Single Cast Research Articles

Fabrication with magnetic-spin coating: Influence of magnetic-inertia energy ratio on gold-pickering ferrofluid droplet assembly morphology

Magnetic self-assembly of nanoparticles is a well-known technique for creating thin-film array-patterned functional microstructures. However, an uncontrollable hierarchical assembly formation of magnetically stimulated particles has hindered the desired formation of free-standing two-dimensional (2D) array patterns in thin-film layers. In this study, we proposed a fluidic shearing effect from spin coating to reduce magnetically stimulated particles’ disarrayed and complex chain formations, thus promoting linear array formations, even as the film becomes thinner. A series of tests were conducted on a gold-Pickering ferrofluid emulsion (GPFE) dispersed in 15.2 mPas aqueous polyvinyl alcohol (PVAh), which was subjected to varying spin speeds under magnetic setups such as single (SI), compound (CC), and concentric (CR). These setups were chosen to observe the influence of magnetic field strength and distribution on the generated pattern profile from microscopic binary images of the resulting thin films. The aim was to quantify the formed chain thickness (ChT), chain gaps (ChG), and chain lengths (ChL) to capture the morphology and geometrical features of the formed patterns. Our results showed that the quantified values of these profiles and their dimensionless relationships were significantly influenced by the ratio between the applied magnetic packing energy and the centrifugally controlled fluidic energy, QPD. This investigation showed that ChT/ChG for a corresponding QPD value is 98.6% the same for all configurations, and CR was the best setup going forward, as it yielded the lowest array quality defectivity of 14%. Therefore, we assert that this fabrication method offers flexibility, cost-effectiveness, and expandability in generating linear array patterns that contain graduating variability in grating order dimensions within a single cast that can serve efficiently as a substrate for biomolecules under enhanced Raman and Infrared spectroscopies.

CRACKING PATTERN ANALYSIS OF THE TURNING BAND METHOD (TBM) APPLICATION ON A SINGLE-REINFORCEMENT BAR CONCRETE BEAM MODELLING USING THE MAZARS DAMAGE

The development of crack patterns in reinforced concrete structures is a randomly stochastic process influenced by the heterogeneous nature of concrete materials, which impacts the sensitivity to damage and variability in mechanical properties. The numerical simulation of damage pattern appearance on the reinforced concrete for special building structures needs a realistic result, especially in terms of crack distribution. The Turning Band Method (TBM) serves as a tool for assessing the variability of concrete heterogeneity, functioning as an operator to generate a random variable for each specific field. In this study, the investigation of crack patterns in reinforced concrete structures involves using a simple concrete beam sample, measuring 10x10x50 cm3, with a single longitudinal reinforcement cast in the centre. This beam is subjected to an axial tensile loading, while the Mazar Damage Model is employed as the concrete behaviour law. Through the implementation of The Turning Band Method (TBM) and the variation of the random field parameters, distinct crack patterns are observed, not only the number but also the locations of cracks. The use of a smaller correlation length showed 2 cracks while the larger size had around 1 to 3 cracks, with the first crack localizations of each sample generally occurring in the middle surface, in which a noticeable contrast to non-TBM modelling just displays 1 crack. Furthermore, the resulting probability of cracks for ten random draws demonstrates similarity to experimental tests and numerical simulation of the previous study, both at global and local levels.

Using a micro-device with a deformable ceiling to probe stiffness heterogeneities within 3D cell aggregates

Recent advances in the field of mechanobiology have led to the development of methods to characterise single-cell or monolayer mechanical properties and link them to their functional behaviour. However, there remains a strong need to establish this link for three-dimensional (3D) multicellular aggregates, which better mimic tissue function. Here we present a platform to actuate and observe many such aggregates within one deformable micro-device. The platform consists of a single polydimethylsiloxane piece cast on a 3D-printed mould and bonded to a glass slide or coverslip. It consists of a chamber containing cell spheroids, which is adjacent to air cavities that are fluidically independent. Controlling the air pressure in these air cavities leads to a vertical displacement of the chamber’s ceiling. The device can be used in static or dynamic modes over time scales of seconds to hours, with displacement amplitudes from a few µm to several tens of microns. Further, we show how the compression protocols can be used to obtain measurements of stiffness heterogeneities within individual co-culture spheroids, by comparing image correlations of spheroids at different levels of compression with finite element simulations. The labelling of the cells and their cytoskeleton is combined with image correlation methods to relate the structure of the co-culture spheroid with its mechanical properties at different locations. The device is compatible with various microscopy techniques, including confocal microscopy, which can be used to observe the displacements and rearrangements of single cells and neighbourhoods within the aggregate. The complete experimental and imaging platform can now be used to provide multi-scale measurements that link single-cell behaviour with the global mechanical response of the aggregates.

A comparison of two immobilization methods in the conservative treatment of pediatric distal forearm fractures: Long arm cast versus single sugar-tong splint.

The aim of this study was to compare the results of single sugar-tong splint (SSTS) and long arm cast (LAC) as an immobilization method in pediatric distal forearm fractures. Between January 2016 and December 2019, a total of 186 pediatric patients (143 males, 43 females; mean age: 10.3±3 years; range, 4 to 15 years) with distal forearm fractures were retrospectively analyzed. The patients were divided into two groups according to the immobilization method: SSTS group (n=74) and LAC group (n=112). All patients were evaluated at the time of admission, immediately after the reduction, and at one, two, and four weeks. Sagittal and coronal plane angulations and translation percentages of the radius at each visit were calculated. Alterations in coronal angle, sagittal angle, sagittal translation and coronal translation were calculated by subtracting the measurements after reduction from the measurements at four weeks. Both groups were comparable in terms of demographic characteristics, fracture localization, and side of injured extremity. There was a statistically significant difference only in the sagittal angulations in the first (LAC: 4.7; SSTS: 6.5; p=0.009) and second week (LAC: 5.3; SSTS: 6.8; p=0.024). The rest of radiological measurements were comparable. In the LAC group, seven patients had re-intervention (three manipulations, four surgeries) and in the SSTS group, three patients had re-intervention (two manipulations, one surgery) (p=0.657). Our study results suggest that SSTS and LAC are comparable in terms of radiological results and need for re-intervention as an immobilization method of pediatric distal forearm fractures.

Justification of use of fixed retainers based on the analysis of size of the incisor and canine crowns

Anatomical features of the teeth should be accounted for dental treatment plans. The need for constant monitoring of changes in the dentition system determines the relevance of this research. The study aimed to establish the size of anterior teeth with the help of odontometry. We made bi-layer single stage impressions and cast diagnostic models of the anterior teeth of 50 male and 50 female participants aged 18–24 years. The absolute sizes of crowns of incisors and canines were established. To assess the reduction of lateral incisors, we calculated the interincisor index (Ii) of teeth 22 and 21; sexual dimorphism was determined using the Garn–Lewis formula. It was discovered that there are no differences in the mesiodistal widths of crowns of contralateral teeth on the right and left sides (p > 0.05). The mesiodistal width of crowns of anterior teeth decreases (significant changes) in the following order: maxillary central incisors → maxillary canines → mandibular canines and maxillary lateral incisors → mandibular lateral incisors → mandibular central incisors. The degree of reduction of lateral incisors is low (Ii = 74.9) and more prominent in males than in females. In the examined patients, the greatest mean length of crowns of anterior teeth is that of upper central incisors and lower canines, while upper canines are shorter in length and upper lateral incisors, lower central and lateral incisors have the shortest mean crown length. Males have longer (mean length) crowns of lower canines, upper incisors and canines than females, the difference being significant (p < 0.001). The parameters of the crowns determined in this study showed that they have sufficient height and mesiodistal width, which, together with the low degree of reduction of the lateral incisors, justifies the possibility of direct fabrication of orthodontic fixed retainers. The data can also be used at the stage of dental treatment planning.

A Comparative Study of High Temperature Tensile and Creep Testing Between Standard and Miniature Specimens: Applicability and Limits

This study concerns the quasi-static and time-dependent mechanical behavior obtained via the miniaturized electro-thermal mechanical testing (ETMT) approach for single crystal (SX) and conventional cast Mar-M-247 superalloy. The experimental outcome was benchmarked against standardized testing procedures. It is found that tensile yielding behavior can be captured accurately by the ETMT approach up to 1100 ^{circ }C, provided the appropriate type of thermocouple (T/C) is chosen. Furthermore, creep rupture behavior is underestimated by the miniaturized set-up. High repeatability of the rupture time was obtained for the SX case, whereas a significant scatter was observed for the conventional cast case. The discrepancies are assessed in detail; discussion centers around analytical and practical considerations, such as temperature uncertainty due to parasitic voltage and the choice of T/C, microstructural change as a result of the Joule heating, representative gauge volume, and strain rate non-linearity. Consequently, the applicability and limits of the miniaturized approach are examined critically, and improvements were suggested where appropriate.

EVALUATION OF THE PILE BEARING CAPACITY IN ROCK INTERBEDDED BY COHESION SOILS UNDER VERTICAL LOADING

Introduction . The current regulatory calculation procedure for piles in rocks provides a means to determine the bearing capacity of a pile embedded in a solid rock mass containing no weak interlayers. However, it is not uncommon in actual design practice for rocky soils to be interbedded with softer and less stiff dispersive soils, whose presence affects pile performance. In this case, a summation of estimated resistances along the pile length and at its foot overestimates its estimated bearing capacity, which does not correspond to the actual work due to the different rates of friction force generation in soils of varying formations. Aim . To develop a procedure for determining the bearing capacity of a single bored cast in place pile interacting with rock mass interbedded with cohision soils under vertical indentation loading. Materials and Methods . The procedure for estimating the skin friction resistance of a pile penetrating rocky and dispersive soils is based on the analysis of static pile tests and numerical simulation, taking into account tabulated and analytical solutions given in regulatory literature. Results . A procedure for determining the bearing capacity of a single pile interacting with a rock mass interbedded with cohision soils was developed using tabulated solutions given in regulatory literature, empirical dependencies, and numerical simulation. As a criterion for the ultimate shear resistance of bearing soil, a formula for reference settlement S ref is proposed, which factors in pile dimensions and the characteristics of the pile shaft material. The extent to which the pile bearing capacity is sensitive to the parameters of the model and computational assumptions of numerical modeling is analyzed. The presented examples of determining the design pile bearing capacity via the proposed procedure show results similar to experimental data obtained in the field tests. Conclusions . The presented method allows engineers to factor in the skin friction resistance of cohision soil interbedding in the rock mass to increase its design bearing capacity.

Reliability study on the fatigue life of film cooling blades in advanced aero-engine turbines: Neglected crystal orientation uncertainty in casting

The orientation uncertainty of single-crystal turbine blades is a neglected practical engineering problem, and previous research has paid little attention to it. The work innovatively presents the random distribution regularity of the spatial orientation formed in the casting of single crystal blades and its influence on the structural reliability, which establish a foundation for the orientation design of blades. In this work, the uncertain characteristics of the spatial orientation for single crystal cast blades are mathematically quantified. Meanwhile, based on the classical material constitutive and life equations, the elastic-plastic theoretical and fatigue life evaluation models related to orientation are deduced and firstly applied to turbine blade engineering analysis. The elastic-plastic stress distributions of single-crystal turbine blades considering thermal effects are obtained by the fluid-structure interaction simulation. The spatial orientation distribution characteristics is presented from analyzing hundreds of samples. Finally, the influence of the uncertain orientation on the low cycle fatigue life reliability and structural failure probability of single-crystal turbine blades are clarified for the first time by using the BP neural network and stepwise response method. Our results demonstrate that crystal orientation uncertainty, especially in long-life design, can cause a serious failure probability, proving the necessity of orientation control for single crystal turbine blades clearly.

STUDY OF RS17872000 POLYMORPHISM IN CALPAIN (CAPN1) AND
 RS109221039 CALPASTATIN (CAST) GENES IN MEAT PRODUCTIVITY CATTLE

Allelic variants of single nucleotide CAPN1 and CAST polymorphisms in cattle are associated with “marbling” and “tenderness” of meat. SNPs in CAPN1 (rs17872000) and CAST (rs109221039) genes in beef cattle breeds being bred in the Republic of Belarus were studied using KASP and real-time PCR methods. Genetic structure analysis of studied samples from cattle populations by the CAPN1 gene showed that the frequency of occurrence of the preferential Callele associated with “marbling” in Aberdeen Angus cattle was 34.3%, in the Limousine breed ― 14.3%, and in the Hereford breed ― 13.9%. The frequency of occurrence of the preferential A allele (CAST), which determines increased “tenderness” of meat, was 87.1% in the Aberdeen Angus breed, 75.5% in the Limousin, and 77.8% in the Hereford. The use of genetic markers as an important additional criterion in meat cattle breeding in combination with main
 zootechnical methods will allow improving meat productivity.

The Dance Company Film

The Dance Company Film

Elastic Intramedullary Nails in the Treatment of Pediatric Length Unstable Femur Fractures.

Elastic intramedullary nails (EINs) are the treatment of choice for school-age children (5 to 12) with diaphyseal femur fractures. Previous literature suggests that EINs are an effective treatment for stable fracture patterns, but may be inadequate for unstable fracture patterns. The purpose of this study was to evaluate whether patients with length unstable fractures had a higher complication rate than those with length stable fractures when treated with EINs. All patients with diaphyseal femur fractures treated with EINs over a 22-year period at a single institution were reviewed. Patients were excluded if they had a pathologic fracture, neuromuscular disorder, spinal cord injury with subsequent involvement of affected limb, metabolic bone disease, or if they did not have at least 6-month follow-up. A total of 85 patients with 87 diaphyseal femur fractures treated with EINs were included in the study. In all, 57.5% of the fractures were categorized as length stable and 42.5% were length unstable. Fourteen percent of length stable patients had a residual angular deformity compared with 5.4% of the length unstable group (P=0.24). The length unstable group experienced more shortening at the fracture site than the patients in the length stable group (P=0.003), but no patient required further intervention for their shortening. Two patients in the length stable group experienced overgrowth >2 cm and required subsequent surgery. No relationship was observed between fracture pattern and frequency of complications (length stable 8% vs. length unstable 10.8%, P=0.69). Finally, the knee immobilizer group (10.7%) and the long leg cast group (18.2%) had significantly higher complication rates than the single leg spica cast group (0%, P<0.05). There was no significant difference in complication rate between length stable and unstable fractures treated with EINs. Adjunctive spica casting may be protective against postoperative complications. While fracture shortening was more likely in the length unstable group, it did not result in increased rate of limb length discrepancy at final follow-up. Level IV, Case Series.

Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering.

ABSTRACTPurposeTo develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization.MethodsA 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly.ResultsSurgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period.ConclusionsSurgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Arizona Passes Sweeping Legislation on MH Parity, Access to Care

Arizona Passes Sweeping Legislation on MH Parity, Access to Care

MicroCT X-ray comparison of aligner gap and thickness of six brands of aligners: an in-vitro study

BackgroundTo investigate and compare the gap (i.e. fit) and thickness of six aligner systems (Airnivol, ALL IN, Arc Angel, F22, Invisalign and Nuvola) using industrial computed tomography (CT). The null hypothesis was that there would be no detectable differences in either measurement between the aligners investigated.Materials and methodsPassive aligners of each brand were fitted to one single resin cast prototyped from an STL file from a single patient. The samples obtained were examined under high-resolution micro-CT, and the resulting tomographic microphotographs and volumetric data were compared. 3D analysis investigated the gap volume, the mean gap width and the maximum gap width of each sample. A total of 204 linear 2D measurements were made on 18 microtomographic images to investigate the aligner gap and thickness among different systems. Investigated regions were the central incisor, canine and first molar. The resulting measurements were analysed by ANOVA and compared using Tukey’s post hoc analysis (P < 0.05).Results3D analysis revealed that the F22 displayed lower gap volume and mean gap width, followed by Airnivol and Invisalign, whereas Airnivol the lowest maximum gap width. 2D analysis showed that F22 had the lowest mean gap and aligner thickness at all teeth investigated. Comparison of the 2D point values revealed statistically significant differences between brands in terms of both measurements (P < 0.05), with the exception of six points in the gap analysis and one in the thickness analysis.ConclusionsThere are differences between the six aligner systems examined in terms of 2D and 3D measurements of aligner thickness and gap.

MgO-Lignin Dual Phase Filler as an Effective Modifier of Polyethylene Film Properties.

Functional magnesium oxide-lignin hybrid materials were obtained via mechanical grinding. Their particle shape and size as well as physicochemical properties were characterized. MgO-lignin materials with biocomponent content (between 20% and 80% amount of total weight of filler) were used as a partially bio-structured modifier of low density polyethylene. The composites with 5% by weight of dual fillers and polyethylene grafted with maleic anhydride were compounded in a twin screw extruder working in co-rotating mode. The prepared blends were cast extruded using a single screw extruder and laboratory cast line. The properties of the obtained films were verified in case of their weldability. The seal strength as well as shear test and tear strength of the welded sheets were examined. The results showed that the shortest equivalent time required to perform correct weld occurred in the system, where the highest amount of lignin was used in hybrid filler MgO-L (1:5 w/w). From mechanical tests of welds, a sharp increase in ultimate seal force was noticed for almost all compositions with lignin, especially where MgO was coupled with a high lignin content. For those composition seal open force raised up to 37.0 N, from the value of 23.6 N, achieved for neat low density polyethylene (LDPE). Tear strength of weld sheets confirmed once more that LDPE composition with MgO-L (1:5 w/w) achieved the highest ultimate force with its value of 71.5 N, and it was ~20.0 N higher than in the case of neat LDPE.

NOTES ON BRONZE POLE-TOPS WITH A GRIFFIN FROM SCYTHIAN ALEKSANDROPOL BARROW

The article proposes a scheme and algorithm for the manufacture of four bronze pole-tops from the Scythian Royal Alexandropol burial mound dated to the second half of the 4th century BC, which can serve as a basis for understanding the manufacturing process or the ancient repair of the similar Scythian replicated products.&#x0D; There is both a general idea of the manufacture of such bronze pole-tops by casting (according to a wax model or in detachable forms), and private judgments about the nature of castings, the correction of defects and the repair of pole-tops and their parts. But at the same time, specific details of the production process by different researchers (S. V. Polin, B. N. Mozolevsky, A. I. Melyukova, L. I. Babenko, A. R. Kantorovich, V. R. Erlikh, etc.) are assumed different, showing a very colorful picture.&#x0D; The process of making bronze pole-tops which were similar in composition, but different in the elaboration and decoration, most likely consisted of the following successive steps: creating a stencil of wax models of griffins in a rectangular frame; revision and decoration by hand of some individual parts on the surface of these wax figures (wings, paws, etc.), giving individuality to each object; attachment and molding of wax plugs; closure of the wax model by the clay mold, its drying and firing (?); casting in metal; destruction of clay mold; machining the surface of the casting.&#x0D; The pole-tops are casted from lead-tin bronze (copper is the base, tin is 9—12 %, lead is 2—3 %, traces of arsenic, iron and nickel). The pole-top (no. Dn 1853 1/6) differs by one feature. On the side edges of the nozzle are high dark triangles with clear boundaries, made by lead-tin plating. On the other objects such ornamentation (?) is not visible.&#x0D; Thus, the considered pole-tops were made using a single stencil and cast according to a single technical scheme.

Experimental investigation of the cooling characteristics of a monobloc cast iron brake disc with fingered hub

The paper compares heat dissipation characteristics of two interchangeable ventilated brake discs, a standard solid hub and a newly developed fingered hub version, both single piece cast designs. The tests were conducted on a specially developed Thermal Flow Rig, which enables disc induction heating to 450°C and cooling for a range of rotational and air speeds, in parallel and angular cross flow. The Rig facilitated very accurate and repeatable experiments to be conducted for numerous combinations of operating conditions. From the recorded cooling curves, average heat transfer coefficients for convection and radiation were extracted and the results also presented in a generic form, using Nusselt numbers. The fingered design demonstrated superior convective heat dissipation, with the improvements varying depending on the rotational speed, air cross flow velocity and angle, as well as disc temperature. The gains were ranging from 3.5% to over 20%. The fingered design is 8.5% lighter and being a single piece cast disc, it remains inexpensive to mass produce.

Behavior of a spherical deformable rolling seismic isolator for lightweight residential construction

This paper presents a study for the development and qualification of a practical low-cost seismic isolation system for lightweight residential construction. The study concludes that single concave rolling isolators cast in high strength concrete with a deformable steel-reinforced plastic rolling ball and a displacement restraint system represent a promising isolation system. A full size isolator suitable for application to typical reinforced concrete houses in Turkey was built and tested. The vertical stiffness, creep characteristics under gravity load and the lateral force–displacement characteristics have been studied. Models for behavior have been developed and validated. These models are useful for response history analysis in commonly available commercial and open source analysis software.

Consistently fitting orthopedic casts

Personalized orthopedic casts largely improve the comfortability and functionality for patients compared to classical plaster casts. Current attempts on the geometric modeling of customized casts have not taken the swelling of the patients' broken extremities into account that causes a gradual deformation during the healing process. Thus, the shape of the injured body parts is not constant during wearing a cast, but may change along with a decreasing swelling. In this paper, we propose a framework for generating 3D printed personal casts that consistently fit and adapt to such deformations and allow to use a single cast throughout the whole healing process. The cast consists of two layers, an outer rigid layer, which provides enough strength and protection of the body parts and an underlying flexible layer that offers adaptability to the deformations. Both layers can be fabricated with standard 3D printers and easily be assembled around the injured body parts. We show a number of 3D printed results and demonstrate the effectiveness of our approach.

Tubular Hair Casts in Trichoscopy of Hair and Scalp Disorders.

Introduction:Hair casts have been reported in a variety of hair and scalp disorders. Trichoscopy allows a quick and noninvasive method for the evaluation of hair and scalp disorders in high magnification. However, the study of hair casts seen in trichoscopy is lacking.Objective:The main objective is to study the occurrence and patterns of tubular hair cast (THC) in different hair and scalp disorders.Patients and Methods:The patients with hair and scalp disorders presenting at the dermatology department of our hospital were evaluated using trichoscopy. Cases of primary parakeratotic disorders and behavioral disorders were excluded. After a detailed history and evaluation of the hair and scalp, histopathology, light microscopic examination, potassium hydroxide examination, and fungal culture were done when necessary.Results:THC was seen in total 21 cases of seven different hair and scalp disorders. Of these, the majority of cases were of discoid lupus erythematosus (DLE) (5/21) and maximum frequency of THCs within a disorder was seen in cases of pemphigus foliaceus (PF) (50%). Proximal casts occurred in 90.47% of cases. Single cast involving two shafts was seen in a case of PF, and two casts within a single shaft were seen in two cases of DLE and one case of alopecia areata.Conclusions:THCs in trichoscopy can be seen in various hair and scalp disorders and their study may help during the diagnosis of those disorders when combined with other trichoscopic features.