Polar Hinges as Functionalized Conformational Constraints in (Bi)cyclic Peptides

Two polar hinges for cyclization of peptides have been developed, leading to bicyclic peptides and cyclized peptides with improved solubility and biological activity. Increasingly, we note that a good aqueous solubility of peptides is an absolute prerequisite, not only to allow handling and purification of our target peptides but also being crucial for biological activity characteristics. Compared to earlier hinges, the 1,1′,1“‐(1,3,5‐triazinane‐1,3,5‐triyl)tris(2‐bromoethanone) (TATB) and 2,4,6‐tris(bromomethyl)‐s‐triazine (TBMT), each containing three nitrogen atoms are structurally similar but chemically very different. Both were accessible in a one‐step fashion from bromoacetonitrile. TATB and TBMT are very suitable for the preparation of more soluble bicyclic peptides. Azide‐modified TATB and TBMT derivatives provide hinges for the preparation of cyclized peptides for incorporation on scaffolds to afford protein mimics.     

Side-chain autoxidation of stigmasterol and analysis of a mixture of phytosterol oxidation products by chromatographic and spectroscopic methods

Although the structure of phytosterols is closely related to cholesterol, there is a gap in knowledge concerning the formation and occurrence of oxidation products from phytosterols. The main objective of this study was to isolate and characterize some side-chain oxidation products formed after autoxidation of stigmasterol. Another objective was to highlight the difficulties in the analysis of phytosterol and a mixture of their oxidation products by GC. Pure stigmasterol was oxidized at 120°C for 72 h in an air-ventilated oven. Preparative TLC separated the oxidation products, and the products were characterized with GC-MS and NMR. In addition to the common ring-structure oxidation compounds, three semipolar oxidation products—24-ethylcholest-5,22-dien-3β,25-diol, 24-ethylcholest-5,22-dien-3β,24-diol, and 24-ethyl-5,22-choladien-3β-ol-24-one—were characterized for the first time by TLC, GC-MS, and NMR. Moreover, the results of the analysis of a large number of oxidation products from sitosterol, campesterol, and stigmasterol by capillary column GC indicated that further efforts and optimization are required in this area.     

Rheokinetics of polymerization of N-laurylmethacrylate

The free radical polymerization of n-laurylmethacrylate has been studied using a combination of rheological and kinetic methods. In addition to classical dilatometry, the extent of reaction of a polymerization was followed in a cone and plate rheometer by measuring the change in the diffraction of a laser beam shone through the polymerizing sample parallel to the plate of the rheometer. The change in diffraction was caused by the change in index of refraction of the monomer becoming polymer, which was related to the extent of reaction. Simultaneous measurements of loss and storage moduli and dynamic viscosity at 1 Hz provided the data necessary for correlating changes in the kinetics with changes in the rheology of the polymerizing system.     

Kinetics of reaction of C36 dimeric fatty acids and ethylenediamine in solution

Kinetic studies were carried out on the reaction between ethylenediamine and C₃₆ dimeric fatty acids using benzyl alcohol as solvent. The reaction was performed at four different temperatures in the range of 160–190°C, and the products were analyzed for acid and amine values intermittently to follow the reaction. The fall in both the values was almost the same throughout the reaction. The kinetics was determined from the fall in acid value, and the reaction was found to be of overall third order and had an activation energy of 30.7 kcal mol^?1 (128.5 kJ mol^?1).     

A −40-dB EVM 20-MHz subsampling multistandard receiver architecture with dynamic carrier detection,bandwidth estimation,and EVM optimization

In this work, a reconfigurable multistandard subsampling receiver with dynamic carrier frequency detection and system-level EVM optimizations is proposed. Ideal software defined radio (SDR) receivers promise complete flexibility at the expense of high-performance analog-to-digital converters (ADCs) that are challenging to implement in current technologies for low-power applications. This scenario leads to the research of digital intensive sampling receivers with discrete-time signal processing (DTSP) implemented in analog domain. This approach makes it feasible to move channel selection filtering and dynamic gain adaptability from analog to digital domain. The proposed receiver employs subsampling down-conversion along with subband filters to dynamically detect the carrier frequency of the incoming signal, estimate its bandwidth, and identify if the signal is present in one of the target standard bands. This carrier detection provides a unique capability to reconfigure the receiver dynamically. Additionally, in this work, system-level EVM optimization is proposed considering frequency synthesizer phase noise, IQ mismatch, sampling frequency selection and block-level gain, noise, and nonlinearity. The RF front end of the proposed receiver is modeled in Verilog-AMS whereas the digital signal processing is implemented in Simulink-Matlab. The complete receiver has been verified to detect and process three different bands belonging to three different standards (GSM, UMTS, and WLAN) with the carrier frequency ranging from 0.9 to 2.5 GHz. Test signals with 4-QAM modulation, maximum bandwidth of 20 MHz, and input-dynamic range from –109 to –20 dBm is utilized to demonstrate the receiver performance including an EVM of –40 dB.     

Preliminary Investigation of the Corrosion Behavior of Proprietary Micro-alloyed Steels in Aerated and Deaerated Brine Solutions

The corrosion performance of fairly new generation of micro-alloyed steels was compared in different concentrations of aerated and deaerated brines. Electrochemical polarization, weight loss and surface analyses techniques were employed. The results showed a threshold of corrosion rate at 3.5 wt.% NaCl in both aerated and deaerated solutions. The average corrosion current density for steel B, for example, increased from 1.3 µA cm^?2 in 1 wt.% NaCl to 1.5 µA cm^?2 in 3.5 wt.% NaCl, but decreased to 1.4 µA cm^?2 in 10 wt.% deaerated NaCl solutions. The aerated solutions exhibited an average of over 80% increase in corrosion current density in the respective concentrations when compared with the deaerated solution. These results can be attributed to the effects of dissolved oxygen (DO) which has a maximum solubility in 3.5 wt.% NaCl. DO as a depolarizer and electron acceptor in cathodic reactions accelerates anodic metal dissolution. The difference in carbon content and microstructures occasioned by thermo-mechanical treatment contributed to the witnessed variation in corrosion performance of the steels. Specifically, the results of the various corrosion techniques corroborated each other and showed that the corrosion rate of the micro-alloyed steels can be ranked as CR_{Steel A} < CR_X65 < CR_{Steel B} < CR_{Steel C}.     

CYBERSECURITY: THE ENDGAME – PART ONE

Abstract

As companies —board members, senior management, risk and information technology managers - strive to grow while strengthening reputation, minimizing security incidents, preparing for and responding to them; they often find themselves struggling with the cybersecurity approaches they thought would help. Unlike Avengers and Captain Marvel, a losing endgame. As cyber threats and attacks become more sophisticated; this article first explains how daily struggles cannot be fixed just by better implementation. Why? Because so many struggles are caused by structural, not implementation, flaws. Thus, structural flaws must be fixed. Second, it points to a better endgame – using proven business management methods to simplify complexity and improve outcomes, especially Total Quality Management and innovation initiatives. Third, because change is challenging, the article offers backstories, tips and engaging questions to make it easier for leaders to manage daily operations amidst shifting priorities while fostering transformation in the spirit of innovation.     

A panel data analysis of the determinants of oil consumption: The case of Australia

The goal of this paper is to examine the determinants of oil consumption for a panel consisting of six Australian States and one territory, namely Queensland, New South Wales, Victoria, Tasmania, South Australia, Western Australia, and the Northern territory, for the period 1985–2006. We find that oil consumption, oil prices and income are panel cointegrated. We estimate long-run elasticities and find that oil prices have had a statistically insignificant impact on oil consumption, while income has had a statistically significant positive effect on oil consumption.     

Solid-state mixed-potential sensor employing tin-doped indium oxide sensing electrode and scandium oxide-stabilised zirconia electrolyte

The sensing properties of the planar mixed-potential CO sensor coupling scandia-stabilized zirconia (ScsZ) as electrolyte and tin-doped indium oxide (ITO) as sensing electrode to different CO concentrations from ～100 ppm to ～500 ppm have been investigated. The monodispersed ITO particles with spherical shape have been obtained by hydrothermally treating the mixture of the coprecipitated gels with urea as an additive. Directly using urea as the mineralizer, the two coexisting morphologies such as rod-like and spherical shapes have been obtained. The sensor coupling spherical 5 at.% tin-doped indium oxide (5ITO) electrode shows better sensitivity than the sensors coupling both spherical 8 at.% tin-doped indium oxide (S8ITO) and 8 at.% tin-doped indium oxide (RS8ITO) containing rod-like particles. The sensor coupling spherical 5 at.% tin-doped indium oxide (5ITO) electrode also exhibits highly reproducible and stable signals to different CO concentrations.