Symmetrical Deposition Research Articles

Simulation of the influences of surface topography of deposited layer on arc shape and state in arc based additive forming

The stacking deposition and the overlapping deposition are usually employed in arc based additive forming process, which will result in different surface topographies of deposited layer. Consequently, the shape and state, heat and mass transfer of electric arc will be affected by the surface topography of deposited layer. A three-dimensional numerical model of electric arc based on magnetic fluid dynamics, local thermodynamic equilibrium and optical thin assumption for arc based additive forming process with pure argon shielding gas is presented. Simultaneously, four kinds of deposited layer model with different surface topographies are established, which are the deposited layer models of planar substrate, namely the substrate without weld bead, deposited layer model of single-pass single-layer, deposited layer model of single-pass two-layers, and deposited layer model of overlapping. The numerical calculation is performed on condition that deposition current and the distance between the electrodes are constant. And the simulation results include the profile of electric arc, corresponding temperature field, flow field, current density, electromagnetic force, and the arc pressure distribution. The temperature field of planar substrate accords well with other researcher's experimental result, and the profiles of electric arc are in good agreement with images captured by high-speed camera. Surface topography of deposited layer plays a decisive role in determining the profile of electric arc under the same process conditions. The comparison of evolvement among the distributions on specified paths shows that the electric arc of planar substrate has higher temperature, velocity, current density and pressure in the arc center, arising from completely symmetrical deposition layer model and smaller contact area between the arc and the substrate; the number of layers of single-pass multi-layer deposited layer has little influence on various parameters of electric arc, but because the deposited layer height changes, the temperature and pressure on the outside of deposited layer have small deviation; asymmetric arc profile will form when the overlapping deposition is performed. There is a relatively low temperature in the arc center, resulting from larger contact area between the arc and the surface of deposited layer. In addition, the distributions of current density, electromagnetic force and pressure deflect to the deposited layer. The above conclusions can provide a theoretical basis for basic research and process decision of arc based additive forming, and it can also provide the parameters for the subsequent weld pool dynamics and metal transfer simulation.

A case of Fahr's syndrome with rare atypical presentation as hemiplegia

AbstractCalcification of basal ganglia or Fahr's disease is a rare disease characterized by bilateral and symmetrical intracranial deposition of calcium mainly in cerebral basal ganglia. Basal ganglia calcification secondary to endocrinological cause is known as Fahr's syndrome. Motor and neuropsychiatric symptoms are prominent features. We report a case presented with hemiplegia without any psychiatric symptoms. Radiological findings were suggestive of bilateral calcification of cerebellar hemispheres and basal ganglia. Parathyroid hormone levels were low with no significant findings in other investigations along with negative family history. Based on the radiological and biochemical findings the case was diagnosed as fahr's syndrome.

O056. Migraine as presenting symptom of SLC20A2gene mutations.

Background Idiopathic basal ganglia calcifications (IBGC), also known as Fahr’s disease, are neurological diseases characterized by symmetric calcium deposits in basal ganglia and other brain regions. Clinically, IBGC patients show high phenotypic heterogeneity, both in the clinical manifestations and neuroradiological findings. Recently, PDGFRB, PDGFB, XPR1 and SLC20A2 have been identified as causative genes for IBGC [1]. The aim of this study was to report on two Italian patients with idiopathic basal ganglia calcifications associated with novel mutations in the SLC20A2 gene who both presented with episodic migraine.

Improved diamond‐like carbon coating deposition uniformity on cylindrical sample by its suspension in RF PECVD chamber

The paper discusses the uniformity of diamond‐like carbon (DLC) thin overlays deposited with radio frequency plasma‐enhanced chemical vapor deposition (RF PECVD) method on optical fibers with induced long‐period gratings (LPGs). When refractive index around the LPG increases, a spectral response of the LPG strongly depends on properties of the overlay. Using LPG suspended in the RF PECVD chamber, we have found that DLC thickness distribution around the fiber highly depend on a distance between the LPG and the electrode. More asymmetrical deposition, which takes place when the LPG is located closer to the electrode, induces appearance of a series of additional resonances in LPG transmission spectrum. It has been found that for the fiber suspended 7.2 mm over the electrode the coating has the highest uniformity. Higher uniformity obtained by fiber suspension in the chamber has been compared with the effect resulting from fiber rotation between two consecutive processes. It is shown that more symmetrical deposition is obtained for the suspended samples than for the rotated ones.

Effect of Intraluminal Thrombus Asymmetrical Deposition on Abdominal Aortic Aneurysm Growth Rate

Purpose: To determine the relationship between asymmetrical intraluminal thrombus (ILT) deposition in abdominal aortic aneurysm (AAA) and growth rate and to explore its biomechanical perspective. Methods: Thirty-four patients with AAA underwent at least 2 computed tomography scans during surveillance. The volumes of the AAA (VAAA) and thrombus (VILT) and the maximum thrombus thickness (ILTthick) were computed. Thrombus distribution was evaluated by introducing the asymmetrical thrombus deposition index (ATDI), with positive and negative values (–1<ATDI<1) associated with anterior and posterior ILT deposition, respectively. Finite element analysis was applied to estimate wall stress. Aneurysms were divided into high and low growth rate groups based on the cohort’s median growth rate, and the abovementioned parameters were compared between groups. Results: Most AAAs had asymmetrical anterior thrombus deposition. The high and low growth rate groups did not present significant differences in maximum diameter, VAAA, VILT, or maximum ILTthick. However, the high growth rate group had significantly higher ATDI (p=0.02). The ATDI<0 group (posterior ILT distribution) presented a significantly lower median growth rate compared to that of ATDI≥0 group (anterior or symmetrical ILT deposition; p=0.029). The specificity of an ATDI<0 criterion for identifying AAAs with a growth rate below the cohort median was 89%. The ATDI<0 group had a significantly lower posterior maximum wall stress compared with that of the ATDI≥0 group (p=0.03). Overall peak wall stress did not differ between groups. Conclusion: Posterior thrombus deposition in AAAs is associated with significantly lower growth rate and lower posterior maximum wall stress compared with that of AAAs with anterior thrombus deposition and could potentially indicate a lower rupture risk.

Study of the impact of Tau phosphorylation on its internalization and processing in cultured neuronal cells

Study of the impact of Tau phosphorylation on its internalization and processing in cultured neuronal cells

Excellent passivation of thin silicon wafers by HF-free hydrogen plasma etching using an industrial ICPECVD tool

In this work, hydrogen plasma etching of surface oxides was successfully accomplished on thin (∼100 µm) planar n-type Czochralski silicon wafers prior to intrinsic hydrogenated amorphous silicon [a-Si:H(i)] deposition for heterojunction solar cells, using an industrial inductively coupled plasma-enhanced chemical vapour deposition (ICPECVD) platform. The plasma etching process is intended as a dry alternative to the conventional wet-chemical hydrofluoric acid (HF) dip for solar cell processing. After symmetrical deposition of an a-Si:H(i) passivation layer, high effective carrier lifetimes of up to 3.7 ms are obtained, which are equivalent to effective surface recombination velocities of 1.3 cm s–1 and an implied open-circuit voltage (Voc) of 741 mV. The passivation quality is excellent and comparable to other high quality a-Si:H(i) passivation. High-resolution transmission electron microscopy shows evidence of plasma-silicon interactions and a sub-nanometre interfacial layer. Using electron energy-loss spectroscopy, this layer is further investigated and confirmed to be hydrogenated suboxide layers. (© 2015 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

Frequent and symmetric deposition of misfolded tau oligomers within presynaptic and postsynaptic terminals in Alzheimer's disease.

The accumulation of neurofibrillary tangles in Alzheimer’s disease (AD) propagates with characteristic spatiotemporal patterns which follow brain network connections, implying trans-synaptic transmission of tauopathy. Since misfolded tau has been shown to transmit across synapses in AD animal models, we hypothesized that synapses in AD patients may contain misfolded tau. By immunofluorescence imaging of bipartite synapses from AD subjects, we detected tau protein in 38.4% of presynaptic and 50.9% of postsynaptic terminals. The pre/post distribution for hyperphosphorylated tau was 26.9%/30.7%, and for misfolded tau 18.3%/19.3%. In the temporal cortex, microscopic aggregates of tau, containing ultra-stable oligomers, were estimated to accumulate within trillions of synapses, outnumbering macroscopic tau aggregates such as tangles by 10000 fold. Non-demented elderly also showed considerable synaptic tau hyperphosphorylation and some misfolding, implicating the synapse as one of the first subcellular compartments affected by tauopathy. Misfolding of tau protein appeared to occur in situ inside synaptic terminals, without mislocalizing or mistrafficking. Misfolded tau at synapses may represent early signs of neuronal degeneration, mediators of synaptotoxicity, and anatomical substrates for transmitting tauopathy, but its actual role in these processes remain to be elucidated.Electronic supplementary materialThe online version of this article (doi:10.1186/s40478-014-0146-2) contains supplementary material, which is available to authorized users.

Homogeneity analysis of sculptured thin films deposited in symmetric style through glancing angle deposition technique

The symmetric deposition technique is often used to improve the uniformity of sculptured thin film (STF). In this paper, optical properties of STF with the columnar angles ±β are analyzed theoretically, based on the characteristic matrix method for extraordinary waves. Then, the transmittances of uniformity monolayer and bilayer STF in symmetrical style are calculated to show the effect of the bilayer structure on the optical properties of STF. The inhomogeneity of STF is involved in analyzing the differences in transmittance and phase retardation between monolayer and bilayer STF deposited in symmetric style. The results show that optical homogeneity of STF can be improved by depositing in symmetric style at the normal incidence, but it is not the same case as the oblique incidence.

POLYNEURITIS CRANIALIS MULTIPLEX DUE TO MYELOMA RELAPSE

A 48 year old man presented with a sub-acute painless complete right sided ptosis, diplopia, dysphonia, dysphagia and left foot drop. He had a PMH of Multiple Myeloma (MM) in remission after 3 cycles of chemotherapy. On examination he had complete right 3rd, left 12th, bilateral 9th and 10th and cranial nerve palsies along with a left foot drop. A meningeal infiltrative process was suspected. MRI neuraxis revealed subtle leptomeningeal enhancement in the lumbar spine, symmetrical nodular deposits around the jugular foramen bilaterally and enhancement of the right cavernous sinus. Plasma IgG was raised. CSF cytology revealed mitotic plasma cells confirming the clinical suspicion of CNS myelomatosis however a bone marrow biopsy did not show evidence of myeloma relapse. CNS involvement occurs in around 1 % of cases of MM and predicts poor prognosis. This case highlights that a relapse of MM can present in the form of Polyneuritis Cranialis Multiplex without bone marrow evidence of relapse. CNS disease can also be present at initial diagnosis of MM. CNS Myelomatosis should therefore be considered in the differential diagnosis of contiguous or non-contiguous multiple cranial nerve palsies. Investigations should be initiated urgently so that aggressive treatment can start promptly.

A case of psychosis due to Fahr's syndrome and response to behavioral disturbances with risperidone and oxcarbazepine.

Calcification of basal ganglia or Fahr's syndrome is a rare disease characterized by bilateral and symmetrical intracranial deposition of calcium mainly in cerebral basal ganglia. Motor and neuropsychiatric symptoms are prominent features. We report a case presented with a few motor symptoms, features of delirium and prominent psychiatric symptoms (disorganized behavior) predominantly evident after the improvement in delirium. Radiological findings were suggestive of bilateral basal ganglia calcification. Parathyroid hormone levels were low with no significant findings in other investigations and negative family history. Patient showed significant improvement in behavioral disturbances with risperidone, low dose of lorazepam, oxcarbazepine, and memantine.

Fast-growing multiple symmetric lipomatosis

Multiple symmetric lipomatosis (MSL) is a rare disease characterized by symmetrical massive fatty deposits on the face, neck, shoulders, and upper trunk. We report a 74-year-old man who complained of painless subcutaneous nodules on his posterior neck that developed 3 weeks earlier. In a week, variably-sized similar lesions developed on both his shoulders and upper extremities. At the time of his hospital visit, several firm nodules as big as a walnut to a child’s fist and with the normal-skin-hue were observed on his posterior neck, both shoulders, upper extremities, and trunk. The histological examination of his upper left arm revealed more mature adipocytes without encapsulation in the subcutaneous tissue. MSL was generally known to occur slowly over months or years. However, this is an unusual case that showed a fast-growing nature.

Frequent and symmetric deposition of misfolded tau oligomers within presynaptic and postsynaptic terminals in Alzheimer¿s disease

The accumulation of neurofibrillary tangles in Alzheimer’s disease (AD) propagates with characteristic spatiotemporal patterns which follow brain network connections, implying trans-synaptic transmission of tauopathy. Since misfolded tau has been shown to transmit across synapses in AD animal models, we hypothesized that synapses in AD patients may contain misfolded tau. By immunofluorescence imaging of bipartite synapses from AD subjects, we detected tau protein in 38.4% of presynaptic and 50.9% of postsynaptic terminals. The pre/post distribution for hyperphosphorylated tau was 26.9%/30.7%, and for misfolded tau 18.3%/19.3%. In the temporal cortex, microscopic aggregates of tau, containing ultra-stable oligomers, were estimated to accumulate within trillions of synapses, outnumbering macroscopic tau aggregates such as tangles by 10000 fold. Non-demented elderly also showed considerable synaptic tau hyperphosphorylation and some misfolding, implicating the synapse as one of the first subcellular compartments affected by tauopathy. Misfolding of tau protein appeared to occur in situ inside synaptic terminals, without mislocalizing or mistrafficking. Misfolded tau at synapses may represent early signs of neuronal degeneration, mediators of synaptotoxicity, and anatomical substrates for transmitting tauopathy, but its actual role in these processes remain to be elucidated.

Letter to the Editor Madelung’s disease in a patient with chronic alcohol abuse

A 47-year-old man with a history of chronic alcohol abuse was admitted to our hospital because of symmetrical face soft tissue enlargement for differential diagnosis. The lesions had appeared 4 years earlier and had been asymptomatic. Physical examination revealed painless, elastic tumors of the subcutaneous tissue in the mandibular angle region, with no clear relation to lymph nodes or salivary glands (Figure 1A). The laboratory tests showed elevated aspartate aminotransferase (ALT), 127 U/l; elevated alanine aminotransferase (ALT), 91 U/l, elevated γ-glutamyl transpeptidase (GGT), 643 U/l, and elevated lactate dehydrogenase (LDH) activity, 342 U/l. Test for antinuclear antibodies (ANA) was negative. HIV and HCV infections were excluded. Lipid profile results were within the normal range. An abdominal ultrasound revealed a fatty liver, but no other abnormality was noted. Ultrasonography of the parotid, submandibular and cervical region confirmed the correct size and structure of the salivary and thyroid glands and slight enlargement of the lymph nodes in both submandibular regions. In the place of visible symmetric thickening there was a tissue described as lipofibroma, 49 mm × 24 mm on the right side and 44 mm × 23 mm in size on the left side. Fine-needle biopsy revealed lipomatous tissue. A diagnosis of Madelung's disease was made. Figure 1 A – Frontal view of the patient at time of first hospitalization with visible symmetrical fatty masses. B, C – Frontal and lateral view of the patient at follow-up visit after 1 year; increase in the primary fatty deposit At the follow-up visit after 1 year, the patient had a computed tomography (CT) scan performed, which showed a slight increase in the primary fatty deposit and the appearance of another in the neck area (Figure 2A–C). Six months later the patient was disqualified from surgical treatment. The decision was motivated by the non-life-threatening condition and asymptomatic nature of the masses. Figure 2A–C Head and neck CT showing the symmetrical enhancement of the lipomatous tissue Madelung's disease (also known as benign symmetric lipomatosis or Launois-Bensaude syndrome) is a rare metabolic disorder of unknown etiology [1]. This disease usually affects men at the age of 30 to 60 years from the Mediterranean area. In reported cases, almost 90% of patients had a history of long-term alcohol abuse [2]. The disease is characterized by the presence of prominent, symmetrical deposits of non-encapsulated adipose tissue in the region of head, neck, nape and upper parts of the trunk [2, 3]. In contrast to other cases described in the literature, in our patient, the primary subcutaneous fat masses appeared in the parotid region, while the most common initial location is the neck. Although benign in nature, sometimes the fatty masses can reach very large sizes causing dyspnea, dysphagia, fatigue, and reduced neck movement ability [4]. The differential diagnosis includes familial multiple lipomatosis, simple obesity, Cushing's syndrome, angiolipoma, neurofibroma and liposarcoma [2, 4, 5]. The most effective treatment is surgery, especially in patients with esthetic deformity or compression of the aerodigestive tract [1, 3].

Familial bilateral peritrochanteric lipomatosis

Sir, An unusual abnormal fat distribution of the lower part of the body is characterized by massive and symmetric deposits in the groins, trochanters, buttocks, and hips, which contrast sharply with the normal upper part of the body. The massive lipomatosis of the lower part of the body can be classified into three types: type 1, the familial symmetrical lipomatosis that affects the groins, trochanters, hips, buttocks, and thighs; type 2, the bilateral peritrochanteric familial lipomatosis; and type 3, the unilateral peritrochanteric lipomatosis. This deformity affects only women aged between 18 and 50 in the Mediterranean region [1]. Further, isolated abnormal bilateral peritrochanteric lipomatosis has rarely been reported in literature. We report two patients, a mother and her daughter, with isolated bilateral peritrochanteric lipomatosis, who had normal fat distribution of the upper half of the body which was in contrast with the abnormal lower half. The mother, a 42-year-old patient, presented with bilateral abnormal fat distribution of the lower part of the body. Peritrochanteric fat deposits had appeared at the age of 13 and increased with time. The physical examination revealed bilateral isolated, well-demarcated peritrochanteric lipomatosis and normal fat distribution of the upper half of the body (Fig. 1a). The patient was 167 cm tall and weighed 72 kg (body mass index [BMI]=25.8 kg/m). Laboratory and endocrinologic tests included the serum concentrations of lipoprotein, lipoprotein lipase activity, cholesterol, triglycerides, uric acid, fasting glucose, serum estradiol, and testosterone levels, and thyroid function parameters were within normal limits. Histological study of lipoaspirate showed subcutaneous fatty tissue. The daugther, a 22-year-old patient, also presented with bilateral abnormal fat distribution of the lower part of the body. The patient's signs had appeared at age of 12 also increasing with time. The physical examination revealed bilateral isolated, well-demarcated peritrochanteric lipomatosis although it was more evident on the left side (Fig. 2a). The patient was 169 cm tall and weighed 67 kg (BMI=23.5 kg/m). Laboratory and endocrinological tests were within normal limits. Histological study of lipoaspirate showed subcutaneous fatty tissue. Both patients underwent general anesthesia and all procedures were initiated with infusion of tumescent solution (1 L normal saline solution, 30 mg lidocaine, and 1 mL of 1:1,000 epinephrine) [2]. A suction-assisted liposuction method was employed using 4and 6-mm cannulae. Suction started deep into the superficial fascia and ended with superficial liposuction [3]. Incisionswere closedwith6-0 polyprolene and dressings were applied. A second limited liposuction was planned to treat the irregularities in the first case. Results were satisfactory in both cases (Figs. 1b and 2b). Isolated abnormal bilateral peritrochanteric lipomatosis has rarely been reported in literature. In 2006, Goshtasby et al. presented a case of isolated bilateral peritrochanteric lipomatosis of the soft tissue overlying the trochanters [4]. The unusual distribution of fat in the lower body should be differentiated from the familial multiple nodular symmetrical lipomatosis, where the lipomas are nodular, circumscribed, subcutaneous in location, and more common on the extremities and trunk rather than around the neck, shoulder, or the upper torso [5]. Stavropoulos and his colleagues have suggested that the term symmetric lipomatosis referred to two separate disorders, benign multiple symmetric lipomatosis and female S. Şenturk (*) Department of Plastic and Reconstructive Surgery, Mevlana (Rumi) University Hospital, Konya, Turkey e-mail: drssenturk@hotmail.com

Optical Fiber Micro-Taper with Circular Symmetric Gold Coating for Sensor Applications Based on Surface Plasmon Resonance

We describe a novel, fully symmetrical deposition method, based on a sputtering technique and use of a gold ring target for deposition of a gold layer uniform around the taper waist. With such a circular symmetric coating, the plasmon resonance effect in the fiber taper becomes completely independent of the polarization of the illuminating light. We have measured the complex refractive index of such sputtered gold layers. On this basis, model calculations have been performed to describe the plasmon resonance as a function of taper waist diameter, gold layer thickness, analyte interaction length, and analyte refractive index. Optimized parameters especially for measurement in aqueous solutions are derived from these theoretical calculations. Experimental results are shown to be in good agreement with the theoretical analysis.

Fahr's disease: a rare neurodegenerative disorder

Fahr's disease is a rare neurodegenerative disorder that is characterized by the bilateral symmetrical deposition of calcium in the basal ganglia, thalamus, dentate nuclei and centrum semiovale in the absence of hypoparathyroidism. It is often familial. Hereby, we are reporting a rare case of Fahr's disease who presented with repeated episodes of seizures and was diagnosed as Fahr's disease after performing computed tomographic (CT) scan.DOI: http://dx.doi.org/10.3126/hren.v10i2.6589 Health Renaissance 2012; Vol 10 (No.2); 155-156

Lipomatosis of the orbits: possibly a form of Madelung's disease

Sir, Madelung's disease is a systemic disorder, which is typically characterized by symmetrical deposits of adipose tissue in the neck and upper back. In 1888, Madelung collected a series of cases outlining the macroscopic structure and clinical features of this disease. It is more common in males and associated with high alcohol consumption.1 In this report, we present the clinical and radiological manifestations of Madelung's disease in the orbits, which to our knowledge has not been described before.

Symmetrical Antidirectional Metallization for Stress Compensation of Transfer-Bonded Monocrystalline Silicon Membranes

This paper demonstrates a very robust and fabrication-parameter insensitive concept of full stress compensation in metallized monocrystalline silicon membranes by symmetrical antidirectional metal deposition on both sides of a transfer-bonded silicon membrane. This concept results in previously unmatched near-perfectly flat, temperature-compensated, and high-reliability metal-coated membranes, independent on the thickness, residual stress, and material of the metal layers. Application examples are high-performance optical mirror devices and quasi-optical tunable microwave surfaces, the latter being presented in this paper. The influence of the thickness ratio of the metal films on the membrane curvature is investigated, demonstrating a controllable curvature range from -0.3 to 0.1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> for the investigated devices by varying the top-to-bottom metal thickness ratio from 0.38 to 3.5 using metal thicknesses from 200 to 800 nm. Near-zero curvature down to 0.004 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> is also demonstrated. Theoretical analysis of the stress-compensated multilayer structures and characterization results of fabricated test devices are included in this paper, as well as the influence of unsymmetrically etched structures in the two metallization layers on the stress-induced curvature. Reliability tests up to 100 million cycles showed no detectable change in curvature or plastic deformation, proving the robustness and repeatability of this new design concept of zero-curvature temperature-compensated monocrystalline silicon-core membranes with thick metal coating.

Rare locations of multiple symmetric lipomatosis (Madelung’s disease)

Multiple symmetric lipomatosis (MSL) is a rare disease of unknown etiology, which is characterized by the presence of massive symmetric deposits of unencapsulated fatty deposits around the face, back of the head, neck, upper arms, abdomen, back, and upper leg in a very specific distribution pattern giving the patients a “Michelin Man” resemblance [1, 2]. Because of this characteristic and the absolute symmetry, the condition is often dismissed as simple obesity. The condition often develops over a period of months to years. It is characterized by a steady increase in weight, despite all attempts at dieting, which often leads to the judgment of “a noncompliant patient.” MSL typically affects male patients from the Mediterranean countries aged 30–60 years. The etiology is still not clear, but a history of alcohol abuse is commonly found [2]. Some reports describe autosomal recessive or autosomal dominant inheritance [3, 4], and the association with mitochondrial dysfunction is also discussed [5]. The enlargement of fat deposits is usually benign, leading to an “only” cosmetic deformity, but cases of dyspnea or dysphagia have been reported [6]. Three case reports of MSL involving the facial nerve [7] and scrotum [8, 9] have been published so far. To the best of our knowledge, we present for the first time a patient with both scrotal and facial nerve involvement. Case report