her full support to the government for renovation.

We must learn “How to love nation” from their devotement.

Mixi vs. Facebook in Japan

Mixi, which was launched in February 2004, is the biggest social networking site in Japan. It is growing rapidly. The site has already more than 5 million users. Around 80% of those users are reported as “active”. The name “Mixi” supposedly refers to the fact that “I” can “mix” with other users. To join Mixi, you need to be invited by an existing member. The Mixi URL assigned to you contains a unique user number beginning at 1 and increased sequentially, it’s easy to tell how recently a user joined.

On the other hand, one year since Facebook was introduced to Japanese market; it is obvious that Facebook is not popular at all in Japan, while it is very successful in most of other countries.
Why Facebook is not popular in Japan?

International Collaboration in Science

Anant Marahatta
Doctoral Student (Chemistry)
Tohoku University
Japan
(ananta037@gmail.com)
(Relevant to my collaboration with Germany)

The general meaning of an “international collaboration in science” is explained by these advanced words: global science, global networks, global co-authorships, global interaction, global conference, global sharing, and spreading global hand for helping on different disciplines of science and technologies etc.

Though there is no political institution organizing the sciences on an international level, a self-organized, global network had formed in the late 20th century. It has been found that international collaborations are being doubled from 1990 to 2005. While collaborative authorships within nations have also risen.

This is the century of getting revolution in the world due to the different fields of sciences. If the researchers and scientists of any well developed countries have proudly announced that they are eligible enough to carry out any sorts of revolutionary changes in the field of science, they have initiated to deteriorate their countries themselves. So for getting several supports and ideas, all the countries if possible must be the member of the international collaboration. Any one can analyze that, international collaboration improves all the countries of the world by applying a range of tools including social network analysis and factor analysis, to expose the network.

There has been a rapidly growing literature discussing the increase in international linkages in science. Authors have been approaching the questions from three perspectives: 1) scientific analysis of the increase in the interconnectedness. 2) Social sciences analysis of collaboration in general and international linkages in particular and 3) policy analysis of the implications of linkages for funding and outcomes. The increase in investment in research and development from governments and non-governmental organizations (such as the World Bank) is for using science as a tool to aid development and for contributing to the diffusion of capacity into the collaborating countries. Scientific collaboration may lead to a range of outcomes such as publication of co-authored articles is one of these outputs.

Collaboration in the technology sector refers to a wide variety of tools that enable groups of people to work together. Collaboration encompasses both asynchronous and synchronous methods of communication and serves as an umbrella-term for a wide variety of software packages. Perhaps the most commonly associated form of synchronous collaboration is web conference using tools such as WebEX or Microsoft Live Meeting but the term can easily be applied to instant messaging as well.

According to the available information, at the global level, the network of interactions is shown to be very strong and highly interconnected. Above figure illustrates the association of all the countries of the world in 2000. The main point is that science is a highly interconnected network, with a dense core and a number of periphery countries.

Thus international collaboration seems one of the important tools for making revolutionary change in the world by developing and introducing the multidisciplinary fields.

An argue with CalTech. Chemistry Grad.

Anant Babu Marahatta
Ph.D. student
Tohoku University
(ananta037@gmail.com)

Theme of this article is: “Knowing English is not enough to present Chemistry but one must know Chemistry in English.”
(some thing about Amphidynamic Crystal)

In order to strengthen and enhance the education and research functions of graduate schools of Japanese universities, Ministry of Education, Culture, Sports, Science and Technology (MEXT) introduced the “Global COE (Centers of Excellence) Program in some of the top universities of Japan on 2002. Another main objective is to foster highly creative young researchers who will become world’s leaders in their respective fields through experiencing and practicing research of the highest world standard.Molecular complex Chemistry is one of the fields covered by the GCOE.

Being one of the Chemistry doctoral students of the nation’s high tech. university [Tohoku University] with the nation’s largest chemistry department, I also belong to the network of GCOE program. One of the annual events of the Tohoku Univ. sponsored by this program is to provide a chance for the doctoral students to lead a week long Int’l conference. Including the key speakers and the chairpersons of each section, every participant must be the Ph.D. candidate of Chemistry. The professors only act as a facilitator. He/she never interferes the students’ leadership.

One of the key speakers of the program was from California institute of Technology (CalTech). He was presenting his research work related to coordination chemistry and was chanting the effects of ligands to synthesize the Supramolecules with the metal ions. He was also claiming that his research output is fabulous and praiseworthy. One of the major parts of that molecule was the phenylene ring encapsulated into the cage that can create enough free space for undergoing smooth rotation. He was calling this ring as a “spacer” because the surrounding spokes can control the space around the phenylene. Any way, we around 200 students were listening his interesting speech. Being a chair person of this section, I was feeling that he was pretending some hidden facts behind his research area even though he was very bold and smart guy. He presented well and wrapped his talk by thanking his collaborators.

Then, it’s my time to open the floor for the discussion. I asked the participants for the comments and the queries. Some students asked about the effects of the coordinating efficiency of ligands’ and some other related stuffs. A Tohoku professor was suggesting him about the possibility of changing properties of that supramolecule by changing central metal ions.

Before announcing the next speaker, I raised my query about that spacer so called phenylene ring. I am/ was very much familiar with such molecules having central rotating part encased into the static part. I also knew that such type of molecular crystals with rotating part and static part in a same molecule are called Amphidynamic crystal, but this is a very new type which I encountered while reading a paper published on 2002. My question was “does your molecular crystal belong to Amphidynamic crystal?” But that guy did not understand the last term and instead asked me for the clarification. I just clarified him by reminding the term “Amphibia” and then called the next speaker.

Immediately after this session, the same guy approached and said to me “Knowing English is not enough to present chemistry but one must know chemistry in English.” Excellent understanding!!!! isn’t it?

Small Science Vs. Large Science

Anant　Babu Marahatta
Ph.D. student in chemistry
Tohoku University, Japan

Science carried out by individuals or small teams of investigators is said to be “small science” and the science carried out for large scientific data gathering programs is said to be “large science”.

Research done by individuals or small teams of investigators has been crucial for many of the important discoveries made in all branches of science. The individual or small group research work has been the first step for bringing up the revolutionary changes in the world. Such type of research facilitates the researcher to concentrate in the particular problem and hence increases the thinking level of the researchers as well. It has been found that the research work performed by the individuals or by the small teams is more accurate and reproducible. Since every branch of science needs accuracy which in fact catalyses the rate of tailoring and building up the new inventions and discoveries. These discoveries provide the fundamental basis for the application of scientific knowledge to national economic and societal goals.

Small science helps to define the goals and directions of large scientific data gathering projects [so called large science]. In turn, these data feed and are often best synthesized and interpreted by the long-term efforts of the small science community. In small science, the rate of manipulation of data is almost nil due to the accuracy which perfectly orients into the solutions of the problems.

Are Carbon Nanotubes the Future of VLSI Interconnections?

Original paper is published by-
K. Banerjee and N. Srivastava
University of California


Summarised by Anant

What is VLSI?
• Very-large-scale integration (VLSI) is the process of creating integrated circuits by combining thousands of transistor-based circuits into a single chip.
• VLSI began in the 1970s when complex semiconductor and communication technologies were being developed. The microprocessor is a VLSI device.
New wiring solutions…!
• Metallic carbon nanotubes (CNTs) are promising candidates that can potentially address the challenges faced by copper and thereby extend the lifetime of electrical interconnects.
• carbon nanotubes (CNTs) have aroused a tremendous amount of interest in their use as building blocks of future integrated circuits due to their outstanding electrical properties

CNT based interconnects can potentially offer significant advantages over copper.
• CNTs exhibit extraordinary strength and unique electrical properties are efficient conductors of heat and are metallic in nature.
•SWCNTs are a very important variety of CNT because they exhibit important electric properties that are not shared by MWCNTs. The remarkable properties of SWCNTs stem from the symmetry and unusual electronic structure of grapheme [one atom thick sheet of graphite].

∙An isolated CNT can carry current densities in excess of 1010 A/cm2 without any signs of
damage even at an elevated temperature of 250 0C. However, the high resistance associated with an isolated CNT (greater than 6.45 KΩ) necessitates the use of a bundle (rope) of CNTs conducting current in parallel to form an interconnection. CNT bundle interconnects have superior performance compared to Cu.

∙For short CNT bundle with small length (L), [especially for L < λCNT], resistance is higher than that of a Cu interconnect because the large contact resistance dominates the overall CNT resistance. However, for long interconnect lengths; i.e. long CNT bundle interconnects have smaller resistance than their Cu counterparts [ L>λCNT].
∙The interconnect delay can be reduced considerably by using densely packed CNT bundle interconnects, so that large power savings can be achieved. CNT bundle interconnects can reduce intermediate level interconnect delay by more than 60% due to their lower resistance.

Reliability and Thermal Analysis
∙Due to strong sp2 bonding, carbon nanotubes are much less susceptible to electro-migration (EM) problems [that plague copper interconnects] and can carry very high current densities. Metallic single-walled CNT bundles have been shown to be able to carry extremely high current densities of the order of 109 A/cm2. Cu interconnects = 106 A/cm2 due to EM.
∙A 100 x 50 nm2 cross-section Cu interconnect can carry current up to 50 μA, whereas a 1 nm diameter CNT can carry upto 20-25 uA current. Hence, from a reliability perspective, a few CNTs are enough to match the current carrying capacity of a typical Cu interconnect.
However, the need to reduce interconnect resistance (and hence delay) makes it necessary to pack several thousands of CNTs in a bundle.
Conclusion
∙There is no any experimental work or theoretical analysis yet about the nature of electromagnetic interactions between non-isolated (or tangled) nanotubes. So the authors have not considered their mutual effect during conduction, however they highlighted that this challengeable investigation should be done before using them in a circuit though these challenges are not expected to cause any fundamental problems.