PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

A single-molecule guide to understanding chemical reactions better

A single-molecule guide to understanding chemical reactions better
2021-02-04
(Press-News.org) Scientists globally aim to control chemical reactions--an ambitious goal that requires identifying the steps taken by initial reactants to arrive at the final products as the reaction takes place. While this dream remains to be realized, techniques for probing chemical reactions have become sufficiently advanced to render it possible. In fact, chemical reactions can now be monitored based on the change of electronic properties of a single molecule! Thanks to the scanning tunneling microscope (STM), this is also simple to accomplish. Why not then utilize a single-molecule approach to uncover reaction pathways as well?

With this goal, scientists from Tokyo Institute of Technology, Japan decided to explore DNA "hybridization" (formation of a double-stranded DNA from two single-stranded DNA) by measuring the changes in single-molecule electrical conductivity using an STM. "Single-molecule investigations can often reveal new details on chemical and biological processes that cannot be identified in a bulk collection of molecules due to the averaging out of individual molecule behavior," explains Prof Tomoaki Nishino, who was part of the study, recently published in Chemical Science.

The scientists attached a single-stranded DNA (ssDNA) to an STM tip made of gold and used a flat gold film to stick the complementary strand on it via a process known as "adsorption." They then applied a bias voltage between the coated STM tip and the gold surface and brought the tip extremely near to the surface without touching it (Fig. 1). This, in turn, allowed a current to flow through the space in between due to a process known as "quantum tunneling". Chemists monitored the time variation of this tunneling current as the DNA strands interacted with each other.

The team obtained current traces depicting plateau regions formed of steep inclines and subsequent declines in the tunneling current. Further, these plateaus did not form when either the gold surface was not modified with ssDNA or was modified with a non-complementary strand. Based on this, scientists attributed the plateaus to the formation of a double-stranded DNA (dsDNA) resulting from hybridization of ssDNA on the STM tip and the surface. Equivalently, they attributed the abrupt decrease in current to the breakdown or "dehybridization" of the dsDNA due to thermal agitation.

The team next investigated the kinetics (time evolution of reaction) of the dehybridization and hybridization processes using experimental results and molecular dynamics simulations. The former revealed a plateau conductance independent of DNA concentration, confirming that the current measurements reflected single-molecule conductance, while the latter suggested the formation of a partially hybridized DNA intermediate that could not be detected from conductance alone.

Interestingly, the hybridization efficiency was higher for high DNA concentration samples, contradicting the findings of a previous study made with bulk ssDNA solution. Chemists attributed this observation to the absence of bulk diffusion in their study.

"These new insights should contribute to improved performance for many DNA-based diagnoses," observes Prof Nishino, excited about the findings, "In addition, our method can be extended to the investigation of intermolecular chemical reactions between a variety of single molecules, enabling a mechanistic understanding of chemical reactions as well as discovery of novel chemical reactivity from a single-molecule perspective."

INFORMATION:


[Attachments] See images for this press release:
A single-molecule guide to understanding chemical reactions better

ELSE PRESS RELEASES FROM THIS DATE:

Molecule from nature provides fully recyclable polymers

Molecule from nature provides fully recyclable polymers
2021-02-04
Plastics are among the most successful materials of modern times. However, they also create a huge waste problem. Scientists from the University of Groningen (The Netherlands) and the East China University of Science and Technology (ECUST) in Shanghai produced different polymers from lipoic acid, a natural molecule. These polymers are easily depolymerized under mild conditions. Some 87 per cent of the monomers can be recovered in their pure form and re-used to make new polymers of virgin quality. The process is described in an article that was published in the journal Matter on 4 February. A problem with recycling plastics is that it usually results in a lower-quality product. The best results are obtained by chemical recycling, in which the polymers are broken ...

CU offers plan for improving mental health care for resident physicians

2021-02-04
A pilot program to offer mental health services offered resident physicians at the University of Colorado School of Medicine provides a model for confidential and affordable help, according to an article published today by the journal Academic Medicine. For the 2017-2018 class, 80 resident physicians in the internal medicine and in internal medicine-pediatrics programs were enrolled in a mental health program that provided scheduled appointments at the campus mental health center. Residents were allowed to opt-out of the appointments. The cost of the appointments was covered by the residency programs, not charged to residents. Programs received ...

Scientists optimized technology for production of optical materials for microelectronics

Scientists optimized technology for production of optical materials for microelectronics
2021-02-04
Scientists of Far Eastern Federal University (FEFU) have advanced the technology of high-speed sintering for optical ceramics (Nd3+:YAG), i.e. active elements generating laser emission in the near-infrared wavelength range (1.06 μm) for cutting the edge microelectronics and medicine. The researchers have managed to reduce significantly the initial nanopowders consolidation period (10 - 100 times) forming a nanostructure with ensured high optical transparency of the ceramic material. A related article appears in Optical Materials. Diode-pumped ...

Uncovering a link between inflammation and heart disease

2021-02-04
Inflammation is supposed to help protect us--it's part of an immune response to fight off pathogens and clear infections. But patients with cardiac disease often have chronic inflammation that damages their hearts, even with no infection present. In a recent study published in Circulation, immunologists at Tufts University School of Medicine in collaboration with investigators at Vanderbilt University and Tufts Medical Center revealed a mechanism that is activating T cells, a type of immune cell, and causing inflammation in the heart. "Not all inflammation is the same," says Pilar Alcaide, a Kenneth and JoAnn G. Wellner Professor at Tufts School of Medicine and corresponding ...

Unusual 2019-2020 flu season linked to more transmissible strain

2021-02-04
The 2019-2020 flu season in the U.S. was unusual in a number of ways. Cases picked up in August rather than the more typical fall and early winter months, and it hit children particularly hard. It was also dominated early on by a Type B influenza virus instead of one of the much more common Type A viruses like H1N1 or H3N2. A new study by researchers at the University of Georgia suggests that these dynamics were driven largely by a new, more transmissible strain encountering a population with very little existing immunity to it. Their findings, just published in the Proceedings of the National Academy of Sciences, have implications for future vaccination ...

Dementia-related psychosis: GSA experts identify ways to improve care

2021-02-04
A new white paper from The Gerontological Society of America (GSA) highlights the variety of challenges that persons with dementia-related psychosis and their caregivers have encountered during moves through different health care settings -- and proposes strategies to address these challenges. It is estimated that over 2 million Americans with dementia experience delusions (false beliefs) and hallucinations (seeing or hearing things that others do not see or hear). This group of symptoms, known as dementia-related psychosis, frequently goes undetected in people who may ...

DNA-based technique allows researchers to determine age of living beluga whales in Alaska

DNA-based technique allows researchers to determine age of living beluga whales in Alaska
2021-02-04
NEWPORT, Ore. - Researchers can now determine the age and sex of living beluga whales in Alaska's Cook Inlet thanks to a new DNA-based technique that uses information from small samples of skin tissue. Accurate age estimates are vital to conservation efforts for Cook Inlet belugas, which were listed as endangered following a significant population decline in the 1990s. Previously, researchers could only determine the age of beluga whales by studying the teeth of dead animals. The new aging method uses DNA methylation data and machine learning to develop a model that captures ...

Time management can work but in unexpected ways, according to new research

Time management can work but in unexpected ways, according to new research
2021-02-04
If you have a second, try typing "time management" into your favourite search engine. You will get literally millions of results: books, tips, lessons, do's and don'ts. It's a big industry. But as END ...

Horse remains reveal new insights into how Native peoples raised horses

Horse remains reveal new insights into how Native peoples raised horses
2021-02-04
A new analysis of a horse previously believed to be from the Ice Age shows that the animal actually died just a few hundred years ago--and was raised, ridden and cared for by Native peoples. The study sheds light on the early relationships between horses and their guardians in the Americas. The findings, published today in the journal American Antiquity, are the latest in the saga of the "Lehi horse." In 2018, a Utah couple was doing landscaping in their backyard near the city of Provo when they unearthed something surprising: an almost complete skeleton of a horse about the size of a Shetland pony. Scientists and the media took note. Preliminary data suggested ...

In Ethiopia, mother's wealth more protective against child marriage than father's

2021-02-04
For a girl in Ethiopia, her mother's wealth can protect her from becoming a child bride - but if a father prefers child marriage, his own wealth may increase the likelihood that she will be married before 18, according to a Rutgers University-New Brunswick study. Published in the journal World Development, the study found that girls whose mothers have more asset holdings - a cellphone, bicycle, sewing machine, jewelry or other valuables - have a reduced rate of entering into a child marriage, while the rate is higher for girls whose fathers have more asset holdings. "Child marriage is concerning from a human rights, health and economic perspective," said the study's author Felix Muchomba, assistant professor at the Rutgers School of Social Work. "Girls married before ...

LAST 30 PRESS RELEASES:

Thirty-year mystery of dissonance in the “ringing” of black holes explained

Less intensive works best for agricultural soil

Arctic rivers project receives “national champion” designation from frontiers foundation

Computational biology paves the way for new ALS tests

Study offers new hope for babies born with opioid withdrawal syndrome

UT, Volkswagen Group of America celebrate research partnership

New Medicare program could dramatically improve affordability for cancer drugs – if patients enroll

Are ‘zombie’ skin cells harmful or helpful? The answer may be in their shapes

University of Cincinnati Cancer Center presents research at AACR 2025

Head and neck, breast, lung and survivorship studies headline Dana-Farber research at AACR Annual Meeting 2025

AACR: Researchers share promising results from MD Anderson clinical trials

New research explains why our waistlines expand in middle age

Advancements in muon detection: Taishan Antineutrino Observatory's innovative top veto tracker

Chips off the old block

Microvascular decompression combined with nerve combing for atypical trigeminal neuralgia

Cutting the complexity from digital carpentry

Lung immune cell type “quietly” controls inflammation in COVID-19

Fiscal impact of expanded Medicare coverage for GLP-1 receptor agonists to treat obesity

State and sociodemographic trends in US cigarette smoking with future projections

Young adults drive historic decline in smoking

NFCR congratulates Dr. Robert C. Bast, Jr. on receiving the AACR-Daniel D. Von Hoff Award for Outstanding Contributions to Education and Training in Cancer Research

Chimpanzee stem cells offer new insights into early embryonic development

This injected protein-like polymer helps tissues heal after a heart attack

FlexTech inaugural issue launches, pioneering interdisciplinary innovation in flexible technology

In Down syndrome mice, 40Hz light and sound improve cognition, neurogenesis, connectivity

Methyl eugenol: potential to inhibit oxidative stress, address related diseases, and its toxicological effects

A vascularized multilayer chip reveals shear stress-induced angiogenesis in diverse fluid conditions

AI helps unravel a cause of Alzheimer's disease and identify a therapeutic candidate

Coalition of Autism Scientists critiques US Department of Health and Human Services Autism Research Initiative

Structure dictates effectiveness, safety in nanomedicine

[Press-News.org] A single-molecule guide to understanding chemical reactions better