Feasibility of Human Platelet Lysate as an Alternative to Foetal Bovine Serum for In Vitro Expansion of Chondrocytes.

Osteoarthritis (OA) is a degenerative joint disease that affects a lot of people worldwide. Current treatment for OA mainly focuses on halting or slowing down the disease progress and to improve the patient's quality of life and functionality. Autologous chondrocyte implantation (ACI) is a new treatment modality with the potential to promote regeneration of worn cartilage. Traditionally, foetal bovine serum (FBS) is used to expand the chondrocytes. However, the use of FBS is not ideal for the expansion of cells mean for clinical applications as it possesses the risk of animal pathogen transmission and animal protein transfer to host. Human platelet lysate (HPL) appears to be a suitable alternative to FBS as it is rich in biological factors that enhance cell proliferation. Thus far, HPL has been found to be superior in promoting chondrocyte proliferation compared to FBS. However, both HPL and FBS cannot prevent chondrocyte dedifferentiation. Discrepant results have been reported for the maintenance of chondrocyte redifferentiation potential by HPL. These differences are likely due to the diversity in the HPL preparation methods. In the future, more studies on HPL need to be performed to develop a standardized technique which is capable of producing HPL that can maintain the chondrocyte redifferentiation potential reproducibly. This review discusses the in vitro expansion of chondrocytes with FBS and HPL, focusing on its capability to promote the proliferation and maintain the chondrogenic characteristics of chondrocytes.

Effect of different stent configurations using Lattice Boltzmann method and particles image velocimetry on artery bifurcation aneurysm problem.

Proper design of stent for application at specific aneurysm effect arteries could help to reduce the issues with thrombosis and aneurysm. In this paper, four types of stent configuration namely half-Y (6 mm), half-Y (4 mm), cross-bar, and full-Y configuration will implanted on real 3D artery bifurcation aneurysm effected arteries. Comparisons were then conducted based on the flow patterns after stent placement using both LBM-based solver and PIV experimental findings. According to the data obtained from all 4 stent designs, the flow profiles and the computed velocity from both methods were in agreement with each other. Both methods found that half-Y (6 mm) stent configuration is by far the best configuration in reducing the blood velocity at the vicinity of the aneurysm sac. The analysis also show that the half-Y (6 mm) stent configuration recorded the highest percentage of velocity reduction and managed to substantially reduce the pressure at the bifurcation region. This high flow velocity reduction through the use of half-Y stent could consequently promote the formation of thrombus thereby reducing the risk of rupture in the aneurysm sac.

Intraoperative visualization of cranial nerve schwannomas using second-window indocyanine green: A case series.

BACKGROUND: Second Window Indocyanine Green (SWIG) is a novel intraoperative imaging technique that uses near-infrared (NIR) light for intra-operative tumor visualization using the well-known fluorophore indocyanine green (ICG). Because schwannomas often incorporate the nerve into the encapsulated tumor and impinge on surrounding neural structures, SWIG is a promising technique to improve tumor resection while sparing the nerve. OBJECTIVE: To demonstrate the use of SWIG in resection of cranial nerve schwannomas. METHODS: Three patients with cranial nerve schwannomas (i.e., trigeminal, vestibular, and vagus) underwent SWIG-guided resection. During surgery, NIR visualization was used intermittently used to detect fluorescence to guide resection. Signal-to-background ratio was then calculated to quantify fluorescence. RESULTS: Patients were infused with ICG at a dose of 5.0 mg/kg 24 hours before surgery. Each patient achieved total or near-total resection and relief of symptoms with lack of recurrence at six-month follow-up. The average SBR calculated was 3.79, comparable to values for SWIG-guided resection of other brain and spine tumors. CONCLUSION: This case series is the first published report of trigeminal and vagus nerve schwannoma resection using the SWIG technique and suggests that SWIG may be used to detect all schwannomas, alongside many other types of brain tumor. This paper also demonstrates the importance of preoperative ICG infusion timing and discusses the inverse pattern of NIR signal that may be observed when infusion occurs outside of the optimal timing. This provides direction for future studies investigating the administration of SWIG to resect cranial nerve schwannomas and other brain tumors.

Effect of Welding Parameters on Al/Mg Dissimilar Friction Stir Lap Welding with and without Ultrasonic Vibration.

The amount of heat input during welding impacts the weld's thermal and mechanical behavior and the joint's properties. The current study involved conducting AA 6061 and AZ31B Mg dissimilar welding, using friction stir lap welding (FSLW) and ultrasonic vibration-enhanced FSLW (UVeFSLW). The comparison and analysis of the welding load, the weld's macro-microstructure, intermetallic compounds (IMCs), and joint properties were conducted by adjusting the process parameters. The study also examined the effect of ultrasonic vibration (UV) variations on welding heat input. The study demonstrated that it is possible to reduce the welding load by employing UV. Moreover, this impact becomes more pronounced as the welding heat input decreases. Additionally, the material flow in the weld, the width of the weld nugget zone, and the continuous IMC layer are significantly influenced by ultrasonic vibration, irrespective of the heat input during welding. However, the impact on large areas of irregular IMCs or eutectic structures is relatively small. Furthermore, achieving better joint properties becomes more feasible when a higher welding speed is employed for the Al alloy placed on top. Specifically, the impact of UV becomes more evident at higher welding speeds (≥220 mm/min).

Urgent carotid endarterectomy with distal mechanical thrombectomy.

We review the technique for carotid endarterectomy (CEA) and direct carotid access for distal thrombectomy after attempted proximal thrombectomy in the setting of tandem occlusions. A patient in their 70s presented with right facial droop and drooling and was found to have critical left carotid stenosis with filling defect in the cavernous segment of the left internal carotid artery consistent with vessel occlusion, Thrombolysis in Cerebral Infarction (TICI) 0, and left M2 middle cerebral artery (MCA) occlusion. After multiple attempts with different wire shapes guided by microcatheter injections within the carotid bulb, we were unable to cross the occlusion. Conversion to open CEA with distal thrombectomy was elected. Following closure of the arteriotomy, direct carotid access using a 5Fr radial artery sheath was achieved within the open surgical field for distal thrombectomy. A 5Fr aspiration catheter was navigated to the left M2 MCA where a stent retriever was then recaptured and TICI 2B reperfusion was achieved.

Ruptured Anterior Inferior Cerebellar Artery Aneurysm From a Persistent Trigeminal Artery: A Case Report.

Persistent trigeminal artery (PTA) is the most common remnant of the primitive carotid-vertebrobasilar anastomoses, which typically form and obliterate during the early stages of human embryonic development. While PTA can be non-pathologic and is usually an incidental finding, it is also associated with various other vascular abnormalities, such as arteriovenous malformations and fistulae, but most commonly cerebral aneurysms. In these cases, aneurysms are usually reported in the anterior cerebral circulation or in the PTA trunk itself; to date, only one report exists of an associated aneurysm in the posterior circulation (basilar artery). These associated vascular pathologies are not only a source of morbidity and mortality but can also complicate subsequent endovascular treatment due to different flow patterns and increased vessel tortuosity. In this case report, we present the first reported case of PTA-associated aneurysm in the anterior inferior cerebellar artery and its resulting impact on the endovascular treatment of this aneurysm.

Dose optimization of second window indocyanine green in meningioma patients.

OBJECTIVE: Surgery remains the first line treatment for meningiomas and can benefit from fluorescence-guided surgical techniques such as second-window indocyanine green (SWIG). In the current study, we compared the use of the standard SWIG dose of 5.0 mg/kg relative to 2.5 mg/kg indocyanine green (ICG) in meningioma patients. METHODS: Patients were prospectively enrolled in an IRB-approved study of SWIG and received either the standard dose of 5.0 mg/kg or a reduced dose of 2.5 mg/kg of ICG around 24 h prior to their surgery. Intraoperative near-infrared fluorescence imaging was performed with exo- and endoscopic systems. Signal-to-background ratio (SBR) was calculated to quantify fluorescence and was compared between 5.0 mg/kg and 2.5 mg/kg ICG. All patients received pre-operative MRI and, in select cases, the pre-operative MRI was correlated to intraoperative fluorescence imaging. RESULTS/DISCUSSION: In the current study, we found no significant difference in the SBR of meningiomas in patients that were administered with either 5.0 mg/kg or 2.5 mg/kg ICG. However, in five patients that received the standard-dose SWIG regimen of 5.0 mg/kg ICG we observed dose-related fluorescence quenching - referred to as "inversion" - that interfered with tumor visualization during fluorescence-guided surgery (FGS). When correlated to pre-operative MRI, a similar rim pattern was observed around the primary tumor on T2 FLAIR, which, in retrospect, could be used as a predictor for inversion during FGS in meningioma patients receiving standard-dose ICG. CONCLUSION: This study demonstrated that a reduced ICG dose was as effective as standard-dose SWIG in meningioma patients. We therefore recommend to adjust the standard ICG dose for meningioma patients to 2.5 mg/kg particularly when rim enhancement is observed on pre-operative T2 FLAIR.

Management and outcomes of cerebrovascular injuries after gunshot wounds to the cervical spine.

STUDY DESIGN: This study was a multicenter retrospective analysis of cervical spine gunshot wound (GSW) patients. OBJECTIVE: The present study was conducted to evaluate the management and outcomes of vascular injuries following GSW involving the cervical spine. SUMMARY OF BACKGROUND DATA: Gunshot wounds (GSW) injuring the cervical spine are associated with high rates of vascular injury. METHODS: Charts of patients with GSW involving the cervical spine at two Level 1 trauma centers were reviewed from 2010 to 2021 for demographics, injury characteristics, management and follow-up. Statistical analysis included T tests and ANOVA for comparisons of continuous variables and chi-square testing for categorical variables, non-parametric tests were used when indicated. Beta-binomial models were used to estimate the probabilities outcomes. Bayesian regression models were utilized to compute risk ratios (RR) and their 95 % confidence intervals (CI) to enhance the inferential robustness. RESULTS: 40 patients with cervical spine GSW and associated cerebrovascular injury were included in our analysis. 15 % of patients had Biffl grade (BG) V injuries, 50 % grade IV, and 35 % grade III-I. Angiography was performed in 35 % of patients. 5 of these patients (BG V-III) required endovascular treatment for pseudoaneurysm obliteration or parent vessel sacrifice. 7 patients (22 %) showed evidence of progression. 70 % of patients were placed on antiplatelet therapy for stroke prevention. Bayesian regression models with a skeptical prior for cerebral ischemia revealed a mean RR of 4.82 (95 % CI 1.02-14.48) in the BG V group, 0.75 (95 % CI 0.13-2.26) in the BG IV group, and 0.61 (95 % CI 0.06-2.01) in the combined BG III-I group. For demise the mean RR was 3.41 (95 % CI 0.58-10.65) in the BG V group and 1.69 (95 % CI 0.29-5.97) in the BG IV group. In the high BG (V, IV) group, 54.55 % of patients treated with antiplatelet therapy had complications. None of the patients that were treated with antiplatelet therapy in the low BG (III-I) group had complications. CONCLUSIONS: Cervical spine GSWs are associated with high-grade vascular injuries and may require early endovascular intervention. Additionally, a high rate of injury progression was seen on follow up imaging, requiring subsequent intervention. Reintervention and demise were common and observed in high BG (V, IV) groups. The incidence of stroke was low, especially in low BG (I-III) groups, suggesting that daily aspirin prophylaxis is adequate for long-term stroke prevention.

Utilization and reimbursement of diagnostic cerebral angiograms: A Medicare trends analysis from 2013 to 2020.

INTRODUCTION: Increasing life expectancy has caused growing concern about maintaining viable neurointerventional practices due to altered Medicare payment structures. This study analyzes the financial trends of three common diagnostic tests for cerebrovascular disease: cerebral digital subtraction angiography (DSA), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). METHODS: Medicare Part B National Summary Data files from 2013 to 2020 were queried by Current Procedural Terminology (CPT) codes for DSA (36221-36228), CTA (70496, 70498), and MRA (70544-70547, 70549). Inflation-adjusted charges and reimbursement were calculated using the U.S. City Average Consumer Price Index for Medical Services. Regression analysis was performed on charges, reimbursement, and volume. RESULTS: A total of 1,519,245 diagnostic procedures were conducted between 2013 and 2020 (782,370 angiograms, 246,603 CTAs, and 490,272 MRAs). A total of $41.005 million was reimbursed by Medicare in 2020 for these diagnostic procedures. The annual percent change in volume for all procedures was -2.90%. From 2013 to 2020, inflation-adjusted: Medicare total physician reimbursement decreased for cerebral angiograms (-4.12%, p = 0.007), CTAs (-2.77%, p = 0.458), and MRAs (-9.06%, p < 0.001). Procedural volume billed to Medicare decreased for cerebral angiograms (-4.63%, p = 0.007) and MRAs (-2.94%, p = 0.0.81) and increased for CTAs (+3.15%, p = 0.004). The greatest increase in Medicare reimbursement (+66.75%) came from CPT code 36224, "place catheter carotid artery", and the greatest decrease in Medicare reimbursement (-8.66%) came from CPT code 36226, "place catheter vertebral artery." CONCLUSIONS: This study provides an analysis of Medicare reimbursement trends for routine cerebrovascular angiogram techniques. The findings highlight a decline in Medicare reimbursements for neurointerventionalists.

Defect Engineering at Buried Interface of Perovskite Solar Cells.

Perovskite solar cells (PSC) have developed rapidly since the past decade with the aim to produce highly efficient photovoltaic technology at a low cost. Recently, physical and chemical defects at the buried interface of PSC including vacancies, impurities, lattice strain, and voids are identified as the next formidable hurdle to the further advancement of the performance of devices. The presence of these defects has unfavorably impacted many optoelectronic properties in the PSC, such as band alignment, charge extraction/recombination dynamics, ion migration behavior, and hydrophobicity. Herein, a broad but critical discussion on various essential aspects related to defects at the buried interface is provided. In particular, the defects existing at the surface of the underlying charge transporting layer (CTL) and the bottom surface of the perovskite film are initially elaborated. In situ and ex situ characterization approaches adopted to unveil hidden defects are elucidated to determine their influence on the efficiency, operational stability, and photocurrent-voltage hysteresis of PSC. A myriad of innovative strategies including defect management in CTL, the introduction of passivation materials, strain engineering, and morphological control used to address defects are also systematically elucidated to catalyze the further development of more efficient, reliable, and commercially viable photovoltaic devices.

An 8-Week Vitamin D3-Fortified Fruit Drink Supplementation Increases Serum Ferritin Concentration: A Randomized Controlled Trial in Malaysian Women With Low Iron Stores.

BACKGROUND: There is limited randomized controlled trial evidence to support the association between vitamin D deficiency and anemia risk, highlighting the necessity for further investigations into the role of vitamin D in influencing iron status. OBJECTIVE: The aim of this study was to determine the effect of vitamin D3-fortified fruit drink consumption (4,000 IU) on vitamin D and iron status biomarkers among iron-deficient women (serum ferritin of <20 µg/L [to convert µg/L ferritin to ng/mL, multiply by 1]). DESIGN: An 8-week double-blind randomized controlled trial was conducted. SUBJECTS/SETTING: A total of 45 healthy, nonpregnant, nonlactating subjects aged 18 through 40 years (mean [SD] 25.3 [4.6] years) were included in the study, excluding those who donated blood 6 months prior, regularly consumed nutritional supplements, or had gastrointestinal or iron metabolic disorders. INTERVENTION: Subjects were randomly assigned to receive either vitamin D3-fortified fruit drink or a placebo. MAIN OUTCOME MEASURES: Measurements of 25-hydroxyvitamin D (25[OH]D), serum ferritin, high-sensitivity C-reactive protein, and full blood count concentrations were obtained at baseline, interim, and post intervention. STATISTICAL ANALYSES: A mixed model, repeated measures analysis of variance was used to analyze the intervention effect. RESULTS: Attrition rate for the study was 13%, with 6 dropouts, and 39 subjects completed the study. Daily consumption of vitamin D3-fortified fruit drink in the intervention group resulted in significant increases in 25(OH)D and serum ferritin concentrations compared with the placebo group. The intervention group showed significantly higher mean (SD) changes (Δ) in both 25(OH)D (Δ 76.4 [30.2] nmol/L [to convert nmol/L 25(OH)D to ng/mL, multiply by .4] vs Δ -1.3 [10.7] nmol/L; P = .001) and serum ferritin concentrations (Δ 2.2 [4.2] µg/L vs Δ -0.3 [3.4] µg/L; P = .048) between baseline and post intervention. The other iron status biomarkers were not affected by the intervention. CONCLUSIONS: Our study found that daily vitamin D3-fortified fruit drink supplementation for 8 weeks effectively improved 25(OH)D and iron stores, indicated by increased serum ferritin concentrations, in iron-deficient women. Further research is needed to evaluate its safety, efficacy, feasibility, and optimal food fortification in diverse populations.

Clinical Image: Contrast-Induced Encephalopathy Mimicking Subarachnoid Hemorrhage.

A 72-year-old female with a history of hypertension and hyperlipidemia presented to the emergency department from an outside hospital with acute confusion and global amnesia immediately following cervical epidural steroid injection with fluoroscopic guidance for radiculopathy relief. On exam, she was oriented to self, but disoriented to place and situation. Otherwise, she was neurologically intact with no deficits. Head computed tomography (CT) revealed diffuse subarachnoid hyperdensities most prominent in the parafalcine region concerning for diffuse subarachnoid hemorrhage and tonsillar herniation concerning for intracranial hypertension. CT angiograms of head and neck were negative for vascular abnormalities. Dual-energy head CT was subsequently performed 4 hours later without IV contrast. The 80 kV sequence revealed prominent diffuse hyperdensity throughout the cerebrospinal fluid spaces in bilateral cerebral hemispheres, basal cisterns, and posterior fossa consistent with the initial CT, but these corresponding regions were relatively less dense on the 150 kV sequence. These findings were consistent with contrast material in the cerebrospinal fluid spaces without evidence of intracranial hemorrhage or transcortical infarct. Three hours later, the patient's transient confusion resolved, and she was discharged home the next morning without any neurological deficit.

Intraoperative angiography via popliteal artery access for spinal neurovascular lesions: an institutional experience and systematic review.

BACKGROUND: Intraoperative DSA is used to confirm complete obliteration of neurovascular pathologies. For spinal neurovascular lesions, femoral access can be challenging given the need to flip the patient after sheath placement. Similarly, radial access can be complicated by arch navigation difficulties. Vascular access via the popliteal artery represents an appealing alternative option; however, data regarding its utility and efficacy in these cases are limited. METHODS: A retrospective series of four consecutive patients between July 2016 and August 2022 who underwent intraoperative spinal DSA via the popliteal artery was analyzed. Additionally, a systematic review was conducted to collect previously reported such cases. Collective patient demographics and operative details are presented to consolidate the available evidence supporting popliteal access. RESULTS: Four patients met the inclusion criteria from our institution. The systematic review yielded six previously published studies reporting 16 additional transpopliteal access cases. Of the 20 total cases (mean±SD age 60.8±17.2 years), 60% were men. Most treated lesions were dural arteriovenous fistulas (80%) located in the thoracic spine (55%) or cervical spine (25%). The left popliteal artery was most accessed and the highest visualized level was the craniocervical junction. All outcomes were either stable or improving after surgery, and no complications were observed. CONCLUSIONS: We report the safety and feasibility of transpopliteal access for intraoperative DSA in the prone position in four cases in addition to 16 previously reported cases in the literature. Our case series highlights popliteal artery access as an alternative to transfemoral or transradial access in this setting.

The Device for Intraventricular Entry guide: a novel solution to a perpetual problem.

OBJECTIVE: The authors designed a low-profile device for reliable ventricular access and prospectively studied its safety, efficacy, and accuracy at a large academic center. METHODS: A novel device for ventricular entry, the Device for Intraventricular Entry (DIVE) guide, was designed and created by the first and senior authors. Fifty patients undergoing external ventricular drainage (EVD) or shunt placement were prospectively enrolled for DIVE-assisted catheter placement at a single academic center. The primary outcome was the catheter tip location on postprocedural CT. Secondary outcomes included number of catheter passes, clinically significant hemorrhages, and procedure-related infections. RESULTS: Fifty patients were enrolled. Indications included subarachnoid hemorrhage, intraventricular hemorrhage, traumatic brain injury, hydrocephalus, pseudotumor, and postsurgical wound drainage. In total, 76% (38/50) of patients underwent right-sided placement and 24% (12/50) underwent left-sided placement. All 100% (50/50) of patients had successful cannulation with an average of 1.06 passes. Postprocedural head CT confirmed ipsilateral frontal horn or third ventricle placement (Kakarla grade 1) in 92% (46/50) of patients and placement in the contralateral lateral ventricle in 8% (4/50) (Kakarla grade 2). There were no clinically significant track hemorrhages or procedural infections. CONCLUSIONS: This single-center prospective study investigated the safety and efficacy of DIVE-assisted ventricular access. In total, 100% of procedures had successful ventricular cannulation, with 92% achieving Kakarla grade 1, with an average of 1.06 passes without any clinical complications.

Optoelectrical Properties of Treated CdSe Thin Films with Variations in Indium Chloride Concentration.

The effect of a nontoxic chloride treatment on the crystallinity and optoelectrical characteristics of a CdSe thin film was studied. A detailed comparative analysis was conducted utilizing four molarities (0.01 M, 0.10 M, 0.15 M, and 0.20 M) of indium (III) chloride (InCl3), where the results showed a notable improvement in CdSe properties. The crystallite size of treated CdSe samples increased from 31.845 nm to 38.819 nm, and the strain in treated films dropped from 4.9 × 10-3 to 4.0 × 10-3, according to XRD measurements. The highest crystallinity resulted from the 0.10 M InCl3-treated CdSe films. The In contents in the prepared samples were verified by compositional analysis, and FESEM images from treated CdSe thin films demonstrated compact and optimal grain arrangements with passivated grain boundaries, which are required for the development of a robust operational solar cell. The UV-Vis plot, similarly, showed that the samples were darkened after treatment and the band gap of 1.7 eV for the as-grown samples fell to roughly 1.5 eV. Furthermore, the Hall effect results suggested that the carrier concentration increased by one order of magnitude for samples treated with 0.10 M of InCl3, but the resistivity remained in the order of 103 ohm/cm2, suggesting that the indium treatment had no considerable effect on resistivity. Hence, despite the deficit in the optical results, samples treated at 0.10 M InCl3 showed promising characteristics as well as the viability of treatment with 0.10 M InCl3 as an alternative to standard CdCl2 treatment.

Intraoperative angiography during neurosurgical procedures on patients in prone, three-quarters prone, and park-bench positions: tertiary single-center experience with systematic review and meta-analysis.

BACKGROUND: There is limited evidence about the role and effectiveness of intraoperative angiography (IOA) during neurosurgical procedures with patients in prone, three-quarters prone, and park-bench positions. OBJECTIVE: To carry out a systematic review and meta-analysis of the literature to evaluate the safety and efficacy of IOA during neurosurgical procedures. METHODS: We reviewed (between January 1960 and July 2022) all studies in which IOAs were performed during neurosurgical procedures with patients in either prone, three-quarters prone, or park-bench positions. Additionally, a cohort of patients from our institutional experience was included. Efficacy outcomes were the rate of successful angiography and the rate of surgical adjustment/revision after IOA. Safety outcomes were the rate of angiography-related complications and mortality. Data were analyzed using a random-effects meta-analysis of proportions, and statistical heterogeneity was assessed. RESULTS: A total of 26 studies with 142 patients plus 32 subjects from our institution were included in the analysis. The rate of successful intraoperative angiography was 98% (95% CI 94% to 99%; I2=0%). The rate of surgical adjustment/revision was 18% (95% CI 12% to 28%; I2=0%). The rate of complications related to the angiography was 1% (95% CI 0% to 5%; I2=0%). There were no deaths associated with IOA. CONCLUSION: We found that IOA performed with patients in prone, three-quarters prone, and park-bench positions is feasible and safe with a non-negligible rate of intraoperative post-angiographical surgical adjustment/revision. Our findings suggest that the performance of IOA to complement vascular neurosurgical procedures might have a valuable role in favoring patient outcomes.

Quality management overview for the production of a tissue-engineered human skin substitute in Malaysia.

Treatments for skin injuries have recently advanced tremendously. Such treatments include allogeneic and xenogeneic transplants and skin substitutes such as tissue-engineered skin, cultured cells, and stem cells. The aim of this paper is to discuss the general overview of the quality assurance and quality control implemented in the manufacturing of cell and tissue product, with emphasis on our experience in the manufacturing of MyDerm®, an autologous bilayered human skin substitute. Manufacturing MyDerm® requires multiple high-risk open manipulation steps, such as tissue processing, cell culture expansion, and skin construct formation. To ensure the safety and efficacy of this product, the good manufacturing practice (GMP) facility should establish a well-designed quality assurance and quality control (QA/QC) programme. Standard operating procedures (SOP) should be implemented to ensure that the manufacturing process is consistent and performed in a controlled manner. All starting materials, including tissue samples, culture media, reagents, and consumables must be verified and tested to confirm their safety, potency, and sterility. The final products should also undergo a QC testing series to guarantee product safety, efficacy, and overall quality. The aseptic techniques of cleanroom operators and the environmental conditions of the facility are also important, as they directly influence the manufacturing of good-quality products. Hence, personnel training and environmental monitoring are necessary to maintain GMP compliance. Furthermore, risk management implementation is another important aspect of QA/QC, as it is used to identify and determine the risk level and to perform risk assessments when necessary. Moreover, procedures for non-conformance reporting should be established to identify, investigate, and correct deviations that occur during manufacturing. This paper provides insight and an overview of the QA/QC aspect during MyDerm® manufacturing in a GMP-compliant facility in the Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia.

Preparation of Fibrinogen-Depleted Human Platelet Lysate to Support Heparin-Free Expansion of Umbilical Cord-Derived Mesenchymal Stem Cells.

Human platelet lysate (hPL) has high levels of fibrinogen and coagulation factors, which can lead to gel and precipitate formation during storage and cell culture. Heparin derived from animals is commonly added to minimize these risks, but cannot completely eliminate them. Thus, this study proposes an alternative method to prepare fibrinogen-depleted hPL (Fd-hPL) that supports heparin-free expansion of mesenchymal stem cells (MSCs). hPL was added to heparin to prepare heparin-hPL (H-hPL), whilst Fd-hPL was prepared by adding calcium salt to hPL to remove the fibrin clot. The concentrations of calcium, fibrinogen, and growth factors in H-hPL and Fd-hPL were compared. The effects of H-hPL and Fd-hPL on umbilical cord-derived MSCs (UC-MSCs) were assessed. The results showed that Fd-hPL possessed a significantly higher calcium concentration and a lower fibrinogen level than H-hPL. The concentrations of BDNF, TGF-ß1, and PDGF-BB showed no significant difference between H-hPL and Fd-hPL, but Fd-hPL had a lower VEGF concentration. Fd-hPL retained the characteristics of UC-MSCs, as it did not affect the cell viability, proliferation, multilineage differentiation potential, or surface marker expression. In conclusion, Fd-hPL effectively supported the in vitro expansion of MSCs without compromising their characteristics, positioning it as a potential substitute for FBS in MSC culture.

Lattice mismatch alleviation in p-CdTe/n-Si heterostructure by surface engineering on Si substrate.

The study used magnetron sputtering to investigate the growth of cadmium telluride (CdTe) thin films on surface treated n-type silicon (n-Si) substrates. The n-Si substrates were textured using potassium hydroxide (KOH) before the sputter deposition of CdTe. This was followed by cadmium chloride treatment to reduce the strain at the interface of CdTe and Si, which is caused by the incompatible lattice and thermal expansion mismatch (CTE). X-ray diffraction (XRD) analysis showed that the lowest FWHM and dislocation densities were obtained for CdCl2/CdTe/txt-nSi, which aligns with the scanning electron microscopy (SEM) results. In the SEM images, the interface bonding between the CdTe and Si surfaces was visible in the cross-sections, and the top-view images revealed sputtered CdTe thin films conforming to the patterns of pyramidal textured Si as an engineered surface to capture more light to maximize absorption in the CdTe/Si tandem design. The Energy dispersive X-ray (EDX) results showed that all the CdTe deposited on textured n-Si exhibited more Te atoms than Cd atoms, irrespective of the CdCl2 treatment. The presented results suggest that the texturization and CdCl2 treatment improved the morphology and grain boundary passivation of the sputtered CdTe. The adhesiveness of CdTe on the n-Si substrate was also significantly enhanced. Our findings further demonstrate that proper surface treatment of the Si substrate can greatly improve the quality of CdTe grown on Si by reducing the strain that occurs during the growth process. This study demonstrates a valuable method for enhancing the integration of CdTe with Si for two-junction tandem solar cell applications.

A comprehensive review of flexible cadmium telluride solar cells with back surface field layer.

Recent advancements in CdTe solar cell technology have introduced the integration of flexible substrates, providing lightweight and adaptable energy solutions for various applications. Some of the notable applications of flexible solar photovoltaic technology include building integrated photovoltaic systems (BIPV), transportation, aerospace, satellites, etc. However, despite this advancement, certain issues regarding metal and p-CdTe remained unresolved. Besides, the fabrication of a full-working device on flexible glass is challenging and requires special consideration due to the unstable morphology and structural properties of deposited film on ultra-thin glass substrates. The existing gap in knowledge about the vast potential of flexible CdTe solar cells on UTG substrates and their possible applications blocks their full capacity utilization. Hence, this comprehensive review paper exclusively concentrates on the obstacles associated with the implementation of CdTe solar cells on UTG substrates with a potential back surface field (BSF) layer. The significance of this study lies in its meticulous identification and analysis of the substantial challenges associated with integrating flexible CdTe onto UTG substrates and leveraging Cu-doped ZnTe as a potential BSF layer to enhance the performance of flexible CdTe solar cells.