Mediated Electrochemistry to Mimic Biology's Oxidative Assembly of Functional Matrices

Biology uses diffusible oxidants to perform functions that range from signaling to matrix assembly, and these oxidation chemistries offer surprising selectivities. Here, it is reported that mediated electrochemistry can access the richness of such oxidation chemistries. Specifically, electrode‐imposed voltage inputs are used to locally generate oxidized mediators that can diffuse into polymer solutions and induce the formation of covalent bonds for the deposition and functionalization of hydrogels at the electrode surface. Depending on the mediator's redox potential (E⁰), it is possible to “gate” the voltage inputs to target specific residues (e.g., thiols or amines) and oxidation chemistries. Further, mediators of varying E⁰ offer different reactivities and thus allow control of reaction‐diffusion rates to modulate the hydrogel's crosslink density and mechanical properties. Importantly, this mediated oxidation can be performed under physiologically relevant conditions to preserve labile biological functionalities (e.g., cell viability and protein function). Finally, it is demonstrated that protein fusion tags can be engineered to have “targetable” amino acid residues that enable protein function to be oxidatively conjugated to electrodeposited hydrogels. In summary, mediated electrochemistry can engage orthogonal oxidation chemistries to create functionalized matrices and thus mediated electrochemistry should add important capabilities to the electrofabrication toolbox.     

Peptides from Vh regions of antibodies to DNA activate T cell help to upregulate autoantibody synthesis

A model is a mathematical representation of a system that can be used to explore the system in a number of ways: to determine the system's internal connections, to calculate properties of the system such as flow rates and pool sizes, and to make predictions about the system's behavior under different conditions. The use of modeling to explore whole-body metabolism is demonstrated using a compartmental model of zinc kinetics as an example. Because models are useful tools for exploring systems, a facility called a "model library" is being established on the Internet to provide access to working versions of published models.     

Zwitterionic Nanocages Overcome the Efficacy Loss of Biologic Drugs

For biotherapeutics that require multiple administrations to fully cure diseases, the induction of undesirable immune response is one common cause for the failure of their treatment. Covalent binding of hydrophilic polymers to proteins is commonly employed to mitigate potential immune responses. However, while this technique is proved to partially reduce the antibodies (Abs) reactive to proteins, it may induce Abs toward their associated polymers and thus result in the loss of efficacy. Zwitterionic poly(carboxybetaine) (PCB) is recently shown to improve the immunologic properties of proteins without inducing any antipolymer Abs against itself. However, it is unclear if the improved immunologic profiles can translate to better clinical outcomes since improved immunogenicity cannot directly reflect amelioration in efficacy. Here, a PCB nanocage (PCB NC) is developed, which can physically encase proteins while keeping their structure intact. PCB NC encapsulation of uricase, a highly immunogenic enzyme, is demonstrated to eradicate all the immune responses. To bridge the gap between immunogenicity and efficacy studies, the therapeutic performance of PCB NC uricase is evaluated and compared with its PEGylated counterpart in a clinical‐mimicking gouty rat model to determine any loss of efficacy evoked after five administrations.     

The integration solution of copper barrier deposition for nanometer interconnect process

As the dimensions of devices are shrunk quickly, the requirements of metallization become more critical. For VIA barrier and seeding layer filling and deposition, the process was mostly applied with the copper physical vapor deposition methodology in the back-end of line flow of the interconnection metallization. The criteria for barrier and seeding layer deposition are the metal continuity inside the VIA feature and grain size and orientation control for film diffusion barrier and qualities. Besides, while the interconnection size shrunk to nano-scale, the barrier thickness would be very thinner to maintain the VIA resistance; however, it would face the film conformity and continuity consistence within the wafer and different features. The integration solution would be developed and studied with the re-sputter process step adding into the convectional physical vapor deposition process. The resputter process step could not only improve the film conformity and continuity in the VIA's sidewall; but also reduce the resistance of VIA feature over 20%. The improvement of the resputter method adding into the deposition process would be contributed to the standard barrier deposition in the nano-scale feature of the interconnect. Besides, we also discussed the effect of the film properties after the resputter process introduced into the barrier deposition.     

Side-polished multimode fiber biosensor based on surface plasmon resonance with halogen light

A side-polished multimode fiber sensor based on surface plasmon resonance (SPR) as the transducing element with a halogen light source is proposed. The SPR fiber sensor is side polished until half the core is closed and coated with a 37 nm gold thin film by dc sputtering. The SPR curve on the optical spectrum is described by an optical spectrum analyzer and can sense a range of widths in wavelengths of SPR effects. The measurement system using the halogen light source is constructed for several real-time detections that are carried out for the measurement of the index liquid detections for the sensitivity analysis. The sensing fiber is demonstrated with a series of refractive index (RI) liquids and set for several experiments, including the stability, repeatability, and resolution calibration. The results for the halogen light source with the resolution of the measurement based on wavelength interrogation were 3 x 10(-6) refractive index units (RIUs). The SPR dip shifted in wavelength is used as a measure of the RI change at a surface, and this RI change varies directly with the number of biomolecules at the surface. The SPR dip shift in wavelength, which was hybridized at 0.1 microM of the target DNA to the probe DNA, was 8.66 nm. The all-fiber multimode SPR sensor, which has the advantages of being low cost, being disposable, having high stability and linearity, being free of labeling, and having potential for real-time detection, permit the sensor and system to be used in biochemical sensing and environmental monitoring.     

Effect of deviation on delamination by saw drill

Various cutting techniques are available to drill holes, but drilling is the most common way in secondary machining of composite materials owing to the need for structure joining. Twist drills are widely used in the industry to produce holes rapidly and economically. Since the twist drill has a chisel edge, increasing the length of a chisel edge will result in an increase in the thrust force generated. Whereas, a saw drill has no chisel edge; it utilizes the peripheral distribution of the thrust force for drilling. As a result, the saw drill can achieve better a machining quality in drilling composite laminates than twist drill. The deviation of cutting edge that occurs in saw drill would result in an increase of thrust force during drilling, causing delamination damage when drilling composite materials in particular. A comprehensive model concerning delamination induced by the thrust force of a deviation saw drill during drilling composite materials has been established in the present study. For a deviation saw drill, the critical thrust force that triggers delamination increases with increasing β. A lower feed rate has to be used with an increasing deviation saw drill in order to prevent delamination damage. The results agree with real industrial experience. A guide for avoiding the drill deviation during drill regrinding or drill wear has been proved analytically by the proposed model, especially when the deviation ratio (β) affects the critical thrust force. This approach can be extended to examine similar deviation effects of various drills.     

Study on the Stability of Ion-exchange Resin Catalysts:Ⅰ. TGA as a Rapid Evaluating Method

The thermal stability of five commercial ion-exchange resin catalysts was studied by means of thermal gravimetric analysis(TGA) at elevated temperatures of up to 600℃and isothermal temperatures in the range of 150℃and 200℃.Resin samples with different initial water contents were also investigated.The study indicated that TGA,as a complementary evaluating method for the plug flow reactor system approach,could be used as a fast analyzing means for study on the thermal stability of ion-exchange resin cataly...