The linear mechanical model for hand-arm system

The paper presents a study regarding the linear mechanical models corresponding to hand-arm system. These models was simplified unused the joint in wrist, elbow and shoulder. Also, for these mechanical models effectuated the equations system that would integrate, it obtained the solutions (displacements and velocities) finally. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Host–guest system of Vitamin B10 in β-cyclodextrin: characterization of the interaction in solution and in solid state

Conventional drugs are usually formulated for the immediate release of the medicinal substances and for obtaining the desired therapeutic effect. The aim of this paper was to investigate the possible interactions between Vitamin B10 and β-cyclodextrin (β-CD), to determine the physical-chemical characteristics and the interactions present in the corresponding inclusion compound. The so-obtained compounds were characterized by X-ray diffraction, DSC and FTIR spectroscopy. ¹H NMR and UV–vis spectroscopic methods were employed to study the inclusion process in aqueous solution. The X-ray powder diffraction patterns demonstrate the inclusion compound formation, especially for the lyophilized product where the amorphous phase dominates. The existence of the inclusion compounds obtained by different methods was confirmed by comparing with DSC and FTIR data of the pure compounds and the (1:1) Vitamin B10:β-CD physical mixture (pm). ¹H NMR measurements on aqueous solutions of Vitamin B10 and β-CD in D₂O allowed us to establish the corresponding Vitamin B10’s and cyclodextrin’s protons implied in the complexation process. 2D NMR spectroscopy established the geometry of the inclusion complex. ¹H NMR, UV–Vis and fluorescence data were used to obtain the stoichiometry and the stability constant of the complex.     

In situ monitoring the sol–gel transition for polyacrylamide gel

The effects of heating rate and shear stress on the sol–gel transition for a polyacrylamide gel during in situ preparation were investigated by dynamic rheology. The gelation evolution was also studied through monitoring of the static gelation process by means of temperature, pH, and conductivity variation. The gels were prepared by polymerization of acrylamide crosslinked with N,N′-methylenebisacrylamide using a redox initiation based on potassium persulfate/ascorbic acid. In situ gelation process was studied using oscillatory deformation tests at constant frequency of 0.1 Hz for different heating rate (from 0.5 to 5 °C/min) and shear stress (in the range of 0.1 to 10 Pa). The paper was presented at the third annual rheology conference, AERC 2006, Crete, Greece, 27–29 April 2006.     

Contribution to polymer nanoparticles analysis by laser light scattering

The applications of laser light scattering (LLS) to polymer physics and colloid science have been extensive and noteworthy, especially in particle-size analysis. The study presents an example of LLS application to the characterization of interpolymer complexation of poly(aspartic acid) with a vinylic polymer, by particle size and zeta potential evaluation. The LLS technique is complemented by oscillatory rheological data. The complexes have a potential biomedical application by bioactive substances attachment.     

Inclusion of the Niflumic Acid Anion in β-cyclodextrin: A Solution NMR and X-ray Structural Investigation

We report parallel solution and solid state studies of the inclusion of the anionic form of the non-steroidal anti-inflammatory drug niflumic acid (2-[[3-(trifluoromethyl)phenyl]-amino]-3-pyridinecarboxylic acid) in the host g -cyclodextrin ( g -CD). 1 H NMR data for the interaction between host and guest in aqueous solution recorded at 300 MHz indicated a strong preference for insertion of the trifluoromethylphenyl residue, rather than the pyridinecarboxylate moiety, in the host cavity. A 1:1 complex stoichiometry was determined by the continuous variation method utilising chemical shifts of both host and guest protons. Analysis of the data using a new flexible program developed for this purpose yielded an overall association constant K of 336 M m 1 at 298 K. The NMR data indicate a dynamic equilibrium between complexed and uncomplexed species but do not distinguish guest entry from the primary and secondary sides of the host. Reaction between the Cs + salt of niflumic acid and g -CD yielded the crystalline complex ( g -CD) 2 ·(Cs + niflumate m ) 4 ·22H 2 O whose single crystal X-ray structure was determined. A novel inclusion mode for this host, namely entry of guest trifluoromethylphenyl residues from both the primary and secondary sides, was revealed by the X-ray analysis.     

Research about moving restrictions of cervical spine under the action of mechanical vibrations

The cervical spine is very important human body part, because it sustains the head and it has a higher mobility than the other parts of human spine. The vibration could influence the work performance but also could have a negative influence on human body health. There are many elements, which could be damaged: eyes, ears, brain, mandible, neck's muscle, C1 to C7 vertebras. When the operator is exposed to vibrations for a long time, he can fill a strong pain at the neck. Injuries to the cervical spine are common at the level of the second cervical vertebrae, but neurological injury is uncommon. If it does occur, however, it may cause death or profound disability, including paralysis of the arms or legs. We purpose in this study to develop a biomechanical model for the cervical vertebras and identify the influence of mechanical vibrations on human cervical spine and human head. For this study is necessary to compute the entire moving system of the neck-head. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

RuO<Subscript>4</Subscript>-mediated oxidation of<Emphasis Type="Italic">N</Emphasis>-benzylated tertiary amines. Are amine<Emphasis Type="Italic">N</Emphasis>-oxides and iminium cations reaction intermediates?

N-Benzylmorpholine,-piperidine, and-pyrrolidine (1A-C, resp.) are oxidised by RuO₄ (generated in situ) at both endocyclic and exocyclic (benzylic) N—α-methylene positions to afford lactams (and dioxo-derivatives) and benzaldehyde (and benzoyl derivatives), respectively. The N-oxides of 1A-C, formed by a minor side reaction, are not involved as intermediates. Control experiments showed the transient formation of endo- and exocyclic iminium cations trapped with NaCN as the corresponding nitriles. The proposed course of the RuO₄-mediated oxidation of 1A-C involves the consecutive steps 1⇒iminium cations+cyclic enamine⇒oxidation products. The endocyclic/exocyclic regioselectivity of the oxidation reaction lies between 0.8 (for 1A) and 2.1 (for 1B). The amine cation radical and the N-α-C· carbon-centered radical seem not to be involved.     

Advancement in the Biomedical Applications of the (Nano)gel Structures Based on Particular Polysaccharides

(Nano)gels from macromolecular compounds—natural, synthetic, or a combination thereof, suitable crosslinkers—and conferred characteristics—such as degradability, size, charge, amphiphilicity, responsiveness, and softness—are capable of responding to the challenges imposed by bioengineering applications. Polysaccharide‐based gels have received particular attention in this field. This review addresses recent advancement in the use of (nano)gel structures prepared only from compounds based on gellan gum, heparin, chondroitin sulfate, carrageenan, guar gum, galactose, or agarose, which represent an important part of the special class of natural polymers, the polysaccharides. Also, future trends are taken into discussion regarding the (nano)gels' use in biomedical applications such as biomimetics, biosensors, artificial muscles, and chemical separations in relation with their ability to be used as a vehicle for various biomolecules due to their physicochemical properties, biocompatibility, and biodegradability.