Can isometric resistance training safely reduce high blood pressure?

When was the last time you had your blood pressure checked? High blood pressure affects 1.13 billion people around the globe and in 2019, it accounted for 10.8 million deaths. Worldwide, it’s the leading risk factor for mortality. More than a third of the Australian population over the age of 18 has high blood pressure, yet it’s estimated 50 per cent of Australians don’t realise they’re living with it.

As high blood pressure puts you at high risk of having a heart attack or stroke (cardiovascular disease), it’s important to keep track of your blood pressure. People over the age of 18 are advised to have a blood pressure check at least every two years.

Given the impact of this global health challenge, there is a clear need for strategies to reduce the prevalence and severity of high blood pressure, and exercise is one such strategy. While aerobic and dynamic resistance exercise appear effective at reducing blood pressure, a new study led by UNSW Medicine & Health researchers has revealed isometric resistance training (IRT) as an emerging mode of exercise demonstrating effectiveness in reducing office blood pressure. Office blood pressure refers to your pressure when taken during a GP visit, for example. It is taken at one time-period, usually when you’re sitting down.

What is isometric resistance training?

IRT is a type of strength training. During IRT, the muscles produce force but do not change length. For example, pushing against a wall or holding a ‘plank’. This is different to more traditional strength training like a squat or a push up or where muscles shorten and lengthen during the movement.

Currently, IRT is not recommended by several international guidelines for the management of high blood pressure. This was mostly due to concerns over its safety because the static nature of IRT causes blood pressure to increase markedly during exercise, particularly when performed using large muscle groups or at high intensity, compared to traditional strength exercise such as lifting weights or aerobic exercise such as walking or cycling.

However, lead authors of the study Mr Harrison Hansford and Dr Matthew Jones, both accredited exercise physiologists at the School of Health Sciences said their research showed IRT to be safe.

“We were interested in how IRT reduced blood pressure in people with high blood pressure. We also wanted to know whether IRT was safe. We found that IRT was very safe and caused meaningful changes in blood pressure — almost as much as what you’d expect to see with blood pressure lowering medications,” explained Dr Jones.

He said exercise is important for the management of high blood pressure, but the researchers acknowledged many Australians were physically inactive, with ‘lack of time’ commonly cited as a reason.

“IRT is a time-efficient means of reducing blood pressure, needing only 12 minutes a day, two to three days per week to produce the effects we found in our review.”

“While the studies included in our review normally used a specialised handgrip device, it’s possible we would see the same effects simply by asking participants to make a fist and squeeze it at a certain intensity for the prescribed amount of time. This means IRT could easily be performed while participants are sitting down watching TV,” said Dr Jones.

“We also found IRT caused improvements in other measures of blood pressure including central blood pressure (the pressure in the heart’s largest artery — the aorta, and an important predictor of cardiovascular disease) and to a lesser extent ambulatory blood pressure (average blood pressure across a 24-hour period), neither of which had previously been reviewed.”

Although previous studies had shown IRT as being effective for lowering office blood pressure, the studies had not comprehensively examined the safety of IRT.

IRT is accessible and easy to perform

Dr Jones said IRT is a very accessible and easy to perform intervention. He highlighted how exciting it was to know such a simple intervention could have such a strong effect on reducing blood pressure — the leading risk factor for mortality, globally.

“It’s particularly exciting for people who may have difficulty performing more ‘traditional’ exercise such as walking, cycling or strength training knowing they have another exercise type in their toolkit to help manage their high blood pressure.”

Dr Jones noted the research team were surprised there were not increased risks of adverse events in older adults.

“In fact, there were actually lower rates of adverse events in older adults, making it a very appealing mode of exercise, especially in those with mobility restrictions who may not be able to do other exercises like aerobic or dynamic resistance training.”

Dr Jones acknowledged research limitations in terms of the studies included in the scientific literature review, which were not always of ‘high quality’. This means the research team cannot be entirely confident in their results. Dr Jones also acknowledged relatively few studies examined lower body IRT, or IRT using different doses and intensities. Therefore, it is still unclear how different types and doses of IRT may affect results, and whether these would also be safe.

“There is a clear need for a large, high-quality randomised controlled trials to better assess the effect of IRT on blood pressure. To conduct such a study would be a clear goal for the future. It would also be useful to study how different types and doses of IRT affect results, and whether this differs between males and females, so this would also be a goal of future research.”

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Fertility:Key protein helps sperm do their job in timely fashion

Mammalian sperm cannot fertilize an egg from the get-go. It’s an ability acquired only after insemination, during passage through the female reproductive tract, and requires two consecutive, time-sensitive processes to provide sperm with the physical and biochemical traits necessary to complete their fundamental job.

The first process is called capacitation, which alters the physiology of each spermatozoa, changing the membrane of the head to help it penetrate the hard, outer layer of an egg — the zona pellucida — and chemistry in the tail to generate greater motility, the ability to move and swim.

The second process is acrosome reaction (AR), a chemical action that involves releasing enzymes in the spermatozoa’s head that further boost penetration of the zona pellucida.

Both processes are essential to successful fertilization of an egg, and AR is time-dependent: It cannot take place too early or too late. Indeed, premature AR has been associated with idiopathic (spontaneous) male infertility.

Neither process, however, is well understood in terms of the underlying molecular mechanisms involved. In a new paper, publishing August 19, 2021 in the journal eLife, a team of researchers at University of California San Diego School of Medicine detail how GIV/Girdin, a ubiquitous signaling molecule plays a critical role in male fertility, orchestrating capacitation and AR to promote sperm motility, survival and fertilization success.

Specifically, the research team, led by senior author Pradipta Ghosh, MD, professor in the departments of Medicine and Cellular and Molecular Medicine at UC San Diego School of Medicine, found that GIV — a member of the G protein family that serve as molecular switches inside cells, transmitting and fine-tuning signals — regulates the activity of enzymes that turn on and turn off the processes of capacitation and AR.

“The findings demonstrate how GIV orchestrates distinct signaling programs in sperm that separated by space and time, effectively supporting capacitation while inhibiting premature AR,” said Ghosh. “As a result, GIV plays an essential role in male fertility.”

Infertility affects an estimated 8 to 12 percent of couples globally, with males being a primary or contributing factor in roughly half of all cases, according to published studies. Causes of male infertility are multiple, but roughly 25 percent involve either sperm transport disorders or idiopathic factors in sperm with no apparent dysfunction.

“GIV is required for male fertility, and low levels of GIV transcripts in men is invariably associated with infertility,” said Ghosh. “We’ve found evidence that GIV may perform different roles in the capacitation of sperm, findings that shed new light on both how defective GIV-signaling might be used as a potential marker for male infertility and how inhibitors of GIV-dependent signaling inhibit fertility by reducing sperm motility and viability and by promoting premature acrosome reaction.

“The latter, ironically enough, may be a promising strategy for development of a male contraceptive pill specifically targeting sperm.”

Co-authors include: Sequoyah Reynoso, Vanessa Castillo, Gajanan D. Katkar, Inmaculada Lopez-Sanchez, Sahar Taheri, Celia R. Espinoza, Christina Rohena, Debashis Sahoo and Pascal Gagneux, all at UC San Diego.

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Materials provided by University of California – San Diego. Original written by Scott La Fee. Note: Content may be edited for style and length.

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New fossils show what the ancestral brains of arthropods looked like

Exquisitely preserved fossils left behind by creatures living more than half a billion years ago reveal in great detail identical structures that researchers have long hypothesized must have contributed to the archetypal brain that has been inherited by all arthropods. Arthropods are the most diverse and species-rich taxonomic group of animals and include insects, crustaceans, spiders and scorpions, as well as other, less familiar lineages such as millipedes and centipedes.

The fossils, belonging to an arthropod known as Leanchoilia, confirm the presence — predicted by earlier studies in genetics and developmental biology of insect and spider embryos — of an extreme frontal domain of the brain that is not segmented and is invisible in modern adult arthropods. Despite being invisible, this frontal domain gives rise to several crucial neural centers in the adult arthropod brain, including stem cells that eventually provide centers involved in decision-making and memory. This frontal domain was hypothesized to be distinct from the forebrain, midbrain and hindbrain seen in living arthropods, and it was given the name prosocerebrum, with “proso” meaning “front.”

Described in a paper published today in the journal Current Biology, the fossils provide the first evidence of the existence of this discrete prosocerebral brain region, which has a legacy that shows up during the embryonic development of modern arthropods, according to paper lead author Nicholas Strausfeld, a Regents Professor of Neuroscience at the University of Arizona.

“The extraordinary fossils we describe are unlike anything that has been seen before,” Strausfeld said. “Two nervous systems, already unique because they are identically preserved, show that half a billion years ago this most anterior brain region was present and structurally distinct before the evolutionary appearance of the three segmental ganglia that denote the fore-, mid- and hindbrain.”

The term ganglion refers to a system of networks forming a nerve center that occurs in each segment of the nervous system of an arthropod. In living arthropods, the three ganglia that mark the three-part brain condensed together to form a solid mass, obscuring their evolutionary origin as segmented structures.

Fossils of Brain Tissue are Extremely Rare

Discovered in deposits of the Kaili formation — a geological formation in the Guizhou province of southwest China — the fossilized remains of Leanchoilia date back to the Cambrian period, about 508 million years ago. The Kaili fossils occur in sedimentary rock that has high concentrations of iron, the presence of which probably helped preserve soft tissue, which subsequently was replaced by carbon deposits.

“The Kaili fossils open a window for us to glimpse the body plan evolution of animals that lived more than half a billion years ago,” said the paper’s first author, Tian Lan of the Guizhou Research Center for Palaeobiology at Guizhou University in China. “For the first time, we now know that arthropod fossils of the Kaili formation have the potential to preserve neural tissue that show us the primitive brain of the early stem arthropod existing at the dawn of the animal world.”

“Nervous systems, as other soft tissues, are difficult to fossilize,” added co-author Pedro Martinez of the Universitat de Barcelona and Institut Catalá in Barcelona, Spain. “This makes the study of the early evolution of neural systems a challenging task.”

The fossils also shed new light on the evolutionary origin of two separate visual systems in arthropod evolution: pairs of front-facing eyes or sideward looking eyes, the descendants of which are still present in species living today.

Many arthropods, including insects and crustaceans, have a distinct bilateral pair of faceted compound eyes and another set of less obvious eyes — with more primitive architecture — known as nauplius eyes, or ocelli. These are structurally similar to the principal eyes of spiders and scorpions. These simpler eyes correspond to the prosocerebrum’s forward eyes in Leanchoilia, in line with evidence obtained by previous studies analyzing gene expression patterns during embryonic development of living arthropods.

Leanchoilia‘s sideward eyes, on the other hand, relate to the protocerebrum, which is the segmental ganglion defining the arthropod forebrain, lying just behind the prosocerebrum. In living arthropods, the protocerebrum provides the compound eyes of insects and crustaceans, or the lateral single-lens eyes of arachnids, centipedes and millipedes. The visual centers serving those eyes also belong to the brain’s protocerebral region.

Strausfeld explained that in living arthropods, the protocerebrum, or forebrain, has incorporated — in a way, swallowed up — the ancient centers provided by the prosocerebrum, so that it is no longer discernible as a distinct anatomical entity.

The fossils are so well-preserved that they demonstrate that in addition to frontward eyes, the prosocerebrum has also given rise to ganglia associated with the labrum, or “upper lip,” of modern arthropods. The fossils also confirm an earlier hypothesis suggesting that the labrum must have originally evolved from the grasping appendages of Radiodonta, a group of stem-arthropods that were top predators during the Cambrian period.

“When compared with other, similar fossil material belonging to more advanced lineages, the organization of the Leanchoilia brain demonstrates that the ganglionic arrangement of the early brain underwent condensation and fusion of its components, which explains why in living species the prosocerebrum cannot be individually distinguished,” Strausfeld said.

Implications for Brain Evolution in Vertebrates

In addition to closing a century-old gap in the understanding of arthropod brain evolution, the findings have important implications for the early evolution of vertebrate brains, Strausfeld said.

Although simple, fishlike animals existed at the same time as these now-fossilized arthropods, there are no convincing fossils of their brains and, thus, neither fossil evidence nor anatomical evidence for a prosocerebrum in vertebrates. Yet, modern studies show that genes defining the fore- mid- and hindbrains of, for example, mice correspond to genes defining the three ganglionic divisions of the arthropod brain. And in vertebrates, certain crucial centers involved in decision making and in learning and memory have some genetic correspondences with the higher centers in the arthropod brain, which originated in the ancient arthropod prosocerebrum.

Thus, it is plausible that even earlier than the Cambrian period, possibly even before the evolution of segmentally organized body plans, the common ancestor of both vertebrates and invertebrates possessed basic circuits for simple cognition and decision making. And while an ancient prosocerebral-like brain might have been present in the very early ancestors of vertebrates, no such fossil has even suggested evidence for a discrete, nonsegmental domain.

“Nevertheless, one can reasonably speculate that vertebrates have embedded in their ‘modern’ brains parts of an ancient, non-segmented brain that has so far only been demonstrable in an early arthropod, such as Leanchoilia,” Strausfeld said.

Additional co-authors on the study are Yuanlong Zhao of the Guizhou Research Center for Palaeobiology at Guizhou University in Guiyang, China; Fangchen Zhao of the State Key Laboratory of Palaeobiology and Stratigraphy of the Chinese Academy of Sciences in Nanjing, China; and You He of Shanghai Synchrotron Radiation Facility.

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Varying immune cell levels in canine brain tumors could provide therapeutic targets

A new study reveals that high-grade gliomas, or brain tumors, in dogs contained more immune cells associated with suppressing immune response than low-grade gliomas. The work, which is the most extensive examination of immune cell infiltration in canine glioma to date, adds to the body of evidence that these brain tumors might recruit cells that aid in immunosuppression. The findings could have implications for future immunotherapy-based glioma treatments in both humans and dogs.

Glial cells are support cells located throughout the brain and spinal cord. When those cells become cancerous, the resulting tumor is called a glioma. In dogs, gliomas are the second most common type of tumor in the central nervous system and represent about 35% of all intracranial cancers. Median survival time for dogs with glioma treated with radiation therapy ranges from nine to 14 months, which is similar to the 14 month median survival time for humans treated with a combination of surgery, radiation and chemotherapy.

There are three types of canine glioma: oligodendroglioma, astrocytoma or undefined glioma. Each of these subtypes can be further classified as low or high-grade based on certain microscopic features. Although glioma subtype and grade affect survival and treatment choice in humans, it is currently unknown whether the same is true for dogs.

Immunotherapy harnesses the power of the body’s immune system to attack cancer. Though immunotherapy has shown promise in certain types of cancers, it hasn’t been successful in glioma in humans, possibly because gliomas have been shown to suppress the immune system in order to facilitate tumor growth. Researchers are trying to better understand the interaction between glioma and the immune system with hopes of improving therapeutic outcomes.

“If we want to pursue immunotherapy for glioma, we first need to understand how these tumors interact with the immune system,” says Gregory Krane, first author of the research and a veterinary pathologist who recently received his Ph.D. from North Carolina State University. “There are many shared features between canine and human glioma, which makes researching the immune system in canine glioma a good approach to addressing questions about this cancer in both humans and dogs.”

The multi-institutional research team examined 73 different gliomas obtained from veterinary patients seen at the NC State College of Veterinary Medicine between 2006 and 2018. Utilizing immunohistochemical tagging and computerized image analysis, the team identified the numbers of each type of immune cell in each tumor: B lymphocytes, T lymphocytes, regulatory T lymphocytes (Tregs) and macrophages. The team found higher numbers of Tregs and polarized macrophages in high- versus low-grade tumors, but no differences for other immune cells between different tumor types or grades.

“Tregs inhibit aspects of the immune response,” Krane says. “In healthy individuals, this prevents autoimmune disease. But cancers can recruit and activate Tregs to prevent the immune system from attacking the tumor. We found that Tregs were more abundant in high-grade gliomas than in low-grade gliomas. We hypothesize that Tregs may be involved in glioma-mediated immunosuppression, although that will require further research.”

The research team also counted the number of macrophages in each tumor, which can be polarized to either end of a spectrum referred to as M1 or M2 polarization. In a general sense, M1-polarized macrophages are pro-inflammatory and anti-tumor, and M2-polarized macrophages are the opposite. They found that the macrophage population in high-grade gliomas tended to be polarized towards the M2 phenotype.

“These macrophage polarization data can expand the glioma immunosuppression hypothesis by providing another mechanism by which gliomas may suppress the immune system in the dog,” Krane says.

Krane is hopeful that this study may lead to a better understanding of how gliomas affect the immune system, and eventually to improved immunotherapies for glioma. “Using the dog as a preclinical model for understanding the immune response to glioma could lead to treatments that will help both dogs and people,” Krane says. “Though further work is needed, our data provide some support to utilize canine patients with glioma to evaluate therapies targeting Tregs or macrophage polarization designed for use in humans.”

The research was published online in July 2021 in Veterinary Pathology and was supported by the National Institute of Environmental Health Sciences’ National Toxicology Program (NIEHS/NTP), NC State’s College of Veterinary Medicine, and Charles River Laboratories. Christopher Mariani, associate professor of neurology at NC State and principal investigator of NC State’s Comparative Neuroimmunology and Neuro-oncology Laboratory, is corresponding author. Other NC State co-authors were associate professors of pathology David Malarkey and Debra Tokarz, and veterinary student Britani Rainess. Researchers from NIEHS/NTP, Charles River Laboratories, the University of Alabama at Birmingham, Cornell University and Integrated Laboratory Systems coauthored the work.

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Materials provided by North Carolina State University. Original written by Tracey Peake. Note: Content may be edited for style and length.

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Researchers uncover the biology and treatment behind a rare autoinflammatory disease

The absence of a protein that activates the body’s antiviral defenses can cause a rare rheumatoid-like autoinflammatory condition that is treatable with an FDA-approved class of drugs known as TNF (tumor necrosis factor) inhibitors, a global research team led by Mount Sinai has found.

The condition, which is now termed TBK1 deficiency, was previously known to scientists but its name, cause and treatment were identified for the first time in the study published August 6 in Cell.

The scientists reported that the absence of the protein, known as TBK1 (TANK-binding kinase 1), renders cells vulnerable to a jarring form of programmed cell death in response to TNF, but that this genetic defect can be effectively and quickly addressed by therapeutic agents that block the source of the inflammation.

Homozygous mutations in TBK1, which occur when copies of the aberrant gene encoding the protein are passed on by both parents, are extremely rare. Based on past studies in mouse models and human cell cultures, researchers assumed that these mutations would leave individuals susceptible to a wide range of viral infections. They found instead that none of the four people in the cohort they studied, ages 7 to 32, showed signs of inadequate antiviral immunity. Rather, they all suffered from a systemic autoinflammatory condition that resulted from a dysregulated response to TNF, an important protein involved in controlling inflammation and cell death.

“TBK1 signaling activates the body’s antiviral mechanisms to fight off infection and block different stages of viral replication, as well as control TNF-mediated inflammation,” says lead author Justin Taft, PhD, an investigator in the Department of Microbiology, the Precision Immunology Institute, and the Center for Inborn Errors of Immunity at the Icahn School of Medicine at Mount Sinai. “But if a mutation prevents expression of the TBK1 gene or disrupts its function, then cells become overly sensitive to TNF. And that can trigger a disproportionate amount of cell death, which sets off a violent cascade of debris from dying cells that inflames surrounding tissue and fuels the inflammation.”

By treating TBK1-deficient individuals with anti-TNF therapeutics, the Mount Sinai-led team confirmed its suspicions about the underlying biology of the genetically driven condition. “We have essentially defined a new disease and its associated mechanisms of autoinflammation, which previously were managed with steroid treatments, non-steroidal anti-inflammatory drugs, or other non-specific therapeutics clinicians deemed worth trying,” says Dusan Bogunovic, PhD, Director of the Center for Inborn Errors of Immunity; Associate Professor of Oncological Sciences, Microbiology, and Pediatrics; member of the Precision Immunology Institute and The Mindich Child Health and Development Institute; and senior author of the study. “We were able to target the condition directly and effectively with TNF inhibitors once we knew the causative factors of the inflammation. And the clinical improvement was quick and substantial.”

For Dr. Taft, the work of the global team of researchers underscores the power of the increasingly vital field of personalized medicine. “We started with four individuals who were known to have a homozygous TBK1 mutation, and did extensive lab work to determine how the defect could induce this autoinflammatory reaction,” says Dr. Taft. “And from the genetics we uncovered not only a plausible mechanism of the disease and new information around TBK1 biology, but identified a disease-specific treatment that significantly improves the autoinflammatory condition.”

In addition to Mount Sinai, the collaborative research effort included Erasmus University Medical Center in the Netherlands, Mayo Clinic, the National Human Genomic Research Institute, Imperial College London, SRCC Children’s Hospital and Jaslok and Breach Candy Hospitals in Mumbai, India, and Hacettepe University in Ankara, Turkey.

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Scientists develop ‘greener’ way to make fertilizer

A team of international scientists led by Nanyang Technological University, Singapore (NTU Singapore) has devised a new ‘greener’ method to make a key compound in fertiliser, and that may pave the way to a more sustainable agricultural practice as global food demand rises.

Devised by NTU researchers, the method produces a compound known as ‘urea’, which is a natural product found in the urine of mammals, and an essential compound for fertilisers that is mass-produced industrially to increase crop yields.

However, the current Haber-Bosch process used to make urea is energy-intensive, requiring temperatures of 500 degrees Celsius and pressures of two hundred times sea-level atmospheric pressure. It creates significant CO2 emissions, contributing to approximately 2 per cent of global energy annually.

Seeking a more sustainable and energy-efficient method, the team found a way to greatly improve an existing alternative approach to urea production known as electrocatalysis — using electricity to drive chemical reactions in a solution.

Using the nanomaterial indium hydroxide as a catalyst, the researchers reacted nitrate and carbon dioxide and found that the process formed urea five times more efficiently than previously reported attempts using electrocatalysis, specifically by causing the chemical reaction to take place in a ‘highly selective’ manner.

Co-lead author of the study, Professor Alex Yan from the NTU School of Materials Science and Engineering (MSE) said, “Our method essentially manipulates the chemical reaction process to become ‘highly selective’. By picking a better catalyst, we helped the nitrate ions and carbon dioxide molecules to optimally position themselves to facilitate urea formation, while suppressing the creation of unnecessary by-products like hydrogen, leading to higher efficiency and better urea yields.”

The study findings are published in the peer-reviewed scientific journal Nature Sustainability in July, and the alternative urea production method has been patented by NTU.

This new method to produce urea may inspire the future design of sustainable chemistry approaches and contribute to ‘greener’ agricultural practices to feed the world’s growing population, say the research team.

The study reflects the university’s commitment to address humanity’s grand challenges on sustainability as part of the NTU 2025 strategic plan, which seeks to accelerate the translation of research discoveries into innovations that mitigate our impact on the environment.

Greener, simpler, and competitive with industrial methods

As a proof of concept, the scientists tested the efficiency of their devised method in the lab and found that the approach achieved a urea yield of 53.4 per cent, which is competitive with the current Haber-Bosch industrial method, that was first demonstrated in 1910.

The Haber-Bosch, a two-step thermal process, is fossil fuel reliant and can only happen at specific high temperatures, and high-pressure conditions. First, nitrogen and hydrogen are combined to make ammonia. Carbon dioxide is then bonded with it to make urea. By comparison, the new NTU approach is more environmentally friendly and simpler. It uses nitrate — a compound with bonds that require less energy to break — carbon dioxide, and hydrogen to directly trigger urea formation under room temperature.

The new method is simple enough to be adopted at both large and small scales, say the research team. The electrocatalytic device could be easily operated by farmers to generate their own urea for fertilisers. The method could also one day be powered entirely by renewable energy.

First author of the research, Dr Lyu Chade, Research Fellow from the NTU School of MSE said, “With advances in solar technology, we may potentially use sunlight to power the electrocatalysis process in future, which can further help lower global emissions.”

As the next steps, the research team is aiming to achieve even higher yield results and to refine the catalytic selectivity, by exploring catalysts that would trigger faster reactions. They also plan to find a way to power the process using solar energy and to create a prototype device to demonstrate scaled up urea production.

The international research team includes researchers from the University of Texas at Austin, University of Science and Technology of China and Harbin Institute of Technology, China.

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