Experimental validation of new self-voltage balanced 9L-ANPC inverter for photovoltaic applications

Multilevel inverters play an important role in extracting the power from renewable energy resources and delivering the output voltage with high quality to the load. This paper proposes a new single-stage switched capacitor nine-level inverter, which comprises an improved T-type inverter, auxiliary switch, and switched cell unit. The proposed topology effectively reduces the DC-link capacitor voltage and exhibits superior performance over recently switched-capacitor inverter topologies in terms of the number of power components and blocking voltage of the switches. A level-shifted multilevel pulse width modulation scheme with a modified triangular carrier wave is implemented to produce a high-quality stepped output voltage waveform with low switching frequency. The proposed nine-level inverter's effectiveness, driven by the recommended modulation technique, is experimentally verified under varying load conditions. The power loss and efficiency for the proposed nine-level inverter are thoroughly discussed with different loads.

Transcriptomic and Functional Analyses of Mitochondrial Dysfunction in Pressure Overload-Induced Right Ventricular Failure

Background In complex congenital heart disease patients such as those with tetralogy of Fallot, the right ventricle (RV) is subject to pressure overload, leading to RV hypertrophy and eventually RV failure. The mechanisms that promote the transition from stable RV hypertrophy to RV failure are unknown. We evaluated the role of mitochondrial bioenergetics in the development of RV failure. Methods and Results We created a murine model of RV pressure overload by pulmonary artery banding and compared with sham-operated controls. Gene expression by RNA-sequencing, oxidative stress, mitochondrial respiration, dynamics, and structure were assessed in pressure overload-induced RV failure. RV failure was characterized by decreased expression of electron transport chain genes and mitochondrial antioxidant genes (aldehyde dehydrogenase 2 and superoxide dismutase 2) and increased expression of oxidant stress markers (heme oxygenase, 4-hydroxynonenal). The activities of all electron transport chain complexes decreased with RV hypertrophy and further with RV failure (oxidative phosphorylation: sham 552.3±43.07 versus RV hypertrophy 334.3±30.65 versus RV failure 165.4±36.72 pmol/(s×mL), P<0.0001). Mitochondrial fission protein DRP1 (dynamin 1-like) trended toward an increase, while MFF (mitochondrial fission factor) decreased and fusion protein OPA1 (mitochondrial dynamin like GTPase) decreased. In contrast, transcription of electron transport chain genes increased in the left ventricle of RV failure. Conclusions Pressure overload-induced RV failure is characterized by decreased transcription and activity of electron transport chain complexes and increased oxidative stress which are associated with decreased energy generation. An improved understanding of the complex processes of energy generation could aid in developing novel therapies to mitigate mitochondrial dysfunction and delay the onset of RV failure.

Fingerprint of volcanic forcing on the ENSO-Indian monsoon coupling

Coupling of the El Niño-Southern Oscillation (ENSO) and Indian monsoon (IM) is central to seasonal summer monsoon rainfall predictions over the Indian subcontinent, although a nonstationary relationship between the two nonlinear phenomena can limit seasonal predictability. Radiative effects of volcanic aerosols injected into the stratosphere during large volcanic eruptions (LVEs) tend to alter ENSO evolution; however, their impact on ENSO-IM coupling remains unclear. Here, we investigate how LVEs influence the nonlinear behavior of the ENSO and IM dynamical systems using historical data, 25 paleoclimate reconstructions, last-millennium climate simulations, large-ensemble targeted climate sensitivity experiments, and advanced analysis techniques. Our findings show that LVEs promote a significantly enhanced phase-synchronization of the ENSO and IM oscillations, due to an increase in the angular frequency of ENSO. The results also shed innovative insights into the physical mechanism underlying the LVE-induced enhancement of ENSO-IM coupling and strengthen the prospects for improved seasonal monsoon predictions.

4HNE Impairs Myocardial Bioenergetics in Congenital Heart Disease-Induced Right Ventricular Failure

BACKGROUND

In patients with complex congenital heart disease, such as those with tetralogy of Fallot, the right ventricle (RV) is subject to pressure overload stress, leading to RV hypertrophy and eventually RV failure. The role of lipid peroxidation, a potent form of oxidative stress, in mediating RV hypertrophy and failure in congenital heart disease is unknown.

METHODS

Lipid peroxidation and mitochondrial function and structure were assessed in right ventricle (RV) myocardium collected from patients with RV hypertrophy with normal RV systolic function (RV fractional area change, 47.3±3.8%) and in patients with RV failure showing decreased RV systolic function (RV fractional area change, 26.6±3.1%). The mechanism of the effect of lipid peroxidation, mediated by 4-hydroxynonenal ([4HNE] a byproduct of lipid peroxidation) on mitochondrial function and structure was assessed in HL1 murine cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes.

RESULTS

RV failure was characterized by an increase in 4HNE adduction of metabolic and mitochondrial proteins (16 of 27 identified proteins), in particular electron transport chain proteins. Sarcomeric (myosin) and cytoskeletal proteins (desmin, tubulin) also underwent 4HNE adduction. RV failure showed lower oxidative phosphorylation (moderate RV hypertrophy, 287.6±19.75 versus RV failure, 137.8±11.57 pmol/[sec×mL]; P=0.0004), and mitochondrial structural damage. Using a cell model, we show that 4HNE decreases cell number and oxidative phosphorylation (control, 388.1±23.54 versus 4HNE, 143.7±11.64 pmol/[sec×mL]; P<0.0001). Carvedilol, a known antioxidant did not decrease 4HNE adduction of metabolic and mitochondrial proteins and did not improve oxidative phosphorylation.

CONCLUSIONS

Metabolic, mitochondrial, sarcomeric, and cytoskeletal proteins are susceptible to 4HNE-adduction in patients with RV failure. 4HNE decreases mitochondrial oxygen consumption by inhibiting electron transport chain complexes. Carvedilol did not improve the 4HNE-mediated decrease in oxygen consumption. Strategies to decrease lipid peroxidation could improve mitochondrial energy generation and cardiomyocyte survival and improve RV failure in patients with congenital heart disease.

Evaluation of root coverage with pedicled buccal fat pad in class III and class IV gingival recession defects

Background:

Gingival recession (GR) is a common clinical feature of periodontal disease and is an undesirable condition. More than 50% of the population has one or more sites with GR ≥ 1 mm.

Material and Methods:

In this study 15 subjects were subjected to initial periodontal therapy such as ultrasonic scaling and root planning with hand instruments and curettes. Patient is motivated for home care. The buccal fat pad is harvested and sutured in the gingival recession area and followed up for 6 months and root coverage was calculated.

Results:

At baseline mean recession of 5.60 ± 1.18 mm, probing depth of 0.73 ± 0.59 mm, clinical attachment loss of 6.40 ± 1.18 mm were recorded. At the end of 6 months, the mean recession was reduced from 5.60 ± 1.18 mm to 2.87 ± 0.74 mm, probing depth was increased from 0.73 ± 0.59 mm to 1.73 ± 0.70 mm and clinical attachment loss was decreased from 6.40 ± 1.18 mm to 4.53 ± 0.83 mm.The difference between baseline score and six months score for all three parameters are statistically significant.

Conclusion:

Buccal fat pad is a predictable procedure to cover Miller's class III and class IV gingival recession defects. There was a definitive improvement in clinical parameters (reduction in gingival recession, increased probing depth, gain in clinical attachment) after 6 months. There was 46.78% improvement in root coverage which was statistically significant.

3D MHD nonlinear radiative flow of CuO-MgO/methanol hybrid nanofluid beyond an irregular dimension surface with slip effect

The 3D MHD nonlinear radiative hybrid nanofluid flow across an irregular dimension sheet with slip effect is studied numerically. The hybrid nanofluid consists of copper oxide (CuO) and magnesium oxide (MgO) nanoparticles embedded in methanol or methyl alcohol (MA). The governing PDEs’ are altered as ODEs’ using similarities and numerical solutions are attained using shooting scheme. The role of corporal factors on the transport phenomenon is analyzed and reflected by plots and numerical interpretations. Simultaneous solutions presented for CuO-MA nanofluid and CuO-MgO/MA hybrid nanofluid. Results ascertain that the temperature and flow boundary layer thicknesses are not unique for the hybrid nanofluid and nanofluid. The heat transfer enactment of CuO-MA nanofluid is high when equated to CuO-MgO/MA hybrid nanofluid. This concludes that the CuO-MgO combination works as a good insulator.

3-D magnetohydrodynamic AA7072-AA7075/methanol hybrid nanofluid flow above an uneven thickness surface with slip effect

A 3-D magnetohydrodynamic flow of hybrid nanofluid across a stretched plane of non-uniform thickness with slip effects is studied. We pondered aluminum alloys of AA7072 and AA7072 + AA7075 in methanol liquid. The aluminum alloys amalgamated in this study are uniquely manufactured materials, possessing enhanced heat transfer features. AA7072 alloy is a composite mixture of Aluminum & Zinc in the ratio 98 & 1 respectively with added metals Silicon, ferrous and Copper. Equally, AA7075 is a mixture of Aluminum, Zinc, Magnesium, and Copper in the ratio of ~90, ~6, ~3 and ~1 respectively with added metals Silicon ferrous and Magnesium. Numerical solutions are attained using R-K based shooting scheme. Role of physical factors on the flow phenomenon are analyzed and reflected by plots and numerical interpretations. Results ascertain that heat transfer rate of the hybrid nanoliquid is considerably large as matched by the nanofluid. The impact of Lorentz force is less on hybrid nanofluid when equated with nanofluid. Also, the wall thickness parameter tends to improve the Nusselt number of both the solutions.

Gyrotactic microorganisms and thermoelectric effects on the dynamics of 29 nm CuO-water nanofluid over an upper horizontal surface of paraboloid of revolution

Purpose

The purpose of this paper is to provide an insight into the influence of gyrotactic microorganisms and Hall effect on the boundary layer flow of 29 nm CuO-water mixture on the upper pointed surface of a rocket, over the bonnet of a car and upper pointed surface of an aircraft. This is true since all these objects are examples of an object with variable thickness.

Design/methodology/approach

The simplification of Rosseland approximation (Taylor series expansion of T4 about T∞) is avoided; thus, two different parameters relating to the study of nonlinear thermal radiation are obtained. The governing equation is non-dimensionalized, parameterized and solved numerically.

Findings

Maximum vertical and horizontal velocities of the 29 nm CuO-water nanofluid flow is guaranteed at a small value of Peclet number and large value of buoyancy parameter depending on the temperature difference. When the magnitude of thickness parameter χ is small, cross-flow velocity decreases with the velocity index and the opposite effect is observed when the magnitude of χ is large.

Originality/value

Directly or indirectly, the importance of the fluid flow which contains 29 nm CuO nanoparticle, water, and gyrotactic microorganisms in the presence of Hall current has been pointed out as an open question in the literature due to its relevance in imaging, ophthalmological and translational medicine informatics.

miR-21 is associated with fibrosis and right ventricular failure

Combined pulmonary insufficiency (PI) and stenosis (PS) is a common long-term sequela after repair of many forms of congenital heart disease, causing progressive right ventricular (RV) dilation and failure. Little is known of the mechanisms underlying this combination of preload and afterload stressors. We developed a murine model of PI and PS (PI+PS) to identify clinically relevant pathways and biomarkers of disease progression. Diastolic dysfunction was induced (restrictive RV filling, elevated RV end-diastolic pressures) at 1 month after generation of PI+PS and progressed to systolic dysfunction (decreased RV shortening) by 3 months. RV fibrosis progressed from 1 month (4.4% ± 0.4%) to 3 months (9.2% ± 1%), along with TGF-β signaling and tissue expression of profibrotic miR-21. Although plasma miR-21 was upregulated with diastolic dysfunction, it was downregulated with the onset of systolic dysfunction), correlating with RV fibrosis. Plasma miR-21 in children with PI+PS followed a similar pattern. A model of combined RV volume and pressure overload recapitulates the evolution of RV failure unique to patients with prior RV outflow tract surgery. This progression was characterized by enhanced TGF-β and miR-21 signaling. miR-21 may serve as a plasma biomarker of RV failure, with decreased expression heralding the need for valve replacement.

Characterizing the angiogenic activity of patients with single ventricle physiology and aortopulmonary collateral vessels

OBJECTIVES

Patients with single ventricle congenital heart disease often form aortopulmonary collateral vessels via an unclear mechanism. To gain insights into the pathogenesis of aortopulmonary collateral vessels, we correlated angiogenic factor levels with in vitro activity and angiographic aortopulmonary collateral assessment and examined whether patients with single ventricle physiology have increased angiogenic factors that can stimulate endothelial cell sprouting in vitro.

METHODS

In patients with single ventricle physiology (n = 27) and biventricular acyanotic control patients (n = 21), hypoxia-inducible angiogenic factor levels were measured in femoral venous and arterial plasma at cardiac catheterization. To assess plasma angiogenic activity, we used a 3-dimensional in vitro cell sprouting assay that recapitulates angiogenic sprouting. Aortopulmonary collateral angiograms were graded using a 4-point scale.

RESULTS

Compared with controls, patients with single ventricle physiology had increased vascular endothelial growth factor (artery: 58.7 ± 1.2 pg/mL vs 35.3 ± 1.1 pg/mL, P < .01; vein: 34.8 ± 1.1 pg/mL vs 21 ± 1.2 pg/mL, P < .03), stromal-derived factor 1-alpha (artery: 1901.6 ± 1.1 pg/mL vs 1542.6 ± 1.1 pg/mL, P < .03; vein: 2092.8 pg/mL ± 1.1 vs 1752.9 ± 1.1 pg/mL, P < .02), and increased arterial soluble fms-like tyrosine kinase-1, a regulatory vascular endothelial growth factor receptor (612.3 ± 1.2 pg/mL vs 243.1 ± 1.2 pg/mL, P < .003). Plasma factors and sprout formation correlated poorly with aortopulmonary collateral severity.

CONCLUSIONS

We are the first to correlate plasma angiogenic factor levels with angiography and in vitro angiogenic activity in patients with single ventricle disease with aortopulmonary collaterals. Patients with single ventricle disease have increased stromal-derived factor 1-alpha and soluble fms-like tyrosine kinase-1, and their roles in aortopulmonary collateral formation require further investigation. Plasma factors and angiogenic activity correlate poorly with aortopulmonary collateral severity in patients with single ventricles, suggesting complex mechanisms of angiogenesis.

Hurler Scheie Disease

We present a very rare case of mucopolysaccharidosis type I (MPS I) which presented to us with respiratory distress. Our patient had short stature, coarse facial features, claw hands and clouding of both corneae. This article highlights the salient features present in a case of mucopolysaccharidosis type I.

A Simple and Cost Effective Method used for Removal of a Fractured Implant Abutment Screw: A Case Report

The success of dental implants is based primarily on the extent of osseointegration. The failure of dental implants is not only due to biological factors, such as unsuccessful osseointegration or the presence of peri-implantitis, but may also result from technical complications. Fracture of the implant abutment screw can be a serious problem, as the fragment remaining inside the implant may prevent the implant from functioning efficiently as an anchor. A simple and cost effective procedure used for the removal of fractured screw fragments and the successful utilization of the existing prosthesis are described in this clinical report. How to cite this article: Satwalekar P, Chander KS, Reddy BA, Sandeep N, Sandeep N, Satwalekar T. A Simple and Cost Effective Method used for Removal of a Fractured Implant Abutment Screw: A Case Report. J Int Oral Health 2013; 5(5):120-3.

Probiotics and prebiotics in periodontal therapy

There has been a paradigm shift toward ecological and microbial community-based approach in understanding oral diseases. A marked improvement in gastrointestinal health has been reported after using probiotic bacteria and/or prebiotic supplements,which has prompted much interest in the use of this approach for oral applications. Treatment of periodontal disease in recent years has moved toward an antibiotic/antimicrobial model of disease management. With increase in the incidence of resistance to antibiotics, probiotics may be a promising area of research in periodontal therapy. This paper reviews the evidences for the use of probiotics or prebiotics for the prevention of dental caries or periodontal diseases, and also adresses the risk associated with their prolonged use. Many questions have been raised pertaining to the benefits of probiotic administration, as the role of probiotics in periodontics is still in infancy, and a complete understanding of the broad ecological changes induced in the mouth by probiotics or prebiotics is essential to assess their long-term consequences for oral health and disease.

Osteoporosis: "A risk factor for periodontitis"

Aging is one of the major health challenges today. Most of the diseases related to aging, lead to significantly increased morbidity and mortality and higher public expenditure of funds. The interconnection between socio-economic conditions and social vulnerability is reflected in precarious states of health with prominence of high rates of osteoporosis and periodontal disease.Both these diseases have been highlighted in public health because of the impact caused by bone fracture and tooth loss. Thus, the elderly could help live a healthier and more meaningful life with the prevention of these diseases.

Gap junction remodeling and spironolactone-dependent reverse remodeling in the hypertrophied heart

Pressure overload is a common pathological insult to the heart and the resulting hypertrophy is an independent risk factor for sudden cardiac death. Gap junction remodeling (GJR) has been described in hypertrophied hearts; however, a detailed understanding of the remodeling process and its effects on impulse propagation is lacking. Moreover, there has been little progress developing therapeutic strategies to diminish GJR. Accordingly, transverse aortic banding (TAC) was performed in mice to determine the effects of progressive pathological hypertrophy on connexin (Cx)43 expression, posttranslational phosphorylation, gap junction assembly, and impulse propagation. Within 2 weeks after TAC, total and phospho-Cx43 abundance was reduced and incorporation of Cx43 into gap junctional plaques was markedly diminished. These molecular changes were associated with progressive slowing of impulse propagation, as determined by optical mapping with voltage-sensitive dyes. Treatment with the aldosterone receptor antagonist spironolactone, which has been shown to diminish sudden arrhythmic death in clinical trials, was examined for its effects on GJR. We found that spironolactone blunted the development of GJR and also potently reversed established GJR, both at the molecular and functional levels, without diminishing the extent of hypertrophy. These data suggest a potential mechanism for some of the salutary electrophysiological and clinical effects of mineralocorticoid antagonists in myopathic hearts.