In the current study, a new approach was shown to develop an innovative loadcarrying and energy absorbing structure which can fulfill the requirements in the fields of automotive, defense and ...aerospace. Two different topics which have been in great demand in the recent times were combined: sandwich structures and bio-inspiration. Balanus which is a barnacle living along the seashores and on the ships’ surfaces was taken under examination to design a novel sandwich structure core geometry. The designed geometry was manufactured with deep drawing process. The sandwich structures were produced with different face sheets using a pattern to ensure the repeatability of the crushing tests. Firstly, the advantage of the bio-inspired core over the conventional core geometries was shown with a numerical study. Then, the crushing tests were conducted at both quasi-static and dynamic loading rates. Further, the effects of foam filling, confinement, inertia and strain rate sensitivity on the crashworthiness performance of the proposed structure were investigated. In addition to the experimental studies, numerical analyses were also performed using LS-DYNA 971. In the numerical studies, manufacturing process of the core geometry was also modeled to count in the residual stress/strain so that a good proximity was obtained between the experimental and numerical results. Moreover, the penetration and perforation behaviors were inspected. Utility of the proposed geometry where a high resistance is needed against dynamic crushing was demonstrated. Finally, several suggestions were proposed for the future works to elaborate the present study.
Introduction: COVID-19 infection may also occur with ocular manifestations. Paracentral acute middle maculopathy(PAMM) is a condition that causes ischemia in the inner retinal layers characterized by ...disruptions in capillary plexus flow. Also, ischemia in inner retinal layers secondary to COVID-19 infection has not yet been reported.
Case report: The case, presented with the complaint of gradually decreasing visual acuity in the right eye after COVID-19 infection. PAMM was suspected, however, ischemia was detected in all inner retinal layers with Optical coherence tomography angiography.
Discussion: We showed that it should be kept in mind that atypical retinal involvement of COVID-19 infection could present, with this case.
•COVID-19 infection may be the cause of inner retinal infarction.•OCT angiography can be a useful method to detect internal retinal ischemia.•This case shows that COVID-19 infection can also present with a PAMM-like appearance.
The blast loading response of a sandwich structure consisted of bio-inspired (balanus) cores/units was investigated experimentally and numerically. A Direct Pressure Pulse (DPP) set-up was used to ...impose a blast-like loading. The equivalent blast conditions corresponding to the used impact velocities were implemented in the models. A benchmark study was performed by using three different methods namely pure Lagrangian, Arbitrary Lagrangian Eulerian, and hybrid. Dynamic crushing behavior was analyzed and exhibited a higher specific energy absorption capacity than its constituents (core and shell). Among the core configurations, all-front configuration was found the most efficient configuration regarding the specific energy absorption.
•The blast loading response of a sandwich structure was investigated.•The bio-inspired geometry exhibits a higher specific energy absorption capacity.•All-front configuration was found the most efficient configuration regarding SAE.
A thin-walled structure inspired from a biologic creature known as balanus was investigated experimentally and numerically under quasi-static and dynamic loads for load-carrying and energy absorption ...properties. The structure was composed of an inner conical core with a hemispherical cap and an outer shell in frusto-conical shape and formed by deep drawing. The applied deep drawing process was modelled using nonlinear finite element code LS-DYNA to determine the residual stress/strain and the non-linear thickness distribution after the forming process. It was also shown that the load carried by the balanus structure was greater than the arithmetic sum of the load carried by the inner core and by the outer shell separately. Although the mean force increase due to interaction effect at quasi-static strain rate was approximately 5%, while it increased to roughly 26% at dynamic strain rates in drop weight experiments. The numerical models also showed that the outer shell absorbed more energy than the inner core while the difference between the energy absorbing performance of the core and shell decreased with increasing deformation rate. The effect of strain rate and inertia on the increase in crush load increased with increasing impact velocity, while the strain rate effect had greater influence than the inertia on the crush load. The increased load carrying capacity of the balanus at quasi-static and dynamic strain rates was ascribed to the interaction between the core and shell and the confinement effect of the outer shell particularly at dynamic strain rate.
•Crushing behavior of a bio-inspired geometry was investigated.•The balanus is the most effective configuration among all structures.•The outer shell absorbed more energy than the inner core.•The strain rate has greater influence than the inertia on crush load.
Aim
We aimed to compare the roles of
68
Ga-FAPI-04 PET/CT and
18
F-FDG PET/CT in the evaluation of primary tumor and metastases in primary and recurrent breast cancer.
Materials and method
Twenty ...female patients with histopathologically confirmed primary and recurrent breast cancer were included in the prospective study. All patients underwent FDG and FAPI PET/CT imaging in the same week. The number of primary and metastatic lesions, SUV
max
values, and tumor-to-background ratios (TBR) were recorded from both scans. Data obtained were statistically compared.
Results
FAPI PET/CT was superior to FDG in detecting breast lesions, as well as hepatic, bone, lymph node, and cerebral metastases in terms of patient- and lesion-based assessments. The sensitivity and specificity of FAPI in detecting primary breast lesions were 100% and 95.6%, respectively, while the sensitivity and specificity of FDG were 78.2% and 100%, respectively. The SUV
max
values of primary breast tumors, lymph nodes, lung metastases, and bone metastases were significantly higher on FAPI imaging than FDG imaging (
p
< 0.05). However, SUV
max
values of hepatic metastases did not exhibit a statistically significant difference between two imaging techniques (
p
> 0.05). Also, FAPI imaging yielded significantly higher TBR in breast lesions as well as hepatic, bone, brain and lung metastases compared to FDG (
p
< 0.05).
Conclusion
68
Ga-FAPI-04 PET/CT is superior to
18
F-FDG PET/CT in detecting the primary tumor in patients with breast cancer with its high sensitivity, high SUV
max
, and high TBR.
68
Ga-FAPI-04 PET/CT is also superior to
18
F-FDG PET/CT in detecting lymph node, hepatic, bone, and cerebral metastases because it has lower background activity and higher uptake in subcentimetric lesions.
Systemic autoinflammatory diseases are caused by mutations in genes that function in innate immunity. Here, we report an autoinflammatory disease caused by loss-of-function mutations in OTULIN ...(FAM105B), encoding a deubiquitinase with linear linkage specificity. We identified two missense and one frameshift mutations in one Pakistani and two Turkish families with four affected patients. Patients presented with neonatal-onset fever, neutrophilic dermatitis/panniculitis, and failure to thrive, but without obvious primary immunodeficiency. HEK293 cells transfected with mutated OTULIN had decreased enzyme activity relative to cells transfected with WT OTULIN, and showed a substantial defect in the linear deubiquitination of target molecules. Stimulated patients’ fibroblasts and peripheral blood mononuclear cells showed evidence for increased signaling in the canonical NF-κB pathway and accumulated linear ubiquitin aggregates. Levels of proinflammatory cytokines were significantly increased in the supernatants of stimulated primary cells and serum samples. This discovery adds to the emerging spectrum of human diseases caused by defects in the ubiquitin pathway and suggests a role for targeted cytokine therapies.
It is necessary to know the manufacturer and model of a previously implanted shoulder prosthesis before performing Total Shoulder Arthroplasty operations, which may need to be performed repeatedly in ...accordance with the need for repair or replacement. In cases where the patient’s previous records cannot be found, where the records are not clear, or the surgery was conducted abroad, the specialist should identify the implant manufacturer and model during preoperative X-ray controls. In this study, an auxiliary expert system is proposed for classifying manufacturers of shoulder implants on the basis of X-ray images that is automated, objective, and based on hybrid machine learning models. In the proposed system, ten different hybrid models consisting of a combination of deep learning and machine learning algorithms were created and statistically tested. According to the experimental results, an accuracy of 95.07% was achieved using the DenseNet201 + Logistic Regression model, one of the proposed hybrid machine learning models (p < 0.05). The proposed hybrid machine learning algorithms achieve the goal of low cost and high performance compared to other studies in the literature. The results lead the authors to believe that the proposed system could be used in hospitals as an automatic and objective system for assisting orthopedists in the rapid and effective determination of shoulder implant types before performing revision surgery.
GENERATING TURKISH LYRICS WITH LONG SHORT TERM MEMORY
Communications Faculty of Sciences University of Ankara. Series A2-A3: physics, engineerigng physics, electronic engineering and astronomy,
06/2020
Journal Article
Biomaterials are indispensable elements for improving human health and quality of life. Applications of biomaterials include the use of phantoms as tissue replacement in diagnostics (biosensors), ...medical supplies (blood bags and surgical instruments), therapeutic treatments (medical implants and devices), regenerative medicine (tissue engineered skin and cartilage), and radiation dosimetric studies. Since polymers are organic, they offer a much more versatile usage area than metals and ceramic biomaterials, particularly in soft tissue substitutes. The wide physical, mechanical, and chemical properties provided by polymers have encouraged extensive research, development, and application of polymeric biomaterials. Their usage as a soft tissue phantom is at the forefront of these applications.
In this study, the ionization, recoils, phonon release, collision events, and lateral straggle properties of polymeric biomaterials e.g., polymethylmetacrylate (PMMA), polystyrene, polyethylene, polypropylene, and polyvinylchloride closest to soft tissue are investigated in carbon therapy application. The Brag peak location achieved for PMMA is quite close to that of soft tissue, within 4.8%, average recoils within 0.5%, and collision event parameter within 0.6%, however, lateral scattering is comparatively larger by roughly 6.8%, according to TRIM-based Monte Carlo simulation results. Thus, when carbon ion is taken into account, the current findings show that PMMA is one of the possible polymeric biomaterials to simulate soft tissue in terms of radiation interaction properties.
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