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Patterns and trends in the burden of Alzheimer’s disease and related dementias in China (1990–2021) and predictions to 2040
No full textBackground: The epidemiology of Alzheimer's disease and related dementias (ADRD) in China is understudied as compared to global levels. Objective: The aim of this study was to examine the trend of dementia epidemiology in China from 1990 to 2021 and provide predictions for the next two decades. Methods: The Global Burden of Disease study (GBD) 2021 were used to analyze the prevalence, incidence, mortality, and disability-adjusted life years (DALYs) rates due to ADRD in China and globally. Joinpoint regression analysis was used to analyze the epidemiological trends from 1990 to 2021. A forecast of ADRD prevalence trends was conducted utilizing Autoregressive Integrated Moving Average (ARIMA) models. Results: China was experiencing a growing burden of ADRD. As of 2021, the number of people with dementia in China had risen to 56.85 million (95%CI: 49.38, 64.98), up from 21.80 (95%CI: 19.07, 24.84) million in 1990. The prevalence, incidence, mortality, and DALY rates all indicated a greater disease burden among the Chinese population compared to global levels, with a significantly higher burden in the female group. The projected prevalence rate was expected to increase by 60% compared to the current prevalence rate. Conclusions: As the population in China continues to age, ADRD presents an undeniable challenge. To mitigate the growing burden of ADRD and improve the overall health of the population, it is essential to establish a comprehensive plan that focuses on increasing public awareness and enhancing the quality of life for all, with special attention given to women.</p
Estimated incidence and clinical presentation of Noma in Northern Nigeria (1999–2024)
No full textNoma (Cancrum Oris), a recent addition to the WHO list of neglected tropical diseases, is a severe, rapidly progressing necrotizing disease of the oral cavity and facial complex with a case fatality rate of 90% if untreated. Active disease is common among children between two and six years in Sub-Saharan Africa while noma sequelae may be seen in individuals at any age. Though most cases have been reported in northern Nigeria, little research is available on the incidence of noma and its clinical presentation in this region using comprehensive data. Therefore, this study aims to estimate the incidence of noma and its clinical presentation in Northern Nigeria among different age groups. We collected retrospective data of 1,383 consecutive patients managed at Noma Children’s Hospital, Sokoto, Nigeria between 1999 and 2024 for incidence estimation and description of the clinical presentation of noma. Incidence calculation was done using the WHO Oral Health Unit strategy designed with the Delphi method. Our results showed that patients were between 8 months and 80 years old with a median age (IQR) of 6 years (3–15). More patients presented with acute noma than arrested noma (67.3% vs 32.7%). The estimated incidence of noma in northern Nigeria during the study period was 87.8 cases per 100,000, with Sokoto state having the highest incidence of 691.4 cases per 100,000, while Adamawa state had the lowest incidence of 11.2 cases per 100,000. The annual average and median incidence of noma across all years was 3.4 and 1.6 cases per 100,000 (range: 0.2-16.6 cases per 100,000), although between 2020 and 2024, the annual average and median incidence estimates were 12.0 and 12.6 cases per 100,000. Also, this study found the incidence of noma cases with gangrene to be higher than cases with oedema or acute necrotizing ulcerative gingivitis. These findings confirm the high incidence and impact of noma in northern Nigeria in the last two and half decades and highlight the need to intensify awareness of risk factors and early signs of noma within communities in the region and to conduct community-based screening to promote the identification and cost-effective treatment of reversible early noma disease.</p
Deformation behavior and strengthening mechanisms of high-entropy alloys under high strain rate across wide temperature ranges
No full textThis study systematically investigates the deformation mechanism and strengthening effects of the CoCrFeNiMn0.75Cu0.25 high-entropy alloy (HEA) under dynamic tensile loading across a wide temperature range (93 K to 1073 K). The HEA exhibits a ∼30 % enhancement in strength and ductility at 93 K relative to its performance at 298 K. These superior properties result from the synergistic interactions among deformation bands, stacking faults, multiscale twinning, dislocations, and Lomer-Cottrell (L-C) locks, which enhance work hardening and delay fracture. At 873 K, dislocation slip becomes dominant, and dynamic recovery is activated, facilitating stress redistribution and more uniform macroscopic deformation. At 1073 K, discontinuous dynamic recrystallization occurs within deformation bands, producing refined grains that redistribute stress and maintain elongation above 60 %, ensuring superior plasticity despite thermal softening. These findings indicate that temperature strongly influences microstructural evolution, with thermally activated dislocation motion, recovery, and recrystallization playing critical roles in determining the deformation response at high strain rates. This study provides new insights into the temperature-dependent strengthening mechanisms in HEAs, which have implications for the development of advanced materials for extreme environments
The simplified Chinese version of the Nonrestorative Sleep Scale in Chinese young adults and measurement invariance across language and age
No full textBackground: To assess the psychometric properties of the simplified Chinese version of the Nonrestorative Sleep Scale (NRSS) in Chinese young adults and examine measurement invariance across language and age. Methods: After cognitive debriefing, the simplified Chinese NRSS was administered to university students in mainland China in this cross-sectional survey (Study 1). The Pittsburgh Sleep Quality Index (PSQI), the Patient Health Questionnaire (PHQ-4), and sociodemographic characteristics were also self-reported. The sample was randomly split into two halves to examine the scale structure using exploratory factor analysis (EFA) and asses the psychometric properties of the identified structure by confirmatory factor analysis (CFA), respectively. Incorporating data from two additional studies (Study 2: a survey of Hong Kong Chinese adults; Study 3: a survey of mainland Chinese adolescents), multigroup CFA models were conducted to examine the measurement invariance across language and age, followed by a t-test to determine group differences once invariance was established. Results: In the 570 participants of Study 1 (28.8% male, age 20.2 ± 1.5 years), the EFA revealed a four-factor structure. The root mean square error of approximation, comparative fit index, and standardized root mean square residual in the CFA model were 0.053, 0.995, and 0.054, respectively. The statistically significant correlations of NRSS with PSQI (r = − 0.61) and PHQ-4 (r = − 0.53) demonstrated the convergent validity of NRSS. The internal consistency of the whole scale was 0.84. Measurement invariance was concluded between traditional and simplified Chinese NRSS and between young adults and adolescents with the change of comparative fit index and root mean square error of approximation smaller than 0.010. The effect size (Cohen’s d) of difference between mainland Chinese adults and Hong Kong Chinese adults ranged from 0.193 to 0.771, while that between mainland Chinese adults and adolescents ranged from 0.027 to 0.345. Conclusion: The simplified Chinese 12-item NRSS is valid and reliable for assessing NRS among Chinese young adults, and it can be used to measure and compare NRS between individuals using simplified Chinese and traditional Chinese, as well as across different age groups within the simplified Chinese user population.</p
Differences in interaction strategy use between L1 and L2 group discussions of primary school students
No full textStudents’ development of multilingual competence has attracted increasing attention from language researchers and educators. However, research on students’ interaction strategy use in group discussions across different language settings remains scarce. In this study, therefore, we examined interaction strategy use in Cantonese as a first language (L1) and Putonghua as a second language (L2) during group discussion tasks among 42 primary school students in Hong Kong. We also investigated the effects of interaction strategy use on performance in respective tasks. We discovered that students employed significantly more interaction strategies in L1 than in L2, with a higher contribution to L1 task performance. Specifically, three of the five strategies identified—Strategy 2 (S2) asking for opinions, S3 expressing attitude, and S5 non-verbal language—were employed more frequently in L1 than in L2. Furthermore, we found that strategy use had various effects on oral performance between the two languages. In the L1 task, S1 expressing actively, S3 expressing attitude, and S4 giving clarification significantly predicted students’ group discussion performance, whereas this effect was only observed in S1 expressing actively in the L2 task. Pedagogical implications for primary students’ learning of interaction strategies for group discussions in both L1 and L2 are discussed
Altered bile acid and coproporphyrin-I disposition in patients with autosomal dominant polycystic kidney disease
No full textAims: Serum, liver and urinary bile acids are increased, and hepatic transport protein levels are decreased in a non-clinical model of polycystic kidney disease. Similar changes in patients with autosomal dominant polycystic kidney disease (ADPKD) may predispose them to drug-induced liver injury (DILI) and hepatic drug–drug interactions (DDIs). Systemic coproporphyrin-I (CP-I), an endogenous biomarker for hepatic OATP1B function and MRP2 substrate, is used to evaluate OATP1B-mediated DDI risk in humans. In this clinical observational cohort-comparison study, bile acid profiles and CP-I concentrations in healthy volunteers and patients with ADPKD were compared. Methods: Serum and urine samples from healthy volunteers (n = 16) and patients with ADPKD (n = 8) were collected. Serum bile acids, and serum and urine CP-I concentrations, were quantified by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Results: Patients with ADPKD exhibited increased serum concentrations of total (1.3-fold) and taurine-conjugated (2.8-fold) bile acids compared to healthy volunteers. Specifically, serum concentrations of six bile acids known to be more hydrophobic/hepatotoxic (glycochenodeoxycholate, taurochenodeoxycholate, taurodeoxycholate, lithocholate, glycolithocholate and taurolithocholate) were increased (1.5-, 2.9-, 2.8-, 1.6-, 1.7- and 2.7-fold, respectively) in patients with ADPKD. Furthermore, serum CP-I concentrations were elevated and the renal clearance of CP-I was reduced in patients with ADPKD compared to healthy volunteers. Conclusions: Increased exposure to bile acids may increase susceptibility to DILI in some patients with ADPKD. Furthermore, the observed increase in serum CP-I concentrations could be attributed, in part, to impaired OATP1B function in patients with ADPKD, which could increase the risk of DDIs involving OATP1B substrates compared to healthy volunteers
Efficacy of an online self-pace Cantonese phonetic transcript training module for speech therapy students
No full textBackground:Clinical phonetic transcription is a crucial skill for speech therapists (STs) in both clinical practice and research. In addition to phonetic transcriptions in English, ST students in Hong Kong are also expected to perform phonetic transcriptions in Cantonese to cater for local clinical needs. However, there are limited resources for Cantonese transcription training. This study aimed to develop an online self-paced training module for Cantonese phonetic transcription and investigate its efficacy in improving ST students’ transcription skills.Methods:An online self-paced phonetic transcription module was created using Blackboard Learn. Participants (N=59), including 29 less experienced year 1 and 30 more experienced year 2 masters ST students, viewed five lecture videos and completed five exercises at introductory, intermediate, and advanced levels. Pre- and post-training tests were also administered.Results:A two-way repeated-measure analyses of variance was performed to evaluate the effects of group (experience level) and time (pre- vs post-training) on the test scores. Results showed a significant main effect for time but not for group nor the interaction between group and time. Post-hoc pairwise comparisons with Bonferroni adjustment revealed significant differences between pre- vs post-training scores in both groups, indicating a substantial improvement in the participants’ phonetic transcription performance after training, regardless of experience level.Conclusion: The online self-paced Cantonese phonetic transcription training module effectively improved ST students’ transcription skills, regardless of their prior experience level. This study highlights the potential of online self-paced learning resources in enhancing specialized clinical skills for ST students. The developed module addresses the need for Cantonese-specific transcription training materials and can serve as a valuable resource for ST education programs in Hong Kong and other Cantonese-speaking regions. Further research is recommended to explore the long-term retention of the acquired skills and the module’s effectiveness in a larger sample of ST students.</p
Connectivity Determination Algorithm for Complex Directed Networks
No full textConnectivity characterizes the ability of information transmission in systems modeled by complex networks. It is essential to develop an efficient connectivity determination algorithm with low time complexity and minimal storage requirements. To fulfill this need, a connectivity determination algorithm is designed by incorporating Tarjan's algorithm to identify strongly connected components and leveraging a depth-first search idea to traverse the reachability. This algorithm can ascertain strong connectivity, unilateral connectivity, and weak connectivity of complex directed networks. Besides, the accessibility matrix of complex directed networks is computed and visualized through an interface. As this algorithm relies on only two depth-first searches to accomplish connectivity determination tasks, its computational complexity does not exceed O(n2), where n denotes the number of network nodes. Experiments carried out on some specific networks reveal that the probability of network connections decreases with the increasing number of nodes in directed injective graphs, while in Erdős–Rényi graphs, the likelihood of connections increases as the number of nodes increases. Finally, a comparative example and an application example are provided to demonstrate the effectiveness of the algorithm program.</p
Social Mobility as Causal Intervention
No full textThe study of mobility effects is an important subject of study in sociology. Empirical investigations of individual mobility effects, however, have been hindered by one fundamental limitation, the unidentifiability of mobility effects when origin and destination are held constant. Given this fundamental limitation, we propose to reconceptualize mobility effects from the micro- to macro-level. Instead of micro-level mobility effects, the primary focus of the past literature, we ask alternative research questions about macro-level mobility effects: What happens to the population distribution of an outcome if we manipulate the mobility regime, that is, if we alter the observed association between social origin and social destination? We relate individual-level mobility experience to macro-level mobility effects under special interventions. The proposed method bridges the macro and micro agendas in social stratification research, and has wider applications in social stratification beyond the study of mobility effects. We illustrate the method with two analyses that evaluate the impact of social mobility on average fertility and income inequality in the United States. We provide an open-source software, the R package socmob, that implements the method.</p
Neuroprotection of desferrioxamine and/or melatonin in in vitro intracerebral hemorrhage model
No full text
Intracerebral haemorrhage (ICH) is a devastating disease with high mortality and poor prognosis that accounts for 20% of all strokes. Current management is mostly supportive since specific therapeutics are yet to be discovered. Hence, voluminous efforts had been devoted in past years to understand the pathophysiology of ICH, and to search for novel neuroprotective drugs.
This dissertation continued the effort on the search for novel therapeutic drugs for ICH. It first reviewed existing literature, providing an updated summary on the pathogenic processes of ICH, with a particular focus on the damage caused by oxidative stress and iron toxicity. The extravasated blood leaked during ICH plays an indispensable role in its secondary injury. Shortly after ICH, extravasated red blood cells are lysed to give hemoglobin, which is degraded into heme, subsequently to iron. Not only does each of these conversion steps contribute to oxidative stress, but iron in particular is capable of generating considerable amount of reactive oxygen species (ROS). Melatonin is endogenously produced by the pineal gland as a hormone for sleep-wake cycle regulation, but is considered to possess neuroprotective effects due to its ROS-chelating properties, as well as its ability in enhancing endogenous antioxidative capacity. Meanwhile, desferrioxamine is an established drug for transfusion-dependent iron toxicity. It is capable of binding to iron to prevent its further damage, such as the generation of oxidative stress. Notably, as a therapeutic against ICH, desferrioxamine had advanced to clinical trials in recent years, yet its efficacy was marginal. An adjuvant that could raise this borderline efficacy of desferrioxamine, such as melatonin, which is safe and readily available, would be worthy of consideration. Finally, we propose melatonin-desferrioxamine co-treatment as a potential therapeutic regimen for ICH which may be worthy of investigation.
The subsequent experimental sections investigated the efficacy of desferrioxamine, melatonin, individually and in combination, in mitigating neuronal damage induced by hemin, in an in vitro ICH model. An in vitro ICH model was first set up and tested, in which hemin (35μM) was added to SHSY-5Y neuronal cells to simulate cellular environment after ICH. The neuroprotective efficacy of desferrioxamine and melatonin were subsequently evaluated by viability studies, with desferrioxamine demonstrating remarkable efficacy, having reversed the toxicity induced by hemin entirely. However, in this model, melatonin only showed limited effectiveness despite testing in various concentrations, pretreatment durations, and with reduced hemin toxicity. Cotreatment of melatonin and desferrioxamine significantly improved cellular survival after hemin-induced injury, but did not enhance neuroprotection more than desferrioxamine treatment alone.
Given desferrioxamine's efficacy, its mechanism of action was studied in further detail. The hypothesis was that Nrf2 was responsible for desferrioxamine’s neuroprotective effect, as Nrf2 was known to be a pivotal regulator of antioxidative pathways. Through the use of Nrf2 inhibitor, cell viability studies, and Western blot technique, desferrioxamine was found to upregulate Nrf2 expression, while Nrf2 inhibition attenuated desferrioxamine's neuroprotective effect. We hence concluded that desferrioxamine achieved neuroprotection through Nrf2 pathways, and that Nrf2 may be a potential actionable target in the management of ICH.published_or_final_versionMedicineMasterMaster of Research in Medicin