The structure development in the continuous laser-heated drawing process of poly(ethylene 2,6-naphthalene dicarboxylate) (PEN) fiber was analyzed by in-situ X-ray diffraction measurement. Because of the rapid and uniform laser-heating, and the resultant steady-state nature of the necking-drawing, the structure development after the on-set of necking could be measured in the time resolution of several hundred microseconds. We found for the first time the temporal appearance of meridional (001') diffraction at several milliseconds after the on-set of necking indicating that the mesophase structure similar to the one reported for poly(ethylene terephthalate) was also formed in the initial stage of fiber structure development of PEN. The d-spacing of the (001') diffraction 1.230 ± 0.003 nm was shorter than the c-axis lengths of both Į and ȕ crystals. IntroductionPoly(ethylene 2,6-naphthalene dicarboxylate) (PEN), containing naphthalene ring in its backbone, possesses higher glass-transition temperature (T g ) and higher melting temperature (T m ) than those of poly(ethylene terephthalate) (PET). Due to the stiff molecular chain of PEN, it can be expected to give high-performance fibers having excellent physical properties for engineering uses.There have been studied on hot-drawing and cold-drawing processes in PEN fibers and films, [1,2] in which the drawability of amorphous PEN was reported to depend on molecular weight and strain rate. The structural changes in the neck-drawing of amorphous PEN films have been investigated through off-line measurement using synchrotron X-ray radiation, [1,3] which revealed the appearance of smectic order with a period of 1.25 nm corresponding to a chain repeat length associated with a sinusoidal conformation of the polymer chains. It was 5% shorter than the chain repeat length of a more extended Į-conformation. However, so far, there has been found no report about on-line characterization of structure development process with orientation-induced crystallization in PEN fiber and films.Several studies on the on-line characterization of the fiber structure development during the drawing have been conducted using simultaneous synchrotron radiation as well as laboratory X-ray generators for WAXD and SAXS. [4][5][6][7][8][9][10][11] Many of these studies concerned PET. Our research group has studied on the fiber structure development process in the continuous laser-drawing for PET and PTT fibers through on-line WAXD and SAXS measurements [9] with synchrotron radiation systems [10,11,12] . Quantitative analyses on the fiber structure development mechanism were accomplished by direct measurement in the vicinity of the neck-deformation point, in which drawing behavior, fiber temperature changes, and WAXD/SAXS were measured as a function of elapsed time after the neck-deformation. [9][10][11][12] The elapsed time, calculated from distance between measurement point and the neck-deformation point, is high accuracy because the neck point could be fixed within confined region by rapid and unifo...

The structural development of poly(ethylene 2,6-naphthalene dicarboxylate) (PEN) fibers was analyzed by in situ X-ray diffraction and fiber temperature measurements. The PEN fiber was drawn continuously under three drawing stresses, where the neck-drawing point was fixed accurately by CO2 laser irradiation heating. The developed crystal structures of the drawn fibers depended on the drawing stresses, that is, only the α-crystal was obtained under a drawing stress of 148 MPa, an α-rich mixed crystal was obtained for 54 MPa, and a β-rich mixed crystal was obtained under 23 MPa stress. Fiber containing over 70% β-crystal was obtained in the third case. Orientation-induced crystallization rates (K) and crystallization induction times (t0) were estimated for the three drawing stresses: K= 2210 s -1 and t0= 0.5 ms for 148 MPa, K= 940 s -1 and t0= 1.0 ms for 54 MPa, and K= 655 s -1 and t0= 4.0 ms for 23MPa. In addition, the drawing stress acted as a definitive influence not only on the resulting crystal form but also on the chain conformation of the mesophase structure. The d-spacing of the (001') diffraction increased with drawing stress, and the longer (001') spacing generated the α-crystal while the comparatively shorter (001') spacing yielded the β-crystal. The dspacings of 1.27 and 1.23 nm for the drawing stresses of 148 and 23 MPa, respectively, were somewhat shorter than the c-axis lengths of the α-and β-crystals of 1.32 and 1.27 nm, respectively.

We describe the case of a 78 year-old man presenting with multiple edematous erythemas, fever, and arthralgia who subsequently developed neutrophil infiltration into the cartilage of the bilateral auricularis, consistent with relapsing polychondritis. A Skin biopsy of the erythema on his right arm showed dense neutrophilic infiltration into the dermis, while a bone marrow aspirate revealed myelodysplastic syndromes with characteristic vacuoles in myeloid precursor cells. Although the patient achieved remission with high–dose oral prednisolone, the inflammatory symptoms relapsed, and he was resistant to colchicine and cyclosporine. The patient spontaneously developed left leg edema and high-output cardiac failure caused by an arteriovenous fistula with a common iliac artery aneurysm. We successfully performed a two-stage surgery using internal iliac artery coil embolization and endovascular aortic repair of the iliac aneurysm. We assumed the patient was suffering from large-vessel vasculitis such as giant cell arteritis or Takayasu arteritis. We treated him with tocilizumab in addition to prednisolone, and the febrile events and elevated C-reactive protein levels improved. One year later, sequencing of ubiquitylation initiating E1 enzyme (UBA1) using peripheral blood leukocytes revealed somatic variants (c.121A > C p.Met41Leu), confirming the diagnosis of vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome. This case suggests that arteriovenous fistula could be a complication of VEXAS syndrome with large-vessel vasculitis, and adequate surgical intervention and prompt diagnosis are essential for rescue. Although arteriovenous fistula is a rare complication of VEXAS syndrome, physicians should be aware of this complication to ensure prompt diagnosis and timely surgical intervention.

Zn/Al Layered Double Hydroxide (Zn/Al LDH) consists of positively charged metal hydroxide sheets with anions located between the layers to compensate charges. By the reaction of carbonate Zn/Al LDH (CO3(2-)) with 2-naphthoic acid, two intercalation compounds were obtained indicating the occurrence of ion exchange reaction. Interlayer spacing increased from 0.76 nm to 1.9 nm and 2.4 nm, respectively by the intercalation reaction. Upon the treatment of two intercalation compounds in supercritical CO2, layer structure of the intercalation compound with 2.4 nm disappeared although no change occurred in the intercalation compound with 1.9 nm.