Dense, high-entropy carbide cobalt-bonded hardmetals with two different compositions, namely (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co and (Ta-Ti-Nb-V-W)C-19.2 vol% Co, were successfully manufactured by gas pressure sintering (SinterHIP) at 1400 °C and 100 bar Ar pressure. The microstructure of these hardmetals consists of a rigid skeletal carbide phase embedded in a tough Co binder phase. EDS mappings showed that the high-entropy carbide phase did not decompose and that a typical hardmetal microstructure was realized. Only in the case of the (Hf-Ta-Ti-Nb-V)C-Co hardmetal was some undissolved TaC and HfO2, as well as some clustered vanadium titanium carbide phase, found, resulting in a split-up of the HEC phase into two very similar HEC phases. This resulted in a reduced hardness to fracture toughness ratio for this composition. Measurements of magnetic saturation polarization showed values between 57.5% and 70% of theoretical magnetic saturation polarization, indicating marginal dissolution of the carbide-forming metal elements in the binder phase. The hardness value HV10 for (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co was 1203 HV10 and 1432 HV10 for (Ta-Ti-Nb-V-W)C-19.2 vol% Co.

Dense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure sintering/sinter–HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar as well as SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9 to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the substitution of Hf with W leads to an increase in the mean grain size of 5–10 times the size of the (Hf, Ta, Nb, Ti, V,)C samples. Vacuum-sintered samples showed uniform grain size distribution regardless of composition. EDS mapping revealed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis showed the structure of mostly single-phase cubic high-entropy carbides. Hardness measurements revealed that (Hf, Ta, Nb, Ti, V)C samples possess higher hardness values than (Ta, Nb, Ti, V, W)C samples.

Background To evaluate depth perception in Primary open angle glaucoma (POAG), glaucoma suspects compared to controls and to determine the association between depth perception and severity of glaucoma. Methods This was a hospital based, comparative, cross-sectional study. The ethical clearance was taken from institutional review committee of Institute of Medicine [Reference no.399 (6–11) E2 077-078]. Agematched, equal number of participants in each group (N=20) were evaluated with both Titmus and Frisby stereoacuity tests to measure depth perception as stereopsis threshold in seconds of arc. The participants were selected using the purposive sampling technique. Results There was no differences in age, sex, or best corrected visual acuity, intraocular pressure, central corneal thickness (CCT), found among the three groups (POAG, Glaucoma Suspects and Control) respectively. However, there was significant difference in cup disc ratio (CDR) between the groups. Equal number of male and female were there in each group, while in POAG group male to female ratio was 3:2. The mean stereoacuity threshold in control group was 53.5±23.23 seconds of arc with Titmus test and 38.75±18.83 seconds of arc with Frisby stereoacuity test. The difference in threshold was significant between control and glaucoma suspect with Titmus (t=1.991, p=0.05) and with Frisby (t=2.114, p=0.04). The difference was also significant in POAG group by Titmus (t=3.135, p=0.0033) and by Frisby (t=3.014, p=0.004). More so, with increasing severity of glaucoma, the mean threshold of stereopsis increased as seen with both Titmus and Frisby Tests (ANOVA, p < 0.001) Conclusion Primary open angle glaucoma patients and glaucoma suspects, showed significant reduction in depth perception. Decreased stereoacuity was associated with greater glaucomatous visual field loss.

Purpose: This retrospective study aims to describe the pattern of visual field defects among patients presenting with neuro-ophthalmological diseases in a tertiary hospital of Kathmandu. Materials and Methods: Medical records of patients undergoing Goldmann visual fields (GVF) for neuro-ophthalmological diseases from July 2019 to June 2021 were retrospectively reviewed. Patient demographics, laterality of the disease, clinical diagnosis and pattern of visual field defect were evaluated and entered and analyzed using SPSS version 20 using descriptive univariate and bivariate analysis. Results: A total of 216 subjects (378 eyes) with the mean age 34.52±14.80 years were included in the study. The visual field defects were divided 4 categories: optic nerve disorders (76.4%, n=165), chiasmal disorders (17.6%, n=38), retrochiasmal disorders (2.8%, n=6) and miscellaneous (3.2%, n=7). Disc edema/papilledema was the most common diagnosis in optic nerve disorders with enlarged blind spot (79.1%) and constriction of visual fields (18.3%) as pattern of visual field defects followed by optic neuritis. Common lesions affecting the chiasma in our study were craniopharyngioma on whom 50% had the classical temporal field involvement (bitemporal-20%, inferotemporal-20% and superotemporal-10%) and pituitary lesions where 30% showed constriction of peripheral fields, 57.5% showed temporal field defects (mostly superotemporal) in both eyes. Retrochiasmal lesions were less common but all showed a bilateral and homonymous pattern of visual field defect. Conclusion: Optic nerve disorders were the most common group of conditions undergoing visual fields. Understanding the varied patterns of visual field defects can aid in early diagnosis and guide timely treatment of common neuro-ophthalmological diseases.