Dysprosium doped copper oxide (Cu1-xDyxO) nanoparticles enabled bifunctional electrode for overall water splitting

The production of hydrogen, a favourable alternative to an unsustainable fossil fuel remains as a significant hurdle with the pertaining challenge in the design of proficient, highly productive and sustainable electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, the dysprosium (Dy) doped copper oxide (Cu_1-xDy_xO) nanoparticles were synthesized via solution combustion technique and utilized as a non-noble metal based bi-functional electrocatalyst for overall water splitting. Due to the improved surface to volume ratio and conductivity, the optimized Cu_1-xDy_xO (x = 0.01, 0.02) electrocatalysts exhibited impressive HER and OER performance respectively in 1 M KOH delivering a current density of 10 mAcm^?2 at a potential of ?0.18 V vs RHE for HER and 1.53 V vs RHE for OER. Moreover, the Dy doped CuO electrocatalyst used as a bi-functional catalyst for overall water splitting achieved a potential of 1.56 V at a current density 10 mAcm^?2 and relatively high current density of 66 mAcm^?2 at a peak potential of 2 V. A long term stability of 24 h was achieved for a cell voltage of 2.2 V at a constant current density of 30 mAcm^?2 with only 10% of the initial current loss. This showcases the accumulative opportunity of dysprosium as a dopant in CuO nanoparticles for fabricating a highly effective and low-cost bi-functional electrocatalyst for overall water splitting.     

Optimization of flow in additively manufactured porous columns with graded permeability

Chemical engineering systems often involve a functional porous medium, such as in catalyzed reactive flows, fluid purifiers, and chromatographic separations. Ideally, the flow rates throughout the porous medium are uniform, and all portions of the medium contribute efficiently to its function. The permeability is a property of a porous medium that depends on pore geometry and relates flow rate to pressure drop. Additive manufacturing techniques raise the possibilities that permeability can be arbitrarily specified in three dimensions, and that a broader range of permeabilities can be achieved than by traditional manufacturing methods. Using numerical optimization methods, we show that designs with spatially varying permeability can achieve greater flow uniformity than designs with uniform permeability. We consider geometries involving hemispherical regions that distribute flow, as in many glass chromatography columns. By several measures, significant improvements in flow uniformity can be obtained by modifying permeability only near the inlet and outlet.     

Modeling ion implantation of HgCdTe

Ion implantation of boron is used to create n on p photodiodes in vacancy-doped mercury cadmium telluride (MC.T). The junction is formed by Hg interstitials from the implant damage region diffusing into the MC.T and annihilating Hg vacancies. The resultant doping profile is n⁺/n^-/p, where the n⁺ region is near the surface and roughly coincides with the implant damage, the n^- region is where Hg vacancies have been annihilated revealing a residual grown-in donor, and the p region remains doped by Hg vacancy double acceptors. We have recently developed a new process modeling tool for simulating junction formation in MC.T by ion implantation. The interstitial source in the damage region is represented by stored interstitials whose distribution depends on the implant dose. These interstitials are released into the bulk at a constant, user defined rate. Once released, they diffuse away from the damage region and annihilate any Hg vacancies they encounter. In this paper, we present results of simulations using this tool and show how it can be used to quantitatively analyze the effects of variations in processing conditions, including implant dose, annealing temperature, and doping background.     

Alteration of Sertoli cell differentiation in the presence of carcinoma in situ in human testes

PURPOSE: We investigated Sertoli cells in testicular biopsies with carcinoma in situ (CIS) in respect to cytokeratin expression to elucidate the status of Sertoli cell differentiation adjacent to CIS in human testes. Cytokeratin 18 intermediate filaments indicate a state of undifferentiation usually observed in Sertoli cells of prepubertal testes. MATERIALS AND METHODS: 29 testicular biopsies presenting CIS were investigated by means of immunohistochemistry, using a polyclonal antibody against placental-alkaline phosphatase to detect CIS cells and a monoclonal antibody against human cytokeratin 18 to show expression of cytokeratin 18 intermediate filaments in Sertoli cells. RESULTS: All tubules bearing CIS showed positive cytokeratin expression of Sertoli cells if tubules were devoid of normal germ cells. However, a total of 13 specimen revealed CIS cells together with normal germ cells. In the presence of CIS cells together with round or elongated spermatids, adjacent Sertoli cells did not express cytokeratin immunoreactivity. In the case of combined presence of CIS and spermatogonia and primary spermatocytes, Sertoli cells could be found either immunopositive or immunonegative, and were positive in tubules with CIS and spermatogonia only. CONCLUSIONS: Sertoli cells associated with CIS cells undergo a process of dedifferentiation, seen by the re-expression of cytokeratin intermediate filaments. We suggest that this dedifferentiation results in a loss of Sertoli cell function and leads to a cessation of spermatogenic activity.     

An epidemic of roller-blade injuries in children

Roller blading is a new and increasingly popular leisure activity in many countries. We reviewed 110 consecutive patients with roller-blade injuries between 1 January and 30 June 1996. The patients ranged from 4 to 14 years in age (mean 6.5 years). Eighty-three (75.4%) sustained injuries to the upper limb and 27 (24.5%) injured the lower limb. Fifty-six patients, were girls and 54 were boys. Of the 110 patients, 79 (72.7%) sustained fractures, 28 (25.4%) soft tissue injuries and 3 (2.7%) dislocations. Eighty-three (75.4%) of the patients wore no protective equipment on the limbs. Four months following injury 103 (93.6%) patients were fully recovered. The mean duration of school absence was 3 days. Subsequently 101 children returned to using roller-blades following injury. Seventy-three (66.3%) of these now use protective equipment. We found that injuries were unrelated to age or duration of roller-blading experience or to the brand-name of roller blades used, and that most of our patients wore no protective equipment at the time of injury.     

Intralesional radiolabeled human monoclonal IgM in human tumor xenografts

Sensory-perceptual abnormalities in people with autism are discussed from two perspectives: published firsthand accounts and existing psychological research evidence. A range of abnormalities, including hyper- and hyposensitivity, sensory distortion and overload, and multichannel receptivity and processing difficulties, are described in firsthand accounts and frequently portrayed as central to the autistic experience. A number of dangers are inherent in uncritically accepting these accounts at face value and in any wider generalization to the autistic population as a whole. Evidence from clinical studies suggests that unusual sensory responses are present in a majority of autistic children, that they are manifested very early in development, and that they may be linked with other aspects of autistic behavior. In addition, experimental studies using a range of indices have found evidence of unusual responses to sensory stimuli in autistic subjects. However the clinical and experimental research to date suffers from serious methodological limitations and more systematic investigation is warranted. Key issues for future psychological research in the area are identified.     

The use of residuals in statistical modeling for fatigue-crackgrowth under constant amplitude loading

Various models have been proposed over the years to fit crack growth data. Many papers have appeared in which one or more models are mooted and fitted, and various assessments made of the quality of the fit. At the basic level the data are plotted, together with the fitted curve, to show agreement of experimental and predicted values. In this paper we suggest that it can be useful and informative to go one step further, examining the residuals, i.e., the differences between the experimental and predicted values. We draw attention to certain statistical methods for such critical assessment and show by example that this can reveal deficiencies in fit not otherwise obvious. In this way suitable modifications to the model can be suggested. Additional plots of estimated parameters are also shown to be informative about models     

Object-oriented DBMS requirements

The requirements on an object-oriented DBMS for management of information in a large, complex enterprise are presented. These requirements aid in the achievement of an environment characterized by data sharing, open architectures, application and data portability, and assurance of data integrity. They were defined from the point of view of a user of the DBMS; therefore they describe the expected functionality of the DBMS and do not specify the method of implementation to achieve this functionality. They encompass requirements on the data model, query and data manipulation languages, the system architecure, interfaces to the system, change management, and transaction management.