The Structures of Gd(III) Chelates Conjugated at the Periphery of 3-(1’-Hexyloxy)ethyl-3-devinylpyropheophorbide-a (HPPH) Have a Significant Impact on the Imaging and Therapy of Cancer

3-(1’-Hexyloxyethyl)-3-devinyl-pyropheophorbide-a (HPPH or Photochlor), a tumor-avid chlorophyll-a derivative currently undergoing human clinical trials, was conjugated at various peripheral positions (position-17 or 20) of HPPH with either Gd(III)-aminobenzyl-DTPA (Gd(III) DTPA) or Gd(III)-aminoethylamido-DOTA (Gd(III) DOTA). The corresponding conjugates were evaluated for in vitro PDT efficacy, T₁, T₂ relaxivities, in vivo fluorescence, and MR imaging under similar treatment parameters. Among these analogs, the water-soluble Gd(III)-aminoethylamido-DOTA linked at position-17 of HPPH, i. e., HPPH-17-Gd(III) DOTA, demonstrated strong potential for tumor imaging by both MR and fluorescence, while maintaining the PDT efficacy in BALB/c mice bearing Colon-26 tumors (7/10 mice were tumor free on day 60). In contrast to Gd(III) DTPA (Magnevist) and Gd(III) DOTA (Dotarem), the HPPH-Gd(III) DOTA retains in the tumor for a long period of time (24 to 48 h) and provides an option of fluorescence-guided cancer therapy. Thus, a single agent can be used for cancer-imaging and therapy. However, further detailed pharmacokinetic, pharmacodynamic, and toxicological studies of the conjugate are required before initiating Phase I human clinical trials.     

Critical Layer Thickness in Exponentially Graded Heteroepitaxial Layers

Exponentially graded semiconductor layers are of interest for use as buffers in heteroepitaxial devices because of their tapered dislocation density and strain profiles. Here we have calculated the critical layer thickness for the onset of lattice relaxation in exponentially graded In _x Ga_1?x As/GaAs (001) heteroepitaxial layers. Upwardly convex grading with \( x = x_{\infty } \left( {1 - {\rm e}^{ - \gamma /y} } \right) \) was considered, where y is the distance from the GaAs interface, γ is a grading length constant, and x _∞ is the limiting mole fraction of In. For these structures the critical layer thickness was determined by an energy-minimization approach and also by consideration of force balance on grown-in dislocations. The force balance calculations underestimate the critical layer thickness unless one accounts for the fact that the first misfit dislocations are introduced at a finite distance above the interface. The critical layer thickness determined by energy minimization, or by a detailed force balance model, is approximately \( h_{\rm{c}} \approx <Exponentially graded semiconductor layers are of interest for use as buffers in heteroepitaxial devices because of their tapered dislocation density and strain profiles. Here we have calculated the critical layer thickness for the onset of lattice relaxation in exponentially graded In _x Ga_1−x As/GaAs (001) heteroepitaxial layers. Upwardly convex grading with x = x_￥ ( 1 - e ^{- g/y} ) x = x_{\infty } \left( {1 - {\rm e}^{ - \gamma /y} } \right) was considered, where y is the distance from the GaAs interface, γ is a grading length constant, and x _∞ is the limiting mole fraction of In. For these structures the critical layer thickness was determined by an energy-minimization approach and also by consideration of force balance on grown-in dislocations. The force balance calculations underestimate the critical layer thickness unless one accounts for the fact that the first misfit dislocations are introduced at a finite distance above the interface. The critical layer thickness determined by energy minimization, or by a detailed force balance model, is approximately h_c ? < h_{\rm{c}} \approx < Although these results were developed for exponentially graded In _x Ga_1−x As/GaAs (001), they may be generalized to other material systems for application to the design of exponentially graded buffer layers in metamorphic device structures such as modulation-doped field-effect transistors and light-emitting diodes.     

An enhanced copy-move forgery detection using machine learning based hybrid optimization model

Multimedia Tools and Applications - In recent years, one of the forgery detection methods is the Copy-Move Forgery Detection (CMFD), which is mostly used approach amongst all the forgery...     

Plastic Flow and Dislocation Compensation in ZnS y Se1?y /GaAs (001) Heterostructures

An important goal of lattice-mismatched semiconductor device design is control of threading dislocation densities, which are of particular importance for optoelectronic devices such as photodetectors and light-emitting diodes. The basis for this field of research is an understanding of the dislocation dynamics in mismatched heteroepitaxial structures. We have developed a dislocation dynamics model including dislocation multiplication, misfit–threading dislocation interactions, annihilation and coalescence, and thermal strain, which can be used to understand the strain relaxation and threading dislocation densities in arbitrarily graded ZnS _y Se_1?y /GaAs (001) structures. On the basis of this model, we demonstrate that the dislocation compensation mechanism, whereby mobile threading dislocations can be removed by insertion of a mismatched interface in a graded structure, can be explained by the bending over of threading dislocations associated with misfit segments of one sense by misfit dislocations having the opposite sense. Dislocation compensation, if utilized in device structures, can provide a pathway for the attainment of devices with low threading dislocation densities (D?<?10⁶?cm^?2) while using the minimum total thickness of epitaxial material, with a reduction in deposition time and source chemicals.     

Physical and electrical properties of combustion synthesized NASICON type Na3Cr2(PO4)3 crystallites: Effect of glycine molar ratios

Thermally stable Na₃Cr₂(PO₄)₃ nano-crystallites are synthesized through novel solution combustion technique using glycine fuel in three molar ratios. Effects of fuel molar ratio on structural and electrical properties are investigated. Reaction parameters like fuel molar ratio, flame temperature and number of moles of gases evolved, play a major role in deciding physical and electrical properties. Out of the synthesized samples, one which contains fuel in 1:1 molar ratio shows highest grain conductivity of 2.35 × 10⁻⁶ S cm⁻¹. Improved conductivity is elucidated by least size and highest density of the crystallites, which in turn is decided by the flame temperature. Ac electrical properties are investigated using complex impedance spectroscopy. Activation energies for dc conduction and relaxation are determined and the results are reported.     

Design of S-Graded Buffer Layers for Metamorphic ZnS y Se1−y /GaAs (001) Semiconductor Devices

We present design equations for error function (or “S-graded”) graded buffers for use in accommodating lattice mismatch of heteroepitaxial semiconductor devices. In an S-graded metamorphic buffer layer the composition and lattice mismatch profiles follow a normal cumulative distribution function. Minimum-energy calculations suggest that the S-graded profile may be beneficial for control of defect densities in lattice-mismatched devices because they have several characteristics which enhance the mobility and glide velocities of dislocations, thereby promoting long misfit segments with relatively few threading arms. First, there is a misfit-dislocation-free zone (MDFZ) adjacent to the interface, which avoids dislocation pinning defects associated with substrate defects. Second, there is another MDFZ near the surface, which reduces pinning interactions near the device layer which will be grown on top. Third, there is a large built-in strain in the top MDFZ, which enhances the glide of dislocations to sweep out threading arms. In this paper we present approximate design equations for the widths of the MDFZs, the built-in strain, and the peak misfit dislocation density for a general S-graded semiconductor with diamond or zincblende crystal structure and (001) orientation, and show that these design equations are in fair agreement with detailed numerical energy-minimization calculations for ZnS _y Se_1?y /GaAs (001) heterostructures.     

Varietal variations in content,characteristics and composition of mango seeds and fat

Wide variations were found in the content, characteristics and composition of seed and fat of 43 varieties of mango (Mangifera indica) fruit. The seed in fruit amounted to 3–25% and kernel in seed 54–85% on an as-is basis. The contents of fat, protein and ash in kernel ranged 3.7–12.6, 4.0–8.1 and 1.0–3.7 (% on dry basis), respectively. Acid value of fat varied from 2.1 to 8.8 and unsaponifiables from 1.0 to 5.3%. The ranges for fatty acids, as determined by gas chromatography, were: 16:0, 3–18; 17:0, traces-2.0; 18:0, 24–57; 18:1, 34–56; 18:2, 1–13 and 20:0, traces-4 (area %). Presented at the Convention of the Oil Technologists’ Association of India, Bombay, February 1980.     

Fetal erythrocyte phospholipid polyunsaturated fatty acids are altered in pregnancy complicated with gestational diabetes mellitus

Insulin resistance and altered maternal metabolism in gestational diabetes mellitus (GDM) may impair fetal arachidonic acid (AA) and docosahexaenoic acid (DHA) status. The objectives were to test the hypothesis that fetal polyunsaturated fatty acids would be altered with GDM and identify factors related to fetal phospholipid (PL) AA and DHA. Maternal and cord vein erythrocyte PL fatty acids were determined in GDM (n=13) and healthy pregnant women (controls, n=12). Cord vein erythrocyte PL AA and DHA concentrations were significantly lower in GDM vs. controls. Maternal blood hemoglobin A₁C was inversely correlated to fetal erythrocyte PL DHA and AA in controls and GDM (n=25). Pregravid body mass index was negatively associated with fetal PL DHA. The data support the hypothesis that there is impairment in fetal accretion of DHA and AA in GDM.     

S-Graded Buffer Layers for Lattice-Mismatched Heteroepitaxial Devices

We have conducted a theoretical study of the equilibrium strain and misfit dislocation density profiles for ??S-graded?? buffer layers of In _x Ga_1?x As on GaAs (001) substrates in which the compositional profile follows a normal cumulative distribution function. On the basis of this modeling work we show that the S-graded layer exhibits misfit dislocation-free regions near the substrate interface and the free surface (or device interface). The equilibrium peak misfit dislocation density as well as the thicknesses of the dislocation-free regions may be tailored by design of the compositional profile; this in turn should enable minimization of the density of electronically active threading dislocations at the top surface. S-graded buffer layers may therefore facilitate the achievement of metamorphic device structures with improved performance compared with similar structures having uniform or linearly graded buffers.