Ultrafast Spectroscopy And Computational Study Of The Photochemistry Of Diphenylphosphoryl Azide: Direct Spectroscopic Observation Of A Singlet Phosphorylnitrene

Mathematical and Physical Sciences: 2nd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)In order to characterize the active site of human paraoxonase 1 (HuPON1), photochemistry of a possible photoaffinity label diphenylphosphoryl azide was studied by femtosecond transient absorption spectroscopy, chemical analysis of light-induced reaction products as well as by RI-CC2/TZVP and TD-B3LYP/TZVP computational methods. Theoretical methods predicted two possible mechanisms for singlet diphenylphosphorylnitrene formation from the photoexcited phosphoryl azide. (i) Energy transfer from the (π, π*) singlet excited state, localized on a phenyl ring, to the azide moiety, thereby leading to the formation of the singlet excited azide, which subsequently loses molecular nitrogen to form the singlet diphenylphosphorylnitrene. (ii) Direct irradiation of the azide moiety to form an excited singlet state of the azide, which in turn loses molecular nitrogen to form the singlet diphenylphosphorylnitrene. Two transient species were observed upon ultrafast photolysis (260 nm) of diphenylphosphoryl azide. The first transient absorption, centered at 475 nm (lifetime (τ) ~ 28 ps), was assigned to a (π, π*) singlet S1 excited state localized on a phenyl ring, and the second transient observed at 525 nm (τ ~ 480 ps) was assigned to singlet diphenylphosphorylnitrene. Experimental and computational results obtained from the study of diphenylphosphoramidate, along with the results obtained with diphenylphosphoryl azide, supported the mechanism of energy transfer from the singlet excited phenyl ring to the azide moiety, followed by nitrogen extrusion to form the singlet phosphorylnitrene. Ultrafast time-resolved studies performed on diphenylphosphoryl azide with the singlet nitrene quencher, tris(trimethylsilyl)silane, confirmed the spectroscopic assignment of singlet diphenylphosphorylnitrene to the 525 nm absorption band.A three-year embargo was granted for this item

AUV trajectory optimization with hydrodynamic forces for Icy Moon Exploration

To explore oceans on ice-covered moons in the solar system, energy-efficient Autonomous Underwater Vehicles (AUVs) with long ranges must cover enough distance to record and collect enough data. These usually underactuated vehicles are hard to control when performing tasks such as vertical docking or the inspection of vertical walls. This paper introduces a control strategy for DeepLeng to navigate in the ice-covered ocean of Jupiter's moon Europa and presents simulation results preceding a discussion on what is further needed for robust control during the mission.Comment: 7 pages, 8 figure

Reactive Power Control in Electrical Power Transmission System

Abstract In this paper, an understanding of reactive power associated with power transmission networks is developed. To make transmission networks operate within desired voltage limits, methods of making up or taking away reactive powerhereafter called reactive-power control-are discussed. Before proceeding further, however, a thorough understanding of the reactive power in ac systems is necessary. This paper is not intended to provide a comprehensive analysis of transmission lines. Rather, its objective is to examine those aspects that enhance the understanding of the interplay between voltages on the line and the resulting reactive-power flows

EVALUATION OF THE INTERACTION OF PIPERINE WITH ANTIDEPRESSANT SERTRALINE AND ANALGESIC PENTAZOCINE, USING DIFFERENT ROUTES OF ADMINISTRATION IN ALBINO MICE

ABSTRACTObjective: To evaluate the effect of piperine on the antidepressant activity of sertraline and analgesic activity of pentazocine and to explore the effectof using oral and parenteral routes of administration on the possible interactions.Methods: Piperine was isolated from commercially obtained Piper nigrum extract. Swiss albino mice of either sex were divided into 8 groups (n=6)receiving: 2% gum acacia (oral, intraperitoneally [i.p.]), standard drug (oral, i.p.), standard drug + piperine (oral, i.p.), piperine (oral, i.p.). Tailsuspension test (TST) was used for antidepressant effect and Eddy's hot plate method for analgesic effect. Sertraline and pentazocine were used asstandard drugs (5 mg/kg) and piperine at 10 mg/kg.Result: In the TST, piperine alone (both routes) decreased immobility time, but the effect was statistically insignificant. Both combination groups(oral and i.p.) showed significantly better activity compared to sertraline oral and i.p. groups, respectively (p<0.05). Oral combination showed activitycomparable to i.p. combination (p>0.05). Piperine did not show any analgesic activity of its own (both routes). Piperine with pentazocine orallyshowed significantly better activity compared to pentazocine (oral) at 1, 2, and 4 hrs, and analgesia at 0.5 hr which pentazocine oral did not. Parenteralcombination was significantly better than pentazocine (i.p.) group at 2 and 4 hrs and better than oral combination at 4 hrs.Conclusion: Piperine has potential to be used in combination with pentazocine due to its bioenhancing effect and with sertraline due to a potentiating/additive effect which can help reduce dose and adverse effects of these drugs.Keywords: Piperine, Pentazocine, Sertraline, Albino mice, Bio enhancement, Potentiation

Constraints Faced by Farmers in Information Seeking in Bundelkhand Region of Uttar Pradesh

This research was conducted with the objective of studying the constraints faced in information seeking by farmers in the Bundelkhand region of Uttar Pradesh. A sample of 210 respondents was randomly selected, and data were collected through a structured and pre-tested interview schedule. The gathered data were analyzed and tabulated to identify constraints related to information seeking in the study area. The findings highlighted various challenges faced by farmers, including issues such as the absence of information in the local language, lack of training, financial constraints, limited educational qualifications, restricted access to computers and information sources, insufficient electricity and internet availability, infrastructure deficiencies, inadequate community facilities, disorganized social structures, and the presence of an inferiority feeling. The study underscores the multifaceted nature of status of constraints faced by the farmers of Bundelkhand in Uttar Pradesh regarding accessing sources of informatio

Electronic Properties Of 4-substituted Naphthalimides

This paper describes a study of excited-state properties of naphthalmide (NI) and four 4-substituted derivatives: 4-chloronaphthalimide (Cl-NI), 4-methylthionaphthalmide (MeS-NI), 4-nitronaphthalimide (O(2)N-NI), and 4-(N,N-dimethylaminonaphthalimide (Me(2)N-NI). Steady-state absorption and fluorescence spectra were collected in solvents of varying polarity to determine the excited-state character of NI derivatives. Furthermore. the excited-state dynamics were studied Using femtosecond transient absorption spectroscopy. The experimental findings were compared to calculated data obtained using time-dependent density functional (TD-DFT) methods. We found that light absorption by all NI derivatives leads to the production of the second excited state (S(2)), which was found to have a n,pi* character. Within similar to 40 ps, the S(2) state undergoes internal conversion to produce the S(1) state. The S(1) state is relatively long-lived (similar to 4 ns) and has charge-transfer character in NI derivatives with electron-withdrawing and electron-donating groups (MeS-NI, O(2)N-Ni, and Me(2)N-NI). In the case of NI and Cl-NI, the S(1) state has a pi,pi* character and undergoes intersystem crossing to produce the T(1) state within 400 ps

Region of Attraction Estimation for Free-Floating Systems under Time-Varying LQR Control

Future Active Debris Removal (ADR) and On Orbit Servicing (OOS) missions demand for elaborate closed loop controllers. Feasible control architectures should take into consideration the inherent coupling of the free floating dynamics and the kinematics of the system. Recently, Time-Varying Linear Quadratic Regulators (TVLQR) have been used to stabilize underactuated systems that exhibit a similar kinodynamic coupling. Furthermore, this control approach integrates synergistically with Lyapunov based region of attraction (ROA) estimation, which, in the context of ADR and OOS, allows for reasoning about composability of different sub-maneuvers. In this paper, TVLQR was used to stabilize an ADR detumbling maneuver in simulation. Moreover, the ROA of the closed loop dynamics was estimated using a probabilistic method. In order to demonstrate the real-world applicability for free floating robots, further experiments were conducted onboard a free floating testbed

Trajectory Optimization and Following for a Three Degrees of Freedom Overactuated Floating Platform

Space robotics applications, such as Active Space Debris Removal (ASDR), require representative testing before launch. A commonly used approach to emulate the microgravity environment in space is air-bearing based platforms on flat-floors, such as the European Space Agency's Orbital Robotics and GNC Lab (ORGL). This work proposes a control architecture for a floating platform at the ORGL, equipped with eight solenoid-valve-based thrusters and one reaction wheel. The control architecture consists of two main components: a trajectory planner that finds optimal trajectories connecting two states and a trajectory follower that follows any physically feasible trajectory. The controller is first evaluated within an introduced simulation, achieving a 100 % success rate at finding and following trajectories to the origin within a Monte-Carlo test. Individual trajectories are also successfully followed by the physical system. In this work, we showcase the ability of the controller to reject disturbances and follow a straight-line trajectory within tens of centimeters.Comment: Accepted to IROS2022, code at https://gitlab.com/anton.bredenbeck/ff-trajectorie

Pinpointing The Extent Of Electronic Delocalization In The Re(i)-to-tetrazine Charge-separated Excited State Using Time-resolved Infrared Spectroscopy

Femtosecond mid-IR transient absorption spectroscopy (TRIR) and time-dependent density functional theory (TD-DFT) calculations on Re(CO)(3)Cl(Me(2)BPTZ) [Me(2)BPTZ = 3,6-bis(5-methyl-2-pyridine)-1,2,4,5-tetrazine] are used to demonstrate that the lowest excited state of the complex is a triplet metal-to-ligand charge-transfer ((3)MLCT) state with a lifetime of 225 ps. The short excited-state lifetime is explained by the energy-gap taw. Vibrational cooling of the (3)MLCT state shows up as early-time dynamics (3.6 ps). The structural changes in the excited state are deduced from the frequency shifts in the TRIR vibrational bands. The vibrational frequencies of the CO groups increase upon excitation as a result of decreased back-bonding between the CO ligands and the oxidized Re center in the (3)MLCT state. The vibrational frequencies of the central tetrazine ring of Me(2)BPTZ decrease because of the decrease in the bond order upon reduction of the Me(2)BPTZ ligand in the (3)MLCT state. Interestingly, the TRIR signals from the pyridine moieties of Me2BPTZ were not detected. These results can be explained by localization of the electronic charge on the central tetrazine ring in the (3)MLCT state of Re(CO)(3)Cl(Me(2)BPTZ), as supported by TD-DFT calculations