On-off Type Research Articles

Grinding-induced supramolecular charge-transfer assemblies with switchable vapochromism toward haloalkane isomers

Synthetic macrocycles have proved to be of great application value in functional charge-transfer systems in the solid state in recent years. Here we show a switchable on-off type vapochromic system toward 1-/2-bromoalkane isomers by constructing solid-state charge-transfer complexes between electron-rich perethylated pillar[5]arene and electron-deficient aromatic acceptors including 4-nitrobenzonitrile and 1,4-dinitrobenzene. These charge-transfer complexes with different colors show opposite color changes upon exposure to the vapors of 1-bromoalkanes (fading) and 2-bromoalkanes (deepening). Single-crystal structures incorporating X-ray powder diffraction and spectral analyses demonstrate that this on-off type vapochromic behavior is mainly attributed to the destruction (off) and reconstruction (on) of the charge-transfer interactions between perethylated pillar[5]arene and the acceptors, for which the competitive host-guest binding of 1-bromoalkanes and the solid-state structural transformation triggered by 2-bromoalkanes are respectively responsible. This work provides a simple colorimetric method for distinguishing positional isomers with similar physical and chemical properties.

Hepatogastric fistula: a complication of pyogenic liver abscess in a patient with the Brugarda syndrome - A rare case report.

A 22-year-old male presented to the emergency room with a known case of Brugarda pattern ECG with chief complaints of on-and-off abdominal pain and fever for 2 weeks and shortness of breath for one day. On evaluation, echocardiography showed a clot in the inferior vena cava (IVC) and right atrium (RA), and on computed tomography scan of the abdomen revealed a liver abscess with transmural gastric perforation. During, an exploratory laparotomy where a fistula joining the left lobe of the liver and stomach was detected, and an emergency excision was done. The patient was shifted to the ICU and later developed septic shock, which was managed medically. Usually, thrombosis of the portal vein and the hepatic vein is a very common complication of a PLA but vascular complications like IVC, RA thrombosis, and hepatogastric fistula have been reported rarely. Our case is peculiar hepatogastric fistulization along with IVC/RA clots in a patient with Brugarda pattern ECG. The typical clinical manifestation of a patient with hepatogenic fistula is absent in our patient and presented with an on-off type of fever, epigastric pain, and shortness of breath and was managed surgically. Hepatogasric fistula, thrombosis of the IVC, and RA are a rare complications of PLA. The patient with Brugarda syndrome is at high risk as its clinical manifestation gets exaggerated during sepsis.

New constraints on decaying dark matter from INTEGRAL/SPI

ABSTRACTBased on almost 20 yr of data collected by the high-resolution spectrometer SPI on board the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), we present constraints on a decaying dark matter particle undergoing a decay into two bodies, at least one of which is a photon, manifesting itself via a narrow line-like spectral feature. Our ON-OFF type analysis of the Milky Way observations allowed us to constrain the lifetime to be ≳1020−1021 yr for DM particles with masses $40\, \text{keV}\, \lt \, M_{\text{DM}}\, \lt \, 14\, \text{MeV}$. Within this mass range, our analysis also reveals 32 line-like features detected at ≥3σ significance, 29 of which coincide with known instrumental and astrophysical lines. In particular, we report on the detection of the electron-positron annihilation (511 keV) and 26Al (1809 keV) lines with spatial profiles consistent with previous results in the literature. For the particular case of the sterile neutrino DM, we report the limits on the mixing angle as a function of sterile neutrino mass. We discuss the dominant impact of systematic uncertainties connected to the strongly time-variable INTEGRAL/SPI instrumental background as well as the ones connected to the uncertainties of MW DM density profile measurements on the derived results.

The structure and diversity of retinal ganglion cells in the masked greenling Hexagrammos octogrammus Pallas, 1814 (Pisces: Scorpaeniformes: Hexagrammidae).

The authors studied the structure and diversity of retinal ganglion cells (GC) in the masked greenling Hexagrammos octogrammus. In vivo labelling with horseradish peroxidase revealed GCs of various structures in retinal wholemounts. A total of 154 cells were camera lucida drawn, and their digital models were generated. Each cell was characterized by 17 structural and topological parameters. Using nine clustering algorithms, a variety of clusterings were obtained. The optimum clustering was found using silhouette analysis. It was based on a set of three variables associated with dendritic field size and dendrite stratification depth in the retina. A total of nine cell types were discovered. A number of non-parametric tests showed significant pair-wise between-cluster differences in at least four parameters with medium and large effect sizes. Three large-field types differed mainly in dendritic field size, total dendrite length, level of dendrite stratification in the retina and position of somata. Six medium- to small-field types differed mainly in the structural complexity of dendritic arbors and level of dendrite arborization. Cells similar and obviously homologous to types 1-4 were identified in many fish species, including teleosts. Potential homologues of type 5 cells were identified in fewer teleost species. Cells similar to types 6-9 in relative dendritic field size and dendrite arborization pattern were also described in several teleostean species. Nonetheless, their homology is more questionable as their stratification patterns do not match so well as they do in large types. Potential functional matches of the GC types were identified in a number of teleostean species. Type 1 and 2 cells probably match spontaneously active units with the large receptive field centre, so-called dimming and lightening detectors; type 4 may be a counterpart of changing contrast detectors with medium receptive field centre size preferring fast-moving stimuli. Type 3 (biplexiform) cells have no obvious functional matches. Probable functional matches of types 6, 8 and 9 belong to ON-centre elements with small receptive fields such as ON-type direction-selective cells, ON-type spot detectors or ON-type spontaneously active units. Type 5 and 7 cells may match ON-OFF type units, in particular, changing contrast detectors or orientation-selective units. Potential functional matches of GC types presently described are involved in a wide spectrum of visual reactions related to adaptation to gradual change in illumination, predator escape, prey detection and capture, habitat selection and social behaviour.

Hardware Design of Low Cost Myoelectric Controlled Prosthetic Hand For Engineering Laboratory

This study presents a low cost, two-channel, on-off type, constant speed myo-electric controlled prosthetic hand project as an educational tool for Biomedical/Control/Mechatronic Engineering. Surface Electromyogram (sEMG) signals were recorded from the muscles of flexor carpi ulnaris and extensor digitorium on the forearm. Signal conditioning of these signals is performed in the analog stages of the system, before passing it on to a microcontroller for further filtering and implementation of control. The control logic is simplified to represent the muscles as being active or inactive, resulting in a very simple on/off control based on the two signals. The on/off control signals are used to drive a myo-electric controlled prosthetic hand-powered by a hobby RC servo motor. A printed circuit board has been designed for the analog stages of the system, and a simple Arduino Microcontroller is used for the digital stages. Other commercial off-the-shelf components were used to keep the cost of the hardware and the software components as low as possible. This project was used as a teaching aid for the final year undergraduate students to demonstrate the use of simple myo-electric signal processing and control techniques.

Origins of direction selectivity in the primate retina

From mouse to primate, there is a striking discontinuity in our current understanding of the neural coding of motion direction. In non-primate mammals, directionally selective cell types and circuits are a signature feature of the retina, situated at the earliest stage of the visual process. In primates, by contrast, direction selectivity is a hallmark of motion processing areas in visual cortex, but has not been found in the retina, despite significant effort. Here we combined functional recordings of light-evoked responses and connectomic reconstruction to identify diverse direction-selective cell types in the macaque monkey retina with distinctive physiological properties and synaptic motifs. This circuitry includes an ON-OFF ganglion cell type, a spiking, ON-OFF polyaxonal amacrine cell and the starburst amacrine cell, all of which show direction selectivity. Moreover, we discovered that macaque starburst cells possess a strong, non-GABAergic, antagonistic surround mediated by input from excitatory bipolar cells that is critical for the generation of radial motion sensitivity in these cells. Our findings open a door to investigation of a precortical circuitry that computes motion direction in the primate visual system.

Single channel digital controller design for a high spinning rate rolling airframe missile

AbstractSpinning/Rolling Airframe Missiles (RAM) mostly use an analog (ON-OFF type) control approach that deflects control surfaces (fins) at minimum and maximum positions continuously, and control is achieved by applying phase shift between the minimum and maximum deflections during a complete roll cycle. Therefore, the control signal shape changes continuously during the roll cycle. In this study, a novel single channel digital controller is designed and tested for a high spinning rate (10–20 Hz) RAM. The digital controller adjusts the amplitude of fin deflections instead of applying a phase shift. In this way, control signal shapes are predetermined in design to completely decouple yaw and pitch dynamics. At the beginning of each roll cycle, the algorithm decides on the control signal shape and amplitude to apply throughout the cycle. Delays on the actuator system and sensor measurements which might lead to instability at high spinning rates are handled effectively thanks to the predetermined control signal shapes that are changing with 90-degree intervals. Detailed geometry of a surface-to-air spinning missile is used to obtain aerodynamic coefficients for the entire flight regime (i.e. from launch to terminal phase) via Missile DATCOM. The 6-DOF flight dynamics model and the controller algorithms are built in MATLAB/Simulink environment. The proposed digital controller is tested systematically for various scenarios and the performance is compared with the conventional analog control approach. The digital controller gives better performance compared to the analog approach under the influence of servo delays and sensor noise.

SINTESIS KEMOSENSOR ION CN- BERBASIS TURUNAN PIRAZOLIN DENGAN LOGAM Cu

One of the toxic anions such as cyanide (CN-) has a negative impact on living things. Pyrazoline derivatives can be complexed with transition metals and used as CN- ion fluorosensor, because pyrazoline derivatives have fluorescence properties. This study aims to synthesize of CN- ion chemosensors based on pyrazoline derivative namely para-di-2-(1-phenyl-3-pyridyl-4,5-dihydro-1H-pyrazole-5-yl)benzene with Cu metal. The resulting complex compounds were characterized using Spectrophotometer Infra Red (FTIR), Spectrophotometer UV-Visible, and Spectrofluorometer. Then, a complex compound chemosensor (fluorosensor) study of Cu2+ was carried out with the addition of CN- ions using a spectrofluorometer. The results showed that the synthesis of complex compound Cu2+ was successfully carried out and a brown precipitate was obtained with a yield of 43% with a melting point of 243.3°C. Based on the results of characterization by FTIR (cm-1) generates 3400 (Amine), 2920.88-2852.42 (C-H pyridine), 2360.38 (C=N), 1594.50-1490.39 (C=C aromatic), 1233.67-1021.17 (C-N), 982.66 (Cu-O), 348.00 (Cu-N), and 320-280 (Cu-Cl). The results of the spectroscopy UV-Visible analysis Cu2+ complex compounds at a concentration of 5x10-5 M obtained two absorption peaks, 242 nm and 306 nm. The result of the spectrofluorometer analysis of Cu2+ complex compound were 1516 a.u at a wavelength of 502 nm. The results of the chemosensor (fluorosensor) studies of the Cu2+ complex compound with the addition of CN- ions can be used as a turn on-off type fluorosensor.

Well and ICV management in a carbonate reservoir with high gas content

The management of oil fields that present high gas content is challenging, mainly in cases where this represents a bottleneck for oil production due to gas platform constraints. One way to deal with this problem is with the use of ICVs (Interval Control Valves), which enables the production to be controlled by zones in the wells.In this work, we propose a methodology using reactive control rules for producers and ICVs, with GOR as monitoring variable, to improve the economic performance of the field. We compare the management of the field in three ways: (a) well management by shutting down producers when they reach an uneconomic GOR limit, (b) the use of ICVs on-off type and (c) application of multi-position type ICVs. We extend the application of algorithm IDLHC (Iterative Discrete Latin Hypercube) for the optimization process in this context. This study is made in a synthetic simulation case (Lira1_2022) with characteristics of a Brazilian pre-salt carbonate field with karstic features, high CO2 content and using WAG (Water-Alternate-Gas) injection as recovery mechanism.The results demonstrated that the use of ICVs has a great potential to increase the performance of the field, both in economic and production indicators, when compared to well shut-in management. Both ICV on-off and multi-position types achieved similar results, with a slight advantage to the multi-position type ICVs. The improvement in the field's performance was mainly caused by the interference among zones and wells, in which the closure of less productive wells, or zones, reflected in improvements in other more productive wells.

6-Arylcoumarin as a Scaffold of Photofunctional Molecules with OFF-ON-OFF Type Regulation.

Coumarin has been utilized as a core structure of photofunctional molecules, such as fluorescent sensors and photoremovable protecting groups. Here, we show that the 6-arylcoumarin moiety can provide OFF-ON-OFF type regulatory functionality for such compounds. To illustrate its utility, we synthesized a coumarin derivative bearing two phenolic hydroxy groups at 7-position and on 6-aryl group as a fluorescent sensor showing an OFF-ON-OFF change in fluorescence intensity in response to an increase in pH from a strongly acidic condition. Further, we show that the efficiency of photoreaction of other derivatives with the same hydroxyl groups is switched from "OFF" at pH 3 and 6 to "ON" at pH 9 and then to OFF at pH 12, enabling their application as switchable photoremovable protective groups. These features arise from sequential deprotonation of two hydroxyl groups: the monoanionic form is responsible for the photoinduced fluorescence and photoreaction.

Combined Depth Control Strategy for Low-Speed and Long-Range Autonomous Underwater Vehicles

Autonomous underwater vehicles (AUVs) are increasingly being applied to highly detailed survey and inspection tasks over large ocean regions. These vehicles are required to have underwater hovering and low-speed cruising capabilities, and energy-saving property to enable long-range missions. To this end, a combined depth control strategy is proposed in which an on-off type variable ballast system (VBS) is adopted for satisfactory hovering or fast descending/ascending without propulsion to reach the designated cruising depth, whereas the bow and stern fins act as the actuator to maintain the cruising depth for more energy saving. A hierarchical architecture-based VBS controller, which comprises a ballast water mass planner and an on-off mass flowrate controller, is developed to assure good hovering performance of the on-off type VBS. Both numerical studies and basin tests are conducted on a middle-sized AUV to verify the feasibility and validity of this depth control strategy.

A simple triazole-linked bispyrenyl-based xylofuranose derivative for selective and sensitive fluorometric detection of Cu2+

Triazole-linked xylofuranose derivatives having one pyrene or two pyrene moieties were synthesized and their fluorescence properties towards various cations and anions were investigated. Only, bis-triazoles appended bispyrenyl-based sugar derivative 1 exhibited selective and sensitive fluorescence quenching effect in the presence of Cu2+ ions over a wide range of cations and anions in acetonitrile. The ON-OFF type fluorescence response of 1 was explained by the conformational changes from strong excimer emission of pyrene to weak pyrene monomer emission due to an interaction between Cu2+ and inward-facing triazole groups. The limit of detection (LOD) of sensor 1 for Cu2+ was found to be 0.15 µM, which is well accepted as per WHO’s guidelines.

A Miniature 3D Printed On-Off Linear Pneumatic Actuator and Its Demonstration into a Cartoon Character of a Hopping Lamp

Although 3D printing has been extensively used to create passive machines and mechanisms, 3D printing of actuators is a relatively new concept. 3D printing of actuators allows greater customization, accelerates the design and development, and consequently saves time and money. We present the design and fabrication of a 3D printed, miniature size, double-acting, On-Off type, linear pneumatic actuator. The actuator has an overall length of 8 cm, a bore size of 1.5 cm, and a stroke length of 2.0 cm. The overall weight is 12 gm and it generates a peak output power of 2 W when operating at an input air pressure of 40 psi ( 275 . 79 kPa). This paper demonstrates novel methods to solve the challenges that arise during fabrication that include: (1) chemical post-processing to achieve airtight sealing and a smooth surface finish, (2) strategic placement of a metallic part within 3D printed plastic for higher strength, (3) design of an airtight seal between the cylinder and piston head, (4) chemical bonding of printed parts using adhesive, and (5) use of a lubricant to reduce friction and improve force generation. The power-to-weight ratio of our actuator is comparable to that of high-end commercial actuators of similar size. The utility of the actuator is demonstrated in a series of jumping experiments with the actuator and by incorporating the actuator into a hopping robot inspired by Disney/Pixar Luxo lamp. We conclude that 3D printed pneumatic actuators combine the high power of pneumatics with the low weight of plastics, and structural strength through the selective placement of metal parts, thus offering a promising actuator for robotic applications.

A benzothioate native chemical ligation-based cysteine-selective fluorescent probe

A turn-on fluorescent probe for the detection of cysteine (Cys), an essential amino acid in biological systems, is developed based on Cys-mediated O-phenyl benzothioate native chemical ligation (NCL) for the first time. Cys plays important roles in many physiological processes, thus the development of Cys monitoring methods has been highlighted in fundamental research field. We prepared an on-off type fluorescent probe, CysP-1, which showed highly sensitive and selective response towards Cys. Furthermore, the probe showed superior sensing ability for Cys in the cancer cells with low cytotoxicity, and released hydrogen sulfide (H2S). This successful demonstration will encourage further Cys-related applications in a variety of fields.

Photoelectrochemical biosensor for CEA detection based on SnS2-GR with multiple quenching effects of Au@CuS-GR

A novel signal on-off type photoelectrochemical (PEC) biosensing system was designed for sensitive detection of carcinoembryonic antigen (CEA) based on tin disulfide nanosheets loaded on reduced graphene cxide (SnS2-GR) as the photoactive material and gold nanoparticles coated on reduced graphene oxide-functionalized copper sulfide (Au@CuS-GR) for signal amplification. It's the first time for SnS2-GR was exploited as a sensing matrix. Here, the photocurrent signals of SnS2 were amplified attributed to the sensitization effect of graphene. As signal amplifier, Au@CuS-GR could quench the photocurrents of SnS2-GR not only through the p-n type semiconductor quenching effect as well as the steric hindrance effect, but also as peroxidase mimetics to catalyze the oxidation of 4-Chloro-1-naphthol (4-CN) to produce insoluble product on the electrode surface. Based on the multiple signal amplification ability of Au@CuS-GR, CEA was detected sensitively with a linear range from 0.1 pg mL−1 to 10 ng mL−1 and limit of detection down to 59.9 fg mL−1 (S/N = 3). Meanwhile, the PEC biosensor displayed excellent performance in the assay of human serum sample, showing good application prospects for various target analysis.

ON-Type Retinal Ganglion Cells are Preferentially Affected in STZ-Induced Diabetic Mice.

We investigate morphologic and physiologic alterations of ganglion cells (GCs) in a streptozocin (STZ)-induced diabetic mouse model. Experiments were conducted in flat-mount retinas of mice 3 months after the induction of diabetes. Changes in morphology of four subtypes of GCs (ON-type RGA2 [ON-RGA2], OFF-type RGA2 [OFF-RGA2], ON-type RGC1 [ON-RGC1], and ON-OFF type RGD2 [ON-OFF RGD2]) were characterized in Thy1-YFP transgenic mice. Using whole-cell patch-clamp recording, passive membrane properties and action potential (AP) firing properties were further investigated in transient ON- and OFF-RGA2 cells. Morphologic parameters were significantly altered in the dendrites branching in the ON sublamina of the inner plexiform layer (IPL) for ON-RGA2 cells and ON-OFF RGD2 cells. Much less significant changes, if any, were seen in those arborizing in the OFF sublamina of the IPL for OFF-RGA2 and ON-OFF RGD2 cells. No detectable changes in morphology were seen in RGC1 cells. Electrophysiologically, increased resting membrane potentials and decreased membrane capacitance were found in transient ON-RGA2 cells, but not in transient OFF-RGA2 cells. Similar alterations in AP firing properties, such as an increase in AP width and reduction in maximum spiking rate, were shared by these two subtypes. Furthermore, in response to depolarizing current injections, both cells generated more APs suggesting an enhanced excitability of these cells in diabetic conditions. These differential changes in morphology and electrophysiology in subtypes of GCs may be responsible for reduced contrast sensitivity known to occur during the early stage of diabetic retinopathy.

TCA self-assembled fluorescence probe for Cu (II) ion based on the unique configuration of extra nuclear electrons of metal ions: A TDDFT study

A molecule fluorescence probe of a new ON-OFF type, used for detecting transition metal ions, reported recently, is self-assembled by thiacalix[4]arene(TCA) molecules, micelles and a fluorescence group. It only presents high selectivity for Cu2+ ions, in a solution with the coexistence of Zn2+, Ni2+, Hg2+, Cu2+ Cd2+ ions. Since the mechanism of the ON-OFF signal response of such self-assembled micelle probes has always been a controversial issue of uncertainty, the mechanisms of the signal response and the high selectivity for Cu2+ ions were studied here by DFT/TDDFT method. The spatial arrangement, geometric and electronic structures of the functional units of the probe were calculated, and the response mechanism was investigated by the molecular transition orbital pairs method to explore the origination of the ON-OFF fluorescence signal response. The results told that the signal response process was based on förster resonance energy transfer (FRET) mechanism. The high selectivity for Cu2+ ions was due to the unique electron configuration of the copper complex, by the comparing of the calculation results of the TCA complexes M1-4(TCA)(M = Cu, Hg, Ni). The results provided new sights different from most of the conclusions by the related research works reported.

Putative targets of direction-selective retinal ganglion cells in the tectum opticum of cyprinid fish

Responses of direction selective (DS) units of retinal and tectal origin were recorded extracellularly from the tectum opticum (TO) of immobilized fish. The data were collected from three cyprinid species – goldfish, carp and roach. Responses of the retinal DS ganglion cells (GCs) were recorded from their axon terminals in the superficial layers of TO. According to their preferred directions DS GCs, characterized by small receptive fields (3−8°), can be divided in three distinct groups, each group containing ON and OFF subtypes approximately in equal quantity. Conversely, direction-selective tectal neurons (DS TNs), recorded at two different tectal levels deeper than the zone of retinal DS afferents, are characterized by large receptive fields (up to 60°) and are indifferent to any sign of contrast i.e. can be considered as ON-OFF type units. Fish DS TNs unlike the retinal DS GCs, select four preferred directions. Three types of tectal DS units prefer practically the same directions as those already selected on the retinal level – caudo-rostral, dorso-ventral and ventro-dorsal. The fact that three preferred directions of DS GCs and DS TNs coincide allows us to assume that three types of DS GCs are input neurons for corresponding types of DS TNs. The fourth group of DS TNs has the emergent rostro-caudal preference not explicitly present in any of the DS GC inputs. These units are recorded in deep TO layers exclusively. Receptive fields of these DS neurons could be entirely formed on the tectal level. Possible interrelations between retinal and tectal DS units are discussed.

Epoxy-based polymer incorporating 1-naphthylamine and sebacic acid moieties: A selective fluorescent sensor for ferric ions

A new epoxy-based polymer sensor 1 incorporating 1-naphthylamine and sebacic acid moieties was synthesised. The sensor shows ON-OFF type fluorescence selectivity for Fe3+ over other coexistent metal ions such as Cu2+, Zn2+, Co2+, Ni2+, Cd2+, Hg2+, Mg2+, Sr2+, Pb2+ and Ca2+ ions.

Polyurethane network using 1-naphthylamine embedded epoxy-based polymer: ferric ion selective fluorescent probe

Polyurethane network 1 was prepared through curing of epoxy-based polymer bearing 1-naphthylamine units with tolylene-2,4-diisocyanate as curing agent. With ferric ions, the network was found to exhibit selective ON–OFF-type fluorescence signaling behavior even in the presence of other representative metal ions such as Na+, K+, Ag+, Cu2+, Zn2+, Co2+, Ni2+, Cd2+, Hg2+, Mg2+, Sr2+, Pb2+ and Ca2+ ions.