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Site-specific locking plates have gained popularity for the treatment of fractures. However, the clinical use of a site-specific locking plate for acetabular fractures remains untested due to production limits. To design a universal site-specific locking plate for acetabular fractures, the 3-dimensional (3D) photographic records of 171 pelvises were retrospectively studied to generate a universal posterior innominate bone surface. Using 3D photographical processing software, the 3D coordinate system was reset according to bony landmarks and was scaled based on the acetabular diameter to allow a direct comparison between surfaces. The measured surface was separated into measurement units. At each measurement unit, the authors calculated the average z-axis values in all samples and obtained the 3D coordinate values of the point cloud that could be reconstructed into the universal surface. A plate was subsequently designed in 3D photographical processing software, and the orientation and distribution of locking screws was included. To manufacture a plate, the data were entered into Unigraphics NX version 6.0 software (Siemens PLM Software, Co, Ltd, Plano, Texas) and a CNC digital milling machine (FANUC Co, Ltd, Yamanashi, Japan). The resulting locking plate fit excellently with the reduced bone surface intraoperatively. Plate contouring was avoided intraoperatively. Universal 3.5-mm locking screws locked successfully into the plate, and their orientations were consistent with the design. No screw yielded to acetabular penetration. This method of designing a site-specific acetabular locking plate is practical, and the plates are suitable for clinical use. These site-specific locking plates may be an option for the treatment of acetabular fractures, particularly in elderly patients.

Autophagy is an intracellular catabolic mechanism that maintains the balance of proteins, lipids and aging organelles. 3-Methyladenine (3-MA) is a selective inhibitor of autophagy, whereas rapamycin, an antifungal agent, is a specific inducer of autophagy, inhibiting the protein mammalian target of rapamycin. In the present study, we examined the role of autophagy, inhibited by 3-MA and enhanced by rapamycin, in a model of acute spinal cord injury in rats. We found that rapamycin could significantly increase the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin1 at the injury site. At the same time, the number of neurons and astrocytes with LC3 positive in the spinal cord was upregulated with time. In addition, administration of rapamycin produced an increase in the Basso, Beattie and Bresnahan scores of injured rats, indicating high recovery of locomotor function. Furthermore, expression of the proteins Bcl-2 and Bax was upregulated and downregulated, respectively. By contrast, the results for rats treated with 3-MA, which inhibits autophagy, were the opposite of those seen with the rapamycin-treated rats. These results show that induction of autophagy can produce neuroprotective effects in acute spinal cord injury in rats via inhibition of apoptosis.

PAL spectroscopy and a technique for low-temperature gas sorption together with Brunauer-Emett-Teller (BET) theory (1) were used for the studies of elementary free volumes (EFV) in super-cross-linked polystyrene networks (2,3). The ranges of effective sizes observed by PAL and BET overlap partly confirming and complementing each other very effectively. I. Samples Polystyrene (PS) networks were prepared by the cross-linking of linear PS swollen in a solvent. Cross-agents of different length p-xylylene dichloride (X) and monochloro-dimethylether (E) were used After removing a solvent, the samples had extremely high specific surface up to 1600 m 2 /g

Cross-linked glassy polystyrene (PS) sorbents with different degree of linking (24–150%) were studied using positron annihilation lifetime spectroscopy. Unusual effect of PS swelling due to polymer cross-linking was investigated. Annihilation lifetimes longer than 50 ns, one of the longest among those known for polymer materials, were found. These results and some additional data enabled obtaining information on the parameters of elementary free volumes responsible for the properties of the sorbents.

Diffusion of ortho-positronium ($o$-Ps) in mesoporous silica films with different pore morphologies and its emission from the surfaces were studied using the Ps time-of-flight method and positron annihilation $\ensuremath{\gamma}$-ray energy spectroscopy. Probabilities of $o$-Ps formation are almost the same in the studied films, however, the emission intensity of $o$-Ps from the film with much larger cagelike pores is significantly less than that from the film with much smaller tubelike pores, where Ps diffusion between cages is feasible by tunneling. A simple strategy is suggested to use mesoporous silica film for the generation of dense enough Ps for many-positronium experiments.

Rationale and Objectives Blood perfusion of peripheral nerves plays an important role in regeneration after nerve injury. Functional recovery after a peripheral nerve injury depends not only on the survival of the affected neurons but also on the recovered blood perfusion. Previous studies have shown that it is possible to quantitatively assess blood perfusion of tissue using contrast-enhanced ultrasound (CEUS). The aim of this study was to evaluate the usefulness of CEUS for the quantitative evaluation of blood perfusion of the sciatic nerves with crush injury. Materials and Methods Crush injuries were created in the left sciatic nerve of 30 New Zealand white rabbits. CEUS of the bilateral sciatic nerves was performed in six experimental rabbits at 3 days, 1 week, 2 weeks, 4 weeks, and 8 weeks after injury. Pulse-inversion harmonic imaging was used for real-time CEUS. The other six rabbits were used as a control group. Serial laser Doppler measurements of blood flow and quantitative histologic evaluation were performed parallel to CEUS on all animals. Results Quantitative analysis of CEUS showed that the perfusion index of the crushed sciatic nerves was increased at 3 days after injury, with a peak at 1 week after injury ( P = .000). The area under the curve for the crushed sites was increased at 3 days after injury, with a peak at 2 weeks after injury ( P = .000). The mean transit time and maximum intensity of the crushed site of the left sciatic nerves were not significantly changed during the 2 months after injury ( P = .335 and P = .157 respectively). The perfusion indices measured by CEUS correlated well with those measured by laser Doppler ( r = 0.791, P = .000). Marked Wallerian degeneration was found at the crushed site of sciatic nerves at 3 days after injury. The percentage of degenerated myelinated axons was increased during the first 2 weeks after injury and then decreased during the following period. Regenerated axons with small diameter and thin myelin sheaths were found at 2 weeks after injury and during the following period. Conclusions CEUS may provide a new imaging method to quantitatively analyze blood perfusion of injured peripheral nerves.

To investigate the surgical treatment effectiveness of acetabular transverse and posterior wall fractures by Kocher-Langenbeck approach.Between January 2002 and February 2009, 17 patients with acetabular transverse and posterior wall fractures were treated with Kocher-Langenbeck approach and fracture reduction and fixation. There were 12 males and 5 females with an average age of 33.4 years (range, 20-65 years). The disease causes were traffic accident in 16 cases and falling from height in 1 case. The disease duration was 6 hours to 11 days. According to Letournel classification, all fractures were rated as acetabular transverse and posterior wall fractures. Concomitant injuries included posterior hip dislocation in 3 cases, fracture of extremities in 8 cases, injury of sciatic nerve in 3 cases, craniocerebral injury in 1 case, and lienal rupture in 1 case.The incisions healed primarily and no complication of infection and deep venous thrombosis occurred after operation. All patients were followed up 12 to 36 months with an average of 19 months. The X-ray films showed that fracture healed 3 to 5 months after operation. After operation, anatomic reduction was found in 9 cases, satisfactory reduction in 5 cases, and unsatisfactory reduction in 3 cases according to Matta et al criterion. According to modified grading system of Merle D'Aubigne and Postel, the results were excellent in 4 cases, good in 9, fair in 3, and poor in 1 at last follow-up with an excellent and good rate of 76.5%. The nerve function was recovered in patients with sciatic nerve injury at 12 months after symptomatic treatment. Traumatic arthritis occurred in 5 cases, avascular necrosis of the femoral head in 1, and heterotopic ossification in 5 between 9 weeks and 12 months after operation.For acetabular transverse and posterior wall fractures, it is important to make adequate preoperative preparation, to get the imaging data, and to perform open reduction and internal fixation with Kocher-Langenbeck approach as early as possible.

Free volume of polystyrene films treated with supercritical carbon dioxide (SCCO 2) were examined by positron annihilation lifetime spectroscopy. Variation of the free volume sizes after the SCCO 2 treatment due to the release of trapped CO 2 and structural relaxation of the polymer was observed. After 500 h from the depressurization, the free volume of the treated films free from CO 2 was approximately 0.306 nm in radius and much larger than that of the untreated films of approximately 0.295 nm in radius due to the freezing of the swollen structure caused by the large solubility of CO 2.

In this paper, we report the thermalization process of positronium (Ps) in various mesoporous silica/hybrid silica films with pore surfaces decorated by different groups, such as -OH, -H, and -$\mathrm{C}{\mathrm{H}}_{3}$, studied by Ps time-of-flight measurement. Thermalization of Ps in pores with -OH and -H was found to be more efficient than in pores decorated with -$\mathrm{C}{\mathrm{H}}_{3}$. This can be understood from the point of view that Ps thermalization rates upon collisions with these groups are different due to their different effective masses. Therefore, our observation shows that Ps slowing down in mesoporous silica/hybrid silica films is strongly dependent on the pore surface chemistry.

Indium tin oxide (ITO) thin films were deposited on silicon substrates by radio-frequency magnetron sputtering. The influence of annealing temperature on the crystallite, surface morphology, defects evolution, and electrical property of the thin films was studied. The conductivity of the ITO films was significantly enhanced by two orders of magnitude by increasing the annealing temperature up to 600 °C, which was interpreted in point view of defects evolution in ITO films as revealed by positron annihilation. It was interesting to find that positron diffusion length was amazingly comparable to crystallite size in ITO films annealed below 300 °C, indicating positrons were preferentially localized and annihilated in defects around crystallite boundaries. By further increasing the temperature, positron diffusion length was far beyond the grain size with little increment. This demonstrated that defects were effectively removed around grain boundaries. The results indicated defect structure around crystallite/grain boundaries played an important role on carrier transportation in nanocrystal ITO films.

We performed a 2-year follow-up survey of 523 patients with peripheral nerve injuries caused by the earthquake in Wenchuan, Sichuan Province, China. Nerve injuries were classified into three types: type I injuries were nerve transection injuries, type II injuries were nerve compression injuries, and type III injuries displayed no direct neurological dysfunction due to trauma. In this study, 31 patients had type I injuries involving 41 nerves, 419 had type II injuries involving 823 nerves, and 73 had type III injuries involving 150 nerves. Twenty-two patients had open transection nerve injury. The restoration of peripheral nerve function after different treatments was evaluated. Surgical decompression favorably affected nerve recovery. Physiotherapy was effective for type I and type II nerve injuries, but not substantially for type III nerve injury. Pharmacotherapy had little effect on type II or type III nerve injuries. Targeted decompression surgery and physiotherapy contributed to the effective treatment of nerve transection and compression injuries. The Louisiana State University Health Sciences Center score for nerve injury severity declined with increasing duration of being trapped. In the first year after treatment, the Louisiana State University Health Sciences Center score for grades 3 to 5 nerve injury increased by 28.2% to 81.8%. If scores were still poor (0 or 1) after a 1-year period of treatment, further treatment was not effective.

An enhanced positronium (Ps) formation in low-temperature polymers has been widely observed. The additional positronium formation is due to shallow trapped electrons in them. Positron annihilation lifetime spectroscopy was applied to investigate the Ps formation in a series of polymers, such as low-density polyethylene, ethylene-methyl methacrylate copolymers with various methyl methacrylate contents, and pure poly(methyl methacrylate) at low temperature. An analysis of the experimental data based on simple kinetic equations enables one to understand the Ps formation mechanism in polymers during low-temperature positron annihilation experiments as functions of the temperature and elapsed time. Good fittings of the experimental data were obtained. The fitting parameters seemed to show clear physical meanings.

Porous silica films were synthesized via a sol-gel method using tetraethyl orthosilicate with mixing hexadecyltrimethylammonium bromide (CTAB) as a structural template. Doppler broadening of positron annihilation radiation spectroscopy based on a slow positron beam and ellipsometry were applied to the study of the prepared silica films. The obtained results suggested that a nanoscopic structure change for the porous silica films takes place around 15 wt% of the CTAB loading.

Defects in undoped and antimony (Sb)-doped tin oxide thin films fabricated via a sol-gel method have been investigated using a slow positron beam by which an annihilation lineshape parameter is used to evaluate defects in the films. With increasing calcination temperature, the resistivity for undoped films increased because of removal of oxygen vacancies in them; however, the resistivity gradually declined for Sb-doped films upon annealing at higher temperatures, mainly due to weakened carrier scattering with fewer residual defects. The results show that defects as well as dopants play an important role in determining the resistivity of tin oxide films.

Porous silica films were synthesized via a sol-gel method using a nonionic amphiphilic triblock copolymer (F127) and a cationic surfactant (CTAB) as the structural templates with varying weight ratio. Positron annihilation Doppler broadening spectroscopy based on a slow positron beam was used to study the prepared silica films. For the porous silica films, the S parameter increased gradually with increasing the surfactant loading, which showed that higher porosity was introduced in the silica films with more porogen amount.

Silicon samples H-implanted to a dose of 3×1016 cm−2 were analyzed by positron annihilation and ion backscattering techniques to investigate the growth of H-induced nanocavities at different annealing temperatures (400–900 °C). Positron annihilation lifetime spectroscopy revealed a constant increase in the vacancy cluster size (i.e., nanocavity size) as the annealing temperature increased. On the other hand, Doppler broadening and ion channeling measurements suggested strong interaction between the implanted H and the defects depending on the annealing temperature. Furthermore, Au-gettering experiments revealed that transient gettering sites are formed at 600 °C between the H projected range and the surface. These results indicated that H desorption is one of the key factors in the optimization of the gettering process with H-induced nanocavities.

Lifetimes of ortho-positronium in mesoporous silica films were measured before and after surface trimethylsilylation of –OH groups. Variations of positronium lifetimes in the mesopores upon the surface modification indicate that the interaction between positronium and the pore surface is weakened in the pores, whose surface is covered with –CH3 groups, in comparison with those covered with –OH groups. This is consistent with the authors’ previous observation that positronium slowing down is less efficient in the pores covered with –CH3 groups. The present work demonstrates that in the porosimetric application of positron annihilation lifetime spectroscopy, the interaction between positronium and the pore surface has to be properly taken into consideration.

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