Crystal growth,characterization and Density functional theory computations of supramolecular N‐carbamothioyl acetamide

Single crystals of N‐carbamothioylacetamide (NCTA) were grown by slow evaporation technique at constant temperature. The structure is elucidated by single crystal XRD analysis. The studies reveal that the molecule is associated with accommodating weak C–O···H, N–H···O, N–H···S, C–H···N, C···C and H···H stacking interactions which are responsible for the formation and strengthening of supramolecular assembly. Inter‐ and intramolecular hydrogen bonding interactions exhibit supramolecular architecture in the crystal packing. Two different types of architecture, i.e., a column like packing, and cluster network type of infrastructure are observed. Hirshfeld surfaces and Fingerprint plots were used to locate and analyze the percentage of hydrogen bonding interactions. The various functional groups present in the molecule are confirmed by FT‐IR analysis. Density functional theory computations of the vibrational spectrum, molecular geometry, HOMO‐LUMO energy gaps, NBO and hyperpolarizability (β) were successfully evaluated. Facts concerning with the size, shape, charge density distribution and site of chemical reactivity of the molecule have been obtained by mapping electron density with electrostatic potential (ESP).     

Microfluidic Thermally Activated Materials for Rapid Control of Macroscopic Compliance

Macroscopic structures that can undergo rapid and reversible stiffness transitions can serve as functional polymeric materials for many applications in robotics and medical devices. Thermomechanical phase transitions can provide a suitable mechanism for transient control of mechanical properties. However, the characteristic time scale for actuation is large and dictated by the dimensions of the structure. Embedding vascular networks within bulk polymers can reduce the characteristic length scale of the material and permit rapid and reversible thermomechanical transitions. Here, perfusable bulk materials with embedded microvascular networks are reported that can undergo rapid and reversible stiffness transitions. Acrylate‐based thermoplastic structures exhibit storage moduli with a dynamic range between E′ = 1.02 ± 0.07 GPa and E′ = 13.5 ± 0.7 MPa over time scales as small as 2.4 ± 0.5 s using an aqueous thermal perfusate. The spatiotemporal evolutions of temperature profiles are accurately predicted using finite element simulations and compared to experimental values. Rigid‐compliant transitions are leveraged in a demonstration in which a microvascularized device is used to grasp an external object without the aid of moving parts.     

Generalized analysis of subcarrier multiplexing in dispersive fiber-optic links using Mach-Zehnder external modulator

A new exact analytical model is presented to analyze the dispersive transmission in subcarrier multiplexing (SCM) fiber-optic links using dual-drive Mach-Zehnder external modulator (DD-MZM). The model is very general and can be applied to almost all operating conditions of DD-MZM, such as bias point, drive level, phase shift, and modulation index difference between DD-MZM drives. The model results in simple, new, and closed-form expressions for output power spectrum, permitting an accurate and fast analysis of such links. Two special cases, double sideband (DSB) and single-sideband (SSB) modulation, are studied in detail. Some important system parameters, such as 1-dB compression point, the input third-order intercept point (IIP3), and the system capacity, are derived for the first time. Measured results for system capacity and intermodulation products of different orders match very well with the calculated results.     

Impacts of NBTI and PBTI on SRAM static/dynamic noise margins and cell failure probability

Negative and Positive Bias Temperature Instabilities (NBTI (in PFET) and PBTI (in NFET)) weaken MOSFETs with time. The impact of such device degradation can be severe in Static Random Access Memories (SRAMs) wherein stability is governed by relative strengths of FETs. Degradation in stability with time under ‘worst case condition’ gets more important because of reduced guard-banding due to process induced instability. In this work, circuit insights into worst-case conditions and effect of NBTI and PBTI, individually and in combination, on the stability of an SRAM cell are presented. It is shown that measurable quantities such as static noise-margin are not sufficient to completely understand the combined effect of NBTI and PBTI. Monte-Carlo simulations are performed in a 45 nm PDSOI technology to estimate the increase in cell failure probability with time. In worst case, NBTI and PBTI both degrade read stability (significantly) and writability (marginally). Further, we analyze the choice of optimal power supply considering the trade-off between short-term stability (due to process variations) and long-term stability (due to NBTI/PBTI) to achieve six-sigma confidence in SRAM cell robustness.     

Arsenic redistribution induced by low-temperature Ni silicidation at 450°C on shallow junctions

Redistribution of arsenic (As) during silicidation of a 13-nm Ni film on an n⁺/p junction at 450°C is investigated. NiSi formation is observed by x-ray diffraction, micro-Raman scattering spectroscopy, and Rutherford backscattering spectroscopy (RBS). Both secondary ion mass spectroscopy and RBS data indicate the redistribution and accumulation of As into two layers after the low-temperature annealing. The deeper accumulation peak, located just near the silicide/silicon interface, is attributed to As segregation from silicide into Si substrate. The shallower accumulation peak is located in a vacancy-cluster layer several nanometers below the silicide film surface. The vacancy-cluster layer, characterized by cross-sectional transmission electron microscopy, separates the silicide film into two layers, and is attributed to the well-known Kirkendall effect.     

Synthesis and characterization of Ni-implanted and 200-MeV Ag ion-irradiated CeO2 thin films

CeO₂ thin films were deposited on quartz substrates by using the rf-sputtering technique. The 80-keV Ni^- ion-implanted and, subsequently, post-annealed films have shown the formation of Ni oxide and Ni metallic phases at 7 at% of Ni concentration. Such secondary phases were dissolved by swift heavy ion irradiation with 200-MeV Ag⁺¹⁵ ion beams. Structural properties, surface roughness, and magnetic behavior of the samples were investigated by X-ray diffraction, atomic force microscopy, and hysteresis loop measurements, respectively. Dissolution of secondary phases has been discussed in the light of irradiation-induced local temperature rise and energy loss processes.     

Characterization of the interactions between synthetic nematic LCs and model cell membranes

Differential scanning calorimetry (DSC) was used to characterize interactions of synthetic LCs, 4‐pentyl‐4′‐cyanobiphenyl (5CB) and TL205 (a mixture of cyclohexane‐fluorinated biphenyls and fluorinated terphenyls) with simple mimics of cell membranes. The investigation was motivated by reports that living cells can be placed into contact with TL205 without apparent toxicity, whereas contact of cells with 5CB leads to cell death. The tendency was examined for 5CB and TL205 to spontaneously partition into and influence the organization for model cell membranes composed of phospholipids. Upon contact of an aqueous dispersion of DPPC liposomes with neat LC for 4 h, 5CB partitioned into the liposomes at a weight ratio of 5:1 DPPC:5CB, whereas TL205 partitioned at a ratio of 310:1 DPPC:TL205. DSC endotherms indicated that the 5CB spontaneously partitioned into the liposomes was far more perturbing than TL205. DSC endotherms of DPPC bilayers containing the same concentration of either 5CB or TL205 also revealed 5CB to be more perturbing than TL205. The effect of up to 7.8 wt % of TL205 was small, resulting in a shift in the melting transition from 41.4°C to 40.1°C and a minor change in peak width, indicating only minor effects on the organization of the bilayer. These effects are similar to those caused by cholesterol in DPPC bilayers. In contrast, 5CB shifted the DPPC melting transition from 41.4°C to ～36°C and increased the width of the transition peak by a factor of ten, indicating a destabilization of the ordered phase in the bilayer and a disruption of the cooperative nature of the gel‐to‐LC transition of the phospholipid bilayer. Taken together, the results demonstrate that 5CB and TL205 differ significantly in their interactions with model cell membranes, which suggests one possible origin of their different toxicities toward cells.     

Concentration of fish serum albumin (FSA) in the aqueous extract of Indonesian Perciformes fishes’ muscle tissue

Fish serum albumin (FSA) is an aquatic resource that has potential to be developed as nutraceutical. Therefore, research was undertaken to assess albumin levels in the aqueous extract of muscle tissue of several Perciformes commonly available at a local fish market in Indonesia. Three random replicates for each of 17 Perciformes species were collected and assessed for their FSA content by application of a reversed-phase (C4) HPLC analytical method. Results of these analyses showed that the albumin concentration of the extracts was in the range 3.49–12.61 g/L, and that they varied significantly (P < 0.05) between species and families. This finding may mean that FSA levels are species and family dependent, something that could be investigated in future studies. As fishes from the family Scrombidae showed the highest concentration (12.61 g/L) of FSA, they would likely have the most value as a source for production of albumin-based nutritional and/or clinical products.     

Generation of Different Modulation Formats Using Sagnac Fiber Loop With One Electroabsorption Modulator

A simple structure is proposed to generate different modulation formats using a single electroabsorption modulator (EAM). The configuration is based on a Sagnac loop containing two polarization controllers and an EAM which modulates the clockwise and counterclockwise propagating waves inside the Sagnac loop. Measured results demonstrate switchable single-sideband suppression for both reflected and transmitted signals. The second-order harmonic suppression and carrier suppressed modulation are also achieved. A simple analysis explains most of the observed effects.     

Crystal growth,structure and characterization of diglycine zinc dipicrate: Centrosymmetric crystal exhibiting second harmonic generation efficiency

A new cadmium coordination polymer, formulated as [Cd(L)(phen)]_n, were prepared by hydrothermal reactions based on 3,4-dibromothiophene-2,5-dicarboxylic acid (H₂L) and 1,10-phenanthroline (phen) mixed organic linkers. In the complex, adjacent Cd²⁺ ions are linked by L^2? anions to form a one-dimensional (1D) [CdL]_n chain with [Cd₂(COO)₂] as the secondary building unit (SBU). These adjacent chains are further stacked together by direct C?Br···Br halogen bonds interactions, generating a two-dimensional (2D) supramolecular structure. From the viewpoint of topology, the 2D supramolecular network can be rationalized to a 3,4-connected 3,4L13 net with {4.6²}₂{4².6².8²} topology.