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Amperometric determination of L-cysteine using a glassy carbon electrode modified with palladium nanoparticles grown on reduced graphene oxide in a Nafion matrix

Yusoff N, Rameshkumar P, Mohamed Noor A, Huang NM

Mikrochim Acta, 2018 04 03;185(4):246.
PMID: 29616348 DOI: 10.1007/s00604-018-2782-x

An amperometric sensor for L-Cys is described which consists of a glassy carbon electrode (GCE) that was modified with reduced graphene oxide placed in a Nafion film and decorated with palladium nanoparticles (PdNPs). The film was synthesized by a hydrothermal method. The PdNPs have an average diameter of about 10 nm and a spherical shape. The modified GCE gives a linear electro-oxidative response to L-Cys (typically at +0.6 V vs. SCE) within the 0.5 to 10 μM concentration range. Other figures of merit include a response time of less than 2 s, a 0.15 μM lower detection limit (at signal to noise ratio of 3), and an analytical sensitivity of 1.30 μA·μM-1·cm-2. The sensor displays selectivity over ascorbic acid, uric acid, dopamine, hydrogen peroxide, urea, and glucose. The modified GCE was applied to the determination of L-Cys in human urine samples and gave excellent recoveries. Graphical abstract Spherical palladium nanoparticles (PdNPs) on reduced graphene oxide-Nafion (rGO-Nf) films were synthesized using a hydrothermal method. This nanohybrid was used for modifying a glassy carbon electrode to develop a sensor electrode for detecting L-cysteine that has fast response (less than 2 s), low detection limit (0.15 μM), and good sensitivity (0.092 μA μM-1 cm-2).
Fulltext Dental patient knowledge about the effects of smoking and attitudes about the role of dentists in smoking cessation

Yahya NA, Saub R, Nor MM, Yusoff N

Southeast Asian J. Trop. Med. Public Health, 2017 Mar;48(2):473-84.
PMID: 29642311

Dentists can offer their patients who smoke tobacco assistance with smoking cessation. We conducted this study to assess dental patient knowledge about the effects of smoking and perceptions and attitudes regarding the role of dentists in smoking cessation counselling. We conducted this study to inform tobacco cessation programs that could potentially include dentists. We conducted a cross-sectional study using a self-administered questionnaire among 375 patients. The mean age of subjects was 33.4 years; females comprised 51.5%. Participants were divided into 3 groups: those who never smoked (n = 263, 70.7%), smokers (n = 92, 24.7%), and ex-smokers (n = 17, 4.5%). Significantly more participants (p = 0.046) who never smoked (92.9%) knew smoking can cause bad breath than smokers(86.9%). Significantly more participants (p = 0.002) who never smoked (74.8%) knew smoking can cause periodontal disease than smokers (57.6%). Significantly
more participants (p < 0.001) who never smoked (84.5%) knew smoking can cause
oral cancer than smokers (66.7%). Significantly more participants (p < 0.001) who never smoked (86.7%) knew smoking can cause lung cancer than smokers (69.7%). Significantly more participants who never smoked (85.5%) felt dentists should be interested in the smoking status of their patients (p = 0.004) than smokers (72.6%). Significantly more participants (p = 0.08) who never smoked (69.6%) stated dentists should give smoking cessation advice than smokers/ex-smokers (59.0%). Smoker/ex-smokers had less knowledge about the effects of smoking on oral and general health than non-smokers. Both smokers/ex-smokers and non-smokers felt dentists should provide smoking cessation advice.
Fulltext Inhibition of NF-κB Signaling Reduces the Stemness Characteristics of Lung Cancer Stem Cells

Zakaria N, Mohd Yusoff N, Zakaria Z, Widera D, Yahaya BH

Front Oncol, 2018;8:166.
PMID: 29868483 DOI: 10.3389/fonc.2018.00166

Cancer stem cells (CSCs) are a subpopulation of cancer cells that play a pivotal role in tumor development, invasion, metastasis, and recurrence. We and others have reported significant involvement of the NF-κB pathway in regulating CSCs of non-small cell lung cancer (NSCLC). In this study, we evaluated the effects of NF-κB inhibition on self-renewal, stemness, migration, and expression of genes involved in the epithelial to mesenchymal transition (EMT) and apoptosis resistance in lung CSCs. Different concentrations of the NF-κB inhibitor BMS-345541 (0.4, 4.0, and 10.0 µM), an inhibitor the NF-κB upstream kinase IKKβ, were used to treat both lung CSCs (CD166+CD44+, CD166+EpCAM+) and non-CSC NSCLC cells (CD166-CD44-, CD166-EpCAM-) in A549 and H2170 cell lines. We assessed the impact of BMS-345541 on the ability to form tumorspheres (self-renewal assay), expression of stemness genes (SOX2, OCT4, NANOG, SCA-1, and KLF4), migration, and expression of EMT and apoptosis-related genes. Inhibition of NF-κB by BMS-345541 effectively reduced the stemness, self-renewal, and migration capacity of lung CSCs. Moreover, expression of genes involved in the EMT (SNAI1 and TWIST) and apoptosis resistance (BCL-2, BAX, and BIRC5) was significantly reduced following the treatments, suggesting that NF-κB inhibition is sufficient to prevent the EMT and induce apoptosis in lung CSCs. Our findings suggest that NF-κB inhibition could reduce the capability of CSCs to maintain their population within the tumor mass, potentially decelerating cancer progression, relapse, and chemotherapy resistance.
An analysis of genetic association in opioid dependence susceptibility

Nagaya D, Zahari Z, Saleem M, Yahaya BH, Tan SC, Yusoff NM

J Clin Pharm Ther, 2018 Feb;43(1):80-86.
PMID: 28656735 DOI: 10.1111/jcpt.12585

WHAT IS KNOWN: Drug addiction is a novelty-seeking personality trait that is associated with the candidate genes OPRD1 (opioid delta receptors), OPRK1 (opioid kappa receptors) and PDYN (prodynorphin). However, associations between single nucleotide polymorphisms (SNPs) rs1042114 (80G>T) of the OPRD1 gene, rs702764 (843 A>G) of the OPRK1 gene, and rs910080 (3' UTR _743T>C), rs1997794 (5' UTR -381A>G) and rs1022563 (3' UTR) of the PDYN gene and novelty seeking remain controversial as reported results have not been reproducible.
OBJECTIVE: The goal of this study was to determine the frequencies of SNPs rs1042114, rs702764, rs1997794, rs1022563 and rs910080 in the Malaysian population and to study their association with opioid dependence in Malaysian Malays.
METHODS: A total of 459 Malay male with opioid dependence and 543 healthy male (controls) subjects were included in this study. SNPs were genotyped using the TaqMan SNP genotyping assay. Statistical analysis was performed using Golden Helix SVS software suite to identify the distribution of allele and genotype frequencies, and SNP-SNP interactions were also analysed in this study.
RESULTS AND DISCUSSION: SNP rs1042114 in the OPRD1 gene is strongly associated with opiate addiction (P=.0001). In individuals homozygous for this risk allele, the likelihood of opiate addiction is increased by a factor 1.62 (95% confidence interval (CI) 1.412-1.875). Polymorphic alleles at SNP rs702764 of OPRK1 were not associated with opioid dependence. A significant association between opioid dependence and SNP rs910080 of PDYN (P=.0217) was detected, but there was no association for SNPs rs199774 and rs1022563. A significant interaction was also identified between homozygous wild-type genotype TT of rs702764 with the risk genotypes TG/GG of rs1042114 (odds ratio (OR)=2.111 (95% CI 1.227-3.631), P=.0069) and with the risk genotypes GA/AA of rs910080 (OR=1.415 (95% CI 1.04-1.912), P=.0239).
WHAT IS NEW AND CONCLUSION: The results indicate that SNPs rs1042114 and rs910080 contribute to vulnerability to opioid dependence in the Malaysian Malay population. These results will help us to understand the effect of the SNPs and the SNP-SNP interaction on opioid dependence and may assist in efforts to screen vulnerable individuals and match them with individually tailored prevention and treatment strategies.
Cellulitis: An unusual manifestation of Neisseria meningitidis infection

Muhd Yusoff NH, Zainol Rashid Z, Sulong A, Shafiee MN, Ismail Z

Malays J Pathol, 2019 Dec;41(3):351-354.
PMID: 31901921

INTRODUCTION: Neisseria meningitidis infections often cause severe meningitis as well as bacteraemia. However, cellulitis in meningococcal diseases have rarely been described. Here, we report a case of right lower limb cellulitis caused by N. meningitidis.
CASE REPORT: A 69-year-old woman presented with fever and lower limb swelling. She had diabetes mellitus, hypertension, dyslipidaemia and a history of surgical resection of vulvar carcinoma. N. meningitidis was isolated from her blood culture.
DISCUSSION: This report provides additional evidence in support of N. meningitidis as a cause of cellulitis.
Total anthelmintic failure to control nematode parasites of small ruminants on government breeding farms in Sabah, East Malaysia

Chandrawathani P, Yusoff N, Wan LC, Ham A, Waller PJ

Vet Res Commun, 2004 Aug;28(6):479-89.
PMID: 15509022

Government-owned small-ruminant breeding farms in Malaysia provide the source of sheep and goats to smallholder farmers in the country. In the eastern Malaysian state of Sabah, high-level stock losses have been recorded on these farms for several years, frequently accompanied by clinical signs indicating pathogenic levels of infections with the nematode parasite Haemonchus contortus. This suggests that their dependence on chemotherapy to control parasite infections had failed. Accordingly, tests for anthelmintic efficacy using the faecal egg count reduction test (FECRT) on the range of drugs used to control nematode parasites were carried out on the five government small-ruminant breeding farms in Sabah. These tests showed a total failure of the benzimidazole, imidothiazole, macrocyclic lactone and salicylanilide groups of anthelmintics to control H. contortus infections of sheep and goats on all farms. Drastic changes in animal management need to be made in an attempt to deal with this situation, for which suggestions are made.
Self-perceived mental well-being amongst Malaysian dentists

Ab-Murat N, Mason L, Kadir RA, Yusoff N

Int J Occup Saf Ergon, 2018 Jun;24(2):233-239.
PMID: 28010176 DOI: 10.1080/10803548.2016.1268869

PURPOSE: To assess Malaysian dentists' perceptions of their mental well-being.
METHODS: A self-administered questionnaire was developed based on a conceptual framework of mental health and well-being model. Two aspects were assessed, namely the physiological (two domains) and the psychological (six domains). Participants were asked to rate their experiences of the aforementioned aspects using a 5-point Likert scale ranging from all the time to never.
RESULTS: The response rate was 81%. Most of the dentists (61.7%) perceived having positive mental well-being. Under the physiological aspect, most respondents reported that they were 'generally happy' (93.3%), but about 30% stated they were 'stressed physically and emotionally'. Of the six domains under the psychological aspect, positive well-being was observed in the 'sense of coherence' and 'behavioural stress' domains. Participants who were above 40 years old, married and had children reported having a more positive mental well-being when compared with their counterparts.
CONCLUSION: Overall, most Malaysian dentists perceived having a positive mental well-being. It is crucial, however, to closely monitor and initiate early interventions for those with negative symptoms to ensure the safe practice of dentistry.
Design and validation of a bi-axial loading bioreactor for mechanical stimulation of engineered cartilage

Yusoff N, Abu Osman NA, Pingguan-Murphy B

Med Eng Phys, 2011 Jul;33(6):782-8.
PMID: 21356602 DOI: 10.1016/j.medengphy.2011.01.013

A mechanical-conditioning bioreactor has been developed to provide bi-axial loading to three-dimensional (3D) tissue constructs within a highly controlled environment. The computer-controlled bioreactor is capable of applying axial compressive and shear deformations, individually or simultaneously at various regimes of strain and frequency. The reliability and reproducibility of the system were verified through validation of the spatial and temporal accuracy of platen movement, which was maintained over the operating length of the system. In the presence of actual specimens, the system was verified to be able to deliver precise bi-axial load to the specimens, in which the deformation of every specimen was observed to be relatively homogeneous. The primary use of the bioreactor is in the culture of chondrocytes seeded within an agarose hydrogel while subjected to physiological compressive and shear deformation. The system has been designed specifically to permit the repeatable quantification and characterisation of the biosynthetic activity of cells in response to a wide range of short and long term multi-dimensional loading regimes.
Fulltext Passively mode locked thulium and thulium/holmium doped fiber lasers using MXene Nb2C coated microfiber

Ahmad H, Ramli R, Ismail NN, Aidit SN, Yusoff N, Samion MZ

Sci Rep, 2021 Jun 02;11(1):11652.
PMID: 34078979 DOI: 10.1038/s41598-021-90978-x

As a result of the emergence of two-dimensional (2D) materials for various opto-electronics applications, a new class of materials named MXenes have been attracting interests due to their outstanding nonlinear properties. In this work, an MXene niobium carbide (Nb2C) was proposed and demonstrated as a saturable absorber to induce mode-locking in thulium- and thulium/holmium-doped fiber lasers. The Nb2C solution was first prepared using the liquid exfoliation technique, and then deposited onto a microfiber for integration into the laser cavity. Stable mode-locking operation was observed in both laser cavities, where the center wavelengths of the laser were recorded at 1944 nm for the TDFL and 1950 nm for the THDFL. The generated pulses in the TDFL and THDFL had repetition rates of 9.35 and 11.76 MHz respectively, while their corresponding pulse widths were 1.67 and 1.34 ps. Both of the lasers were highly stable, having SNR values of more than 52 dB and showed no major fluctuations when tested for their long-term stabilities. The results demonstrate an excellent performance of the Nb2C as a saturable absorber, offering opportunities to further explore MXenes for future photonics devices.
Fulltext Generation of Q-switched Pulses in Thulium-doped and Thulium/Holmium-co-doped Fiber Lasers using MAX phase (Ti3AlC2)

Ahmad H, Kamely AA, Yusoff N, Bayang L, Samion MZ

Sci Rep, 2020 Jun 08;10(1):9233.
PMID: 32514045 DOI: 10.1038/s41598-020-66141-3

A MAX phase Ti3AlC2 thin film is demonstrated as a saturable absorber (SA) to induce Q-switching in the 2.0 μm region. The Ti3AlC2 thin film is sandwiched between two fiber ferrules and integrated into thulium doped fiber laser (TDFL) and thulium-holmium doped fiber laser (THDFL) cavities. Stable Q-switched pulses are observed at 1980.79 nm and 1959.3 nm in the TDFL and THDFL cavities respectively, with repetition rates of 32.57 kHz and 21.94 kHz and corresponding pulse widths of 2.72 μs and 3.9 μs for both cavities. The performance of the Ti3AlC2 based SA for Q-switching operation indicates the high potential of other MAX phase materials to serve as SAs in future photonics systems.
Fulltext How Much We Think of Ourselves and How Little We Think of Others: An Investigation of the Neuronal Signature of Self-Consciousness between Different Personality Traits through an Event-Related Potential Study

Hassan AB, Begum T, Reza MF, Yusoff N

Malays J Med Sci, 2016 Nov;23(6):70-82.
PMID: 28090181 MyJurnal DOI: 10.21315/mjms2016.23.6.8

Previous studies have revealed that self-related tasks (items) receive more attention than non-self-related, and that they elicit event-related potential (ERP) components with larger amplitudes. Since personality has been reported as one of the biological correlates influencing these components, as well as our behavioural differences, it is important to examine how it affects our self-consciousness in relation to tasks of varied relevance and the neurological basis.
Fulltext Dengue virus type 2 (DENV2)-induced oxidative responses in monocytes from glucose-6-phosphate dehydrogenase (G6PD)-deficient and G6PD normal subjects

Al-Alimi AA, Ali SA, Al-Hassan FM, Idris FM, Teow SY, Mohd Yusoff N

PLoS Negl Trop Dis, 2014 Mar;8(3):e2711.
PMID: 24625456 DOI: 10.1371/journal.pntd.0002711

Dengue virus is endemic in peninsular Malaysia. The clinical manifestations vary depending on the incubation period of the virus as well as the immunity of the patients. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is prevalent in Malaysia where the incidence is 3.2%. It has been noted that some G6PD-deficient individuals suffer from more severe clinical presentation of dengue infection. In this study, we aim to investigate the oxidative responses of DENV2-infected monocytes from G6PD-deficient individuals.
Fulltext G6PD Viangchan and G6PD Mediterranean are the main variants in G6PD deficiency in the Malay population of Malaysia

Mohd Yusoff N, Shirakawa T, Nishiyama K, Choo KE, Isa MN, Matsuo M

Southeast Asian J. Trop. Med. Public Health, 2003;34 Suppl 3:135-7.
PMID: 15906717

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked red blood cell enzymopathy common in malaria endemic areas. Individuals affected by this disease show a wide variety of clinical signs of acute hemolytic anemia. Mutations of the G6PD gene in the Malay population with G6PD deficiency in Kelantan, a state in North East Malaysia were studied. Ninety-three individuals with G6PD deficiency were subjected to mutation analysis of the G6PD gene using polymerase chain reaction based techniques of multiplex PCR. Of the ninety-three DNA samples studied, molecular defects were identified in 80 cases (86%). Variants were heterogeneous - 28.7% were found to have a G to A nucleotide change at nucleotide 871 of the G6PD gene (G871A), corresponding to G6PD Viangchan. The other major mutations were G6PD Mediterranean, G6PD Vanua Lava, G6PD Coimbra, G6PD Kaiping, G6PD Orissa, G6PD Mahidol, G6PD Canton and G6PD Chatham. These results showed that there are heterogeneous mutations of the G6PD gene associated with G6PD deficiency and that G6PD Viangchan and G6PD Mediterranean account for the main variants in G6PD deficiency among the Malay population in Malaysia.
The evolutionary origins of Southeast Asian Ovalocytosis

Paquette AM, Harahap A, Laosombat V, Patnode JM, Satyagraha A, Sudoyo H, et al.

Infect Genet Evol, 2015 Aug;34:153-9.
PMID: 26047685 DOI: 10.1016/j.meegid.2015.06.002

Southeast Asian Ovalocytosis (SAO) is a common red blood cell disorder that is maintained as a balanced polymorphism in human populations. In individuals heterozygous for the SAO-causing mutation there are minimal detrimental effects and well-documented protection from severe malaria caused by Plasmodium vivax and Plasmodium falciparum; however, the SAO-causing mutation is fully lethal in utero when homozygous. The present-day high frequency of SAO in Island Southeast Asia indicates the trait is maintained by strong heterozygote advantage. Our study elucidates the evolutionary origin of SAO by characterizing DNA sequence variation in a 9.5 kilobase region surrounding the causal mutation in the SLC4A1 gene. We find substantial haplotype diversity among SAO chromosomes and estimate the age of the trait to be approximately 10,005 years (95% CI: 4930-23,200 years). This date is far older than any other human malaria-resistance trait examined previously in Southeast Asia, and considerably pre-dates the widespread adoption of agriculture associated with the spread of speakers of Austronesian languages some 4000 years ago. Using a genealogy-based method we find no evidence of historical positive selection acting on SAO (s=0.0, 95% CI: 0.0-0.03), in sharp contrast to the strong present-day selection coefficient (e.g., 0.09) estimated from the frequency of this recessively lethal trait. This discrepancy may be due to a recent increase in malaria-driven selection pressure following the spread of agriculture, with SAO targeted as a standing variant by positive selection in malarial populations.
Fulltext Lessons Learnt from the Development and Implementation of an Online Assessment System for Medical Science Programmes

Er HM, Nadarajah VD, Hays RB, Yusoff N, Loh KLY

Med Sci Educ, 2019 Dec;29(4):1103-1108.
PMID: 34457589 DOI: 10.1007/s40670-019-00802-5

Challenges in assessment implementation include assessment blueprinting, accuracy and timeliness of result processing, item analysis and personalised feedback. These challenges were addressed by an online assessment system (OAS) that translates the educational framework of outcome-based education (OBE) into an integrated platform applicable across academic programmes. OBE principles of transparency, measurability, relevance, and individualisation was feasibly addressed using technology. The system development required continuous stakeholder engagement and feedback. Its implementation involved change management at institutional level with shifts in procedures, responsibilities, staff competencies and resource allocation. This article describes approaches taken and the lessons learned in developing and implementing OAS to enhance assessment practice for medical science programmes.
Three new species of Acanthocephala from Acanthogyrus (Acanthosentis) (Acanthocephala: Quadrigyridae) from tinfoil barb fish, Barbonymus schwanenfeldii in Lake Kenyir, Terengganu, Malaysia

Mohd-Agos S, Mohd-Husin N, Zakariah MI, Yusoff NAH, Wahab W, Jones JB, et al.

Trop Biomed, 2021 Sep 01;38(3):387-395.
PMID: 34608112 DOI: 10.47665/tb.38.3.064

This study was carried out in order to identify acanthocephalan species complexes, based on morphological variability, infecting Barbonymus schwanenfeldii from Lake Kenyir, Terengganu, Malaysia. Acanthocephala were fixed in ethanol, stained with aceto-carmine and studied morphologically by using a light microscope. Variation in morphological traits such as proboscis, proboscis receptacle, egg, testes shape and location, number of hooks and cement gland has been traditionally used to diagnose the acanthocephalans species but the delimitations between closely related species are still confusing and are always questionable among taxonomists. Molecular analysis was used for support the identification. Morphological variability prospecting reveals the presence of three different new species complexes from the subgenus Acanthosentis by referring published taxonomic keys. These new species may be distinguished from the other 46 described species of Acanthosentis by having six unique structures: the presence of an anterior parareceptacle structure (PRS); vaginal sleeve structure; a paired lateral, cone-shaped, muscular jacket surrounding the vagina; alternating pattern and size of proboscis hooks, variation in proboscis size and shape; the presence of the circular collar ring around the neck between the proboscis and trunk and lastly the presence of a muscular-like structure attached to the collar ring on the proboscis. These acanthocephalans found in the intestine of B. schwanenfeldii in Kenyir Lake Malaysia represent new species, named Acanthogyrus ( Acanthosentis) kenyirensis n.sp., A. ( A.) terengganuensis n.sp. and A. ( A.) tembatensis n. sp.
Performance of the hybrid growth sequencing batch reactor (HG-SBR) for biodegradation of phenol under various toxicity conditions

Yusoff N, Ong SA, Ho LN, Wong YS, Saad FNM, Khalik W, et al.

J Environ Sci (China), 2019 Jan;75:64-72.
PMID: 30473308 DOI: 10.1016/j.jes.2018.03.001

Hybrid growth microorganisms in sequencing batch reactors have proven effective for treating the toxic compound phenol, but the toxicity effect under different toxicity conditions has rarely been discussed. Therefore, the performance of the HG-SBR under toxic, acute and chronic organic loading can provide the overall operating conditions of the system. Toxic organic loading (TOL) was monitored during the first 7hr while introducing 50mg/L phenol to the system. The system was adversely affected with the sudden introduction of phenol to the virgin activated sludge, which caused a low degradation rate and high dissolved oxygen consumption during TOL. Acute organic loading (AOL) had significant effects at high phenol concentrations (600, 800 1000mg/L). The specific oxygen uptake rate (SOUR) gradually decreased to 4.9mg O2/(g MLVSS·hr) at 1000mg/L of phenol compared to 12.74mg O2/(g MLVSS·hr) for 200mg/L of phenol. The HG-SBR was further monitored during chronic organic loading (COL) over 67days. The effects of organic loading were more apparent at 800mg/L and 1000mg/L phenol concentrations, as the removal range was between 22%-30% and 18%-46% respectively, which indicated the severe effects of COL.
High allele frequency of CYP2C9*3 (rs1057910) in a Negrito's subtribe population in Malaysia; Aboriginal people of Jahai

Rosdi RA, Mohd Yusoff N, Ismail R, Soo Choon T, Saleem M, Musa N, et al.

Ann Hum Biol, 2015 Sep 24.
PMID: 26402341

CYP2C9 gene polymorphisms modulate inter-individual variations in the human body's responses to various endogenous and exogenous drug substrates. To date, little is known about the CYP2C9 gene polymorphisms among the aboriginal populations of the world, including those in Malaysia.
Mesenchymal Stromal Cells-Derived Exosome and the Roles in the Treatment of Traumatic Brain Injury

Mot YY, Moses EJ, Mohd Yusoff N, Ling KH, Yong YK, Tan JJ

Cell Mol Neurobiol, 2023 Mar;43(2):469-489.
PMID: 35103872 DOI: 10.1007/s10571-022-01201-y

Traumatic brain injury (TBI) could result in life-long disabilities and death. Though the mechanical insult causes primary injury, the secondary injury due to dysregulated responses following neuronal apoptosis and inflammation is often the cause for more detrimental consequences. Mesenchymal stromal cell (MSC) has been extensively investigated as the emerging therapeutic for TBI, and the functional properties are chiefly attributed to their secretome, especially the exosomes. Delivering these nanosize exosomes have shown to ameliorate post-traumatic injury and restore brain functions. Recent technology advances also allow engineering MSC-derived exosomes to carry specific biomolecules of interest to augment their therapeutic outcome. In this review, we discuss the pathophysiology of TBI and summarize the recent progress in the applications of MSCs-derived exosomes, the roles and the signalling mechanisms underlying the protective effects in the treatment of the TBI.
Fulltext 2 μm passively mode-locked thulium-doped fiber lasers with Ta2AlC-deposited tapered and side-polished fibers

Ahmad H, Azri MFM, Ramli R, Samion MZ, Yusoff N, Lim KS

Sci Rep, 2021 Oct 28;11(1):21278.
PMID: 34711908 DOI: 10.1038/s41598-021-99928-z

In this work, mode-locked thulium-doped fiber lasers operating in the 2 µm wavelength region were demonstrated using tantalum aluminum carbide (Ta2AlC)-based saturable absorbers (SAs) utilizing the evanescent wave interaction. The Ta2AlC MAX Phase was prepared by dissolving the Ta2AlC powder in isopropyl alcohol and then deposited onto three different evanescent field-based devices, which were the tapered fiber, side-polished fiber, and arc-shaped fiber. Flame-brushing and wheel-polishing techniques were used to fabricate the tapered and arc-shaped fibers, respectively, while the side-polished fiber was purchased commercially. All three SA devices generated stable mode-locked pulses at center wavelengths of 1937, 1931, and 1929 nm for the tapered, side-polished, and arc-shaped fibers. The frequency of the mode-locked pulses was 10.73 MHz for the tapered fiber, 9.58 MHz for the side-polished fiber, and 10.16 MHz for the arc-shaped fiber. The measured pulse widths were 1.678, 1.734, and 1.817 ps for each of the three SA devices. The long-term stability of the mode-locked lasers was tested for each configuration over a 2-h duration. The lasers also showed little to no fluctuations in the center wavelengths and the peak optical intensities, demonstrating a reliable, ultrafast laser system.

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