Author Archives: admin

Silencing Wind Turbine Blade Noise using Active Noise Control

As the development in wind energy increases globally, solutions and more understanding are sought continuously on the complexities and general effects of wind turbine noise. To understand this problem, studies and evaluations of the source of this type of noise is required. Wind turbine noise consists of low frequency and high frequency noise and this study focuses on reducing the noise in the low frequency range.

The research has implication for health issues as the low frequency noise is said to cause fatigue and restlessness in humans and also low work performance. A basic knowledge of the characteristics of wind turbine noise, under several conditions, presents an immense opportunity for wind turbine operators and manufacturers as well.

The study of wind turbine noise is an opportunity to build knowledge and keep driving renewable energy.

Wind turbines while operating produce noise from the rotating mechanical parts and from the interaction of the blades with surrounding airflow. The noise produced by the blades consists of low frequency noise, airfoil self-noise and inflow turbulence noise. Active Noise Control (ANC) however, is a technique known to produce high level of attenuation in the low frequency range. The question therefore arose whether ANC can be used to reduce noise on wind turbines

 The study was conducted to investigate the potentiality of using ANC on wind turbines for low frequency noise reduction. To this end, a wind turbine noise assessment was carried out on a test turbine facility in Stellenbosch, Capetown, South Africa and the procedure was based on IEC 61400-11 standard.

An active noise control system is proposed for reducing the noise level from wind turbine blades using the FXLMS adaptive filter. The input to the system is noise signal which was measured according to IEC 61400-II standard and NLMS algorithm was used for updating filter coefficients and the implementation was based on MATLAB.

 FXLMS algorithm was able to minimize residual error. The results of the simulation show that noise was reduced by about 29dB. The Welch power spectral density estimate using spectral estimation of the signal was computed and the main frequency was found to be 86.13Hz also referred to as the true frequency. From the MATLAB simulations the highest magnitude of noise was found to be between 0-200Hz.

Role of regeneration in tissue repairing and therapies

Present review article emphasizes role of regeneration mechanism in various tissues and its use in organ transplantation for wound healing and repairing. This review also addresses tissue engineering methods and use of new biological scaffold materials and promising candidates such as immunomodulators, adhesions, integrins in tissue repairing and induction of regeneration in injured tissues. This article also explains uses of various stem cell types in transplantation technologies and its applications in regenerative medicine and therapeutics. In addition, role of various molecules of immune cell system, gene cascades and transcription specific proteins (TSPs) and growth factors in formation of microenvironment for differentiation are also explained. Mechanisms of regeneration in various animal tissues such as tendon and ligament, cartilage need progenitor cells show chondrogenic and proliferative potential and form elastic cartilage that needs long-term tissue maintenance. Similarly, regeneration of bone, limbs and local tissues, skeletal myoblasts, cardiac and smooth muscle cells is explained in detail. It makes clear that combined transplantation of specifically-processed human secondary CSs enhance infarct repair through the complementary enhancement of cardiopoietic regenerative and paracrine protective effect that can be maximize for achieving higher therapeutic benefits. Regenerative medicine has wider application in the field of tissue repairing, wound healing and transplantation therapeutics. Mechanism of regeneration in various tissues such neural, skeletal, cardiac, muscular, adipose and gonadial tissues, and bone marrow is described in detail. In addition repairing of adipose tissue damage, regenerative gonadial tissue damage repairing, and restoration of immune power,

Regenerative medicines belong to processes of creating living cells, replacing or regenerating human cells, tissues or organs. However, for repairing of age related effects, physical or biological injuries various biological and tissue engineering methods and stem cell therapies are used to restore the normal function. This article also suggest an urgent need for development of new advanced methods, technologies, bio-matrices, polymers and scaffold materials, and cell based therapies to overcome the problem of disable and injured patients. Regenerative medicine is an inter-disciplinarily innovative research area which has wider applications in the field of oncology, embryology, immunology, physiology, cardiovascular, nephrology, anatomy and clinical biology mainly in organ and tissue transplantation. However, by applying biological and tissue engineering methods self-sustained growth of degenerated or injured organ tissues could be achieved. Truly regenerative tissue re-juvenation has provided life to millions of accidental disabled peoples. No doubt, limb regeneration and its replacement assisted millions of disables to walk or those who have faced accidents and bear brutal multiple injuries in limbs. Moreover, limb regeneration by somatic cell induction and tissue replacement therapies are proved boon for millions. Similarly, repairing of chronically ischemic muscles has provided a grand success in management of CLI (critical limb ischemia) patients. In addition, cases of acute sciatic traction injury could be solved by axial regeneration of nerve cell. It would be possible by unifying growth factors and gene activities more interactive in vivo. Further, cell programming and regenerative factors found in few animals like newts, axolotls and frogs can be used for clinical trials. Thus by studying the regenerative abilities of planarians and its molecular basis tissue injury restoration and healing of wounds in vertebrates are much possible. Hence, landmark innovations are required in the field of regenerative medicine, tissue engineering, and developmental biology for successful tissue repairing and organ transplants to serve the human society.

 

 

 

 

 

 

 

 

Transdermal delivery of xenon from lipophilic solution and water

Xenon has been considered as an ideal anaesthetic agent. Also, scientific literature presents evidence of the neuroprotective effects of xenon in treatment of traumatic and ischemic brain injury. Data suggest that blockade of NMDA receptors in the nervous system by xenon plays a key role in neuroprotective effects of this agent. Recently, NMDA receptors have been found in the axons of human skin and in the keratinocytes of the epidermis. These receptors are involved in skin barrier function, calcium regulation, and dermatitis development. If this gas penetrates into the skin, we can expect a similar blocking effect of xenon on  skin NMDA receptors. Good source of xenon to the skin can be lipophilic liquid products in which xenon dissolves in a large amount. Moreover, xenon well it penetrates through the water. Therefore as a xenon source may be any emulsion comprising a lipophilic component.

Sufficient to take oil (or emulsion) and dissolve the xenon gas, and this oil (or emulsion)with xenon applied to the skin. Within 2 hours of xenon from oil (or emulsion) will diffuse into the skin. At this time xenon can block hyperactive NMDA receptors. Then xenon diffuses into the dermis and may penetrate into the blood capillaries and blood.

These first experiments were done on rat skin preparations. Therefore, for practical use of the results is necessary to continue this work.

Genetic characterization of Liriodendron seed orchards with EST-SSR markers

Liriodendron is a genus of the magnolia family (Magnoliaceae) in the order Magnoliales. The genus consists of two species, with one native to eastern North America (Liriodendron tulipifera) and another to China and Vietnam (Liriodendron chinense). Commonly known as yellow-poplar, tulip tree, or tulip-poplar, L. tulipifera is a wide-spread, fast-growing pioneering hardwood species with considerable economic and ecological values. Although most seedlings used for reforestation today derive from collections in natural populations, two known seed orchards, established from plus-tree selections, i.e. superior phenotypes, in the 1960’s and 1970’s have been used for local and regional planting needs in Tennessee and South Carolina. However, very little is known about the population genetics of yellow-poplar nor the genetic composition of the existing seed orchards.

In this study, 194 grafted yellow-poplar trees from a Clemson, SC orchard and a, TN orchard were genetically characterized with 15 simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs). The Tennessee Knoxville was established in 1966 and contains 100 grafted ramets, representing 31 genotypes or clones. The Clemson orchard was established in 1976 by grafting multiple ramets of 150 plus trees selected from throughout the 17,500-acre Clemson Experimental Forest. Currently there are 165 surviving trees in the Clemson orchard. Seeds from the orchards have been used for reforestation efforts for a number of years. Of the 15 EST-SSR markers, we found that 14 had a polymorphic information content (PIC) of at least 0.5. There was no significant difference between the Clemson and Knoxville orchards in average effective number of alleles (5.93 vs 3.95), observed and expected heterozygosity (Ho: 0.64 vs 0.58; He: 0.74 vs 0.70), Nei’s expected heterozygosity (0.74 vs. 0.58), or Shannon’s Information index (1.84 vs 1.51). The larger Clemson orchard exhibited a significantly greater number of observed alleles than the Knoxville orchard (15.3 vs 7.4). Overall, substantial genetic diversity is captured in the Clemson and Knoxville orchards.

With a widespread range of distribution, L. tulipifera has adapted to many different ecological conditions and is one of the species becoming increasingly dominant in forests due to its quick respond to increases in light to the forest floor and rapid initial growth rate. Its increasingly important roles in forestry and wood products is making studying Liriodendron of great interest. Our study provides a first look at the genetic diversity and allele richness among selections of this species, and provides a foundation for further genetic and breeding exploration.

 

Spectrum of opportunistic infections among HIV seropositive patients in Delhi region-a study by Delhi state AIDS control society

Globally, there were approximately 35.3 [32.2–38.8] million people living with HIV in 2012. The adult HIV prevalence at national level is 0.27% as estimated in 2011 and has recently been estimated that 2.5 million individuals are living with HIV infection in India. The depletion of T-lymphocytes which result from the proliferation of HIV causes the immune system to become severely compromised and the usually benign infectious agents become pathogenic. A number of microorganisms can be responsible for such opportunistic infections (OIs) in HIV-infected persons who have progressed to AIDS. The Antiretroviral Therapy (ART) started in the mid 1990s was instrumental in reducing the mortality related to HIV infection. ART not only reduces the incidence of OIs but also improves survival rate of PLHIVs.

Globally, more than 9.7 million people living with HIV in low and middle income countries were receiving ART at the end of 2012. Of this, about 640 000 were children. In India, Treatment of Opportunistic Infections (OI) is one of the main goal of comprehensive management to People living with HIV/AIDS (PLHIV) served through Care, Support and Treatment (CST) component of the, National AIDS Control Programme (NACO), Department of AIDS Control, Government of India. Under this initiative, patients have been provided access to free antiretroviral therapy (ART) for a decade (India had its first functional ART center in April’ 2004) and around 7.5 lakhs patients are receiving free ART therapy (second highest in the world) through 425 ART centers, 840 Link ART centers, 37 ART plus centres and 10 Center of Excellence (CoE) till March 2014. In Delhi, the number of PLHIV Alive and on First line ART by the end of March 2014 were 16038 among which 1021 were children below 15 years of age. As per World Health Organisation (WHO), online data record of Oct 2013, the most common life-threatening opportunistic infection affecting people living with HIV/AIDS is Tuberculosis (TB). Oral candidiasis, herpes zoster, cryptococcal meningitis, cerebral toxoplasmosis, and cytomegalovirus retinitis includes other commonly reported OIs. Hence the present study was carried out to find out the most common opportunistic pathogen and different opportunistic pathogens infecting HIV seropositive patients in Delhi region, India.

 

Scientists discover protein that boosts immunity to viruses and cancer

Experiments in mice and human cells have shown that the protein promotes the proliferation of cytotoxic T cells, which kill cancer cells and cells infected with viruses. The discovery was unexpected because the new protein had no known function and doesn’t resemble any other protein.

Researchers from Imperial College London who led the study are now developing a gene therapy designed to boost the infection-fighting cells, and hope to begin human trials in three years.

Cytotoxic T cells are an important component of the immune system, but when faced with serious infections or advanced cancer, they are often unable to proliferate in large enough quantities to fight the disease.

By screening mice with genetic mutations, the Imperial team discovered a strain of mice that produced 10 times as many cytotoxic T cells when infected with a virus compared with normal mice. These mice suppressed the infection more effectively, and were more resistant to cancer. They also produced more of a second type of T cells, memory cells, enabling them to recognise infections they have encountered previously and launch a rapid response.

The mice with enhanced immunity produced high levels of a hitherto unknown protein, which the researchers named lymphocyte expansion molecule, or LEM. They went on to show that LEM modulates the proliferation of human T cells as well as in mice.

The researchers now aim to develop a gene therapy designed to improve immunity by boosting the production of LEM. With the support of Imperial Innovations, the technology commercialisation company for the College, the researchers have filed two patents. A company called ImmunarT has been formed with the aim of commercialising the technology.

Original Content Published by Imperical College London View source

Study finds History of depression puts women at risk for diabetes during pregnancy.

A history of depression may put women at risk for developing diabetes during pregnancy, according to research published in the latest issue of the Journal of Obstetric, Gynecologic & Neonatal Nursing by researchers from Loyola University Chicago Marcella Niehoff School of Nursing (MNSON). This study also pointed to how common depression is during pregnancy and the need for screening and education.

“Women with a history of depression should be aware of their risk for gestational diabetes during pregnancy and raise the issue with their doctor,” said Mary Byrn, PhD, RN, study co-author and assistant professor, MNSON. “Health-care providers also should know and understand the prevalence and symptoms of prenatal depression and gestational diabetes and screen and manage these women appropriately.”

Loyola researchers used the Edinburgh Postnatal Depression Screen to measure symptoms of depression in 135 pregnant women attending routine prenatal care visits. Sixty-five study participants had gestational diabetes. These women were 3.79 times more likely to have a history of depression than women without gestational diabetes. In addition, 20 percent of women with gestational diabetes and 13 percent of women without gestational diabetes had significant symptoms of depression. Anxiety and perceived stress were significant predictive factors of depression for both groups.

Each year, more than 200,000 pregnancies are complicated by gestational diabetes. Pregnant women who have gestational diabetes and the added issue of depression are at an even greater risk for possible negative outcomes. Pregnant women who are depressed are more likely to practice unhealthy behaviors such as smoking, alcohol use and missing prenatal doctor visits.

The relationship between diabetes and depression is complex. Clinicians initially believed that depression in people with diabetes was due to the demands of living with a chronic illness. More contemporary thinking suggests that having depression may precipitate the onset of type 2 diabetes. Therefore, if depression is present prior to pregnancy, it may be important to monitor for the development of gestational diabetes.

“Depression may also contribute to the poor self-management of gestational diabetes and potentially increase the chance for complications during pregnancy,” said Sue Penckofer, PhD, RN, study co-author and professor, MNSON. “We must further explore the relationship between diabetes and depression to help understand and improve prenatal care and outcomes for women and infants”.

Original Content Published by Loyola University Chicago Marcella Niehoff School of Nursing (MNSON)  View source

Article Level metrics

Herbert Publications now providing  Article level metrics for published research by measuring the number of citations, Views, Pdf downloads, Comments on Social networks etc. to determine the Impact of the published research articles.

Article Level Metrics were introduced in the Year 2009 by The Public Library of Science (PLOS)  to measure the dissemination and reach of published research articles.

ALM  helps the researchers, publishers and institutions & Funders by evaluating  the distribution and reach of research.

ALM of the Published article: http://www.hoajonline.com/journals/A-Z/commonmetrics.php?journalid=8&volume=1&article=5

HepK, a protein-histidine kinase from the cyanobacterium Anabaena sp. strain PCC 7120, binds sequence-specifically to DNA

Two-component phosphorelay systems are minimally consisted of a sensory protein-histidine kinase (HK) and a response regulator (RR). HK autophosphorylates its conserved histidine residue in response to stimulus from an environment, this phosphate group then is transferred to a conserved aspartic acid residue of an RR, which is generally a transcription factor. HepK is a member of the family of sensory protein-histidine kinases in two-component phosphorelay systems (TCPS). We previously showed that HepK is an autokinase, and that DevR is its cognate RR, together comprising a mini two-component phosphorelay system that mediates developmental regulation of biosynthesis of a heterocyst envelope polysaccharide in the cyanobacterium Anabaena sp. PCC 7120.  Unlike a typical TCPS, both HepK and DevR lack known DNA-binding domains. However, mutations in hepK, hepC and hepA all block the synthesis of heterocyst envelope polysaccharide. A hepK mutation of Anabaena blocks the induction of hepA expression. We hypothesized that HepK may regulate the transcription of hepA or hepC by binding to DNA. To test this hypothesis we have performed a gel-shift analysis and have shown that although lacking a known DNA-binding motif, a truncated, soluble version of HepK binds sequence-specifically to a fragment of DNA found upstream from hepC, a gene that is located immediately upstream from hepA and also required for the synthesis of heterocyst envelope polysaccharide. The conserved phosphorylation histidine residue of HepK kinase is not required for this DNA-binding activity. Therefore, regulation of the synthesis of heterocyst envelope polysaccharide by HepK may be, at least in part, independent of two-component phosphorylation. The membrane-anchored HepK kinase with specific DNA-binding activity may serve as a membrane-tethered transcription factor, which may require an activation of regulated intramembrane proteolysis. We have found no other example of a protein histidine kinase without a known DNA binding motif that binds DNA sequence-specifically. Our finding may enable development of small DNA molecule as highly specific anti-microbial drugs because protein histidine kinases are broadly conserved in microbial pathogens but absent in humans.

Genomic sequence data have identified no presumptive protein histidine kinase genes in animal genomes including human genome. Since some two-component phosphorelay proteins are essential for the viability, virulence, and drug resistance of microbial pathogens including human fungal and bacterial pathogens, novel anti-microbial drugs targeted to protein histidine kinase in two-component phosphorelay systems may prove high specificity and minimal toxicity.  Several series of inhibitors to bacterial histidine kinase have been reported in the literature, however, most appear to suffer from high hydrophobicity, poor selectivity, and excessive protein binding and/or limited bioavailability.  The strong hydrophobicity of these molecules makes formulation and drug delivery impossible.  Unlike these compounds, small DNA molecules bound specifically by a protein-histidine kinase HepK are able to bypass the drawbacks of conventional inhibitors. These sequence-specific small DNA molecules have several unique advantages in developing of novel anti-microbial drugs, such as high solubility, high specificity, minimal toxicity, efficient synthesis, easy of formulation and delivery.  Therefore, our finding provides an exciting opportunity for developing small DNA molecules as novel anti-microbial drugs.

Neurocan expression and function during early avian embryogenesis

Neurocan is the most abundant lectican considered to be expressed exclusively in the central nervous system. Neurocan interacts with other matrix components, with cell adhesion molecules, growth factors, enzymes and cell surface receptors. The interaction repertoire and evidence from cellular studies indicated an active role in signal transduction and major cellular programs. Relatively little is known about the neurocan tissue-specific distribution and function during embryonic development. This study examined the time of appearance and subsequent spatio-temporal expression pattern of neurocan and its functional activities during the earliest stages of development in the chick embryo.

Neurocan was first detected in the inchoate neural plate and the extracellular matrix in embryos at the definitive streak stage (late gastrula). The expression of neurocan was very intense in the neural tube (developing central nervous system). Another significant observation was the very intense expression of neurocan in premigratory and migrating neural crest cells and in mesenchymal tissues known to be derived from the neural crest. Moreover, neurocan was intense in several areas of active cell migration such as the heart, the dispersing somite, the presumptive pronephric tubules and the blood islands.

download

Inhibition of neurocan function by blocking antibodies resulted in defects in the early embryo consistent with the known biochemical features and interactions of neurocan with signaling molecules: The neural epithelium expanded abnormally in the surface ectoderm (presumptive epidermis) flanking the neural tube showing a change of developmental fate from non-neural to neural possibly because of the diffuse spread of FGF signals. Surface ectoderm cells acquired invasive properties and interacted with the neuroepithelium while cranial neural crest cells formed ectopic aggregates on the apical side of the ectoderm possibly due to perturbation in the tight regulation of cadherin and N-CAM function. Neurocan seems to protect the functional organization of the extracellular matrix and to regulate the diffusion range and the local reception of FGF/BMP signalling activity during the neural-non-neural cell specification. Moreover, neurocan, through its interactions with cell surface molecules, seems to be an extracellular modulator of cell adhesive and signalling activities of epithelial-mesenchymal cells that are central to tissue patterning in the early embryo.

Neurocan was first expressed in the inchoate neural plate at the late gastrula stage. Neurocan expression was very intense in the developing central nervous system as well as in many non-neural tissues. Neurocan seems to modulate signalling in the neural-non-neural tissue specification and the adhesive and signalling activities of epithelial-mesenchymal cells and neural crest cell motility in the early embryo.