Mixed-Precision Deep Learning Based on Computational Memory.

Deep neural networks (DNNs) have revolutionized the field of artificial intelligence and have achieved unprecedented success in cognitive tasks such as image and speech recognition. Training of large DNNs, however, is computationally intensive and this has motivated the search for novel computing architectures targeting this application. A computational memory unit with nanoscale resistive memory devices organized in crossbar arrays could store the synaptic weights in their conductance states and perform the expensive weighted summations in place in a non-von Neumann manner. However, updating the conductance states in a reliable manner during the weight update process is a fundamental challenge that limits the training accuracy of such an implementation. Here, we propose a mixed-precision architecture that combines a computational memory unit performing the weighted summations and imprecise conductance updates with a digital processing unit that accumulates the weight updates in high precision. A combined hardware/software training experiment of a multilayer perceptron based on the proposed architecture using a phase-change memory (PCM) array achieves 97.73% test accuracy on the task of classifying handwritten digits (based on the MNIST dataset), within 0.6% of the software baseline. The architecture is further evaluated using accurate behavioral models of PCM on a wide class of networks, namely convolutional neural networks, long-short-term-memory networks, and generative-adversarial networks. Accuracies comparable to those of floating-point implementations are achieved without being constrained by the non-idealities associated with the PCM devices. A system-level study demonstrates 172 × improvement in energy efficiency of the architecture when used for training a multilayer perceptron compared with a dedicated fully digital 32-bit implementation.

Echinococcus Granulosus in Childhood: A Retrospective Study of 187 Cases and Newer Data.

Echinococcus granulosus, first reported by Goeze in 1782, is the causative parasite of cystic echinococcosis (hydatidosis) especially for countries that are endemic areas. Since the 1970s, the incidence of echinococcosis in Greece has been very high. Nevertheless, with the implementation of special prevention measures in the 1980s, a large reduction in the incidence of hydatidosis meant that it reached European levels. Therefore, we analyzed the demographics, multiple organ localizations of the parasite, diagnosis, and conservative and optimal surgical treatment over a total period of 39 years, especially for pulmonary and hepatic echinococcosis in children. The higher incidence of pulmonary echinococcosis compared with other localizations, male predominance, wide range of age, and various cystic sizes were some of the main demographics. Because cystic echinococcosis remains a main public health problem, we advocate a meticulous clinical investigation and treatment methodology to bridge the gap between knowledge and awareness of this important disease.

Higher levels of melatonin in early stages of adolescent idiopathic scoliosis: toward a new scenario.

BACKGROUND: The melatonin deficiency hypothesis as a central mechanism in the pathogenesis of adolescent idiopathic scoliosis (AIS) is certainly intriguing. However, the actual role of melatonin remains unclear. The aim of this study was to assess the potential clinical value of melatonin serum level in the pathogenesis and the prognosis of AIS progression in patients who were treated nonoperatively. METHODS: Two groups of patients were enrolled. The study group consisted of patients with AIS aged below 14 years who were treated conservatively. In the second group, that is, the control group, age-matched, weight-matched, and height-matched healthy individuals were enrolled. Blood samples were collected from all patients on visit 1 and the serum levels of melatonin were evaluated with the enzyme-linked immunosorbent assay (ELISA) method. The blood sampling procedure was repeated exactly 1 year later (visit 2). RESULTS: Forty-two patients formed the study group (with AIS) and 29 served as the control group. The mean serum value of melatonin on visit 1 was 19.32 pg/mL for the AIS group and 12.23 pg/mL for the control group. This difference was statistically significant (P = 0.014). One year later, 34 patients from the AIS group and 23 from the control group were reevaluated and the mean serum levels of melatonin were 52.43 and 68.44 pg/mL, respectively. No statistically significant difference was found between the 2 groups (P = 0.235). Statistical analysis of the serum melatonin levels of patients with progressing AIS (>5 degrees of the Cobb angle in 1 y) when compared with patients with stable AIS (P = 0.387) or the control group (P = 0.727) failed to show that the deficiency of melatonin may be associated with the progression of AIS. CONCLUSIONS: Higher melatonin levels were observed in conservatively treated patients with AIS, whereas melatonin deficiency was not associated with AIS progression in this study. LEVEL OF EVIDENCE: Level III-case-control study.

Prentiss orchiopexy applied in younger age group.

PURPOSE: To evaluate the efficacy and safety of the operative technique for the correction of cryptorchidism described by Prentiss in the 1950s, who conducted measurements on patients over 6 years of age, and on cadaveric specimens. We applied the technique in a younger age group. MATERIAL AND METHODS: We prospectively studied the results of 50 orchiopexies in children 8-59 months of age (mean 32.3 months), separated into three age groups: 8-18 (N=14), 19-36 (N=18), and 36-59 (N=18) months. The patients were selected for having their undescended testis in the inguinal canal and not reaching the scrotum after adequate inguinal and retroperitoneal dissection. We eliminated the anatomic angulation of the vas deferens and testicular vessels around the internal inguinal ring and inferior epigastric vessels, in order to improve distal scrotal positioning (Prentiss maneuver). We compared the position of the testis before and after the maneuver. We re-examined the children 1 year postoperatively for testicular position and quality. RESULTS: The average gain in scrotal positioning was 6-20 mm (mean 13 mm). At follow-up, 36 testes (78%) had retained a low scrotal position, 10 (20%) a middle scrotal position, and 4 (8%) presented in an upper scrotal position. CONCLUSIONS: The Prentiss maneuver is both safe and efficient when applied to the younger age group, in order to gain adequate intrascrotal cord length and to place the testis in a more distal scrotal position.

Evaluation of long-term functional outcomes after surgical treatment of anorectal malformations.

PURPOSE: The aim of this study was to evaluate the long-term functional outcome in children with anorectal malformations and to correlate them with the type of malformation METHODS: The medical files of children treated for anorectal malformation from 1996 to 2007 were retrospectively reviewed. Data collected included age, gender, type of ARM, associated malformations, type of initial approach, definitive operation, and post-operative management. A multivariate scoring method for fecal continence has been used for evaluation of functional outcome score. RESULTS: Thirty one patients were initially included in the study. Twenty eight of them were evaluated for long-term functional outcomes (mean age 7.25 ± 0.52 years, males 7.96 ± 0.68 years, female 6.46 ± 0.76 years). The mean functional outcome score of all patients was significantly lower compared to that of sex- and age-matched healthy controls (13.92 ± 0.59 to 19.76 ± 0.08, p < 0.0001). No statistical significance was found between the mean functional outcome and the patients' age, gender, or associated anomaly. CONCLUSION: The functional outcome score can be considered as an index of management of defecation disorders in children with anorectal malformation. The long-term functional outcome in children with anorectal malformations is significantly lower than normal controls. Regular follow-ups are required in order to offer them a socially accepted day life.

Study and evaluation of a PCB-MEMS liquid microflow sensor.

This paper presents the evaluation of a miniature liquid microflow sensor, directly integrated on a PCB. The sensor operation is based on the convective heat transfer principle. The heating and sensing elements are thin Pt resistors which are in direct electrical contact with the external copper tracks of the printed circuit board. Due to the low thermal conductivity of the substrate material, a high degree of thermal isolation is obtained which improves the operating characteristics of the device. The sensor is able to operate under both the hot-wire and the calorimetric principle. In order to fully exploit the temperature distribution in the flowing liquid, multiple sensing elements are positioned in various distances from the heater. A special housing was developed which allowed implementation of the sensor into tubes of various cross sectional areas. The sensor sensitivity and measurement range as a function of the sensing element distance were quantified. A minimum resolution of 3 µL/min and a measurement flow range up to 500 µL/min were achieved.

Melanotic neuroectodermal tumor of infancy (MNT1) arising in the skull. Short review of two cases.

INTRODUCTION: Melanotic neuroectodermal tumor of infancy (MNT1) is a rare congenital pigmented neoplasm of neural crest origin, locally aggressive, and rapidly growing that develops during the first year of life. It most commonly arises from the maxilla, the cranial vault, and the mandible. Early diagnosis and radical surgery are critical for a long-term outcome. METHODS: A literature search through PUBMED revealed 43 cases of MNT1 arising in the skull. We reviewed the available literature and studied the presenting symptoms, diagnostic procedures, treatment, rates of recurrences, malignancy, and data of follow-up. We report two further cases of infants aged 4 and 10 months, respectively, with MNT1 arising from the cranial vault who underwent radical excision of the lesion. CONCLUSION: Melanotic neuroectodermal tumor of infancy should be included in the differential diagnosis of skull lesions in infants. Radical surgery must be considered as the treatment of choice and close follow-up for at least 2 years is necessary.