Effect of Direct Vertebral Rotation on the Uninstrumented Lumbar Curve in Thoracic Adolescent Idiopathic Scoliosis

Study DesignRetrospective study.PurposeTo determine the effect and direction of direct vertebral rotation (DVR) in the lowest instrumented vertebra (LIV) on the uninstrumented lumbar curve depending on the lumbar modifier used for the correction of thoracic adolescent idiopathic scoliosis.Overview of LiteratureDVR in the LIV should be implemented in a different direction to obtain better spontaneous lumbar correction depending on the preoperative lumbar spine modifier.MethodsWe retrospectively analyzed 160 patients with thoracic adolescent idiopathic scoliosis treated by pedicle screw instrumentation and rod derotation. Patients who had a distal fusion level between T11 and L1 were divided into two groups: the DVR group versus the No-DVR group. Each group was divided into subgroups depending on the lumbar modifier used: the DVR-A, B, and C groups versus the No-DVR-A, B, and C groups. The DVR-A group was subdivided into two subgroups depending on the direction of screw rotation in the LIV: the DVR-A-O group (opposite direction) and the DVR-A-S group (same direction).ResultsThere were no significant differences in the preoperative curve characteristics between the two groups. The preoperative lumbar curve was corrected in 70% of the patients in the DVR group and in 56% in the No-DVR group. Spontaneous coronal correction of the lumbar curve was better in the DVR-A-S group than that in the No-DVR-A group. However, the DVR-A-O group had the higher incidence of adding-on deformity. The DVR-B and C groups showed better spontaneous correction of lumbar coronal magnitude, apical vertebral translation, and rotation and the LIV tilting.ConclusionsIn lumbar modifiers B and C, screws in the LIV have to be rotated opposite to the direction of the screw rotation of the main thoracic curve; however, in modifier A, the screws have to be rotated in the same direction

Improvements of motion vector in variational echo tracking technique by correction of initial guess

Póster presentado en: 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019

Experimental Study on Electromagnetic Forming of High Strength Steel Sheets with Different Dimensions of Aluminum Driver Plate

Recently, the potential of the electromagnetic forming process has been introduced to form the shallow longitudinal reinforcement ribs in the lateral walls of roll formed parts, made of high strength steel sheets of 340MPa tensile stress grade [1]. However, it seems that the application may not be easy for high strength steel sheet because of its high tensile strength and low electric conductivity. In order to overcome this difficulty, aluminum driver plate could be considered to enhance the formability of high strength steel sheets in the electromagnetic forming process. In this paper, in order to investigate the effect of aluminum driver plate on forming height of high strength steel sheet in electromagnetic forming process, DP780 workpiece sheets were formed into a hemi elliptical protrusion shape with Al1050 driver plate of various thicknesses and sizes. Experiments were performed with a flat spiral coil actuator connected to an electromagnetic forming system. The results, the aluminum driver plate helps to increase the forming height of high strength steel sheets. In addition, the forming height of high strength steel sheet increases as the thickness and size of a driver plate increases

Early Recurring Hepatocellular Carcinoma after Partial Hepatic Resection: Preoperative CT Findings

OBJECTIVE: The purpose of this study was to determine the utility of preoperative CT in predicting early recurrence of hepatocellular carcinoma after partial hepatic resection. MATERIALS AND METHODS: Preoperative three-phase helical CT scans in 53 patients with hepatocellular carcinoma were retrospectively reviewed by two radiologists. In 27 patients (group I), HCC had recurred within six months, while 26 (group II) had remained disease free for at least two years. In each group, preoperative CT findings were evaluated in each group for the tumor size and number, the presence or absence of capsule, distinctness of tumor margin, perinodular extension, and the presence or absence of portal vein thrombosis. RESULTS: In group I, a tumor capsule of tumor was seen in five of 27 patients (19%), and in group II, in 16 of 26 (62%) (p =.001). The tumor margin was distinct in eight patients (30%) in group I and in 20 (77%) in group II (p =.001). Multiple tumors, perinodular extension, and portal vein thrombosis were more frequently seen in group I but the differences were not statistically significant (p >.05). Tumor size was similar in each group (p >.05). CONCLUSION: Preoperative CT findings that may help predict the early recurrence of hepatocellular carcinoma after surgical resection are an absence of capsule of tumors and an indistinct margin. Reference to these findings during preoperative CT can guide clinicians in their choice of treatment.ope

Degree distributions under general node removal: Power-law or Poisson?

Perturbations made to networked systems may result in partial structural loss, such as a blackout in a power-grid system. Investigating the resultant disturbance in network properties is quintessential to understand real networks in action. The removal of nodes is a representative disturbance, but previous studies are seemingly contrasting about its effect on arguably the most fundamental network statistic, the degree distribution. The key question is about the functional form of the degree distributions that can be altered during node removal or sampling, which is decisive in the remaining subnetwork's static and dynamical properties. In this work, we clarify the situation by utilizing the relative entropies with respect to the reference distributions in the Poisson and power-law form. Introducing general sequential node removal processes with continuously different levels of hub protection to encompass a series of scenarios including random removal and preferred or protective removal of the hub, we classify the altered degree distributions starting from various power-law forms by comparing two relative entropy values. From the extensive investigation in various scenarios based on direct node-removal simulations and by solving the rate equation of degree distributions, we discover in the parameter space two distinct regimes, one where the degree distribution is closer to the power-law reference distribution and the other closer to the Poisson distribution.Comment: 12 pages, 7 figure

Venous Hemangioma of Parapharyngeal Space with Calcification

A hemangioma of the parapharyngeal space (PPS) is an extremely rare tumor and is responsible for 0.5-1% of all tumors occurring in the PPS. We report a case of PPS venous hemangioma in a 49-year-old woman presenting with diffuse swelling in the submandibular region. A preoperative computed tomography (CT) scan showed a cystic mass with multiple calcifications in the PPS. The calcific nodules were round and about 2 mm in diameter. The hemangioma was completely resected via a transcervical approach. During surgery, we found several calcific nodules, which represented phleoboliths or areas of thrombosis with dystrophic calcification. Despite its rarity, a venous hemangioma of the PPS should be considered in a differential diagnosis when a cystic mass with calcification is found by CT scan. To our knowledge, this is the first reported case of a PPS venous hemangioma; we describe its pathognomonic findings on imaging

Pig-to-Nonhuman Primate (NHP) Naked Islet Xenotransplantation

Islet transplantation is an established therapy for selected type 1 diabetes (T1D) patients with severe hypoglycemic unawareness and glycemic liability despite of insulin treatment. However, the donor organ is limited. Porcine islets are the best alternative source to overcome this limitation, and pig-to-nonhuman primate (NHP) naked islet xenotransplantation studies are being performed worldwide. Several studies including our own have presented successful proof-of-concept results based on immunosuppression regimen including the anti-CD154 monoclonal antibody. Particularly, long-term control of diabetes by adult porcine islet transplantation has been demonstrated in five consecutive monkeys, and the longest survival was ~1000 days after transplantation. Currently, pig-to-NHP islet xenotransplantation based on clinically applicable immunosuppression regimen is being pursued. In this chapter, we will describe all the procedures of pig-to-NHP naked islet xenotransplantation: (1) the porcine islet isolation from designated pathogen-free (DPF) miniature pigs, (2) diabetes induction in monkeys, (3) transplantation procedure via the portal vein, (4) immune monitoring comprising humoral and cellular immunity after porcine islet transplantation, and finally (5) liver biopsy and subsequent immunohistochemical procedure in detail