Nanomedicine for Targeted Drug Delivery in Cancer Chemotherapy

Cancer is the uncontrolled proliferation of cells which subsequent spread of other organs of the human body (metastasis). The major therapeutic approaches of cancer chemotherapy are to deliver the correct amount of drug molecule in the desired site (malignant cells) for longer duration of action. Nanomedicine basically by passive as well as active targeting has been implemented for recognition, diagnosis and treatment for cancer and widely accepted in the modern field of oncology. Nanomedicine such as nanoliposomes and polymer based nanoparticles combine with genetic materials administered to the target cells for cancer chemotherapy. The advancement of nanomedicine will improve the therapeutic index of anticancer drug via modulation of pharmacokinetics parameters and tissue distribution to targeted sites. Ligand molecule can be tagged with this nanodevices for recognize the malignant cells via active targeting purposes and drug can be release at the site of specific target area followed by pre-programmed or predictable manner. This novel strategy of drug delivery technology is also applicable for conventional chemotherapy as well as metastatic state of the cancer patients. Targeting of neoplastic cells by nanocarriers play a vital role in novel drug delivery by protecting healthy normal cells from cytotoxicity as well as helpful for preventing the angiogenesis (neovascularization)

Testing a global standard for quantifying species recovery and assessing conservation impact.

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a "Green List of Species" (now the IUCN Green Status of Species). A draft Green Status framework for assessing species' progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species' viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species' recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard

Crystal structure, thermal expansion and electrical conductivity of Nd0.7Sr0.3Fe1−xCoxO3Nd_{0.7} Sr_{0.3} Fe_{1-x}Co_xO_3 (0 \leq x \leq 0.8)

The crystal structure, thermal expansion and electrical conductivity of the solid solutions $Y_{0.8}Ca_{0.2}Fe_{1-x} MnxO_3$ + \delta (0 \leq x \leq 1.0) were investigated. All compositions had the $GdFeO_3$-type orthorhombic perovskite structure with trace amounts of a second phase present in case of x = 0.8 and 1.0. The lattice parameters were determined at room temperature by using X-ray powder diffraction (XRPD). The pseudo-cubic lattice constant decreased with increasing x. The average linear thermal expansion coefficient (a,,) in the temperature range from 673 to 973 K showed negligible change with x up to x = 0.4. The thermal expansion curve for x = 1 had a slope approaching zero in the temperature range from 648 to 948 K. The calculated activation energy values for electrical conduction indicate that conduction occurs primarily by the small polaron hopping mechanism. The drastic drop in electrical conductivity for a small addition of Mn (0 less than or equal to x less than or equal to 0.2) is caused by the preferential foil-nation of $Mn^{4+}$ ions (rather than $Fe^{4+}$)which act as carrier traps. This continues till the charge compensation for the divalent ions on the A-site is complete. The results indicate that with further increase in manganese content (beyond x = 0.4) in the solid solutions, there is an increase in excess oxygen and consequently, a small increase in Mn4+ ions which are charge compensated by the formation of cation vancancies

Crystal structure, thermal expansion and electrical conductivity of Nd0.7Sr0.3Fe1-xCoxO3 (0 <= x <= 0.8)

The crystal structure, thermal expansion and electrical conductivity of the solid solution Nd0.7Sr0.3Fe1-xCoxO3 for 0 less than or equal to x less than or equal to 0.8 were investigated. All compositions had the GdFeO3-type orthorhombic perovskite structure. The lattice parameters were determined at room temperature by X-ray powder diffraction (XRPD). The pseudo-cubic lattice constant decreased continuously with x. The average linear thermal expansion coefficient (TEC) in the temperature range from 573 to 973 K was found to increase with x. The thermal expansion curves for all values of x displayed rapid increase in slope at high temperatures. The electrical conductivity increased with x for the entire temperature range of measurement. The calculated activation energy values indicate that electrical conduction takes place primarily by the small polaron hopping mechanism. The charge compensation for the divalent ion on the A-site is provided by the formation of Fe4+ ions on the B-site (in preference to Co4+ ions) and vacancies on the oxygen sublattice for low values of x. The large increase in the conductivity with x in the range from 0.6 to 0.8 is attributed to the substitution of Fe4+ ions by Co4+ ions. The Fe site has a lower small polaron site energy than Co and hence behaves like a carrier trap, thereby drastically reducing the conductivity. The non-linear behaviour in the dependence of log sigmaT with reciprocal temperature can be attributed to the generation of additional charge carriers with increasing temperature by the charge disproportionation of Co3+ ions. (C) 2002 Elsevier Science B.V. All rights reserved

Crystal structure, thermal expansion and electrical conductivity of Nd<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Fe<SUB>1-x</SUB>Co<SUB>x</SUB>O<SUB>3</SUB> (0&#8804;x<SUB>&#8804;</SUB>0.8)

The crystal structure, thermal expansion and electrical conductivity of the solid solution Nd0.7Sr0.3Fe1-xCoxO3 for 0&#8804;x&#8804;0.8 were investigated. All compositions had the GdFeO3-type orthorhombic perovskite structure. The lattice parameters were determined at room temperature by X-ray powder diffraction (XRPD). The pseudo-cubic lattice constant decreased continuously with x. The average linear thermal expansion coefficient (TEC) in the temperature range from 573 to 973 K was found to increase with x. The thermal expansion curves for all values of x displayed rapid increase in slope at high temperatures. The electrical conductivity increased with x for the entire temperature range of measurement. The calculated activation energy values indicate that electrical conduction takes place primarily by the small polaron hopping mechanism. The charge compensation for the divalent ion on the A-site is provided by the formation of Fe4+ ions on the B-site (in preference to Co4+ ions) and vacancies on the oxygen sublattice for low values of x. The large increase in the conductivity with x in the range from 0.6 to 0.8 is attributed to the substitution of Fe4+ ions by Co4+ ions. The Fe site has a lower small polaron site energy than Co and hence behaves like a carrier trap, thereby drastically reducing the conductivity. The non-linear behaviour in the dependence of log &#963;T with reciprocal temperature can be attributed to the generation of additional charge carriers with increasing temperature by the charge disproportionation of Co3+ ions

Composition-graded solid electrolyte for determination of the Gibbs energy of formation of lanthanum zirconate

A composition-graded solid electrolyte has been used to determine the standard Gibbs free energy of formation of lanthanum zirconate (La₂Zr₂O₇) from the component oxides lanthana (La₂O₃) (A-rare earth) and zirconia (ZrO₂) (monoclinic) in the temperature range of 870–1240 K. The cell used for measurement can be represented as Pt, O₂, CaO + CaF₂∥ CaF₂| (LaF₃)_x(CaF₂)_1-x∥LaF₃+ La₂Zr₂O₇+ ZrO₂, O₂, Pt x=0 x=0.32 A composition-graded electrolyte has been introduced to compensate the solubility effects of the electrode material (lanthanum fluoride, LaF₃) in the solid electrolyte (calcium fluoride, CaF₂). The ability of the graded electrolyte to gen-erate a Nernstian response is demonstrated, using electrodes with known fluorine chemical potentials. For the reaction La₂O₃ (A-rare earth) + 2ZrO2 (monoclinic)&#8594;La₂Zr₂O₇ (pyrochlore), the Gibbs free energy change (ΔG°_f,ox) is given by the formula −133800 −10.32T (±4500) (in units of J/mol). The enthalpy and entropy of formation of La₂Zr₂O₇ obtained in this study are in good agreement with calorimetric data. The “third-law” enthalpy of formation of La₂Zr₂O₇, from the component oxides at 298.15 K, is −133.8 ± 5 kJ/mol

Crystal structure and thermal and electrical properties of the perovskite solid solution Nd1-xSrxFeO3-delta (0 <= x <= 0.4)

The crystal structure, thermal expansion and electrical conductivity of strontium-doped neodymium ferrite (Nd1-xSrxFeO3-delta where 0less than or equal toxless than or equal to0.4) were investigated. All compositions had the GdFeO3-type orthorhombic perovskite structure. The lattice parameters were determined at room temperature by X-ray powder diffraction. The orthorhombic distortion decreases with increasing Sr substitution. The pseudocubic lattice parameter shows a minimum at x=0.3. The thermal expansion curves for x=0.2-0.4 displayed rapid increase in slope at higher temperatures. The electrical conductivity increased with Sr content and temperature. The calculated activation energies for electrical conduction decreased with increasing x. The electrical conductivity can be described by the small polaron hopping mechanism. The charge compensation for divalent ion on the A-site is provided by the formation of Fe4+ ions on the B site and vacancies on the oxygen sublattice. The results indicate two defect domains: for low values of x, the predominant defect is Fe4+ ions, whereas for higher values of x, oxygen vacancies dominate. (C) 2002 Elsevier Science B.V. All rights reserved

Glycol-nitrate combustion synthesis of fine sinter-active yttria

Yttrium oxide has been synthesized from yttrium nitrate by combustion synthesis using ethylene glycol as the fuel. The combustion characteristics, thermal decomposition, crystallite pattern of the reaction product, and densification of the calcined powders were studied for different glycol/nitrate ratios. The microstructural evolution of the reaction product with increasing calcination temperature was studied. By sintering compacted powders at 1698 K for 7.2 hs. 96% of the theoretical density was achieved. The average grain size was 3 mum and there was no evidence of intra-granular porosity

Composition-graded solid electrolyte for determination of the Gibbs energy of formation of lanthanum zirconate

A composition-graded solid electrolyte has been used to determine the standard Gibbs free energy of formation of lanthanum zirconate (La2Zr2O7) from the component oxides lanthana (La2O3) (A-rare earth) and zirconia (ZrO2) (monoclinic) in the temperature range of 870-1240 K. The cell used for measurement can be represented as Pt, O-2, CaO + CaF(2)parallel to CaF2 (x=0) (LaF3)(x)(CaF2)(1-x) parallel to(x=0.32) LaF3 + La2Zr2O7 + ZrO2, O-2, Pt A composition-graded electrolyte has been introduced to compensate the solubility effects of the electrode material (lanthanum fluoride, LaF3) in the solid electrolyte (calcium fluoride, CaF2), The ability of the graded electrolyte to generate a Nernstian response is demonstrated, using electrodes with known fluorine chemical potentials. For the reaction La2O3 (A-rare earth) and (ZrO2) (monoclinic) La2Zr2O7 (pyrochlore), the Gibbs free energy change (Delta G(f,ox)degrees) is given by the formula -133800 - 10.32T (+/-4500) (in units of J/mol), The enthalpy and entropy of formation of La2Zr2O7 obtained in this study are in good agreement with calorimetric data. The "third-law" enthalpy of formation of La2Zr2O7, from the component oxides at 298.15 K, is -133.8 +/- 5 kJ/mol