Displaying publications 41 - 60 of 375 in total

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  1. Fulltext Fungal Planet description sheets: 868-950
    Crous PW, Carnegie AJ, Wingfield MJ, Sharma R, Mughini G, Noordeloos ME, et al.
    Persoonia, 2019 Jun;42:291-473.
    PMID: 31551622 DOI: 10.3767/persoonia.2019.42.11
    Novel species of fungi described in this study include those from various countries as follows: Australia, Chaetomella pseudocircinoseta and Coniella pseudodiospyri on Eucalyptus microcorys leaves, Cladophialophora eucalypti, Teratosphaeria dunnii and Vermiculariopsiella dunnii on Eucalyptus dunnii leaves, Cylindrium grande and Hypsotheca eucalyptorum on Eucalyptus grandis leaves, Elsinoe salignae on Eucalyptus saligna leaves, Marasmius lebeliae on litter of regenerating subtropical rainforest, Phialoseptomonium eucalypti (incl. Phialoseptomonium gen. nov.) on Eucalyptus grandis × camaldulensis leaves, Phlogicylindrium pawpawense on Eucalyptus tereticornis leaves, Phyllosticta longicauda as an endophyte from healthy Eustrephus latifolius leaves, Pseudosydowia eucalyptorum on Eucalyptus sp. leaves, Saitozyma wallum on Banksia aemula leaves, Teratosphaeria henryi on Corymbia henryi leaves. Brazil, Aspergillus bezerrae, Backusella azygospora, Mariannaea terricola and Talaromyces pernambucoensis from soil, Calonectria matogrossensis on Eucalyptus urophylla leaves, Calvatia brasiliensis on soil, Carcinomyces nordestinensis on Bromelia antiacantha leaves, Dendryphiella stromaticola on small branches of an unidentified plant, Nigrospora brasiliensis on Nopalea cochenillifera leaves, Penicillium alagoense as a leaf endophyte on a Miconia sp., Podosordaria nigrobrunnea on dung, Spegazzinia bromeliacearum as a leaf endophyte on Tilandsia catimbauensis, Xylobolus brasiliensis on decaying wood. Bulgaria, Kazachstania molopis from the gut of the beetle Molops piceus. Croatia, Mollisia endocrystallina from a fallen decorticated Picea abies tree trunk. Ecuador, Hygrocybe rodomaculata on soil. Hungary, Alfoldia vorosii (incl. Alfoldia gen. nov.) from Juniperus communis roots, Kiskunsagia ubrizsyi (incl. Kiskunsagia gen. nov.) from Fumana procumbens roots. India, Aureobasidium tremulum as laboratory contaminant, Leucosporidium himalayensis and Naganishia indica from windblown dust on glaciers. Italy, Neodevriesia cycadicola on Cycas sp. leaves, Pseudocercospora pseudomyrticola on Myrtus communis leaves, Ramularia pistaciae on Pistacia lentiscus leaves, Neognomoniopsis quercina (incl. Neognomoniopsis gen. nov.) on Quercus ilex leaves. Japan, Diaporthe fructicola on Passiflora edulis × P. edulis f. flavicarpa fruit, Entoloma nipponicum on leaf litter in a mixed Cryptomeria japonica and Acer spp. forest. Macedonia, Astraeus macedonicus on soil. Malaysia, Fusicladium eucalyptigenum on Eucalyptus sp. twigs, Neoacrodontiella eucalypti (incl. Neoacrodontiella gen. nov.) on Eucalyptus urophylla leaves. Mozambique, Meliola gorongosensis on dead Philenoptera violacea leaflets. Nepal, Coniochaeta dendrobiicola from Dendriobium lognicornu roots. New Zealand, Neodevriesia sexualis and Thozetella neonivea on Archontophoenix cunninghamiana leaves. Norway, Calophoma sandfjordenica from a piece of board on a rocky shoreline, Clavaria parvispora on soil, Didymella finnmarkica from a piece of Pinus sylvestris driftwood. Poland, Sugiyamaella trypani from soil. Portugal, Colletotrichum feijoicola from Acca sellowiana. Russia, Crepidotus tobolensis on Populus tremula debris, Entoloma ekaterinae, Entoloma erhardii and Suillus gastroflavus on soil, Nakazawaea ambrosiae from the galleries of Ips typographus under the bark of Picea abies. Slovenia, Pluteus ludwigii on twigs of broadleaved trees. South Africa, Anungitiomyces stellenboschiensis (incl. Anungitiomyces gen. nov.) and Niesslia stellenboschiana on Eucalyptus sp. leaves, Beltraniella pseudoportoricensis on Podocarpus falcatus leaf litter, Corynespora encephalarti on Encephalartos sp. leaves, Cytospora pavettae on Pavetta revoluta leaves, Helminthosporium erythrinicola on Erythrina humeana leaves, Helminthosporium syzygii on a Syzygium sp. bark canker, Libertasomyces aloeticus on Aloe sp. leaves, Penicillium lunae from Musa sp. fruit, Phyllosticta lauridiae on Lauridia tetragona leaves, Pseudotruncatella bolusanthi (incl. Pseudotruncatellaceae fam. nov.) and Dactylella bolusanthi on Bolusanthus speciosus leaves. Spain, Apenidiella foetida on submerged plant debris, Inocybe grammatoides on Quercus ilex subsp. ilex forest humus, Ossicaulis salomii on soil, Phialemonium guarroi from soil. Thailand, Pantospora chromolaenae on Chromolaena odorata leaves. Ukraine, Cadophora helianthi from Helianthus annuus stems. USA, Boletus pseudopinophilus on soil under slash pine, Botryotrichum foricae, Penicillium americanum and Penicillium minnesotense from air. Vietnam, Lycoperdon vietnamense on soil. Morphological and culture characteristics are supported by DNA barcodes.
  2. Idiopathic scoliosis. Prevalence and ethnic distribution in Singapore schoolchildren
    Daruwalla JS, Balasubramaniam P, Chay SO, Rajan U, Lee HP
    J Bone Joint Surg Br, 1985 Mar;67(2):182-4.
    PMID: 3980521
    Routine examination for spinal deformity as part of a school health screening programme was introduced in Singapore in 1981. The three different ethnic groups included in the study provided figures for the prevalence of idiopathic scoliosis in an Asian population. A three-tier system of examination was used and a total of 110744 children in three age groups were studied. In those aged 6 to 7 years the prevalence was 0.12%. The prevalence in those aged 11 to 12 years was 1.7% for girls and 0.4% for boys, a ratio of 3.2 to 1. In girls aged 16 to 17 years the prevalence was 3.1%. In the latter two age groups there was a significantly higher prevalence in Chinese girls as compared with Malay and Indian girls. The optimal age for school screening seemed to be 11 to 12 years, but repeated examinations may be worthwhile.
  3. Fulltext Increased Resilience Weakens the Relationship between Perceived Stress and Anxiety on Sleep Quality: A Moderated Mediation Analysis of Higher Education Students from 7 Countries
    Du C, Zan MCH, Cho MJ, Fenton JI, Hsiao PY, Hsiao R, et al.
    Clocks Sleep, 2020 Sep;2(3):334-353.
    PMID: 33089208 DOI: 10.3390/clockssleep2030025
    High levels of perceived stress and anxiety among university students are a global concern and are known to negatively influence sleep. However, few studies have explored how stress response styles, like psychological resilience and rumination, might alter these relationships. Using validated tools, perceived stress, anxiety, stress response styles, and sleep behaviors of undergraduate and graduate students from seven countries during the height of the COVID-19 pandemic were characterized in order to examine the relationships between these factors using mediation and moderation analyses. Students enrolled in universities in China, Ireland, Malaysia, Taiwan, South Korea, the Netherlands, and the United States were recruited in May 2020. A total of 2254 students completed this cross-sectional study. Perceived stress and anxiety were negatively associated with sleep quality through the mediation of rumination. Increased psychological resilience weakened the relationships between perceived stress and anxiety on sleep quality. The majority of students reported that COVID-19 negatively influenced their mental health and sleep quality but not sleep duration. Based on these results, university students would likely benefit from sleep education and mental health promotion programs that include trainings to increase psychological resilience and reduce rumination, particularly during times of increased stress.
  4. Fulltext Health Behaviors of Higher Education Students from 7 Countries: Poorer Sleep Quality during the COVID-19 Pandemic Predicts Higher Dietary Risk
    Du C, Zan MCH, Cho MJ, Fenton JI, Hsiao PY, Hsiao R, et al.
    Clocks Sleep, 2021 Jan 15;3(1):12-30.
    PMID: 33467418 DOI: 10.3390/clockssleep3010002
    Health behaviors of higher education students can be negatively influenced by stressful events. The global COVID-19 pandemic presents a unique opportunity to characterize and compare health behaviors across multiple countries and to examine how these behaviors are shaped by the pandemic experience. Undergraduate and graduate students enrolled in universities in China, Ireland, Malaysia, South Korea, Taiwan, the Netherlands and the United States (USA) were recruited into this cross-sectional study. Eligible students filled out an online survey comprised of validated tools for assessing sleep quality and duration, dietary risk, alcohol misuse and physical activity between late April and the end of May 2020. Health behaviors were fairly consistent across countries, and all countries reported poor sleep quality. However, during the survey period, the COVID-19 pandemic influenced the health behaviors of students in European countries and the USA more negatively than Asian countries, which could be attributed to the differences in pandemic time course and caseloads. Students who experienced a decline in sleep quality during the COVID-19 pandemic had higher dietary risk scores than students who did not experience a change in sleep quality (p = 0.001). Improved sleep quality was associated with less sitting time (p = 0.010). Addressing sleep issues among higher education students is a pressing concern, especially during stressful events. These results support the importance of making education and behavior-based sleep programming available for higher education students in order to benefit students' overall health.
  5. Fulltext The Effects of Sleep Quality and Resilience on Perceived Stress, Dietary Behaviors, and Alcohol Misuse: A Mediation-Moderation Analysis of Higher Education Students from Asia, Europe, and North America during the COVID-19 Pandemic
    Du C, Zan MCH, Cho MJ, Fenton JI, Hsiao PY, Hsiao R, et al.
    Nutrients, 2021 Jan 29;13(2).
    PMID: 33572863 DOI: 10.3390/nu13020442
    BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has increased the already high levels of stress that higher education students experience. Stress influences health behaviors, including those related to dietary behaviors, alcohol, and sleep; yet the effects of stress can be mitigated by resilience. To date, past research studying the connections between dietary behaviors, alcohol misuse, sleep, and resilience commonly investigated singular relationships between two of the constructs. The aim of the current study was to explore the relationships between these constructs in a more holistic manner using mediation and moderation analyses.

    METHODS: Higher education students from China, Ireland, Malaysia, South Korea, Taiwan, the Netherlands, and the United States were enrolled in a cross-sectional study from April to May 2020, which was during the beginning of the COVID-19 pandemic for most participants. An online survey, using validated tools, was distributed to assess perceived stress, dietary behaviors, alcohol misuse, sleep quality and duration, and resilience.

    RESULTS: 2254 students completed the study. Results indicated that sleep quality mediated the relationship between perceived stress and dietary behaviors as well as the relationship between perceived stress and alcohol misuse. Further, increased resilience reduced the strength of the relationship between perceived stress and dietary behaviors but not alcohol misuse.

    CONCLUSION: Based on these results, higher education students are likely to benefit from sleep education and resilience training, especially during stressful events.

  6. A new anthraquinone from Morinda citrifolia roots
    Ee GC, Wen YP, Sukari MA, Go R, Lee HL
    Nat Prod Res, 2009;23(14):1322-9.
    PMID: 19735047 DOI: 10.1080/14786410902753138
    An investigation of Morinda citrifolia roots afforded a new anthraquinone, 2-ethoxy-1-hydroxyanthraquinone (1), along with five other known anthraquinones: 1-hydroxy-2-methylanthraquinone (2), damnacanthal (3), nordamnacanthal (4), 2-formyl-1-hydroxyanthraquinone (5) and morindone-6-methyl-ether (6). This is the first report on the isolation of morindone-6-methyl-ether (6) from this plant. The structures of these compounds were elucidated based on spectroscopic analyses such as NMR, MS and IR. Biological evaluation of five pure compounds and all the extracts against the larvae of Aedes aegypti indicated 1-hydroxy-2-methylanthraquinone (2) and damnacanthal (3) were the extracts to exhibit promising larvicidal activities.
  7. Daphnifolin, a new xanthone from Mesua daphnifolia (Guttiferae)
    Ee GC, Lim CK, Ong GP, Sukari MA, Lee HL
    J Asian Nat Prod Res, 2006 Sep;8(6):567-70.
    PMID: 16931434
    A new tetraoxygenated xanthone, daphnifolin (1,3,5-trihydroxy-4-methoxyxanthone), along with three other xanthones, were isolated from the stem bark extracts of Mesua daphnifolia. Their structures were characterized on the basis of 1D and 2D NMR spectral data.
  8. Inophyllin A, a new pyranoxanthone from Calophyllum inophyllum (Guttiferae)
    Ee GC, Kua AS, Lim CK, Jong V, Lee HL
    Nat Prod Res, 2006 May 10;20(5):485-91.
    PMID: 16644547
    In the authors' continuing search for new natural products, their recent studies on the roots of Calophyllum inophyllum (Guttiferae) have yielded a new prenylated pyranoxanthone, Inophyllin A together with the common triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved through (1)H, (13)C, DEPT, COSY, HSQC and HMBC experiments. The molecular mass was determined using MS techniques. The authors report here the isolation of and structural elucidation for Inophyllin A as well as its toxicity test result. The discovery of this new natural product from the unexploited Malaysian forest will certainly contribute to the search for potential natural larvicides.
  9. Fulltext Cytotoxic activities of chemical constituents from Mesua daphnifolia
    Ee GC, Lim CK, Rahmat A, Lee HL
    Trop Biomed, 2005 Dec;22(2):99-102.
    PMID: 16883274
    Detail chemical investigations on the stem bark of Mesua daphnifolia gave three triterpenoids and four xanthones. They are friedelin (1), friedelan-1,3-dione (2), lup-20(29)- en-3ss-ol (3), cudraxanthone G (4), ananixanthone (5), 1,3,5-trihydroxy-4-methoxyxanthone (6) and euxanthone (7). These chemical constituents were tested in vitro for their cytotoxic activities against four cell lines, MDA-MB-231 (human estrogen receptor negative breast cancer), HeLa (cervical carcinoma), CEM-SS (T-lymphoblastic leukemia) and CaOV3 (human ovarian cancer). Compound 4 showed a broad spectrum of activity against the MDA-MB-231, HeLa and CEM-SS cell lines with IC5 0 values of 1.3, 4.0 and 6.7 microg/ml respectively. Meanwhile, the other compounds 1, 2, 3, 5, 6 and 7 gave only selective activities against the cell lines.
  10. Adulticide Resistance Status of Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia: A Statewide Assessment
    Elia-Amira NMR, Chen CD, Low VL, Lau KW, Haziqah-Rashid A, Amelia-Yap ZH, et al.
    J Med Entomol, 2019 10 28;56(6):1715-1725.
    PMID: 31290534 DOI: 10.1093/jme/tjz117
    Resistance status of Aedes albopictus (Diptera: Culicidae) collected from Sabah, East Malaysia, was evaluated against four major classes of adulticides, namely pyrethroid, carbamate, organochlorine, and organophosphate. Adult bioassays conforming to WHO standard protocols were conducted to assess knockdown and mortality rates of Ae. albopictus. Among tested pyrethroid adulticides, only cyfluthrin, lambda-cyaholthrin, and deltamethrin were able to inflict total knockdown. The other adulticide classes mostly failed to cause any knockdown; the highest knockdown rate was only 18.33% for propoxur. With regards to mortality rate, Ae. albopictus was unanimously susceptible toward all pyrethroids, dieldrin, and malathion, but exhibited resistance toward bendiocarb, propoxur, dichlorodiphenyltrichloroethane, and fenitrothion. Additionally, correlation analysis demonstrated cross-resistance between bendiocarb and propoxur, and malathion and propoxur. In conclusion, this study has disclosed that pyrethroids are still generally effective for Aedes control in Sabah, Malaysia. The susceptibility status of Ae. albopictus against pyrethroids in descending order was cyfluthrin > lambda-cyhalothrin > deltamethrin > etofenprox > permethrin.
  11. Organophosphate and Organochlorine Resistance in Larval Stage of Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia
    Elia-Amira NMR, Chen CD, Lau KW, Lee HL, Low VL, Norma-Rashid Y, et al.
    J Econ Entomol, 2018 09 26;111(5):2488-2492.
    PMID: 29982497 DOI: 10.1093/jee/toy184
    The present study aims to investigate the susceptibility status of Aedes albopictus (Skuse) collected from residential areas in Sabah, Malaysia towards eight WHO-recommended dosages of larvicides representing the classes of organophosphates and organochlorines. Field and reference strains of Ae. albopictus larvae were bioassayed in accordance to WHO standard methods using diagnostic dosages of bromophos, malathion, fenthion, fenitrothion, temephos, chlorpyrifos, dichlorodiphenyltrichloroethane (DDT), and dieldrin. The results revealed that Ae. albopictus was resistant (mortality < 90%) towards malathion, temephos, and DDT. In addition, most of the Ae. albopictus strains exhibited a wide range of susceptibilities against bromophos, with mortality ranged from 49.33 to 93.33%. On the contrary, only dieldrin was able to induce 100% mortality against all strains of Ae. albopictus. Tolerance to fenitrothion, fenthion, and chlorpyrifos, with mortality ranging from 81.33 to 97.33%, was also observed in this study.
  12. Assessment of the susceptibility status of Aedes albopictus (Diptera: Culicidae) from Interior, Sandakan and Tawau divisions of Sabah, Malaysia based on WHO diagnostic doses of larvicides
    Elia-Amira NMR, Chen CD, Low VL, Lau KW, Haziqah-Rashid A, Amelia-Yap ZH, et al.
    Trop Biomed, 2021 Jun 01;38(2):196-204.
    PMID: 34172711 DOI: 10.47665/tb.38.2.058
    Susceptibility status of Aedes albopictus (Skuse) sampled from residential areas in Interior, Sandakan and Tawau divisions of Sabah, Malaysia, was evaluated based on the WHOrecommended doses of organochlorine and organophosphate larvicides. To determine susceptibility status, larval bioassays were carried out and post 24-hour mortalities based on WHO resistance classifications were adopted. The results demonstrated that Ae. albopictus larvae were resistant toward 5 out of the 8 larvicides tested. Larvae from all populations were resistant against bromophos, fenitrothion, malathion, temephos and dichlorodiphenyltrichloroethane (DDT), with mortalities ranging from 0.00 to 89.33%. Dieldrin, on the other hand, could induce 100.00% mortalities in all populations, followed by fenthion and chlorpyrifos, with mortalities ranging from 97.33 to 100.00% and 81.33 to 100.00% respectively. Despite most populations exhibiting similitude in their resistance status, larvae from Sandakan exhibited the highest resistance level whereas the lowest level was observed in Keningau. In view of the inadequacy of some larvicides in controlling Ae. albopictus in this study, integrated management such as insecticide rotation or combination of interventions is warranted.
  13. Statewide Efficacy Assessment of Insect Growth Regulators Against Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia: An Alternative Control Strategy?
    Elia-Amira NMR, Chen CD, Low VL, Lau KW, Haziqah-Rashid A, Amelia-Yap ZH, et al.
    J Med Entomol, 2022 01 12;59(1):301-307.
    PMID: 34459477 DOI: 10.1093/jme/tjab146
    The efficacy of three groups of insect growth regulators, namely juvenile hormone mimics (methoprene and pyriproxyfen), chitin synthesis inhibitors (diflubenzuron and novaluron), and molting disruptor (cyromazine) was evaluated for the first time, against Aedes albopictus Skuse (Diptera: Culicidae) larvae from 14 districts in Sabah, Malaysia. The results showed that all field populations of Ae. albopictus were susceptible towards methoprene, pyriproxyfen, diflubenzuron, novaluron, and cyromazine, with resistance ratio values ranging from 0.50-0.90, 0.60-1.00, 0.67-1.17, 0.71-1.29, and 0.74-1.07, respectively. Overall, the efficacy assessment of insect growth regulators in this study showed promising outcomes and they could be further explored as an alternative to conventional insecticides.
  14. Urine as a diagnostic specimen for the detection of Chlamydia trachomatis in Malaysia by ligase chain reaction
    Gaydos CA, Ngeow YF, Lee HH, Canavaggio M, Welsh LE, Johanson J, et al.
    Sex Transm Dis, 1996 9 1;23(5):402-6.
    PMID: 8885072
    BACKGROUND AND OBJECTIVES: Noninvasive urine screening for Chlamydia trachomatis infections offers a valuable public health tool, which could be of vast importance in chlamydial control programs. The authors evaluated a new DNA amplification method, ligase chain reaction (LCR).

    GOALS: The goal was to ascertain whether urine testing could be used as screening method to detect C. trachomatis infections in commercial sex workers, patients at sexually transmitted diseases clinic, and asymptomatic patients in Kuala Lumpur, Malaysia.

    METHODS: First-void urine specimens from 300 men and 300 women were tested by LCR, as well as by a commercially available enzyme immunoassay. The LCR assay amplifies specific sequences within the chlamydial plasmid with ligand-labeled probes, and the resultant amplicons are detected by an automated immunoassay. Specimens with discrepant results were confirmed by another LCR of the specimen that targeted the gene for the major outer membrane protein (OMP1).

    RESULTS: There were 31 LCR-positive male urine and 37 LCR-positive female urine specimens. The resolved sensitivity and specificity for the LCR of the male urine specimens were 100% and 99.6%, respectively, whereas for female urine specimens, the sensitivity and specificity were 100% and 98.5%, respectively. After resolution of discrepant test results by OMP1 LCR, the prevalence was 10% for men and 11% for women. The urine enzyme immunoassay was not useful in diagnosing C. trachomatis infections in either men or women, as the resolved sensitivities were 10% and 15.2%, respectively. The specificities were 99.6% for men and 98.9% for women.

    CONCLUSIONS: Testing first-void urine specimens by LCR is a highly sensitive and specific method to diagnose C. trachomatis infections in men and women, providing health care workers and public health officials with a new molecular amplification assay that uses noninvasive urine specimens for population-based screening purposes.

  15. Fulltext Brain and spinal tumour
    Goh CH, Lu YY, Lau BL, Oy J, Lee HK, Liew D, et al.
    Med J Malaysia, 2014 Dec;69(6):261-7.
    PMID: 25934956 MyJurnal
    This study reviewed the epidemiology of brain and spinal tumours in Sarawak from January 2009 till December 2012. The crude incidence of brain tumour in Sarawak was 4.6 per 100,000 population/year with cumulative rate 0.5%. Meningioma was the most common brain tumour (32.3%) and followed by astrocytoma (19.4%). Only brain metastases showed a rising trend and cases were doubled in 4 years. This accounted for 15.4% and lung carcinoma was the commonest primary. Others tumour load were consistent. Primitive neuroectodermal tumour (PNET) and astrocytoma were common in paediatrics (60%). We encountered more primary spinal tumour rather than spinal metastases. Intradural schwannoma was the commonest and frequently located at thoracic level. The current healthcare system in Sarawak enables a more consolidate data collection to reflect accurate brain tumours incidence. This advantage allows subsequent future survival outcome research and benchmarking for healthcare resource planning.
  16. Antibiotic prophylaxis in elective colorectal surgery
    Gul YA, Lian LH, Jabar FM, Moissinac K
    ANZ J Surg, 2002 Apr;72(4):275-8.
    PMID: 11982514
    Antibiotics are often administered in elective colorectal surgery to prevent wound infection. The tendency for surgeons to prolong the administration of prophylactic antibiotic therapy in the postoperative period is a well-known fact. The aim of this study was to elucidate the pattern of prophylactic antibiotic utilization in elective colorectal surgery and to determine if evidence-based medicine is employed in relation to this practice.
  17. TEMPO-oxidized nanocellulose films derived from coconut residues: Physicochemical, mechanical and electrical properties
    Hassan SH, Velayutham TS, Chen YW, Lee HV
    Int J Biol Macromol, 2021 Jun 01;180:392-402.
    PMID: 33737185 DOI: 10.1016/j.ijbiomac.2021.03.066
    The present work focuses on the development of cellulose nanofibrils (CNF) film that derived from sustainable biomass resources, which potentially to work as bio-based conductive membranes that assembled into supercapacitors. The chemically purified cellulose was isolated from different parts of coconut (coconut shell and its husk) and further subjected to 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation for CNF preparation. Physicochemical properties of prepared CNFs were studied in terms of chemical characteristics & crystallinity, surface functionalities, surface morphology, and thermal properties. Both coconut shell-derived CNF and coconut husk-derived CNF fulfilled with nanocellulose's characteristics with fibres width ranged of 70-120 nm and 150-330 nm, respectively. CNF films were further prepared by solvent casting method to measure the modulus elasticity, piezoelectric and dielectric properties of the films. Mechanical study indicated that coconut shell-derived CNF film showed a higher value of elastic modulus than the coconut husk-derived CNF film, which was 8.39 GPa and 5.36 GPa, respectively. The effectiveness of electrical aspects for CNF films are well correlated with the crystallinity and thermal properties, associated with it's composition of different coconut's part.
  18. Observation of the Rare Decay of the η Meson to Four Muons
    Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2023 Sep 01;131(9):091903.
    PMID: 37721839 DOI: 10.1103/PhysRevLett.131.091903
    A search for the rare η→μ^{+}μ^{-}μ^{+}μ^{-} double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of 101  fb^{-1}. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the η→μ^{+}μ^{-} decay as normalization, the branching fraction B(η→μ^{+}μ^{-}μ^{+}μ^{-})=[5.0±0.8(stat)±0.7(syst)±0.7(B_{2μ})]×10^{-9} is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions.
  19. Search for Inelastic Dark Matter in Events with Two Displaced Muons and Missing Transverse Momentum in Proton-Proton Collisions at sqrt[s]=13  TeV
    Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2024 Jan 26;132(4):041802.
    PMID: 38335361 DOI: 10.1103/PhysRevLett.132.041802
    A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138  fb^{-1} of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section σ(pp→A^{'}→χ_{1}χ_{2}) and the decay branching fraction B(χ_{2}→χ_{1}μ^{+}μ^{-}), where A^{'} is a dark photon and χ_{1} and χ_{2} are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter.
  20. Search for Scalar Leptoquarks Produced via τ-Lepton-Quark Scattering in pp Collisions at sqrt[s]=13  TeV
    Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2024 Feb 09;132(6):061801.
    PMID: 38394587 DOI: 10.1103/PhysRevLett.132.061801
    The first search for scalar leptoquarks produced in τ-lepton-quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138  fb^{-1}. The reconstructed final state consists of a jet, significant missing transverse momentum, and a τ lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-τ-quark coupling strength.
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