NMR based Serum metabolomics revealed metabolic signatures associated with oxidative stress and mitochondrial damage in brain stroke.

Brain stroke (BS, also known as a cerebrovascular accident), represents a serious global health crisis. It has been a leading cause of permanent disability and unfortunately, frequent fatalities due to lack of timely medical intervention. While progress has been made in prevention and management, the complexities and consequences of stroke continue to pose significant challenges, especially, its impact on patient's quality of life and independence. During stroke, there is a substantial decrease in oxygen supply to the brain leading to alteration of cellular metabolic pathways, including those involved in mitochondrial-damage, leading to mitochondrial-dysfunction. The present proof-of-the-concept metabolomics study has been performed to gain insights into the metabolic pathways altered following a brain stroke and discover new potential targets for timely interventions to mitigate the effects of cellular and mitochondrial damage in BS. The serum metabolic profiles of 108 BS-patients were measured using 800 MHz NMR spectroscopy and compared with 60 age and sex matched normal control (NC) subjects. Compared to NC, the serum levels of glutamate, TCA-cycle intermediates (such as citrate, succinate, etc.), and membrane metabolites (betaine, choline, etc.) were found to be decreased BS patients, whereas those of methionine, mannose, mannitol, phenylalanine, urea, creatine and organic acids (such as 3-hydroxybutyrate and acetone) were found to be elevated in BS patients. These metabolic changes hinted towards hypoxia mediated mitochondrial dysfunction in BS-patients. Further, the area under receiver operating characteristic curve (ROC) values for five metabolic features (methionine, mannitol, phenylalanine, mannose and urea) found to be more than 0.9 suggesting their high sensitivity and specificity for differentiating BS from NC subjects.

Clinical metabolomics by NMR revealed serum metabolic signatures for differentiating sarcoidosis from tuberculosis.

BACKGROUND: Pulmonary sarcoidosis (SAR) and tuberculosis (TB) are two granulomatous lung-diseases and often pose a diagnostic challenge to a treating physicians. OBJECTIVE: The present study aims to explore the diagnostic potential of NMR based serum metabolomics approach to differentiate SAR from TB. MATERIALS AND METHOD: The blood samples were obtained from three study groups: SAR (N = 35), TB (N = 28) and healthy normal subjects (NC, N = 56) and their serum metabolic profiles were measured using 1D 1H CPMG (Carr-Purcell-Meiboom-Gill) NMR spectra recorded at 800 MHz NMR spectrometer. The quantitative metabolic profiles were compared employing a combination of univariate and multivariate statistical analysis methods and evaluated for their diagnostic potential using receiver operating characteristic (ROC) curve analysis. RESULTS: Compared to SAR, the sera of TB patients were characterized by (a) elevated levels of lactate, acetate, 3-hydroxybutyrate (3HB), glutamate and succinate (b) decreased levels of glucose, citrate, pyruvate, glutamine, and several lipid and membrane metabolites (such as very-low/low density lipoproteins (VLDL/LDL), polyunsaturated fatty acids, etc.). CONCLUSION: The metabolic disturbances not only found to be well in concordance with various previous reports, these further demonstrated very high sensitivity and specificity to distinguish SAR from TB patients suggesting serum metabolomics analysis can serve as surrogate method in the diagnosis and clinical management of SAR.

Monolithic integration of InGaAs n-FETs and lasers on Ge substrate.

We report the first monolithic integration of InGaAs channel field-effect transistors with InGaAs/GaAs multiple quantum wells (MQWs) lasers on a common platform, achieving a milestone in the path of enabling low power and high speed opto-electronic integrated circuits (OEICs). The III-V layers used for realizing transistors and lasers were grown epitaxially on the Ge substrate using molecular beam epitaxy (MBE). A Si-CMOS compatible process was developed to realize InGaAs n-FETs with subthreshold swing SS of 93 mV/decade, ION/IOFF ratio of more than 4 orders of magnitude with very low off-state leakage current, and a peak effective mobility of more than 2000 cm2/V·s. In addition, fabrication process uses a low overall processing temperature (≤ 400 °C) to maintain the high quality of the InGaAs/GaAs MQWs for the laser. Room temperature electrically-pumped lasers with a lasing wavelength of 1.03 µm and a linewidth of less than 1.7 nm were realized.

Integration of InGaAs MOSFETs and GaAs/ AlGaAs lasers on Si Substrate for advanced opto-electronic integrated circuits (OEICs).

Lasers monolithically integrated with high speed MOSFETs on the silicon (Si) substrate could be a key to realize low cost, low power, and high speed opto-electronic integrated circuits (OEICs). In this paper, we report the monolithic integration of InGaAs channel transistors with electrically pumped GaAs/AlGaAs lasers on the Si substrate for future advanced OEICs. The laser and transistor layers were grown on the Si substrate by molecular beam epitaxy (MBE) using direct epitaxial growth. InGaAs n-FETs with an ION/IOFF ratio of more than 106 with very low off-state leakage and a low subthreshold swing with a minimum of 82 mV/decade were realized. Electrically pumped GaAs/AlGaAs quantum well (QW) lasers with a lasing wavelength of 795 nm at room temperature were demonstrated. The overall fabrication process has a low thermal budget of no more than 400 °C.

Triple plating of tibia in a complex bicondylar tibial plateau fracture.

High-energy tibial plateau fracture poses a significant challenge and difficulty for orthopaedic surgeons. Fracture of tibial plateau involves major weight bearing joint and may alter knee kinematics. Anatomic reconstruction of the proximal tibial articular surfaces, restoration of the limb axis (limb alignment) and stable fixation permitting early joint motion are the goals of the treatment. In cases of complex bicondylar tibial plateau fractures, isolated lateral plating is frequently associated with varus malalignment and better results have been obtained with bilateral plating through dual incisions. However sometimes a complex type of bicondylar tibial plateau fractures is encountered in which medial plateau has a biplaner fracture in posterior coronal plane as well as sagittal plane. In such fractures it is imperative to fix the medial plateau with buttressing in both planes. One such fracture pattern of the proximal tibia managed by triple plating through dual posteromedial and anterolateral incisions is discussed in this case report with emphasis on mechanisms of this type of injury, surgical approach and management.

Elucidating the impact of sanitary waste on the formation of fat, oil and grease deposits in sewer systems.

The accumulation of fat, oil and grease (FOG) deposits in sanitary sewer systems is a significant cause of sewer overflows, mainly due to their tendency to adhere to pipe walls. The aim of this study is to (i) develop laboratory-prepared FOG deposits using a mixture of iron (Fe) and aluminium (Al) metal ions, fatty acids, saccharides and cooked oils, in addition to various sanitary waste materials such as paper towels, wipes and pads and (ii) examine the characteristics of these FOG deposits. The goals of this study were to (i) gain a deeper understanding of the impact of sanitary waste on the formation of FOG deposits and (ii) discuss the detailed physiochemical properties of these FOG deposits. The findings revealed that FOG deposits can vary in nature, appearing as either a smooth, paste-like substance or a coarse, semi-solid material, depending on the types of waste present in the sewer. Analysis of the fatty acid profile indicated that the FOG deposits with wipes have the highest viscosity (3.2 × 104 Pa s) and larger composition of smaller chain saturated fatty acids (caprylic acid 0.64%, undecanoic acid 5.61%, lauric acid 4.65%, myristic acid 3.21% and palmitic 8.38%). In contrast, FOG deposits with Fe and Al metal impurities have higher heat resistance and thermal stability (melting point of 125 °C) and have larger composition of long chain fatty acids. Furthermore, FTIR analysis confirmed that these FOG deposits are composed of metallic salts of fatty acids, aligning with samples from sewer lines. Our results suggest that FOG deposit formation involves the aggregation of excess calcium, which compresses free fatty acid micelles, and a saponification reaction between the calcium aggregates and free fatty acids. This research illuminates the complex processes behind FOG deposit formation and their varied characteristics, providing valuable insights into potential strategies for preventing FOG-related sewer blockages.

Interplay between superconducting fluctuations and weak localization in disordered TiN thin films.

The interplay between superconducting fluctuations (SFs) and weak localization (WL) has been probed by temperature dependent resistance [R(T)] and magnetoresistance (MR) measurements in two-dimensional disordered superconducting TiN thin films. Within a narrow range of temperature above transition temperature (Tc), the coexistence of SF-mediated positive MR and WL-led negative MR in different ranges of magnetic fields and a crossover from positive MR to negative MR with an increase in temperature are reported herein. The crossover temperature coincides with a characteristic temperature (Tmax) at which a resistance peak appears in the zero-field R(T). The resistance peak and associated magnetoresistance anomalies are addressed using quantum corrections to conductivity (QCC) theory. We show that WL can be accounted for the observed negative MR. By introducing individual coefficients to both SFs and WL contributions, the dominance of one over the other is monitored with respect to temperature. It is observed that just above Tc, SFs dominate; with an increase in temperature, the contributions from both become comparable; and finally, at Tmax, WL takes over completely. The presented approach may be adopted to compare various quantum contributions in two-dimensional superconductors, particularly in the regime where both SFs and WL are pronounced.

Evaluation of Radiopacity of Calcium Silicate-Based and Resin-Based Materials Using Direct Digital Radiography Along With an Aluminium Step Wedge.

Background Radiopacity is a critical property for root canal sealers as it allows for the assessment of the material's placement and quality within the root canal system on radiographic images. The study aimed to evaluate the radiopacity of calcium silicate-based and resin-based materials using direct digital radiography, employing an aluminium step wedge according to American National Standards Institute/International Organization for Standardization (ANSI/ISO) standard protocols for testing the radiopacity of root canal sealers. This study seeks to determine the effectiveness of these materials in meeting the required standards for clinical use. Methodology The materials tested were AH Plus, Apexit Plus, Biodentine and MTA Fillapex in circular disc form and radiographed alongside the aluminium step wedge using direct digital radiography to determine the radiopacity using grey-pixel values. All the materials, viz., AH Plus, Apexit Plus, Biodentine and MTA Fillapex were found satisfactorily radiopaque and met the minimum radiopacity standard, that is, minimum 3mm of aluminium recommended by ANSI/American Dental Association (ADA) Specification No. 57. Results AH Plus exhibited the highest radiopacity with values of 222.54 mm Al Eq (isodensity) and 220.88 mm Al Eq (densitometric), significantly surpassing Apexit Plus, Fillapex and Biodentine (p < 0.001). Apexit Plus and Fillapex showed no significant difference between them (p = 0.238), but both were significantly higher than Biodentine (p < 0.001). Biodentine had the lowest radiopacity among all the sealers tested. Conclusion All the tested materials met the ANSI/ADA minimum radiopacity standard, demonstrating their suitability for clinical use. The materials varied in their levels of radiopacity, demonstrating that they are adequately visible on radiographic images for effective assessment in root canal treatments.

Charge Trapping and Emission during Bias Temperature Stressing of Schottky Gate GaN-on-Silicon HEMT Structures Targeting RF/mm Wave Power Amplifiers.

For operation as power amplifiers in RF applications, high electron mobility transistor (HEMT) structures are subjected to a range of bias conditions, applied at both the gate and drain terminals, as the device is biased from the OFF- to ON-state conditions. The stability of the device threshold voltage (Vt) condition is imperative from a circuit-design perspective and is the focus of this study, where stresses in both the ON and OFF states are explored. We see rapid positive threshold voltage increases under negative bias stress and subsequent recovery (i.e., Vt reduces), whereas conversely, we see a negative Vt shift under positive stress and Vt increase during the subsequent relaxation phase. These effects are correlated with the thickness of the GaN layer and ultimately result from the deep carbon-acceptor levels in the C-GaN back barrier incorporated to screen the buffer between the silicon substrate and the epitaxially grown GaN layer. Methods to mitigate this effect are explored, and the consequences are discussed.

Preclinical evaluation of dalbergin loaded PLGA-galactose-modified nanoparticles against hepatocellular carcinoma via inhibition of the AKT/NF-κB signaling pathway.

Prior research has shown the effectiveness of dalbergin (DL), dalbergin nanoformulation (DLF), and dalbergin-loaded PLGA-galactose-modified nanoparticles (DLMF) in treating hepatocellular carcinoma (HCC) cells. The present investigation constructs upon our previous research and delves into the molecular mechanisms contributing to the anticancer effects of DLF and DLMF. This study examined the anti-cancer effects of DL, DLF, and DLMF by diethyl nitrosamine (DEN)-induced HCC model in albino Wistar rats. In addition, we performed biochemical, antioxidant, lipid profile tests, and histological studies of liver tissue. The anticancer efficacy of DLMF is equivalent to that of 5-fluorouracil, a commercially available therapy for HCC. Immunoblotting studies revealed a reduction in the expression of many apoptotic markers, such as p53, BAX, and Cyt-C, in HCC. Conversely, the expression of Bcl-2, TNF-α, NFκB, p-AKT, and STAT-3 was elevated. Nevertheless, the administration of DL, DLF, and DLMF effectively controlled the levels of these apoptotic markers, resulting in a considerable decrease in the expression of Bcl-2, TNF-α, NFκB, p-AKT, and STAT-3. Specifically, the activation of TNF-alpha and STAT-3 triggers the signalling pathways that include the Bcl-2 family of proteins, Cyt-C, caspase 3, and 9. This ultimately leads to apoptosis and the suppression of cell growth. Furthermore, metabolomic analysis using 1H NMR indicated that the metabolites of animals reverted to normal levels after the treatment.

Novel carbamodithioate regulates cellular hypoxia through chemical activation of prolyl hydroxylase-2 for breast cancer chemoprevention.

Inhibition of prolylhydroxylase-2 (PHD-2) in both normoxic and hypoxic cells is a critical component of solid tumours. The present study aimed to identify small molecules with PHD-2 activation potential. Virtually screening 4342 chemical compounds for structural similarity to R59949 and docking with PHD-2. To find the best drug candidate, hits were assessed for drug likeliness, antihypoxic and antineoplastic potential. The selected drug candidate's PHD-2 activation, cytotoxic and apoptotic potentials were assessed using 2-oxoglutarate, MTT, AO/EtBr and JC-1 staining. The drug candidate was also tested for its in-vivo chemopreventive efficacy against DMBA-induced mammary gland cancer alone and in combination with Tirapazamine (TPZ). Virtual screening and 2-oxoglutarate assay showed BBAP-6 as lead compound. BBAP-6 exhibited cytotoxic and apoptotic activity against ER+ MCF-7. In carmine staining and histology, BBAP-6 alone or in combination with TPZ restored normal surface morphology of the mammary gland after DMBA produced malignant alterations. Immunoblotting revealed that BBAP-6 reduced NF-κB expression, activated PHD-2 and induced intrinsic apoptotic pathway. Serum metabolomics conducted with 1H NMR confirmed that BBAP-6 prevented HIF-1α and NF-κB-induced metabolic changes in DMBA mammary gland cancer model. In a nutshell, it can be concluded that BBAP-6 activates PHD-2 and exhibits anticancer potential.

Disseminated histoplasmosis in an apparently immunocompetent individual from north India: a case report and review.

Mucocutaneous histoplasmosis is frequently reported in patients with acquired immune deficiency syndrome (AIDS), but it is rare in immunocompetent hosts. Disseminated histoplasmosis involving skin and larynx in a 50-year-old immunocompetent male is described from a non-endemic area in India. The infection appeared to be imported from Thailand. The patient responded very well to intravenous amphotericin B followed by itraconazole. A review of all cases of histoplasmosis occurring in immunocompetent patients from India is reported. Most cases are reported from the Gangetic plains. Adrenals are the most common organ involved in immunocompetent patients, but adrenal insufficiency is not common. Skin lesions and oral ulcers are seen in more than one-third of patients. Predisposing factors like exposure to birds, farming, mining, diabetes were observed in few patients.

Bone mineral density in patients with predialysis chronic kidney disease.

BACKGROUND: There is limited data available especially in Indian Population about prevalence of reduced bone mineral density (BMD) and various factors associated with it in CKD patients not on dialysis. MATERIAL: This study included 75 adult patients. Patients were divided into three groups depending upon GFR. Serum creatinine, albumin, calcium, phosphate (PO4), alkaline phosphatase, iPTH and Vitamin D were measured at baseline. BMD was measured by dual energy X-ray absorptiometry. RESULTS: There were 51 male and 24 female patients. The mean serum phosphate, alkaline phosphatase and iPTH levels increased steadily as CKD progressed. On the other hand, mean corrected serum calcium and Vitamin D levels decreased progressively in group A, B and C. The mean serum PTH values in group A, B and C were 137.16 ± 109.85, 265.02 ± 132.03 and 328.14 ± 119.23 pg/mL, respectively and there was significant increase in mean PTH level from group A to group C (p < 0.05). The mean level of vitamin D showed a trend of declination from group A to C (p < 0.05). Z-score for group A, group B and group C was 1.11 ± 2.39, 0.87 ± 2.66 and -0.92 ± 1.59, respectively. Similarly, T score for the three groups were 0.47 ± 2.34, -0.4 ± 2.00 and -1.524 ± 1.42. Both T-score and Z-score positively correlated with GFR. There was negative correlation between Z-score and iPTH, and positive correlation with Vitamin D. CONCLUSION: Reduced bone density was seen early in the course of CKD as estimated from reduced BMD levels, increased prevalence of osteoporosis and increased fracture risk and it worsened with the progression of CKD.

Evaluation of spectrum of peripheral neuropathy in predialysis patients with chronic kidney disease.

INTRODUCTION: Neurological complications secondary to the uremic state, contribute largely to the morbidity and mortality in patients with renal failure. The prevalence of peripheral neuropathy remains high in advanced renal dysfunction. MATERIALS AND METHODS: The present cross-sectional study was conducted on 100 adult patients of chronic kidney disease between 18 and 75 years of age with serum creatinine greater than 2 mg/dL. Apart from routine examination and baseline investigations, detailed history was elicited pertaining to patients' neurological symptoms, and scored according to the Neurological Symptom Score. Motor nerve conduction velocity was measured from right median, ulnar, peroneal, and tibial nerves. RESULTS: It was observed that neurological symptoms increased steadily with raise in serum creatinine. The mean nerve conduction velocities (NCVs) of right median nerve, ulnar nerve, peroneal nerve, and tibial nerve were 51.34 ± 6.07, 53.04 ± 5.91, 44.72 ± 6.14, and 44.20 ± 5.17, respectively. The NCVs of all the tested nerves decreased significantly with increase in serum creatinine levels (p < 0.01): 70% of the patients had uremic polyneuropathy; 6% had asymptomatic neuropathy, 51% had symptomatic non-disabling neuropathy, while disabling neuropathy was seen in 13% of the patients. CONCLUSION: Our data suggests that NCV testing when complimented with meticulous neurological assessment can provide invaluable input. These tests apart from helping us detect neuropathy in advanced renal dysfunction; can also detect the disease in largely asymptomatic patients which avoids the necessity to order for detailed neurophysiological investigation.

Synthesis and characterization of nanostructured graphene-doped selenium.

In this work, we explore various properties of elemental selenium glass (g-Se) by doping with graphene through the facile melt-quench technique. The structural information of the synthesized sample was found by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Raman spectroscopy. The analyses confirm that the graphene-doped g-Se behaves like a glass-ceramic material. Electrical and dielectric measurements were performed to discover the consequences of graphene incorporation on the nano-structure of g-Se. The electrical measurements of the dielectric parameters (i.e., dielectric constant ε' and loss ε'') and conductivity (σ ac) reveal that graphene incorporation causes a rise in the dielectric constant but simultaneously increases dielectric loss. The enhancement in ε' and ε'' values is thought to be a consequence of the interface effect between graphene and the host selenium glass. Calorimetric experiments were performed in a standard differential scanning calorimetry (DSC) unit on the glassy nanocomposite in non-isothermal mode. By measuring the kinetic temperatures at four heating rates, the kinetics of the crystallization/glass transition were studied. The results were examined to understand the role of graphene doping on the well-known phase transitions (i.e., glass transition and crystallization) of g-Se.

Granularity mediated multiple reentrances with negative magnetoresistance in disordered TiN thin films.

Granular superconductors are the common examples of experimentally accessible model systems which can be used to explore various fascinating quantum phenomena that are fundamentally important and technologically relevant. One such phenomenon is the occurrence of reentrant resistive states in granular superconductors. Here, we report the observation of multiple reentrant resistive states for a disordered TiN thin film in its temperature and magnetic field dependent resistance measurements, R(T) and R(B), respectively. At each of the peak-temperatures corresponding to the zero-field R(T), a resistance peak appears in the R(B) around zero field which leads to a negative magnetoresistance (MR) region in its surrounding. These low-field negative MR regions appear for both perpendicular and parallel field directions with relatively higher amplitude and larger width for the parallel field. By adopting a granularity-based model, we show that the superconducting fluctuations in granular superconductors may lead to the observed reentrant states and the corresponding negative MR. Here, we propose that the reduction in the density of states in the fermionic channel due to the formation of Cooper pairs leads to the reentrant resistive state and the competition between the conduction processes in the single particle and Cooper channels result into the multiple resistive reentrances.

Selective-Area Epitaxy of InGaAsP Buffer Multilayer for In-Plane InAs Nanowire Integration.

In order to use III-V compound semiconductors as active channel materials in advanced electronic and quantum devices, it is important to achieve a good epitaxial growth on silicon substrates. As a first step toward this, we report on the selective-area growth of GaP/InGaP/InP/InAsP buffer layer nanotemplates on GaP substrates which are closely lattice-matched to silicon, suitable for the integration of in-plane InAs nanowires. Scanning electron microscopy reveals a perfect surface selectivity and uniform layer growth inside 150 and 200 nm large SiO2 mask openings. Compositional and structural characterization of the optimized structure performed by transmission electron microscopy shows the evolution of the major facet planes and allows a strain distribution analysis. Chemically uniform layers with well-defined heterointerfaces are obtained, and the topmost InAs layer is free from any dislocation. Our study demonstrates that a growth sequence of thin layers with progressively increasing lattice parameters is effective to efficiently relax the strain and eventually obtain high quality in-plane InAs nanowires on large lattice-mismatched substrates.

ECM Mimicking Biodegradable Nanofibrous Scaffold Enriched with Curcumin/ZnO to Accelerate Diabetic Wound Healing via Multifunctional Bioactivity.

Introduction: Foot ulceration is one of the most severe and debilitating complications of diabetes, which leads to the cause of non-traumatic lower-extremity amputation in 15-24% of affected individuals. The healing of diabetic foot (DF) is a significant therapeutic problem due to complications from the multifactorial healing process. Electrospun nanofibrous scaffold loaded with various wound dressing materials has excellent wound healing properties due to its multifunctional action. Purpose: This work aimed to develop and characterize chitosan (CS)-polyvinyl alcohol (PVA) blended electrospun multifunctional nanofiber loaded with curcumin (CUR) and zinc oxide (ZnO) to accelerate diabetic wound healing in STZ-induced diabetic rats. Results: In-vitro characterization results revealed that nanofiber was fabricated successfully using the electrospinning technique. SEM results confirmed the smooth surface with web-like fiber nanostructure diameter ranging from 200 - 250 nm. An in-vitro release study confirmed the sustained release of CUR and ZnO for a prolonged time. In-vitro cell-line studies demonstrated significantly low cytotoxicity of nanofiber in HaCaT cells. Anti-bacterial studies demonstrated good anti-bacterial and anti-biofilm activities of nanofiber. In-vivo animal studies demonstrated an excellent wound-healing efficiency of the nanofibers in STZ-induced diabetic rats. Furthermore, the ELISA assay revealed that the optimized nanofiber membrane terminated the inflammatory phases successfully by downregulating the pro-inflammatory cytokines (TNF-α, MMP-2, and MMP-9) in wound healing. In-vitro and in-vivo studies conclude that the developed nanofiber loaded with bioactive material can promote diabetic wound healing efficiently via multifunction action such as the sustained release of bioactive molecules for a prolonged time of duration, proving anti-bacterial/anti-biofilm properties and acceleration of cell migration and proliferation process during the wound healing. Discussion: CUR-ZnO electrospun nanofibers could be a promising drug delivery platform with the potential to be scaled up to treat diabetic foot ulcers effectively.

A robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events.

Disorder induced phase slip (PS) events appearing in the current voltage characteristics (IVCs) are reported for two-dimensional TiN thin films produced by a robust substrate mediated nitridation technique. Here, high temperature annealing of Ti/Si3N4 based metal/substrate assembly is the key to produce majority phase TiN accompanied by TiSi2 & elemental Si as minority phases. The method itself introduces different level of disorder intrinsically by tuning the amount of the non-superconducting minority phases that are controlled by annealing temperature (Ta) and the film thickness. The superconducting critical temperature (Tc) strongly depends on Ta and the maximum Tc obtained from the demonstrated technique is about 4.8 K for the thickness range ~ 12 nm and above. Besides, the dynamics of IVCs get modulated by the appearance of intermediated resistive steps for decreased Ta and the steps get more prominent for reduced thickness. Further, the deviation in the temperature dependent critical current (Ic) from the Ginzburg-Landau theoretical limit varies strongly with the thickness. Finally, the Tc, intermediate resistive steps in the IVCs and the depairing current are observed to alter in a similar fashion with Ta and the thickness indicating the robustness of the synthesis process to fabricate disordered nitride-based superconductor.

Monolithic Integration of Nano-Ridge Engineered InGaP/GaAs HBTs on 300 mm Si Substrate.

Nano-ridge engineering (NRE) is a novel method to monolithically integrate III-V devices on a 300 mm Si platform. In this work, NRE is applied to InGaP/GaAs heterojunction bipolar transistors (HBTs), enabling hybrid III-V/CMOS technology for RF applications. The NRE HBT stacks were grown by metal-organic vapor-phase epitaxy on 300 mm Si (001) wafers with a double trench-patterned oxide template, in an industrial deposition chamber. Aspect ratio trapping in the narrow bottom part of a trench results in a threading dislocation density below 106∙cm-2 in the device layers in the wide upper part of that trench. NRE is used to create larger area NRs with a flat (001) surface, suitable for HBT device fabrication. Transmission electron microscopy inspection of the HBT stacks revealed restricted twin formation after the InGaP emitter layer contacts the oxide sidewall. Several structures, with varying InGaP growth conditions, were made, to further study this phenomenon. HBT devices-consisting of several nano-ridges in parallel-were processed for DC and RF characterization. A maximum DC gain of 112 was obtained and a cut-off frequency ft of ~17 GHz was achieved. These results show the potential of NRE III-V devices for hybrid III-V/CMOS technology for emerging RF applications.