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Solution Processed Bi-Based Sensitized Solar Cell: Effects of Post Heat Treatment

Chai YC, Jun HK

J Nanosci Nanotechnol, 2019 Jun 01;19(6):3505-3510.
PMID: 30744778 DOI: 10.1166/jnn.2019.16099

Nanosize semiconductors have been used as active sensitizers for the application of quantum dot-sensitized solar cells (QDSSC). "Green" sensitizers are introduced as an alternative for the toxic Cd and Pb based compounds. In this work, Bi₂S₃ quantum dots (QDs) were fabricated and used as sensitizers in QDSSC. QDs were grown on TiO₂ electrode via solution dipping process. Although the performance of "green" QDSSC is not as high as that of CdS or CdSe based QDSSCs, its performance can be enhanced with post heat treatment. The effect is dependent on the heat treatment temperature profile where gradual increase of sintering temperature is preferred. The effects of post heat treatment on Bi₂S₃ sensitized TiO₂ electrodes are investigated and discussed.
Fulltext Pathological laughter associated with cerebral lupus: a case report

Singh J, Ahmad N, Chai YC

ASEAN Journal of Psychiatry, 2017;18(1):107-113.
MyJurnal

Objective: Pathological laughter, pseudobulbar affect or a myriad of its other synonyms, is a condition common secondary to neurological injury, presenting with uncontrolled laughing or crying, appearing to be mood-incongruent and significantly debilitating. The objective of this case report is to highlight a rare case of pathological laughter associated with Cerebral Lupus.
Methods: We report a case of a 27-year-old lady presenting with signs and symptoms of stroke with dysarthria progressing to aphasia and then pathological laughter, with an underlying poorly controlled Systemic Lupus Erythematosus, manifesting as Cerebral Lupus.
Results: An improvement in affect congruency followed by decreased frequency of outbreaks among bouts of pathological laughter.
Conclusion: The combination of Escitalopram and Topiramate is effective in the symptomatic treatment of Pathological Laughter.
Fulltext Outcome of Endoprosthesis used in Limb Salvage Surgery in a Malaysian Orthopaedic Oncology Centre

Ng YH, Chai YC, Mazli N, Jaafar NF, Ibrahim S

Malays Orthop J, 2024 Mar;18(1):60-65.
PMID: 38638655 DOI: 10.5704/MOJ.2403.008

INTRODUCTION: To describe the duration of survival among bone tumour patients with endoprosthesis reconstruction and to determine frequency of implant failure, revision of surgery, and amputation after endoprosthesis reconstruction.
MATERIALS AND METHODS: A retrospective cross-sectional review of all patients with either primary bone tumour or secondary bone metastases treated with en bloc resection and endoprosthesis reconstruction from January 2008 to December 2020.
RESULTS: A total of 35 failures were recorded among the 27 (48.2%) patients with endoprostheses. Some of the patients suffered from one to three types of modes of failure on different timelines during the course of the disease. Up to eight patients suffered from more than one type of failure throughout the course of the disease. Out of all modes of failure, local recurrence (type 5 failure) was the most common, accounting for 25.0% of all failure cases. Four patients (7.1%) eventually underwent amputation, which were either due to infection (2 patients) or disease progression causing local recurrence (2 patients).
CONCLUSION: The overall result of endoprosthesis reconstruction performed in our centre was compatible with other centres around the world. Moreover, limb salvage surgery should be performed carefully in a selected patient group to maximise the benefits of surgery.
Fulltext In vivo ectopic bone formation by devitalized mineralized stem cell carriers produced under mineralizing culture condition

Chai YC, Geris L, Bolander J, Pyka G, Van Bael S, Luyten FP, et al.

Biores Open Access, 2014 Dec 1;3(6):265-77.
PMID: 25469312 DOI: 10.1089/biores.2014.0050

Functionalization of tissue engineering scaffolds with in vitro-generated bone-like extracellular matrix (ECM) represents an effective biomimetic approach to promote osteogenic differentiation of stem cells in vitro. However, the bone-forming capacity of these constructs (seeded with or without cells) is so far not apparent. In this study, we aimed at developing a mineralizing culture condition to biofunctionalize three-dimensional (3D) porous scaffolds with highly mineralized ECM in order to produce devitalized, osteoinductive mineralized carriers for human periosteal-derived progenitors (hPDCs). For this, three medium formulations [i.e., growth medium only (BM1), with ascorbic acid (BM2), and with ascorbic acid and dexamethasone (BM3)] supplemented with calcium (Ca(2+)) and phosphate (PO4 (3-)) ions simultaneously as mineralizing source were investigated. The results showed that, besides the significant impacts on enhancing cell proliferation (the highest in BM3 condition), the formulated mineralizing media differentially regulated the osteochondro-related gene markers in a medium-dependent manner (e.g., significant upregulation of BMP2, bone sialoprotein, osteocalcin, and Wnt5a in BM2 condition). This has resulted in distinguished cell populations that were identifiable by specific gene signatures as demonstrated by the principle component analysis. Through devitalization, mineralized carriers with apatite crystal structures unique to each medium condition (by X-ray diffraction and SEM analysis) were obtained. Quantitatively, BM3 condition produced carriers with the highest mineral and collagen contents as well as human-specific VEGF proteins, followed by BM2 and BM1 conditions. Encouragingly, all mineralized carriers (after reseeded with hPDCs) induced bone formation after 8 weeks of subcutaneous implantation in nude mice models, with BM2-carriers inducing the highest bone volume, and the lowest in the BM3 condition (as quantitated by nano-computed tomography [nano-CT]). Histological analysis revealed different bone formation patterns, either bone ossicles containing bone marrow surrounding the scaffold struts (in BM2) or bone apposition directly on the struts' surface (in BM1 and BM3). In conclusion, we have presented experimental data on the feasibility to produce devitalized osteoinductive mineralized carriers by functionalizing 3D porous scaffolds with an in vitro cell-made mineralized matrix under the mineralizing culture conditions.
Effects of anodizing parameters and heat treatment on nanotopographical features, bioactivity, and cell culture response of additively manufactured porous titanium

Amin Yavari S, Chai YC, Böttger AJ, Wauthle R, Schrooten J, Weinans H, et al.

Mater Sci Eng C Mater Biol Appl, 2015 Jun;51:132-8.
PMID: 25842117 DOI: 10.1016/j.msec.2015.02.050

Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20V anodizing time: 30min to 3h) are used for anodizing porous titanium structures that were later heat treated at 500°C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500°C improve the cell culture response of porous titanium.
Innovative psychological first aid (PFA) in the new normal for frontliners

Thum CC, Chai YC, Zaman Huri S, Wan Nawawi WZ, Ibrahim N

Perspect Psychiatr Care, 2021 Apr;57(2):965-967.
PMID: 32770539 DOI: 10.1111/ppc.12600

PURPOSE: Psychological first aid (PFA) is utilized in the direct aftermath of crisis events. As the world grappled with Covid-19, PFA was provided for staff members in Hospital Sultan Ismail. In adherence to the New Normal, innovative approaches had to be taken. We engaged clients through virtual communication methods. PFA Solat was organized to assist Muslim staff fulfil religious obligations while being on the frontlines.
CONCLUSIONS: PFA may be useful in helping frontline staff manage stress associated with the increased workload and general anxiety relating to the pandemic.
PRACTICE IMPLICATIONS: It is recommended all staff members, especially those involved in frontline duty, to be provided PFA.
Caregiver depression: The contributing role of depression in patients, stigma, social support and religiosity

Chai YC, Mahadevan R, Ng CG, Chan LF, Md Dai F

Int J Soc Psychiatry, 2018 09;64(6):578-588.
PMID: 30074421 DOI: 10.1177/0020764018792585

BACKGROUND: Depression has been well studied as part of caregiver burden among patients with severe mental illnesses. Curiously, though, there has been little data in terms of caregiver burden with specific focus on depression among caregivers of patients with major depressive disorder (MDD).
AIM: This study aims to determine the rate of depression among caregivers of person with depression and its psychosocial correlates, which include stigma, perceived social support, religious commitment and the severity of the patient's symptoms.
METHODS: A cross-sectional study was conducted among 165 patients diagnosed with MDD using the Mini-International Neuropsychiatric Interview (M.I.N.I.) together with their caregivers. Apart from gathering social demographic data, patients were administered the 16-item Quick Inventory of Depressive Symptomatology-Self-Rated Version (QIDS-SR 16), whereas the caregivers were required to answer Patient Health Questionnaire-9 (PHQ-9), Multidimensional Scale of Perceived Social Support (MSPSS), Duke University Religion Index (DUREL) and Depression Stigma Scale (DSS). Those who scored ⩾5 on PHQ-9 were further assessed with interviewer-rated M.I.N.I. to diagnose the presence of depression.
RESULTS: A total of 47 (28.5%) caregivers were found to have depressive symptoms. Out of that total, 13 (7.9%) were diagnosed to have MDD using M.I.N.I. From univariate analysis, factors associated with depression in caregivers were the severity of symptoms in patients ( p
Bone regeneration performance of surface-treated porous titanium

Amin Yavari S, van der Stok J, Chai YC, Wauthle R, Tahmasebi Birgani Z, Habibovic P, et al.

Biomaterials, 2014 Aug;35(24):6172-81.
PMID: 24811260 DOI: 10.1016/j.biomaterials.2014.04.054

The large surface area of highly porous titanium structures produced by additive manufacturing can be modified using biofunctionalizing surface treatments to improve the bone regeneration performance of these otherwise bioinert biomaterials. In this longitudinal study, we applied and compared three types of biofunctionalizing surface treatments, namely acid-alkali (AcAl), alkali-acid-heat treatment (AlAcH), and anodizing-heat treatment (AnH). The effects of treatments on apatite forming ability, cell attachment, cell proliferation, osteogenic gene expression, bone regeneration, biomechanical stability, and bone-biomaterial contact were evaluated using apatite forming ability test, cell culture assays, and animal experiments. It was found that AcAl and AnH work through completely different routes. While AcAl improved the apatite forming ability of as-manufactured (AsM) specimens, it did not have any positive effect on cell attachment, cell proliferation, and osteogenic gene expression. In contrast, AnH did not improve the apatite forming ability of AsM specimens but showed significantly better cell attachment, cell proliferation, and expression of osteogenic markers. The performance of AlAcH in terms of apatite forming ability and cell response was in between both extremes of AnH and AsM. AcAl resulted in significantly larger volumes of newly formed bone within the pores of the scaffold as compared to AnH. Interestingly, larger volumes of regenerated bone did not translate into improved biomechanical stability as AnH exhibited significantly better biomechanical stability as compared to AcAl suggesting that the beneficial effects of cell-nanotopography modulations somehow surpassed the benefits of improved apatite forming ability. In conclusion, the applied surface treatments have considerable effects on apatite forming ability, cell attachment, cell proliferation, and bone ingrowth of the studied biomaterials. The relationship between these properties and the bone-implant biomechanics is, however, not trivial.