Protein release from interpenetrating polymer network hydrogels triggered by endogenous biomarkers

A biocompatible drug delivery system with a high-sensitive stimuli-responsive behavior is reported. Calcium alginate hydrogels interpenetrated with polyvinyl alcohol–diboronate polymer network (IPN) effectively respond to the presence of hydrogen peroxide through oxidative degradation of boronate esters. The degradation of the IPN entails the reopening of the original alginate pores, resulting in a 5–9 times increase in release rates of encapsulated proteins with molecular masses ranging from 16.7 to 66 kDa. The release can be triggered by hydrogen peroxide concentrations as low as 50 μM in the bulk solution. Alternatively, hydrogen peroxide can also be generated inside the hydrogels by incorporation of oxidase enzymes in the presence of their substrates, such as lactate, glucose, or hypoxanthine, which can serve as biomarkers of certain physiological disorders.     

Controlled Logic Gates—Switch Gate and Fredkin Gate Based on Enzyme‐Biocatalyzed Reactions Realized in Flow Cells

Controlled logic gates, where the logic operations on the Data inputs are performed in the way determined by the Control signal, were designed in a chemical fashion. Specifically, the systems where the Data output signals directed to various output channels depending on the logic value of the Control input signal have been designed based on enzyme biocatalyzed reactions performed in a multi‐cell flow system. In the Switch gate one Data signal was directed to one of two possible output channels depending on the logic value of the Control input signal. In the reversible Fredkin gate the routing of two Data signals between two output channels is controlled by the third Control signal. The flow devices were created using a network of flow cells, each modified with one enzyme that biocatalyzed one chemical reaction. The enzymatic cascade was realized by moving the solution from one reacting cell to another which were organized in a specific network. The modular design of the enzyme‐based systems realized in the flow device allowed easy reconfiguration of the logic system, thus allowing simple extension of the logic operation from the 2‐input/3‐output channels in the Switch gate to the 3‐input/3‐output channels in the Fredkin gate. Further increase of the system complexity for realization of various logic processes is feasible with the use of the flow cell modular design.     

Supralinearity in nuclear research emulsions

Nuclear emulsions processed in discriminating developers, intended to suppress small latent image sites, exhibit supralinear sensitometric blackness-exposure curves, whose character varies according to developing time, concentration, and composition, yielding hittedness ranging from 1 to 8, singly and in combination. These emulsion-processing combinations display the phenomena called ion-kill (sensitization by the transit of a single charged particle) and gamma- kill (sensitization by the overlap of secondary electron paths, whether from x-rays or from the delta-rays of heavy ions) in radiobiology. Here emulsions are blackened by x-rays when these same plates reveal no electron tracks, or no alpha-particle tracks, or even no fission fragment tracks. The supralinearity of the emulsion response to x-rays, and the consequent suppression of low LET radiations suggest that these materials have the potential to mimic the response of biological systems to particulate radiations of different charge and speed.     

Measuring and Modeling the U.S. Regulatory Ecosystem

Over the last 23 years, the U.S. Securities and Exchange Commission has required over 34,000 companies to file over 165,000 annual reports. These reports, the so-called “Form 10-Ks,” contain a characterization of a company’s financial performance and its risks, including the regulatory environment in which a company operates. In this paper, we analyze over 4.5 million references to U.S. Federal Acts and Agencies contained within these reports to measure the regulatory ecosystem, in which companies are organisms inhabiting a regulatory environment. While individuals across the political, economic, and academic world frequently refer to trends in this regulatory ecosystem, far less attention has been paid to supporting such claims with large-scale, longitudinal data. In this paper, in addition to positing a model of regulatory ecosystems, we document an increase in the regulatory energy per filing, i.e., a warming “temperature.” We also find that the diversity of the regulatory ecosystem has been increasing over the past two decades. These findings support the claim that regulatory activity and complexity are increasing, and this framework contributes an important step towards improving academic and policy discussions around legal complexity and regulation.     

Size-dependent tunneling and optical spectroscopy of CdSe quantum rods

Photoluminescence excitation spectroscopy and scanning-tunneling spectroscopy are used to study the electronic states in CdSe quantum rods that manifest a transition from a zero-dimensional to a one-dimensional quantum-confined structure. Both optical and tunneling spectra show that the level structure depends primarily on the diameter of the rod and not its length. With increasing diameter, the band gap and the excited state level spacings shift to the red. The level structure was assigned using a multiband effective-mass model, showing a similar dependence on rod dimensions.     

Determination of plasma lactic acid concentration and specific activity using high-performance liquid chromatography.

Assessment of lactate metabolism is of particular interest during exercise and in disease states such as diabetes, shock, and absorptive abnormalities of short-chain fatty acids by the colon. We describe an analytical method that introduces radio-active tracers and high-performance liquid chromatography (HPLC) to simultaneously analyze concentrations and specific activities (SAs) of plasma lactate. The HPLC conditions included separation on a reversed-phase column (octadecylsilane) and an isocratic buffer (30% acetonitrile in water). [3H]Acetate served as an internal standard. Lactate and acetate were extracted from plasma samples with diethyl ether following a pH adjustment to less than 1.0 and back-extracted into a hydrophilic phase with sodium carbonate (2 mM, pH greater than 10.0). Lactate is detected in the ultraviolet range (242 and 320 nm) by derivatization with alpha-bromoacetophenone. Control plasma samples were studied after an overnight fast for precision and analytical recovery. Calibration curves were linear in the range 0.18-6.0 mM (r = 0.92). The precision was 3% and the analytical recovery was 87%. The detection limit of the method was 36 pmol. Determination of lactate metabolism was performed in a patient with chronic congestive heart failure who was administered primed-continuous L-[U-14C]lactate (10 microCi bolus and 0.3 microCi/min continuously) during a 60-min rest period. Mean arterial lactate concentration and SA were 1.69 +/- 0.2 mM and 253.8 +/- 22 dpm/mumol, respectively. Systemic lactate turnover was 25.65 mumol/kg per min. Lactic acid systemic turnover, organ uptake and release rates can be accurately determined by isocratic HPLC.     

Free products of kω-topological groups with normal amalgamation

It is shown in this paper that if A is a closed normal subgroup of k_ω-topological groups G and H, then the free product of G and H with A amalgamated, G1_AH, exists, is Hausdorff and indeed a k_ω-group.     

Radiation-induced dechlorination of carbon tetrachloride in cyclohexane Solutions. The kinetics of liquid-phase reactions of trichloromethyl radicals

The kinetics of the gamma-radiation induced free-radical chain reaction in solutions of carbon tetrachloride in cyclohexane (RH) has been investigated in the temperature range of 303–383°K. Trichloromethyl radicals were produced by the reaction of radiolytically generated cyclohexyl radicals with carbon tetrachloride. The kinetics of the following reactions were investigated: The following rate expression was obtained: The error limits are the standard deviation from the least mean square Arrhenius plots. Effects of phase on the kinetics of reactions (3) and (4) are considered.     

Further results on integral generalized inverses of integral matrices

This paper further investigates integral generalized inverses of integral matrices.     

A facile synthesis of α-chloroboronic esters via the base induced reaction of α,α-dichloromethyl methyl ether with hindered borinic esters

Treatment of hindered borinic esters, R₂ BOR′; with an equimolar quantity of α,α-dichloromethyl methyl ether and lithium triethylcarboxide yields the α-chloroboronic esters, R₂ CHClB(OCH₃)OR′, in excellent yields. In cases where the steric requirements of R are not sufficient, the steric requirements of R′ can be increased to achieve the synthesis.