Refractive error and visual acuity of elderly Chinese in Selangor and Johor, Malaysia

The first aim of this study was to determine the refractive error and visual acuity of Chinese elderly age 60 and above in Selangor and Johor, Malaysia. The second aim was to determine the percentage of elderly with vision impairment. Participants of this study were from the on-going population-based longitudinal study on neuroprotective model for healthy longevity (TUA) among Malaysian older adults using multistage random sampling. A total of 259 Chinese elderly aged 60 and above from state of Selangor and Johor agreed to participate. Refractive error was determined using autorefractometer Retinomax K-plus followed by subjective refraction. Best corrected visual acuity (VA) was measured using logMAR chart. Analysis was performed on data of 202 participants and the remaining 57 were excluded. Overall percentage of refractive error was higher for hyperopia (54%) compared to myopia (23.2%). High percentage of astigmatism was noted for all age groups (> 50%). Both gender showed similar distribution of refractive status. Mean overall VA was 0.24 ± 0.17 logMAR (≅ 6/9–) and mean VA declined with age. Overall, the percentage of elderly having at least mild vision impairment (> 0.3 logMAR or 6/12) was higher (62.9%) compared to normal vision (≤ 0.3 logMAR). However, percentage of vision impairment (VI) was highest in the mild category compared to others and only one participant had severe VI. This study found a high percentage of Chinese elderly with refractive error. The most common type of refractive error was hyperopia. A high proportion of them had mild vision impairment followed by moderate VI even with best correction. Vision impairment could affect daily life functioning and this effect can be further explored in the future

Soal selidik kendalian kendiri indeks fungsi visual (VF14) dan korelasinya dengan akuiti visual koreksi terbaik pada warga emas

Kajian ini dilakukan untuk menentukan skor kendalian kendiri indeks fungsi visual (VF14) dan korelasinya dengan akuiti visual koreksi terbaik pada warga emas. Subjek kajian ialah warga emas berumur 60 tahun ke atas yang mengambil bahagian dalam kajian yang sedang dijalankan iaitu“Model Perlindungan Neuro Bagi Penuaan Sihat Di Kalangan Warga Emas (TUA). Akuiti visual diukur dengan menggunakan carta logMAR. Penilaian soal selidik kendalian kendiri diukur menggunakan Indeks Fungsi Visual (VF14) berbahasa Melayu yang telah diubah suai. Seramai 482 (93.05%) daripada 518 subjek kajian telah mengambil bahagian dalam kajian ini. Purata umur subjek kajian ialah 69.18 ± 5.67 tahun dan purata akuiti visual koreksi terbaik ialah logMAR 0.21 ± 0.17. Purata skor VF14 ialah 89.65 ± 13.19. Perempuan mempunyai purata skor VF14 yang lebih rendah jika dibandingkan dengan lelaki (skorperempuan89.21 ± 12.76, skorlelaki90.11 ± 13.65) tetapi tidak ada perbezaan secara statistik (z= -1.09, p= 0.277). Terdapat korelasi yang sederhana tetapi signifikan antara skor VF14 dan akuiti visual koreksi terbaik (r = -0.412, p < 0.01). Kesimpulannya, akuiti visual koreksi terbaik sahaja tidak boleh digunakan sebagai indikator untuk menjelaskan perubahan skor VF14. Kajian ini menunjukkan ia hanya menyumbang kepada 17.2% kepada perubahan skor VF14. Gabungan banyak faktor lain seperti faktor sosio demografik (bangsa, status pendidikan dan masalah kesihatan), sensitiviti kontras dan stereopsis perlu diambil kira apabila menilai fungsi visual yang diukur dengan VF14

Cerebral venous thrombosis: a descriptive multicenter study of patients in Pakistan and Middle East

Background and Purpose: The natural history, causative factors, and outcomes of patients with cerebral venous thrombosis from Asia and Middle East have not been well described. This descriptive multicenter study describes the results for cerebral venous thrombosis patients in South Asia and the Middle East. Methods: The retrospective and prospective data of patients with radiologically confirmed cerebral venous thrombosis were collected from 4 centers located in Pakistan and United Arab Emirates. The demographic, clinical, radiological, and outcome data were recorded and analyzed. Primary outcome was death or dependency (modified Rankin score \u3e2) at the time of hospital discharge. Results: This study included 109 patients with cerebral venous thrombosis; the presenting features most commonly being observed were headache (81%), focal motor deficits (45%), seizures (39%), and mental status changes (37%). Important predisposing factors included systemic and central nervous system infection (18%), postpartum state (17%), hyperhomocystinemia (9%), genetic thrombophilia (5%), and oral contraceptive pill use (3%). Ninety-six (67%) patients received therapeutic anticoagulation. Seven patients died and 43 had poor outcome at discharge. Focal motor deficits (OR, 2.93; 95% CI, 1.2–7.5; P=0.018) and hemorrhagic infarctions (OR, 2.81; 95% CI, 1.04–7.85; P=0.041) were independent predictors of unfavorable outcome at discharge. Hemorrhagic infarction was the most significant factor of long-term unfavorable outcome (OR, 5.87; 95% CI, 1.49–23.02; P=0.011). Conclusions: Infections and postpartum state were the most common predisposing factors for cerebral venous thrombosis in this cohort. Most patients (67%) were treated with anticoagulation therapy. Almost 50% of patients were dead or disabled at discharge

Outlining a new collaborative business model as a result of the green Building Information Modelling impact in the AEC supply chain

BIM (Building Information Modelling) technological push has enabled to integrate the design/construction outcomes of 3D-CAD along the product/service AEC (Architecture, Engineering and Construction) SC (supply chain) through an intelligent DMS (Data Management System) based on standard and interoperable data formats. The proposed end-to-end approach overcomes a typical AEC gap, enables the operationalisation of the sustainable/green building LCA (Life Cycle Assessment) and puts together new collaborative relationships with the owner, among SC stakeholders and with new forms of BIM procurement. The outlined collaborative business model is based on the Quality Control and Assurance framework and provides conceptual consistency to the reintroduction of the owner concerns/satisfaction in the SC, as well as enables consistent and accountable relationships between (smart)materials procurement and building specification. An expert’s focus group carried out a preliminary check of the model’s interest/applicability, resulting in recommendations for its further detailing and for propositions development into a systematic enquiring process.info:eu-repo/semantics/acceptedVersio

The Epidemiology and Outcome of Biliary Atresia: Saudi Arabian National Study (2000–2018)

BackgroundThe epidemiology and outcomes of biliary atresia (BA) have been well-documented in national cohorts from two main ethnicities, namely, the Asian Orientals and Caucasians, with incidence ranging from 1 in 5,000 to 1 in 9,000 live births in East Asia and 1 in 15,000 to 19,000 live births in Europe and North America.ObjectiveWe report the first nationwide BA study outside North America, Europe, and East Asia to describe the epidemiology and outcomes of BA in Saudi Arabia.MethodsA national database of BA cases diagnosed between 2000 and 2018 was analyzed. We assessed clearance of jaundice (bilirubin &lt;20 μmol/L) in all cases that underwent Kasai portoenterostomy (KPE). We then estimated survival using the Kaplan–Meier method with endpoints of liver transplantation (LT), death, or survival with native liver (SNL).ResultsBA was diagnosed in 204 infants (106 females; 10% pre-term). The incidence of BA was 1 in 44,365, or 2.254 in 100,000 live births (range, 0.5–4 in 100,000). Polysplenia was diagnosed in 22 cases (11%). The median age at referral was 65 days. A total of 146 children (71.5%) underwent KPE at a median age of 70 days. Clearance of jaundice was achieved in 66 of the 146 (45%) infants. The 10-year SNL after KPE was 25.5%, and the overall 10-year estimated survival was 72.5%. The Kaplan–Meier survival curves for patients undergoing KPE at the age of &lt;60, 61–90, and &gt;90 days showed a SNL rate at 51.6, 33, and 12.5%, respectively, at 5 years (P &lt; 0.001). The 2-, 5-, and 10-year post-LT survival rates were 92.5, 90.6, and 90%, respectively. Undergoing an initial KPE did not impact negatively on the overall LT survival rate when compared to BA cases that underwent primary LT (P = 0.88).ConclusionThe incidence rate of BA in Saudi Arabia is lower than the incidence reported elsewhere. Late referral of BA cases remains a problem in Saudi Arabia; as a result, the SNL rate was lower than reported by other national registries. Hence, national policies devoted to timely referral and earlier age at KPE are needed

Thermal Management of Concentrated Multi-Junction Solar Cells with Graphene-Enhanced Thermal Interface Materials

We report results of experimental investigation of temperature rise in concentrated multi-junction photovoltaic solar cells with graphene-enhanced thermal interface materials. Graphene and few-layer graphene fillers, produced by a scalable environmentally-friendly liquid-phase exfoliation technique, were incorporated into conventional thermal interface materials. Graphene-enhanced thermal interface materials have been applied between a solar cell and heat sink to improve heat dissipation. The performance of the multi-junction solar cells has been tested using an industry-standard solar simulator under a light concentration of up to 2000 suns. It was found that the application of graphene-enhanced thermal interface materials allows one to reduce the solar cell temperature and increase the open-circuit voltage. We demonstrated that the use of graphene helps in recovering a significant amount of the power loss due to solar cell overheating. The obtained results are important for the development of new technologies for thermal management of concentrated photovoltaic solar cells

Graphene-Enhanced Thermal Interface Materials for Thermal Management of Solar Cells

The interest to photovoltaic solar cells as a source of energy for a variety of applications has been rapidly increasing in recent years. Solar cells panels that employ optical concentrators can convert more than 30% of absorbed light into electricity. Most of the remaining 70% of absorbed energy is turned into heat inside the solar cell. The increase in the photovoltaic cell temperature negatively affects its power conversion efficiency and lifetime. In this dissertation research I investigated a feasibility of using graphene fillers in thermal interface materials for improving thermal management of multi-junction concentrator solar cells. Graphene and few-layer graphene fillers, produced by a scalable environmentally-friendly liquid-phase exfoliation technique, were incorporated into conventional thermal interface materials. Characteristics of the composites have been examined with Raman spectroscopy, optical microscopy and thermal conductivity measurements. Graphene-enhanced thermal interface materials have been applied between a solar cell and heat sink to improve heat dissipation. The performance of the single and multi-junction solar cells has been tested using an industry-standard solar simulator under the light concentration of up to 2000 suns. It was found that the application of graphene-enhanced thermal interface materials allows one to reduce the solar cell temperature and increase the open-circuit voltage. We demonstrated that the use of graphene helps in recovering significant amount of the power loss due to solar cell overheating. The obtained results are important for the development of new technologies for thermal management of concentrated and multi-junction photovoltaic solar cells

Thermal Management of Solar Cells

The focus on solar cells as a source of photovoltaic energy is rapidly increasing nowadays. The amount of sun's energy entering earth surface in one hour is more than the world consume in one year. The photovoltaic market has been increasing by more than 20% annually since 2002. Improving solar cells aims at increasing the power conversion efficiency and reducing manufacturing costs. Crystalline silicon is the most commonly used material in making solar cells with more than 90% market use. Solar cells manufactured in 2011 are capable or converting about 15% of its absorbed light energy into output electricity. Solar cells panels that employ optical concentrators can convert up to 30% of absorbed light into electricity. The remaining 70% of absorbed energy is turned into heat inside the solar cell. The continuous decrease in solar cells size coupled with the increase in their energy absorption generates more heat inside the solar cells and raise their temperature. The increasing the solar cell temperature negatively affect its power conversion efficiency and can damage it. Therefore, it is important to control the solar cell temperature and effectively remove the unwanted heat. Most solar cells utilize passive cooling technologies. A basic heat sink can reduce the solar cell temperature by about 15°C, which increases the output power by 6%. When a heat sink is attached to a solar cell, a thermal resistance between the two interfaces can limit the amount of heat transferred between the solar cell and heat sink. This resistance is a result of the small air gaps in between the joined surfaces and caused by the surfaces imperfections. Since air is a poor thermal conductor, we need to fill these gaps with a material that has better thermal conductivity. Thermal interface materials (TIMs) do this task and improves the interfacial contact by decreasing the thermal resistance. The goal of this research is to achieve a better thermal management of solar cells by improving the interface contact between the solar cell and a passively cooled heat sink

The association between myopia and gender in Indian schoolchildren in Kuala Lumpur

A vision screening study was carried out among Indian schoolchildren around Kuala Lumpur to determine whether the prevalence of myopia was higher in boys or girls. Altogether 749 students (49.7% boys and 50.3% girls) aged 7-18 years were screened and their refractive error examined using retinoscopy without cycloplegia. For the right eye 15.1% of the girls’ eyes were found to be myopic as compared to 16.9% of the boys, of which chi-square showed no significant difference (p = 0.44). For the left eye 18.8% of the girls’ eyes were myopic as compared to 16.4% of the boys. Chi square also showed no significant difference (p = 0.26). When high myopia (> -6.00D) was considered, there was no difference found between boys and girls. The number of students with high myopia greater than -6.00D was also very small (0.3%-0.5%). In conclusion, itwas found that there was no significant difference in myopia between girls and boys among Indian schoolchildren