Novel Multifunctional Ascorbic Triazole Derivatives for Amyloidogenic Pathway Inhibition,Anti-Inflammation,and Neuroprotection

Alzheimer’s disease (AD) is a common neurodegenerative disorder. The number of patients with AD is projected to reach 152 million by 2050. Donepezil, rivastigmine, galantamine, and memantine are the only four drugs currently approved by the United States Food and Drug Administration for AD treatment. However, these drugs can only alleviate AD symptoms. Thus, this research focuses on the discovery of novel lead compounds that possess multitarget regulation of AD etiopathology relating to amyloid cascade. The ascorbic acid structure has been designated as a core functional domain due to several characteristics, including antioxidant activities, amyloid aggregation inhibition, and the ability to be transported to the brain and neurons. Multifunctional ascorbic derivatives were synthesized by copper (I)-catalyzed azide–alkyne cycloaddition reaction (click chemistry). The in vitro and cell-based assays showed that compounds 2c and 5c exhibited prominent multifunctional activities as beta-secretase 1 inhibitors, amyloid aggregation inhibitors, and antioxidant, neuroprotectant, and anti-inflammatory agents. Significant changes in activities promoting neuroprotection and anti-inflammation were observed at a considerably low concentration at a nanomolar level. Moreover, an in silico study showed that compounds 2c and 5c were capable of being permeated across the blood–brain barrier by sodium-dependent vitamin C transporter-2.     

Quantitative evaluation of 28 mineral elements by inductively coupled plasma/mass spectrometry and its application in source identification of Indian opium

An analytical method based on inductively coupled plasma/mass spectrometry (ICP/MS) was developed for the determination of 28 mineral elements (Cr, Mn, Co, Ni, Cu, Zn, Ga, Sr, Cd, Ag, Ba, Pb, Bi Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in Indian opium samples. The detection limits were found to be in the range of 0.0008-0.45 ng/mL. The recoveries of spiked samples for each element were found to be in the range of 83-106%, with a precision of less than 9%. A total of 124 opium samples from India were analyzed for the distribution pattern of the 28 mineral elements. Quantitative elemental data were subjected to chemometric analysis in order to determine an optimal classifier to evaluate the source of Indian opium. The study indicated that mineral elements might not be the suitable discriminators for the discrimination of licit opium-growing divisions of India. However, the methodology developed and the analytical data on elemental profile may find important forensic application in discriminating Indian opium with that of licit and illicit opium originating from different geographical regions of world.     

Quantum state reconstruction for rigid rotors

We describe a quantum state reconstruction scheme for dipolar rigid rotors based on determination of the expectation value of the molecular orientation. A key feature is the use of half-cycle pulses to excite the rotor prior to the orientation measurement. The set of expectation values obtained by varying the intensity and polarization of the laser and the time interval between excitation and measurement can be inverted directly to yield the rotor density operator. When the density operator corresponds to the admixture of relatively few rotor states, our procedure successfully reconstructs both pure and mixed states.     

Application of capillary zone electrophoresis in the separation and determination of the principal gum opium alkaloids

We describe the use of capillary zone electrophoresis (CZE) for the qualitative and quantitative determination of major alkaloids (i.e., thebaine, codeine, morphine, papavarine and narcotine) in gum opium involving the analysis of alkaloids without derivatization or purification. Three extractions with 2.5% w/v aqueous acetic acid quantitatively extracted major alkaloids. The separation was carried out by CZE using a 7:3 mixture of methanol and sodium acetate (100 mM, pH 3.1) at a potential of 15 kV, with UV detection at 224 nm. Spiking of pure reference alkaloid standards in the opium extract was used for peak identification. The influences of buffer composition, pH and voltage on the separation of alkaloids were studied. The detection limit of each alkaloid dissolved in methanol was found to be 850 ng/mL (morphine), 450 ng/mL (thebaine), 500 ng/mL (codeine), 550 ng/mL (papaverine), and 500 ng/mL (narcotine) at an injection pressure of 300 mbar (injection volume, 4 nL) with a signal-to-noise ratio of 3:1. The external standard method was used for the quantification of alkaloids. The calibration plot was based on linear regression analysis. The relative standard deviation (RSD) for peak area and migration time was in the range of 1.03-3.56% and 0.34-0.69%, respectively. Percentage compositions (g%) of opium alkaloids in five gum opium samples were found to be in the range of 14.45-15.95 (morphine), 2.0-3.45 (codeine), 1.32-2.73 (thebaine), 0.92-2.37 (papavarine), and 3.85-5.77 (narcotine). The method developed is suitable for the routine analysis of major gum opium alkaloids in samples of forensic importance.     

Injection Locked Millimeter Wave Oscillators at Ka, V, and W-Bands

Injection locked Gunn oscillators have been developed to amplify the upconverted millimeter wave frequencies. They are being used in millimeter wave communication systems at Ka, V and W-Bands respectively.     

Varactor Controlled Gunn Oscillator at W-Band

This paper describes the experimental circuit and measured performance of varactor tuned Gunn oscillator at W-band. The power output of 12.5 dBm has been achieved when packaged GaAs Gunn diode is used. Linear frequency excursion of 150 MHz with power variation of 1 dB has been observed when varactor was given reverse bias from 0 to 20 volts. GaAs hyperabrupt varactor is used in parallel to gunn diode at a distance of odd multiple of g/2 in waveguide channel.     

Charged-particle pseudorapidity density distributions from Au+Au collisions at sqrt[s(NN)]=130 GeV

The charged-particle pseudorapidity density dN(ch)/d eta has been measured for Au+Au collisions at sqrt[s(NN)] = 130 GeV at RHIC, using the PHOBOS apparatus. The total number of charged particles produced for the 3% most-central Au+Au collisions for /eta/相似文献   

New formulation for the high multiplicity asymmetric traveling salesman problem with application to the Chesapeake problem

This paper presents a new model for a special type of traveling salesman problem called the High Multiplicity Asymmetric Traveling Salesman Problem (HMATSP). The formulation adopts a flow-based subtour elimination structure and establishes its validity for this problem. Also, we present computational results to demonstrate the efficacy of our modeling approach. The model is then incorporated as a substructure in a formulation for the lot-sizing problem involving parallel machines and sequence-dependent setup costs, also known as the Chesapeake Problem, and related test problems are solved to optimality for the first time in the literature.     

35 GHz dielectric resonator stabilised gunn oscillator

A 35 GHz dielectric resonator oscillator(DRO) using GaAs Gunn diode in microstrip configuration has been designed and developed. The oscillator, with an integral waveguide-to-microstrip transition, delivered an output greater than 18 dBm. Phase noise of the oscillator is found to be better than –80 dBc/Hz at 100 KHz away from the carrier. A frequency drift of about ±25 MHz has been observed over the temperature range from –10 °C to 50 °C.