The Magneto Electron Statistics in Heavily Doped N Type-Intrinsic-P Type-Intrinsic Structures.

In this paper we study the Electron Statistics in Heavily Doped N Type-Intrinsic-P Type-Intrinsic structures of non-linear optical, tetragonal and opto-electronic materials in the presence of magnetic quantization. It is found taking such heavily doped structures of Cd3As2, CdGeAs2, InAs, InSb, Hg1-xCdxTe, In1-xGaxAsyP1-y as examples that the Fermi energy (EF) oscillates with inverse quantizing magnetic field (1/B) and increases with increasing electron concentration with different numerical magnitudes which is the signature of respective band structure. The numerical value of the Fermi energy is different in different cases due to the different values of the energy band constants.

2D Effective Electron Mass at the Fermi Level in Accumulation and Inversion Layers of MOSFET Nano Devices.

In this paper an attempt is made to study the 2D Fermi Level Mass (FLM) in accumulation and inversion layers of nano MOSFET devices made of nonlinear optical, III-V, ternary, Quaternary, II-VI, IV-VI, Ge and stressed materials by formulating 2D carrier dispersion laws on the basis of k → ⋅ p → ⋅ formalism and considering the energy band constants of a particular material. It is observed taking accumulation and inversion layers of Cd3As2, CdGeAs2, InSb, Hg1-xCdxTe and In1-xGaxAsyP1-y lattice matched to InP, CdS, GaSb and Ge as examples that the FLM depends on sub band index for nano MOSFET devices made of Cd3As2 and CdGeAs2 materials which is the characteristic features such 2D systems. Besides, the FLM depends on the scattering potential in all the cases and the same mass changes with increasing surface electric field. The FLM exists in the band gap which is impossible without heavy doping.

Penile neurovascular structure revisited: immunohistochemical studies with three-dimensional reconstruction.

Penile erection is a neurovascular phenomenon that requires well coordinated and functional interaction between penile vascular and nervous systems. In order to provide a useful tool to examine pathologic changes in the erectile tissue, mainly focusing on penile neurovascular dysfunction, we established the technique to determine the differential distribution of endothelial cells, smooth muscle cells, pericytes, and nerve fibers in the mouse penis using immunohistochemical staining with three-dimensional reconstruction. Immunofluorescent staining of penile tissue was performed with antibodies against CD31 (an endothelial cell marker), smooth muscle α -actin (SMA, a smooth muscle cell marker), NG2 (a pericyte marker), or ßIII-tubulin (a neuronal marker). We reconstructed three-dimensional images of penile vascular or neurovascular system from stacks of two-dimensional images, which allows volume rendering and provides reliable anatomic information. CD31-positive endothelial cells, SMA-positive smooth muscle cells, and NG2-positive pericytes were evenly distributed and composed sinusoidal or venous wall. However, the endothelial layer of the cavernous artery or dorsal artery was mainly covered with smooth muscle cells and rarely associated with pericytes. The reconstructed three-dimensional images clearly visualized typical wavy appearance of nerve fibers that evenly innervate to cavernous sinusoids, cavernous artery, dorsal vein, and dorsal artery. We observed a significant decrease in CD31-positive endothelial cells, NG2-positive pericytes, and ßIII-tubulin-positive nerve fibers in the penis of diabetic mice compared with those in normal condition. Our protocol for immunofluorescent staining with three-dimensional reconstruction will allow a better understanding of the penile neurovascular anatomy and may constitute a standard technique to determine the efficacy of candidate therapeutics targeting therapeutic angiogenesis or neural regeneration.

Calorie restriction reverses age-related alteration of cavernous neurovascular structure in the rat.

Calorie restriction (CR) refers to a reduction of calorie intake without compromising essential nutrients to avoid malnutrition. CR has been established as a non-genetic method of altering longevity and attenuating biological changes associated with aging. Aging is also an important risk factor for erectile dysfunction. The aim of this study was to examine whether CR diet can reverse the age-related alterations of erectile tissue in the aged rat. Four groups of rats were used: young rats (7 months) + ad libitum, aged rats (22 months) + ad libitum, young rats + CR diet, and aged rats + CR diet. The ad libitum group had free access to both food and water, and CR groups were fed 60% of the food intake of their ad libitum littermates, starting from 6 weeks before sacrifice. The penis was harvested and stained with antibodies to von Willebrand factor, smooth muscle α-actin, platelet-derived growth factor receptor-ß, phospho-eNOS, nNOS, and neurofilament. We also performed Masson trichrome staining and TUNEL assay. The blood samples were collected for the measurement of serum total testosterone level. The contents of endothelial cells, smooth muscle cells, pericytes, and neuronal cells as well as serum testosterone levels were significantly lower in the penis of aged rats than in their young littermates. CR significantly restored cavernous endothelial cells, smooth muscle cells, pericytes, and neuronal cell contents and decreased cavernous endothelial cell apoptosis and fibrosis in both young and aged rats. CR also increased serum testosterone level in aged rats, but not in young rats. CR successfully improved age-related derangements in penile neurovascular structures and hormonal disturbance. Along with a variety of lifestyle modifications, our study gave us a scientific rationale for CR as a non-pharmaceutical strategy to reprogram damaged erectile tissue toward neurovascular repair in aged men.

Heisenberg's Uncertainty Principle, Intense Electric Field, Heavily Doped Optoelectronic Quantized Structures and the Electron Statistics.

In this paper we show that the direct application of Heisenberg's uncertainty principle (HUP) leads to the expression of the electron statistics (ES) under extreme degeneracy and intense electric field in bulk, quantum wells, nano wires and in the presence of quantizing magnetic field in III­V, ternary and quaternary materials on the basis of a newly formulated electron dispersion laws without using the usual density-of-states (DOS) function approach for finding out the ES under different physical lattice matched to InP conditions. It appears taking HD InSb, InAs, Hg1−xCdxTe, In1−xGaxAsyP1−y as examples that the Fermi energy increases with increasing electron concentration and the surface electric field in all the cases. Besides the Fermi energy decreases with increasing alloy composition and film thickness in different manners which depend totally on the values of the energy band constants. The Fermi energy oscillates with inverse quantizing magnetic field due to SdH effect. We have also shown that under certain limiting conditions all our generalized results lead to the well known formulas as given in the literature.

Entropy, Electric Field and Heavily Doped Nanowires.

In this paper an attempt is made to study, the entropy in the presence of intense electric field in nanowires (NWs) of heavily doped (HD) III­V and optoelectronic materials on the basis of newly formulated electron dispersion relations within the frame work of k → ⋅ p → formalism. It is found taking HD NWs of InSb, InAs, Hg(1­ x) Cd (x)Te and In(1­ x) Ga( x) As( y) P(1­ y) lattice matched to InP as examples III­V, ternary and quaternary compounds that the entropy increases with increasing electron concentration per unit length and decreasing film thickness in different spiky manners, since the coincidence of Fermi energy with the sub-band energy leads to the step functional dependence of the density state function and this fact is being reflected in the quantized variations of the entropy with the said variables. The entropy increases with increasing electric field and decreasing alloy composition respectively. The numerical values of entropy with all the physical variables are totally band structure dependent for all the cases. The most striking features are that the presence of poles in the dispersion relation of the materials in the absence of band tails creates the complex energy spectra in the corresponding opto-electronic HD NWs and the effective electron mass exists within the band gap which is impossible without the concept of band tailing. The well-known classical result of entropy for non-degenerate bulk semiconductors having parabolic energy bands has been obtained as a special case of our generalized formulation and thus confirming the compatibility test. The content of this paper finds four important applications in the field of quantum effect devices of nanoscience and nanotechnology.

Establishment of in vitro model of erectile dysfunction for the study of high-glucose-induced angiopathy and neuropathy.

Penile erection requires complex interaction between vascular endothelial cells, smooth muscle cells, pericytes, and autonomic nerves. Diabetes mellitus is one of the most common causes of erectile dysfunction (ED) and multiple pathogenic factors, such as cavernous angiopathy and autonomic neuropathy, are associated with diabetic ED. Although a variety of animal models of diabetic ED play an important role in understanding pathophysiologic mechanisms of diabetes-induced ED, these animal models have limitations for addressing the exact cellular or molecular mechanisms involved in ED. Therefore, we established an in vitro model of ED for the study of high-glucose-induced angiopathy and neuropathy. We successfully isolated and cultivated mouse cavernous endothelial cells (MCECs) and mouse cavernous pericytes (MCPs). The cells were exposed to the normal-glucose (5 mmoL) or high-glucose (30 mmoL) condition for 48 h. In vitro matrigel assay revealed impairments in tube formation in primary cultured MCECs or MCPs exposed to high-glucose condition. To study cellular interaction between MCECs and MCPs, co-culture systems including indirect contact, indirect non-contact, and direct mixed co-culture system, were established. We observed impaired tube formation and increased permeability in MCECs-MCPs co-culture exposed to high-glucose condition. To evaluate the effect of high-glucose on neurite sprouting, the mouse major pelvic ganglion (MPG) tissue was harvested and cultivated in matrigel. Neurite outgrowth and nNOS-positive nerve fibers were significantly lower in MPG tissues exposed to the high-glucose condition than in the tissues exposed to the normal-glucose condition. We believe that in vitro model of ED will aid us to understand the role of each cellular component in the pathogenesis of diabetic ED, and also be a useful tool for determining the efficacy of candidate therapeutics targeting vascular or neuronal function. This model would present a new avenue for drug discovery and development of novel therapeutic modalities for erectile dysfunction.

Einstein's Photoemission from Quantum Confined Superlattices.

This paper is dedicated to the 83th Birthday of Late Professor B. R. Nag, D.Sc., formerly Head of the Departments of Radio Physics and Electronics and Electronic Science of the University of Calcutta, a firm believer of the concept of theoretical minimum of Landau and an internationally well known semiconductor physicist, to whom the second author remains ever grateful as a student and research worker from 1974-2004. In this paper, an attempt is made to study, the Einstein's photoemission (EP) from III-V, II-VI, IV-VI, HgTe/CdTe and strained layer quantum well heavily doped superlattices (QWHDSLs) with graded interfaces in the presence of quantizing magnetic field on the basis of newly formulated electron dispersion relations within the frame work of k · p formalism. The EP from III-V, II-VI, IV-VI, HgTe/CdTe and strained layer quantum wells of heavily doped effective mass superlattices respectively has been presented under magnetic quantization. Besides the said emissions, from the quantum dots of the aforementioned heavily doped SLs have further investigated for the purpose of comparison and complete investigation in the context of EP from quantum confined superlattices. Using appropriate SLs, it appears that the EP increases with increasing surface electron concentration and decreasing film thickness in spiky manners, which are the characteristic features of such quantized hetero structures. Under magnetic quantization, the EP oscillates with inverse quantizing magnetic field due to Shuvnikov-de Haas effect. The EP increases with increasing photo energy in a step-like manner and the numerical values of EP with all the physical variables are totally band structure dependent for all the cases. The most striking features are that the presence of poles in the dispersion relation of the materials in the absence of band tails create the complex energy spectra in the corresponding HD constituent materials of such quantum confined superlattices and effective electron mass exists within the band gap which is impossible without the concept of band tails. The well-known result of EP for bulk semiconductors having parabolic energy bands can be obtained as a special case of our generalized formulation and thus confirming the compatibility test. The content of this paper finds four important applications and we have suggested the methods of experimental determinations of important transport quantities in the field of quantum effect devices of nanoscience and nanotechnology.

Einstein's 1D Photo Emission and the Von Klitzing Constant.

An attempt is made to present a very easy integration which generates Von Klitzing constant in one hand and Einstein's 1D photo current from quantum wires having arbitrary band structures under the practical conditions of extreme degeneracy and quantum limits on the other hand, the two radically different concepts, depending on the selection of the values of the upper and lower limits of the integral.

Two Dimensional Effective Electron Mass at the Fermi Level in Quantum Wells of III-V, Ternary and Quaternary Semiconductors.

In this paper we study the influence of strong electric field on the two dimensional (2D)effective electron mass (EEM) at the Fermi level in quantum wells of III-V, ternary and quaternary semiconductors within the framework of k x p formalism by formulating a new 2D electron energy spectrum. It appears taking quantum wells of InSb, InAs, Hg(1-x)Cd(x)Te and In(1-x)Ga(x)As(1-y)P(y) lattice matched to InP as examples that the EEM increases with decreasing film thickness, increasing electric field and increases with increasing surface electron concentration exhibiting spikey oscillations because of the crossing over of the Fermi level by the quantized level in quantum wells and the quantized oscillation occurs when the Fermi energy touches the sub-band energy. The electric field makes the mass quantum number dependent and the oscillatory mass introduces quantum number dependent mass anisotropy in addition to energy. The EEM increases with decreasing alloy composition where the variations are totally band structure dependent. Under certain limiting conditions all the results for all the cases get simplified into the well-known parabolic energy bands and thus confirming the compatibility test. The content of this paper finds three applications in the fields of nano-science and technology.

Effective electron mass in quantum wires of III-V, ternary and quaternary materials.

In this paper, an attempt is made to study the effective electron mass (EEM) in Quantum wires (QWs) of III-V, ternary and quaternary materials on the basis of three and two band models of Kane within the framework of k x p formalism. It has been found, taking QWs of InAs, InSb, GaAs, Hg(1-x)Cd(x)Te and In(1-x)Ga(x)As(1-y)P(t) that the 1D EEM increases with electron concentration per unit length and decreases with increasing film thickness respectively. For ternary and quaternary materials the EEM increases with increase in alloy composition. Under certain special conditions all the results for all the 1-D materials get simplified into the well known parabolic energy bands and thus confirming the compatibility test. The results of this paper find two applications in the fields of nanoscience and technology.

Simple theoretical analysis of the photoemission from quantum confined effective mass superlattices of optoelectronic materials.

The photoemission from quantum wires and dots of effective mass superlattices of optoelectronic materials was investigated on the basis of newly formulated electron energy spectra, in the presence of external light waves, which controls the transport properties of ultra-small electronic devices under intense radiation. The effect of magnetic quantization on the photoemission from the aforementioned superlattices, together with quantum well superlattices under magnetic quantization, has also been investigated in this regard. It appears, taking HgTe/Hg(1-) (x)Cd(x)Te and In(x)Ga(1-) (x)As/InP effective mass superlattices, that the photoemission from these quantized structures is enhanced with increasing photon energy in quantized steps and shows oscillatory dependences with the increasing carrier concentration. In addition, the photoemission decreases with increasing light intensity and wavelength as well as with increasing thickness exhibiting oscillatory spikes. The strong dependence of the photoemission on the light intensity reflects the direct signature of light waves on the carrier energy spectra. The content of this paper finds six different applications in the fields of low dimensional systems in general.