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The convergence of terahertz spectroscopy and single molecule experimentation offers significant promise of enhancement in sensitivity and selectivity in molecular recognition, identification and quantitation germane to military and security applications. This paper provides a brief overview of the constraints set by single molecule recognition systems and reports the results of experiments which address fundamental barriers to the integration of large, patterned bio-compatible molecular opto-electronic systems with silicon based microelectronic systems. Central to this thrust is an approach involving sequential epitaxy on surface bound single stranded DNA one-dimensional substrates. The challenge of producing highly structured macromolecular substrates, which are necessary in order to implement molecular nanolithography, has been addressed experimentally by combining “designer” synthetic DNA with biosynthetically derived plasmid components. By design, these one dimensional templates are composed of domains which contain sites which are recognized, and therefore addressable by either complementary DNA sequences and/or selected enzymes. Such design is necessary in order to access the nominal 2 nm linewidth potential resolution of nanolithography on these one-dimensional substrates. The recognition and binding properties of DNA ensure that the lithographic process is intrinsically self-organizing, and therefore self-aligning, a necessity for assembly processes at the requisite resolution. Another requirement of this molecular epitaxy approach is that the substrate must be immobilized. The challenge of robust surface immobilization is being addressed via the production of the equivalent of molecular tube sockets. In this application, multi-valent core-shell fluorescent quantum dots provide a mechanism to prepare surface attachment sites with a pre-determined 1:1 attachment site : substrate (DNA) molecule ratio.

The immobilization of non-rigid objects is a largely unaddressed subject. We explore the problem by studying the immobilization of a serial chain of polygons connected by rotational joints, or hinges, in a given placement with frictionless point contacts. We show that n + 2 such contacts along edge interiors or at concave vertices suffice to immobilize any serial chain of n ≠ 3 polygons without parallel edges; it remains open whether five contacts can immobilize three hinged polygons. At most n + 3 contacts suffice to immobilize a serial chain of n polygons when the polygons are allowed to have parallel edges. We also study a robust version of immobility, comparable to the classical notion of form closure, which is insensitive to perturbations. The robustness is achieved at the cost of a small increase in the number of contacts: and frictionless point contacts suffice for a chain of n hinged polygons without and with parallel edges respectively.

Let shape P be any simply-connected set in the plane, bounded by a Jordan curve, that is not a circular disk. We say that a set of points I on the boundary of P immobilize the shape if any rigid motion of P in the plane causes at least one point of I to penetrate the interior of P. We prove that four points always suffice to immobilize any shape. For a large class of shapes, which includes polygons without parallel edges, three points are sufficient to immobilize. An O(n log n) algorithm is given that finds a set 3 points that immobilize a given polygon without parallel edges. The algorithm becomes linear for convex polygons. Some results are generalized for d-dimensional polytopes, where 2d points are always sufficient and sometimes necessary to immobilize.

We demonstrate that immobilization of a π-conjugated molecule containing a bipyridine moiety as a hydrogen bond acceptor on Au using a dendrimer-based template with 3,4-dihydroxybenzene moiety at the core as a hydrogen bond donor. The hydrogen bond interaction was used for the linkage between the conjugated molecule and the template to improve the method to fabricate single-molecule arrays we reported before.¹ Although the binding constant is small (K = 120 ± 20 M^-1) in CDCl₃, it was demonstrated that the dendrimer spacer serves as a template to isolate the π-conjugated molecule, and is removable simply with a CH₂Cl₂ rinsing by surface FTIR spectroscopy.

Iron oxide nanoparticles were prepared and functionalized by succinamide based dendrimer. The resultant particles were characterized by XRD, VSM, and FTIR spectroscopy. The results indicate that the dendrimers has effectively functionalized the magnetite nanoparticles which remain dispersive and exhibited super-paramagnetism with a magnetization value of 33.2 emu/g in a field of 2T. Mean particle size as calculated from the AFM was found to be ~ 23 nm. Bovine serum albumin was immobilized on the magnetic nanoparticles as was confirmed by the FTIR results.

Covalent cross-linking of enzymes to magnetite (Fe₃O₄) nanoparticles (MNPs) is one of the useful enzyme immobilization methods which provides repeated use of the catalyst, facilitates enzyme separation from the reaction mixture, and sometimes improves biocatalysts stability. The aim of this study was to immobilize $\alpha$-amylase onto MNPs via covalent attachment using carbodiimide (CDI) molecules. MNPs were synthesized by the co-precipitation method. The size and the structure of the particles were characterized by X-ray diffraction and transmission electron microscopy. The effects of different operational conditions of direct $\alpha$-amylase binding on MNPs in the presence of CDI were investigated by using the shaking method. Fourier transform infrared spectroscopy was used to confirm the success of immobilization. The optimum conditions and catalytic properties of immobilized $\alpha$-amylase were also evaluated. The efficiency of immobilization and the residual activity of the immobilized $\alpha$-amylase were dependent on the mass ratio of MNPs: CDI: $\alpha$-amylase and the immobilization temperature. The optimum pH for the free and immobilized amylase was 6. The free and immobilized $\alpha$-amylase showed maximum activity at 20${}^{\circ }$C and 35${}^{\circ }$C, respectively. The immobilized $\alpha$-amylase was more thermostable than the free one. The retained activity for free $\alpha$-amylase after 19 storage days was 57.7% whereas it was 100% for the immobilized $\alpha$-amylase. In repeated batch experiments, the immobilized $\alpha$-amylase retained a residual activity of 45% after 11 repeated uses. The $K_m$ and $V_{\mathrm{\text{max}}}$ values for the immobilized enzyme were larger than those of the free enzyme. The immobilization of $\alpha$-amylase on MNPs using CDI improves its stability and reusability.

A novel platform has been developed for the sensitive label-free detection of mutation in the TP53 gene, one of the most prominent genes in cancer research. The platform is based on the electrochemical properties of functionalized multi-walled carbon nanotubes (f-MWCNTs), gold nanoparticles (AuNPs), and polypyrrole (PPy). The microscopic structure and morphology of the prepared films on an ITO electrode surface were characterized using X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FTIR). The hybridization events specific to the TP53 gene were monitored using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The modified electrode, which incorporates vertically aligned f-MWCNTs arrays and AuNPs, exhibited enhanced probe DNA attachment density, improving the sensitivity of the DNA sensor. The combination of AuNPs/PPy with an in-situ produced f-MWCNTs array provides a viable strategy for developing a highly sensitive biosensor for fast mutation detection in human cancer types.

One reason for the difficulty to develop effective therapies for stroke is that intrinsic factors, such as stress, may critically influence pathological mechanisms and recovery. In cognitive tasks, stress can both exaggerate and alleviate functional loss after focal ischemia in rodents. Using a comprehensive motor assessment in rats, this study examined if chronic stress and corticosterone treatment affect skill recovery and compensation in a task-specific manner. Groups of rats received daily restraint stress or oral corticosterone supplementation for two weeks prior to a focal motor cortex lesion. After lesion, stress and corticosterone treatments continued for three weeks. Motor performance was assessed in two skilled reaching tasks, skilled walking, forelimb inhibition, forelimb asymmetry and open field behavior. The results revealed that persistent stress and elevated corticosterone levels mainly limit motor recovery. Treated animals dropped larger amounts of food in successful reaches and showed exaggerated loss of forelimb inhibition early after lesion. Stress also caused a moderate, but non-significant increase in infarct size. By contrast, stress and corticosterone treatments promoted reaching success and other quantitative measures in the tray reaching task. Comparative analysis revealed that improvements are due to task-specific development of compensatory strategies. These findings suggest that stress and stress hormones may partially facilitate task-specific and adaptive compensatory movement strategies. The observations support the notion that hypothalamic–pituitary–adrenal axis activation may be a key determinant of recovery and motor system plasticity after ischemic stroke.

Cationic 2,9,16,23-tetrakis(3-N,N,N-trimethylaminoethyloxy)phthalocyaninatozinc(II) and 20,21-bis(4-N,N,N-trimethylaminophenyl)-4,5,9,10,14,15-hexakis(4-t-butylphenyl)porphyrazinatozinc(II) were immobilized in MCM-41 silica by the use of an electrostatic interaction with the deprotonated silanol groups of MCM-41. From nitrogen adsorption isotherms, specific surface areas were estimated as 1031 and 702 m².g⁻¹ for MCM-41 and the composite of 2,9,16,23-tetrakis(3-N,N,N-trimethylaminoethyloxy)phthalocyaninatozinc(II), respectively. From pore-size distribution curves, the maximum pore diameter of MCM-41 and the composite were also estimated as 3.24 and 3.10 nm, respectively. These results revealed that 2,9,16,23-tetrakis(3-N,N,N-trimethylaminoethyloxy)phthalocyaninatozinc(II) was immobilized in the mesopores of MCM-41. While 2,9,16,23-tetrakis(3-N,N,N-trimethylaminoethyloxy)phthalocyaninatozinc(II) formed a dimer with increase in the amount of the complex in the composite, 20,21-bis(4-N,N,N-trimethylaminophenyl)-4,5,9,10,14,15-hexakis(4-t-butylphenyl)porphyrazinatozinc(II) only slightly formed a dimer in the composite, due to steric hindrance of its peripheral substituents. 1,3-diphenylisobenzofuran was photo-oxidized using the composites as the sensitizer in aerated acetonitrile. The reaction proceeded with singlet dioxygen generated by visible-light irradiation of the sensitizers. While the initial reaction rate with the composite of 20,21-bis(4-N,N,N-trimethylaminophenyl)-4,5,9,10,14,15-hexakis(4-t-butylphenyl)porphyrazinatozinc(II) increased in proportion to the increase in the amount of the complex, the initial reaction rate with the composite of 2,9,16,23-tetrakis(3-N,N,N-trimethylaminoethyloxy)phthalocyaninatozinc(II) at first increased, but subsequently decreased due to the formation of the photo-inactive dimer.

A new ruthenium(II) porphyrin disulphide derivative, [Ru(Pds)(CO)], was obtained from ruthenium(II)(carbonyl)deuteroporphyrin(IX), [Ru(DPdc)(CO)] and cystamine. The interaction of this complex with nitric oxide was studied spectrophotometrically and a bathochromic shift of the charge transfer band and considerable change in the α and β bands of the complex were observed. According to the IR spectrum, the product of this interaction is [Ru(DmDP)(NO⁺)(NO₂^-)]. [Ru(Pds)(CO)] was then self-assembled on polycrystalline gold and characterized by X-ray photoelectron spectroscopy. [Ru(Pds)(CO)] was also self-assembled on gold electrode beads and its interaction with nitric oxide in aqueous solution was studied by cyclic voltammetry. A shift in the ruthenium redox process and a new irreversible cathodic peak at -0.59 V were observed, both indicating coordination of NO.

Enhancement of the catalytic activity of phthalocyanine catalysts by immobilizing them on polymer matrix has been studied. It has been found that the immobilization of cobalt(II) phthalocyanines on polymers enhances their catalytic activity in the oxidation of sodium diethyldithiocarbamate by air oxygen under mild conditions.

Microperoxidases 8 (MP8) and 11 (MP11) are heme-containing peptides obtained by the proteolytic digestion of Cytochrome c. They act as mini-enzymes that combine both peroxidase-like and Cytochrome P450-like activities that may be useful in the synthesis of fine chemicals or in the degradation of environmental pollutants. However, their use is limited by their instability in solution due to (i) the bleaching of the heme in the presence of an excess of H₂O₂, (ii) the decoordination of the distal histidine ligand of the iron under acidic conditions and, (iii) their tendency to aggregate in aqueous alkaline solutions, even at low concentrations. Additionally, both MP8 and MP11 show relatively low selectivity, due to the lack of control of the substrates by a specific catalytic pocket on the distal face of the heme. Both stability and selectivity issues can be effectively addressed by immobilization of microperoxidases in solid matrices, which can also lead to their possible recycling from the reaction medium. Considering their relatively small size, the pore inclusion of MPs into Metal-Organic Frameworks appeared to be more adequate compared to other immobilization methods that have been widely investigated for decades. The present minireview describes the catalytic activities of MP8 and MP11, their limitations, and various results describing their immobilization into MOFs which led to MP11- or MP8@MOF hybrid materials that display good activity in the oxidation of dyes and phenol derivatives, with remarkable recyclability due to the stabilization of the MPs inside the MOF cavities. An example of selective oxidation of dyes according to their charge by MP8@MOF hybrid materials is also highlighted.

Cellulase was immobilized on functionalized magnetic silica nanospheres using glutaraldehyde as a cross-linking agent. The morphologies, structures and magnetic properties of this immobilized cellulase were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential thermal analysis and vibrating sample magnetometry. The properties of immobilized cellulase were investigated, including the amount of immobilized cellulase and its relative activity, stability and reusability. The results indicated that immobilized cellulase exhibited better resistance to high temperature and pH inactivation in comparison to free cellulase. Moreover, immobilized cellulase with and without cross-linking agent were investigated and the former had greater amount of immobilized cellulase and better operational stability. The amount of immobilized cellulase with the cross-linking agent was 92 mg/g support. Furthermore, the activity of the immobilized cellulase was still 85.5% of the initial activity after 10 continuous uses, demonstrating the potential of this immobilized cellulase for large-scale biofuel production.

This work designed and prepared a novel type of carrier for immobilization of penicillin G acylase (PGA), and then the performances of the immobilized PGA were studied in detail. The process is presented as follows: First, dopamine (DA), an adhesive biological secondary metabolite, was adopted to form a polydopamine (PDA) coating on the surface of Fe₃O₄ nanoparticles (NPs) prepared by the inverse microemulsion method to generate Fe₃O₄@PDA NPs through in-situ polymerization. After that, the obtained Fe₃O₄@PDA NPs were modified by reversible addition fragmentation chain transfer (RAFT) reagent containing carboxyl groups on its surface. Then, taking N,N diethyl acrylamide (DEA) as the temperature-sensitive monomer, $\beta$-hydroxyethyl methacrylate (HEMA) as the hydrophilic monomer, glycidyl methacrylate (GMA) as the target monomer and methyl methacrylate (MMA) as the monomer controlling the distance between targets, through the “Grafting from” strategy and the RAFT polymerization method, the magnetic temperature-sensitive polymer composite, Fe₃O₄@PDA-g-PDEA-b-PHEMA-b-P(MMA-co-GMA) NPs with different feeding ratios of MMA/GMA, was prepared to realize the immobilization of penicillin G acylase (PGA). Based on samples prepared at each stage of the carrier, the structure and performances were characterized by Fourier Infrared Spectroscopy (FTIR), Transmission Electron Microscope (TEM), X-ray Diffraction (XRD), and Vibration Specimen Magnetometer (VSM), respectively. Besides, the content of RAFT graft Fe₃O₄@PDA was also quantitatively characterized by ICP, and the molecular weight of the polymer was characterized by mass spectrometry. Result showed that the target space influenced enzyme load capacity (ELC), enzyme activity (EA) and enzyme activity recovery rate (EAR) at a large degree, and there was no positive relationship between ELC to EA and EAR. Last, performances of the immobilized PGA, including relative enzyme activity ($R_t$) of immobilized PGA, were 83.9% after storing for 90 days, and 90.3% of the initial activities were still retained after 12 times of repeated use, and the catalytic stability (temperature, pH) and Michaelis–Menten const $K_m$ were investigated with free PGA as control if operation was allowed.

In this study, Bi₂WO₆/Bi₂O₃-loaded polyurethane sponge composite photocatalyst was successfully synthesized via a facile two-step approach. The composite was characterized by X-ray diffraction, ultraviolet-visible diffuse reflectance, and scanning electron microscopy. The Bi₂WO₆/Bi₂O₃ photocatalyst was successfully loaded on polyurethane sponge and the composite displayed enhanced absorption in the ultraviolet-to-visible light region. Furthermore, the composite exhibited enhanced photocatalytic activity and reusability towards the degradation of rhodamine B (RhB) under visible light. This work demonstrates a facile method for synthesizing Bi₂WO₆/Bi₂O₃-loaded polyurethane sponge with enhanced photocatalytic activity and easy immobilization of the photocatalyst for application in environmental purification.

A strategy of immobilizing room temperature ionic liquid (RTIL) in proton-exchange membranes (PEMs) is demonstrated for the first time. After synthesized by ionic exchange and extraction, RTIL is anchored to the surfaces of silica nanoparticles (SiO₂-RTIL) via condensation reaction. Then composite PEMs consisting of sulfonated poly(ether ether ketone) (SPEEK) and silica with RTIL are prepared through the solution casting method. The incorporation of SiO₂-RTIL markedly improves the physical properties of the composite PEMs as compared to the plain SPEEK membrane, which was probably related to the plasticization and additional proton conductivity of the SiO₂-RTIL. The anhydrous proton conductivity of the resultant composite PEM with 30% SiO₂-RTIL was 50 times that of the plain membrane at 150${}^{\circ }$C.

The biological sensing interface on the active area of a piezo transducer is responsible for the sensitivity, specificity, reusability, and reproducibility of these devices. Among the approaches used to functionalize piezo transducers, mixed self-assembled monolayers (MSAMs) are one of the most successful, given that they allow the obtaining of semi-crystalline molecular arrays and the arrangement of a bioreceptor on the surface. But, to deploy MSAMs on a substrate effectively, one must optimize and characterize the structural ratio between them and the bioreceptor. In this paper, we developed a molecular model of the interaction between Bovine Serum Albumin (BSA) and MSAMs-functionalized gold substrates. First, we evaluated the conditions for the functionalization of the substrates and found that a 50:1 16-mercaptohexadecaonic acid (MHDA) to 11 mercapto-1-undecanol (MUA) ratio produced the best features on the surface. We also evaluated the specific conditions to immobilize BSA on MSAMs (using the afore-established ratio) via Atomic Force Microscopy (AFM), and then on a 10MHz quartz crystal microbalance (QCM), and with the data obtained we concluded that a structural ratio of 0.005 (MSAM/BSA) is obtained when 1$\mu$M MHDA and 200$\mu$g/mL BSA were used, provided the most suitable conditions for the functionalization of a piezo transducer.

Background: Although vascularized bone grafting can effectively treat scaphoid nonunion, the optimal duration of the immobilization period after bone grafting is unclear. Therefore, we aimed to examine the difference in the union rate and range of motion between short and long immobilization periods and infer the optimal post-immobilization period after pedicled vascularized bone grafting for scaphoid nonunion treatment.

Methods: A total of 23 wrists (21 men and 1 woman) with scaphoid nonunion treated using an intercompartmental supraretinacular artery pedicled vascularized bone graft were analyzed. We examined the difference in the union rate and range of motion between patients immobilized for less than 49 days (short immobilization group) and those immobilized for more than 49 days (long immobilization group). The range of motion of the wrist joint was measured before and after surgery. Patient outcomes were also assessed.

Results: The overall union rate was 95.6%. A significant difference was found in postoperative extension and flexion between the two groups, but not in terms of the functional outcome. If the intraoperative fixation is solid, intraoperative proximal pole bleeding is confirmed, and the follow-up radiograph shows a normal healing process, we propose immobilization of the wrist for ≤ 7 weeks.

Conclusions: The immobilization duration should depend on the solidity of intraoperative fixation and a satisfactory appearance on follow-up radiography: absence of a gap at the graft interface, surrounding lucency, or movement of the implant and displacement of the graft. If there are no signs of graft failure and fixation is solid, immobilization of the wrist for 7 weeks or less is recommended.

Background: In the conservative management of distal radial fractures (DRFs), the optimal dorsi-volar angulation of the wrist at cast immobilization and proper cast molding to minimize the risk of redisplacement are unclear. This study identified the predictors of fracture redisplacement during cast immobilization for adult DRFs.

Methods: We examined for dorsi-volar angulation, gap index, volar tilt (VT), radial inclination (RI), and radial length (RL) in lateral or posteroanterior radiographs of 90 DRFs. We investigated possible predisposition factors for redisplacement including patient age, sex, extra- or intra-articular fracture, metaphyseal comminution, original displacements, dorsi-volar angulation of the wrist at cast immobilization, restoration of the volar cortex at cast immobilization, and gap index of the cast.

Results: Neither dorsi-volar angulation nor gap index had significant association with an unacceptable alignment nor decrease of VT, RI, and RL. In multivariate analysis, patient age, original displacement, and intra-articular fracture were the significant predictors of an unacceptable alignment or decrease of VT and RI.

Conclusions: Our findings indicate dorsi-volar angulation and cast molding quality have no clinical effect on preventing fracture redisplacement. The predictive factors of the displacement were patient age, original displacement, and intra-articular fracture.

Traditional Chinese Medicine (TCM) modernization has been proposed for many years, but the progress is still slow due to both ideological and technical obstacles. When I went to Japan in 1989, I found Japan has made a great progress on TCM by using modern technology. Therefore, I have studied a fine extract prepared from medicinal herbs (renamed Yi-Zhi-Yi-Shou, YZYS), a prescription of Dowager Cixi’s Yanling-Yishou-Dan of Qing Dynasty, with the current drug investigation strategies. I examined its antioxidant activity both in vitro and in vivo. The in-vitro studies found that YZYS possesses strong antioxidant capacity, such as scavenging various kinds of free radicals, and inhibits free radical-induced peroxidation of brain homogenate, microsomes, mitochondria, amino acids, deoxyribose and DNA. The in-vivo study with immobilization-induced emotional stress in rats, showed that YZYS effectively inhibits stress-induced stomach ulcers and oxidative damage in plasma and the brain. In addition, YZYS is shown to be non-toxic in both acute and chronic toxicity tests. These studies demonstrate that YZYS is a potent natural antioxidant and offer theoretical evidence for the beneficial effect of YZYS on health and brain functions, and that TCM prescriptions can be studied scientifically as modern medical drugs.