Оцінка впливу замісної гормоно-терапії гіпотиреозу на стан вагітності та виношування плоду

Гіпотиреоз – захворювання щитовидної залози, при якому знижується її продуктивність, тиреоїдних гормонів виробляється менше чим необхідно організму для нормальної життєдіяльності. За результатами популяційних досліджень, поширеність гіпотиреозу серед вагітних становить 2-3 %. Серед них близько двох третин мають субклінічний та 0,5 % − маніфестний гіпотиреоз. За даними багатьох дослідників, тільки 20-30% жінок з гіпотиреозом мають клінічні прояви гіпотиреозу, у інших, як правило, захворювання протікає без симптомів. Патологія ЩЗ негативно впливає на перебіг вагітності, розвиток плода й адаптацію новонародженого. Тиреоїдна дисфункція загрожує викиднями, передчасними пологами, відшаруванням плаценти, прееклампсією, післяпологовим тиреоїдитом у матері, а також зниженням інтелектуального потенціалу народжених дітей

Helical Single-Lamellar Crystals Thermotropically Formed in a Synthetic Nonracemic Chiral Main-Chain Polyester

Phase structures and transformation mechanisms of nonracemic chiral biological and synthetic polymers are fundamentally important topics in understanding their macroscopic responses in different environments. It has been known for many years that helical structures and morphologies can exist in low-ordered chiral liquid crystalline (LC) phases. However, when the chiral liquid crystals form highly ordered smectic liquid crystal phases, the helical morphology is suppressed due to the crystallization process. A double-twisted morphology has been observed in many liquid crystalline biopolymers such as dinoflaggellate chromosomes (in Prorocentrum micans) in an in vivo arrangement. Helical crystals grown from solution have been reported in the case of Bombyx mori silk fibroin crystals having the beta modification. This study describes a synthetic nonracemic chiral main-chain LC polyester that is able to thermotropically form helical single lamellar crystals. Flat single lamellar crystals can also be observed under the same crystallization condition. Moreover, flat and helical lamellae can coexist in one single lamellar crystal, within which one form can smoothly transform to the other. Both of these crystals possess the same structure, although translational symmetry is broken in the helical crystals. The polymer chain folding direction in both flat and helical lamellar crystals is determined to be identical, and it is always along the long axis of the lamellae. This finding provides an opportunity to study the chirality effect on phase structure, morphology, and transformation in condensed states of chiral materials. [S0163-1829(99)01042-5]

Double Twist in Helical Polymer Soft Crystals

In natural and synthetic materials having non-racemic chiral centers, chirality and structural ordering each play a distinct role in the formation of ordered states. Configurational chirality can be extended to morphological chirality when the phase, structures possess low liquid crystalline order. In the crystalline states the crystallization process suppresses the chiral helical morphology due to strong ordering interactions, In this Letter, we report the first observation of helical single lamellar crystals of synthetic non-racemic chiral polymers. Experimental evidence shows that the molecular chains twist along both the long and short axes of the helical lamellar crystals, which is the first time a double-twist molecular orientation in a helical crystal has been observed

The remanufacturing evaluation for feasibility and comprehensive benefit of retired grinding machine.

Grinding is the last and most important process of parts processing, the purpose is to achieve high precision and surface roughness. Therefore, grinding machine has the characteristics of high added value, high technology content and great remanufacturing value. However, the evaluation of machine tool remanufacturing is based on imprecise and fuzzy information at present. The aim of this study is to present the remanufacturing evaluation for feasibility and comprehensive benefit of retired grinder. Firstly, according to the unique structure of grinder, the feasibility evaluation model of grinder remanufacturing is established, including technical feasibility criterion, economic feasibility criterion and resource environment feasibility criterion. Secondly, the comprehensive benefit evaluation model of remanufacturing grinder is established, in which the weight of each evaluation criterion is determined by Analytic Hierarchy Process (AHP). Finally, combined with the remanufacturing case of the cylindrical grinder, the evaluation method is verified and analyzed. The results show that the remanufacturing of the waste grinding machine through the feasibility evaluation can obtain better comprehensive benefits, and the remanufacturer can get considerable benefits and reduce the potential risks in the remanufacturing process

Tuning Radial Lamellar Packing and Orientation into Diverse Ring-Banded Spherulites: Effects of Structural Feature and Crystallization Condition

Spherulite morphologies of a highly asymmetrical double crystallizable poly(epsilon-caprolactone-b-ethylene oxide) diblock copolymer in solution-cast films were explored from a unified standpoint of tuning radial lamellar organization via controlled evaporation. Besides Maltese cross spherulites, three kinds of ring-banded spherulites that display non- and half-birefringent concentric ringed features as well as extinction banding were first encountered in the same polymer. Structural analyses based on atomic force microscopy, transmission electron microscopy, and grazing incidence X-ray technique revealed that concentric ringed spherulites possess the nature of a rhythmic variation of the radial lamellar packing and extinction banded spherulites have the origin of a periodic change of the radial lamellar orientation. Morphological transitions among different kinds of spherulites were achieved by altering the drying condition. PEO segment crystallized at low temperatures even if it is being confined by PCL lamellae. Combined with poly(e-caprolactone) and poly(ethylene adipate), the influences of structural feature and crystallization condition on radial lamellar organization of polymer spherulites were discussed. These present findings are encouraged to enhance our understanding and then governing generation of expected polymer crystal morphology for special material performance

Study on the Single Crystals of Poly(3-octylthiophene) Induced by Solvent-Vapor Annealing.

Needle-like single crystals of poly(3-octylthiophene) (P3OT) have been prepared by tetrahydrofuran-vapor annealing. The morphology and structure of the crystals were characterized with optical microscopy, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and wide-angle X-ray diffraction. It is observed that the P3OT molecules are packed with the backbones parallel to the length axis of the crystal and the alkyl side chains perpendicular to the substrate. The field effect transistor based on the P3OT single crystal exhibited a charge carrier mobility of 1.54 x 10(-4) cm(2)/(Vs) and on/off current ratio of 37, and the molecular orientation of the crystal is ascribed to account for the device performance. The time-dependent morphological evolution demonstrated that the crystals underwent Ostwald ripening when annealed

large-scale and highly oriented liquid crystal phase in suspensions of polystyrene-block-poly(l-lactide) single crystals

A large number of lozenge-shaped and sandwiched polystyrene-block-poly(L-lactide) (PS-b-PLLA) single crystals were prepared by the self-seeding technique. The single crystals were nearly monodispersed in both thickness and diameter. They are well-dispersed because of the steric stabilization offered by tethered PS in p-xylene, which is a good solvent for PS. The suspensions were observed to separate into a transparent upper phase and a turbid lower phase. The lower phase showed uniform iridescent stripes extending over the, whole tube between crossed polarizers. The birefringence demonstrates he liquid crystal order, and the uniform stripes reveal that the phase is a well-oriented single domain. The phase transition concentration is rather low. Polarizing light microscopy (PLM) images show Schlieren texture and thread like texture. Small-angle X-ray scattering (SAXS) results showed that the single crystals in the liquid crystal phase oriented horizontally a vertical repeat distance of about 70 nm. Additionally, the possible structure of liquid crystal phase is being discussed. The novel disclike colloidal particle might be useful for anisotropic photonic materials