The Effects of Fiber Orientation and Volume Fraction of Fiber on Mechanical Properties of Additively Manufactured Composite Material

Additive manufacturing (AM) also known as 3D printing has tremendous advancements in recent days with a vast number of applications in industrial, automotive, architecture, consumer projects, fashion, toys, food, art, etc. Composite materials are widely used in structures with weight as a critical factor especially in aerospace industry. Recently, additive manufacturing technology, a rapidly growing innovative technology, has gained lot of importance in making composite materials. The properties of composite materials depend upon the properties of constituent’s matrix and fiber. There is lot of research on effect of fiber orientation on mechanical properties of composite materials made using conventional manufacturing methods. It will be interesting and relevant to study the relationship between the fiber orientation and fiber volume with mechanical properties of additively manufactured composite materials. This thesis work presents experimental investigation of mechanical behavior like tensile strength and fatigue life with variation in fiber orientation and fiber volume fraction of 3D printed composite materials. The aim is to study the best combination of volume fraction of fiber and fiber orientation that has better fatigue strength for additive manufactured composite materials. Using this study, we can decide the type of orientation and volume percent for desired properties. This study also finds the range of fatigue limits of 3d printed composite materials

Serous business: delineating the broad spectrum of diseases with subretinal fluid in the macula

A wide range of ocular diseases can present with serous subretinal fluid in the macula and therefore clinically mimic central serous chorioretinopathy (CSC). In this manuscript, we categorise the diseases and conditions that are part of the differential diagnosis into 12 main pathogenic subgroups: neovascular diseases, vitelliform lesions, inflammatory diseases, ocular tumours, haematological malignancies, paraneoplastic syndromes, genetic dis-eases, ocular developmental anomalies, medication-related conditions and toxicity-related diseases, rhegma-togenous retinal detachment and tractional retinal detachment, retinal vascular diseases, and miscellaneous diseases. In addition, we describe 2 new clinical pictures associated with macular subretinal fluid accumulation, namely serous maculopathy with absence of retinal pigment epithelium (SMARPE) and serous maculopathy due to aspecific choroidopathy (SMACH). Differentiating between these various diseases and CSC can be challenging, and obtaining the correct diagnosis can have immediate therapeutic and prognostic consequences. Here, we describe the key differential diagnostic features of each disease within this clinical spectrum, including repre-sentative case examples. Moreover, we discuss the pathogenesis of each disease in order to facilitate the dif-ferentiation from typical CSC.Ophthalmic researc

Subretinal fluid morphology in chronic central serous chorioretinopathy and its relationship to treatment: a retrospective analysis on PLACE trial data

Purpose To explore subretinal fluid (SRF) morphology in chronic central serous chorioretinopathy (cCSC) after one session of either high-density subthreshold micropulse laser (HSML) treatment or half-dose photodynamic therapy (PDT).Methods We retrospectively obtained optical coherence tomography (OCT) scans from a subset of patients from a randomized controlled trial on treatment-naive eyes with cCSC allocated to either HSML treatment or half-dose PDT. OCT scans were evaluated prior to treatment and 6-8 weeks post-treatment, where we measured maximum SRF height and width, calculated the maximum height-to-maximum width-ratio (maxHWR) and calculated the total SRF volume.Results Forty-one eyes of 39 cCSC patients were included. SRF morphology ranged from flat to dome-shaped, quantified as maxHWR ranging between 0.02 and 0.12. SRF volume was median 0.373 mu l (range: 0.010-4.425 mu l) and did not correlate to maxHWR (rho = -0.004, p = 0.982). Half-dose PDT was superior to HSML treatment in complete SRF resolution (RR = 3.28, p = 0.003) and in morphological changes of SRF (Delta(maximum height), p = 0.001; Delta(maximum width), p < 0.001; Delta(volume), p = 0.025). SRF resolved completely in 19/22 PDT-treated eyes (86%) and 5/19 HSML-treated eyes (26%). SRF volume increased in five eyes (26%) after HSML treatment, and in none of the eyes after half-dose PDT. SRF morphology at baseline did not predict treatment outcomes.Conclusion SRF morphology changed after both HSML treatment and half-dose PDT in cCSC, with SRF disappearing in most PDT-treated patients, whereas SRF volume increased in a sizeable proportion of HSML-treated patients. Baseline SRF characteristics measured in this study were unable to predict outcomes after either HSML treatment or half-dose PDT

NOn-Pachychoroid PEripapillary Schisis (NOPPES) of the retina: a new phenotype and its differential diagnosis

Purpose:The presence of peripapillary intraretinal fluid (IRF) has a broad differential diagnosis, including several types of neovascular and pachychoroid-related diseases. However, the clinician may encounter cases without signs of neovascular or pachychoroid disease, or any other previously described diagnosis. For these patients, we propose the term NOn-Pachychoroid PEripapillary Schisis (NOPPES) of the retina, and we discuss the differential diagnosis.Design:A retrospective chart study set in a tertiary referral center for retinal diseases in Amsterdam, the Netherlands.Methods:Using multimodal imaging, cases suspected of peripapillary pachychoroid syndrome were reviewed. Cases without signs of neovascular or pachychoroid disease were included in this study. These cases were discussed in a group of senior retinal specialists to establish a diagnosis, and if there was no evidence for any previously described diagnostic entity, these cases were categorized as NOPPES.Results:Four cases of NOPPES were identified, 3 female patients and 1 male patient, aged between 58 and 75 years. Two patients were myopic, and 1 patient had a mild hyperopia. Three out of 4 cases showed unilateral peripapillary IRF, and 1 case had bilateral IRF. No improvement was seen after intravitreal bevacizumab or aflibercept, nepafenac eye drops, oral acetazolamide, vitrectomy with internal limiting membrane peeling, or surgery for carotid stenosis. One case showed a reduction in IRF after starting prednisolone eye drops.Conclusions:We describe NOPPES, a new form of peripapillary schisis-like IRF. NOPPES seems relatively therapy-resistant. More research is needed to delineate the clinical spectrum of NOPPES and its pathogenesis and treatment.Ophthalmic researc

Artificial vision: the effectiveness of the OrCam in patients with advanced inherited retinal dystrophies

Purpose To investigate the impact of the OrCam MyEye 2.0 (OrCam) on the quality of life and rehabilitation needs in patients with advanced retinitis pigmentosa (RP) or cone-rod dystrophies (CRD). The OrCam is a wearable low-vision aid that converts visual information to auditive feedback (e.g. text-to-speech, barcode and facial recognition). Methods Patients with a clinical diagnosis of RP (n = 9, 45%) or CRD (n = 11; 55%), and a best-corrected visual acuity of <= 20/400 Snellen were invited to participate in this study. Questionnaires were administered at baseline and after 5.2 (standard deviation +/- 1.5) weeks, which included the Dutch version of the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ), the Participation and Activity Inventory (PAI) and the OrCam Function Questionnaire (OFQ). Results Following OrCam testing, significant improvements were observed in the 'near activities' subscale of the NEI-VFQ (p < 0.001); the 'visual functioning' subscale of the re-engineered NEI-VFQ (p = 0.001); the 'reading' rehabilitation goal of the PAI (p = 0.005) and the overall score of the OFQ (p < 0.001). The observed changes in questionnaire scores did not differ between phenotypes. Advantages and limitations of the OrCam were reported by patients. Three patients (15%) continued rehabilitation with the OrCam after completion of this study. Conclusions The OrCam mainly improves reading domains in patients with advanced stages of RP or CRD. Further improvements in the OrCam are needed to address current limitations, which may enhance its utility for patients with RP or CRD.Ophthalmic researc

Natural course and classification of extensive macular atrophy with pseudodrusen-like appearance

Purpose:To describe the imaging characteristics and topographic expansion of retinal pigment epithelium (RPE) and outer retinal atrophy in extensive macular atrophy with pseudodrusen-like appearance.Methods:Three-year, prospective, observational study. Nine patients with extensive macular atrophy with pseudodrusen-like appearance (17 eyes; 6 women) with no other ocular conditions were annually examined; one eye was excluded because of macular neovascularization. Best-corrected visual acuity measurement, fundus photographs, blue-light autofluorescence, and optical coherence tomography were performed at each visit. Formation of atrophy was analyzed on optical coherence tomography at foveal and extrafoveal areas following the Classification of Atrophy Meeting recommendations. Spatial enlargement throughout four sectors was assessed on blue-light autofluorescence after placing an Early Treatment for Diabetic Retinopathy Study grid centered on the foveola.Results:Mean age was 53.0 +/- 2.1 years at baseline with a follow-up of 36.6 +/- 0.7 months. Thinning of the outer nuclear layer and disruption of the ellipsoid zone initially appeared above areas of RPE-Bruch membrane separation and preceded RPE atrophy. Subfoveal fibrosis was seen in 65% of the eyes. Superior sector involvement was found in all patients at baseline and was significantly larger than the other sectors at any time point (P < 0.001). Best-corrected visual acuity declined from 68.0 +/- 15.7 letters to 44.8 +/- 14.9 letters during the follow-up and was significantly associated with subfoveal atrophy (P < 0.001) and fibrosis (P = 0.02).Conclusion:Our findings suggest that primary alterations in patients with extensive macular atrophy with pseudodrusen-like appearance are present at the outer segment-RPE interface, with the superior Early Treatment for Diabetic Retinopathy Study sector being the most vulnerable, which progresses to extensive atrophy of the RPE and outer retinal layers. Accordingly, we propose a three-stage disease classification.Ophthalmic researc

Part 2: A Pilot Ethnomethodological Study

This second paper reports on a small ethnographic study of Argentine psychiatrists. A carefully selected group of six psychiatrists currently practicing in Buenos Aires par- ticipated in an in-depth semi-structured interview. The transcripts of the interviews were coded and a thematic analysis method was applied to construct a local theory of the professional values constructed by Argentine psy- chiatrists, and the circumstances in which such values were constructed. Our analysis indicated that Argentine psychia- trists constructed a number of values, frequently perceived as obligations to their professional group and the needs of their patients. The two main strategies employed by Ar- gentine psychiatrists were the diagnostic act and advocacy. We also identify that these values emerge in the context of recent broad historical and cultural influences upon the profession of psychiatry in Argentina, and the Argentine population in general

Illness Self-Schema in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a relatively rare autoimmune disease with no known aetiology or cure. In addition to numerous physical symptoms, those living with SLE have also been shown to experience significant emotional and psychosocial difficulties. There has been little psychological research into SLE despite the rapidly increasing interest in health psychology and quality of life issues over the last two decades. One such issue that has commanded particular attention is that of cognitive bias in individuals with chronic pain and/or chronic illness. Cognitive bias toward illness-related information is theorised to indicate the presence of an illness self-schema, and is a valuable tool of investigation as it permits access to a level of cognitive structure that is inaccessible via self-report instruments. The primary focus of the present study is to investigate recall bias for pain- and illness-related words in SLE patients. This bias is explored relative to the recall of neutral words and depression-related words, and also relative to the responses of rheumatoid arthritis (RA) patients and healthy controls. Two hypotheses are proposed: firstly, that bias is related to disease activity; and secondly, that bias is related to the combination of illness and depression. The findings provide support for the second hypothesis, with the additional caveat that the nature of the pain/illness stimuli used is important in determining the presence of cognitive bias. No recall bias for illness-related words as a whole was found in any of the groups, nor was there evidence of a recall bias in the SLE and RA patients when they were divided according to depression status. However, when the illness words were examined separately according to �sensory pain� and �disability-related� words, a clear bias for disability words was found in the depressed patient group. It is concluded that there is a relationship between depression in chronically ill individuals, and the way in which such individuals process disability-related words. In accordance with the schema-enmeshment model (Pincus & Morley, 2001), it is suggested that both a pain-schema and an illness-schema exist, and it is when these two schemas become enmeshed with the self-schema that depression occurs in chronic pain/chronically ill patients. The cognitive bias assessment paradigm adopted in this study-one that is typically used in similar investigations-is lengthy, requires sophisticated equipment and can be difficult to interpret on an individual level. The present study investigates the relationship between cognitive biases in SLE patients and a recently-developed task, PRISM, which appears to symbolise the enmeshment of illness-, pain- and self-schemas. Analyses confirmed that recall of negative illness words was the only independent predictor of PRISM scores. This suggests that PRISM, a quick and easy task to administer, may have considerable usefulness as a clinical tool to assess information relevant to the enmeshment of illness- and self-schema. A greater understanding of schema and the processing styles of chronically ill patients will allow for more effective psychological treatment such that quality of life can be improved

Estimation of current and post-treatment retinal function in chronic central serous chorioretinopathy using artificial intelligence

Refined understanding of the association of retinal microstructure with current and future (post-treatment) function in chronic central serous chorioretinopathy (cCSC) may help to identify patients that would benefit most from treatment. In this post-hoc analysis of data from the prospective, randomized PLACE trial (NCT01797861), we aimed to determine the accuracy of AI-based inference of retinal function from retinal morphology in cCSC. Longitudinal spectral-domain optical coherence tomography (SD-OCT) data from 57 eyes of 57 patients from baseline, week 6-8 and month 7-8 post-treatment were segmented using deep-learning software. Fundus-controlled perimetry data were aligned to the SD-OCT data to extract layer thickness and reflectivity values for each test point. Point-wise retinal sensitivity could be inferred with a (leave-one-out) cross-validated mean absolute error (MAE) [95% CI] of 2.93 dB [2.40-3.46] (scenario 1) using random forest regression. With addition of patient-specific baseline data (scenario 2), retinal sensitivity at remaining follow-up visits was estimated even more accurately with a MAE of 1.07 dB [1.06-1.08]. In scenario 3, month 7-8 post-treatment retinal sensitivity was predicted from baseline SD-OCT data with a MAE of 3.38 dB [2.82-3.94]. Our study shows that localized retinal sensitivity can be inferred from retinal structure in cCSC using machine-learning. Especially, prediction of month 7-8 post-treatment sensitivity with consideration of the treatment as explanatory variable constitutes an important step toward personalized treatment decisions in cCSC.Ophthalmic researc

The LRAT(-/-) rat: CRISPR/Cas9 construction and phenotyping of a new animal model for retinitis pigmentosa

Purpose: We developed and phenotyped a pigmented knockout rat model for lecithin retinol acyltransferase (LRAT) using CRISPR/Cas9. The introduced mutation (c.12delA) is based on a patient group harboring a homologous homozygous frameshift mutation in the LRAT gene (c.12delC), causing a dysfunctional visual (retinoid) cycle. Methods: The introduced mutation was confirmed by DNA and RNA sequencing. The expression of Lrat was determined on both the RNA and protein level in wildtype and knockout animals using RT-PCR and immunohistochemistry. The retinal structure and function, as well as the visual behavior of the Lrat(-/-) and control rats, were characterized using scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), electroretinography (ERG) and vision-based behavioral assays. Results: Wildtype animals had high Lrat mRNA expression in multiple tissues, including the eye and liver. In contrast, hardly any expression was detected in Lrat(-/-) animals. LRAT protein was abundantly present in wildtype animals and absent in Lrat(-/-) animals. Lrat(-/-) animals showed progressively reduced ERG potentials compared to wildtype controls from two weeks of age onwards. Vison-based behavioral assays confirmed reduced vision. Structural abnormalities, such as overall retinal thinning, were observed in Lrat(-/-) animals. The retinal thickness in knockout rats was decreased to roughly 80% by four months of age. No functional or structural differences were observed between wildtype and heterozygote animals. Conclusions: Our Lrat(-/-) rat is a new animal model for retinal dystrophy, especially for the LRAT-subtype of early-onset retinal dystrophies. This model has advantages over the existing mouse models and the RCS rat strain and can be used for translational studies of retinal dystrophies.Ophthalmic researc