Higher-Order Components Dictate Higher-Order Contagion Dynamics in Hypergraphs.

The presence of the giant component is a necessary condition for the emergence of collective behavior in complex networked systems. Unlike networks, hypergraphs have an important native feature that components of hypergraphs might be of higher order, which could be defined in terms of the number of common nodes shared between hyperedges. Although the extensive higher-order component (HOC) could be witnessed ubiquitously in real-world hypergraphs, the role of the giant HOC in collective behavior on hypergraphs has yet to be elucidated. In this Letter, we demonstrate that the presence of the giant HOC fundamentally alters the outbreak patterns of higher-order contagion dynamics on real-world hypergraphs. Most crucially, the giant HOC is required for the higher-order contagion to invade globally from a single seed. We confirm it by using synthetic random hypergraphs containing adjustable and analytically calculable giant HOC.

A prospective study of incidence and outcome of acute kidney injury among hospitalised patients in Malaysia (My-AKI).

INTRODUCTION: The incidence of acute kidney injury (AKI) among hospitalised patients has not been well studied in Malaysia. MATERIALS AND METHODS: We conducted a prospective, multicentre study in seven hospitals in West Malaysia. All the adults admitted in March 2017 fulfilling Kidney Disease Improving Global Outcomes (KDIGO) criteria for AKI were included. RESULTS: Of the 34,204 patients screened, 2,457 developed AKI (7.18%), 13.1% of which occurred in intensive care unit (ICU). There were 60.2% males with a mean age of 57.8 (±17.5) years. The most common comorbidities were hypertension (55.0%), diabetes (46.6%), ischaemic heart disease (15.1%) and chronic kidney disease (12.0%). The commonest causes of AKI were sepsis (41.7%), pre-renal (24.2%) and cardiorenal syndrome (10.8%). Nephrotoxin exposure was reported in 31%. At diagnosis, the proportion of AKI stages 1, 2 and 3 were 79.1%, 9.7%, 11.2%, respectively. Referral to nephrologists was reported in 16.5%. Dialysis was required in 176 (7.2%) patients and 55.6% were performed in the ICU. Acidosis (46.2%), uraemia (31.6%) and electrolyte disturbance (11.1%) were the commonest indications. Continuous renal replacement therapy (CRRT) was required in 14%. The average length of hospital stay was 9.5 days. In-hospital mortality was 16.4%. Among survivors, full and partial renal recovery was seen in 74.7% and 16.4% respectively while 8.9% failed to recover. After a mean follow-up of 13.7 months, 593 (30.2%) of survivors died and 38 (1.9%) initiated chronic dialysis. Mortality was highest among those with malignancies (Hazard Ratio, HR 2.14), chronic liver disease (HR 2.13), neurological disease (HR 1.56) and cardiovascular disease (HR 1.17). CONCLUSION: AKI is common in hospitalised patients and is with associated high mortality during and after hospitalisation.

K-selective percolation: A simple model leading to a rich repertoire of phase transitions.

We propose a K-selective percolation process as a model for iterative removals of nodes with a specific intermediate degree in complex networks. In the model, a random node with degree K is deactivated one by one until no more nodes with degree K remain. The non-monotonic response of the giant component size on various synthetic and real-world networks implies a conclusion that a network can be more robust against such a selective attack by removing further edges. From a theoretical perspective, the K-selective percolation process exhibits a rich repertoire of phase transitions, including double transitions of hybrid and continuous, as well as reentrant transitions. Notably, we observe a tricritical-like point on Erdos-Rényi networks. We also examine a discontinuous transition with unusual order parameter fluctuation and distribution on simple cubic lattices, which does not appear in other percolation models with cascade processes. Finally, we perform finite-size scaling analysis to obtain critical exponents on various transition points, including those exotic ones.

No-exclaves percolation.

Network robustness has been a pivotal issue in the study of system failure in network science since its inception. To shed light on this subject, we introduce and study a new percolation process based on a new cluster called an 'exclave' cluster. The entities comprising exclave clusters in a network are the sets of connected unfailed nodes that are completely surrounded by the failed (i.e., nonfunctional) nodes. The exclave clusters are thus detached from other unfailed parts of the network, thereby becoming effectively nonfunctional. This process defines a new class of clusters of nonfunctional nodes. We call it the no-exclave percolation cluster (NExP cluster), formed by the connected union of failed clusters and the exclave clusters they enclose. Here we showcase the effect of NExP cluster, suggesting a wide and disruptive collapse in two empirical infrastructure networks. We also study on two-dimensional Euclidean lattice to analyze the phase transition behavior using finite-size scaling. The NExP model considering the collective failure clusters uncovers new aspects of network collapse as a percolation process, such as quantitative change of transition point and qualitative change of transition type. Our study discloses hidden indirect damage added to the damage directly from attacks, and thus suggests a new useful way for finding nonfunctioning areas in complex systems under external perturbations as well as internal partial closures.

Post-process optimization of 3D printed poly(lactic-co-glycolic acid) dental implant scaffold for enhanced structure and mechanical properties: effects of sonication duration and power.

We described a technique of a post-process stage to partially remove the poly(vinyl alcohol) (PVA) binder in Poly(lactic-co-glycolic acid) (PLGA) dental scaffolds. The scaffolds were exposed to ultrasonic waves while immersed in an ethanol/acetone solvent mixture that possessed both polar and nonpolar properties. A factorial experiment was conducted in which the scaffolds were treated to three levels of sonication power (pW): 0, 20% (22 W) and 40% (44 W), and soaking duration (t): 5, 15, and 30 min. The treated scaffolds were characterized by FT-IR, optical microscopy, and mechanical (compressive) testing. FT-IR revealed that the amount of PVA decreased with increasing pW and t. Two-way ANOVA revealed that increasing pW and t, respectively, resulted in increasing scaffold surface area to volume (SVR). Sonication and solvent caused structural damage (i.e., unevenness) on the scaffold surface, but the damage was minimal at 20% pW and 30 min. The optimal values of pW and t resulting in enhanced fracture strength, strain and toughness were 20% and 30 min, respectively, which corroborated the findings of minimal structural damage. However, sonication had no significant effects on the scaffold stiffness. Mechanistic analysis of the effects of sonication predicted that the ultrasonic energy absorbed by the scaffold was sufficient to disrupt the van Der Waals bonds between the PVA and PLGA but not high enough to disrupt the covalent bonds within the PLGA. This technique is promising as it can partially remove the PVA from the scaffold, and mitigate problematic issues down the line, such as thermal degradation during sterilization, and undue delay/variability in biodegradation.

Critical behaviors of high-degree adaptive and collective-influence percolation.

How the giant component of a network disappears under attacking nodes or links addresses a key aspect of network robustness, which can be framed into percolation problems. Various strategies to select the node to be deactivated have been studied in the literature, for instance, a simple random failure or high-degree adaptive (HDA) percolation. Recently, a new attack strategy based on a quantity called collective-influence (CI) has been proposed from the perspective of optimal percolation. By successively deactivating the node having the largest CI-centrality value, it was shown to be able to dismantle a network more quickly and abruptly than many of the existing methods. In this paper, we focus on the critical behaviors of the percolation processes following degree-based attack and CI-based attack on random networks. Through extensive Monte Carlo simulations assisted by numerical solutions, we estimate various critical exponents of the HDA percolation and those of the CI percolations. Our results show that these attack-type percolation processes, despite displaying apparently more abrupt collapse, nevertheless exhibit standard mean-field critical behaviors at the percolation transition point. We further discover an extensive degeneracy in top-centrality nodes in both processes, which may provide a hint for understanding the observed results.

Pattern of biopsy-proven renal disease in Sabah: A retrospective cross-sectional study over 3.5 years.

OBJECTIVES: To explore the epidemiological and histopathological patterns of glomerular diseases in Sabah. METHODS: A state-wide cross-sectional study was conducted. There were 336 native renal biopsies in 296 eligible patients from 1st January 2013 to 30th June 2016. All patients aged ≥12 years with sufficient sampling (≥8 glomeruli) for histopathological assessment were included. Graft kidney biopsies, protocol-based biopsies and patients with uncertain demographics were excluded. Demographics of patients, clinical data, laboratory parameters prior to biopsy, and histology findings of renal biopsies were collected from local unit database and recorded into a standardised data collection form. Descriptive statistical analyses were employed and factors associated with Lupus nephritis (LN) were explored using logistic regression. RESULTS: The mean age during biopsy was 34.53 years (Standard Deviation 0.759). Primary glomerulonephritis (PGN) accounted for 42.6% (126) of all native renal biopsies. The commonest cause of PGN was minimal change disease (38.9%, 49) followed by focal segmental glomerulosclerosis (33.3%, 42) and IgA nephropathy (14.3%, 18). LN is the leading cause for secondary glomerulonephritis (SGN) (87.2%, 136). Younger age (Odds Ratio, OR 0.978; 95% Confidence Interval, 95%CI 0.960, 0.996); female gender (OR 17.53; p<0.001); significant proteinuria (OR 132.0; p<0.001); creatinine level at biopsy (OR 11.26; p=0.004); positive antinuclear antibody (ANA) (OR 46.7; p<0.001); and ANA patterns (OR 8.038; p=0.018) were significant in predicting the odds of having LN. CONCLUSION: This is the first epidemiology study of glomerular diseases in Sabah. The predominance of LN suggests lower threshold for renal biopsy in patients with suspected glomerular disorders. We have identified significant predictors for early detection and treatment of LN.

The equilibrium and fixed-bed study of malachite green adsorption on chitosan hydrogels.

Chitosan hydrogel beads were prepared by a precipitation process, and were used to investigate the adsorption of malachite green (MG) oxalate under various conditions. It was found that adsorption equilibrium was most sensitive to the pH value at pH <8 while fixed bed breakthrough kinetics presented asymmetric S-shaped profiles which could not be adequately described by conventional models such as Adams-Bohart and Yoon-Nelson. The possible reasons were discussed and an improved Adams-Bohart model was proposed to better describe the changes in mass transfer mechanisms during adsorption.

Case series of haemothorax secondary to avulsed bullae vessel.

Haemothorax refer to the bleeding in the pleural space. It is commonly due to iatrogenic, blunt or penetrating chest trauma. Non-traumatic haemothorax is a rare entity that can potentially lead to life threatening complications. The initial management of both traumatic and non-traumatic haemothorax includes resuscitation and stabilisation of the patient. We would like to present two cases of non-traumatic haemothorax secondary to an avulsed bullae vessel.

Endometriosis - A rare cause of primary spontaneous pneumothorax.

Catamenial pneumothorax is a rare condition. We report a case of a 36-year-old female who presented with dyspnoea every time before she had her regular menses. Further investigation confirmed that she had catamenial pneumothorax. With this case we wish to highlight this rare diagnostic entity that every clinician should keep in mind.

Hepatitis B virus infection among children of hepatitis B surface antigen positive mothers in a Malaysian hospital.

INTRODUCTION: There have been no published data on the transmission of hepatitis B virus (HBV) infection among children of hepatitis B surface antigen (HBsAg) positive mothers in Malaysia. METHODS: This is a cross-sectional study of all the children of HBsAg-positive mothers who delivered at the University of Malaya Medical Centre between 1993 and 2000. RESULTS: A total of 60 HBsAg-positive mothers and their 154 children participated in the study. HBsAg was detected in four children (2.6%) while IgG antibody to the hepatitis B core antigen (anti-HBc IgG) was detected in seventeen children (11.0%). The mother's age at childbirth was significantly lower in the children with detectable HBsAg (22.5±6.1 years vs. 29.7±4.5 years, p=0.043) and anti-HBc IgG (26.6±6.1 years vs. 30.0±4.3 years, p=0.004). Children born in the 1980s were significantly more likely to have detectable HBsAg (18.8% vs. 0.7%, p=0.004) and anti-HBc IgG (37.5% vs. 8.0%, p=0.000) compared with those born later. All children with detectable HBsAg were born via spontaneous vaginal delivery, and hepatitis B immunoglobulin was either not given or the administration status was unknown. The majority of mothers with chronic HBV infection (70.4%) were not under any regular follow-up for their chronic HBV infection and the main reason was the lack of awareness of the need to do so (47.4%). CONCLUSION: Transmission of HBV infection among children of HBsAg-positive mothers in Malaysia is low. However, attention needs to be given to the high rate of HBsAgpositive mothers who are not on any regular follow-up.

Factors associated with influenza vaccine uptake in older adults living in the community in Singapore.

In Singapore, influenza vaccination is recommended for persons at higher risk of complications of seasonal influenza, including those with chronic medical conditions and the elderly (individuals aged ⩾65 years). We investigated the factors associated with influenza vaccine uptake based on a nationally representative sample of community-dwelling adults aged >50 years. The data for this study were obtained from the National Health Surveillance Survey (NHSS) 2013. The association between influenza vaccine uptake and socio-demographic and health-related variables was analysed using univariable and multivariable logistic regression models. Of 3700 respondents aged ⩾50 years in the NHSS, 15·2% had received seasonal influenza vaccination in the past year. Older age, single marital status and economic inactivity were the socio-demographic variables independently associated with vaccine uptake. Health-related factors which were predictive of influenza vaccine uptake were sufficient total physical activity, better self-rated health, having at least one medical condition at risk of influenza complications and a regular family doctor/general practitioner. Influenza vaccine uptake in community-dwelling older adults was low. Our findings are of relevance in the formulation of public health policies and targeted health promotion strategies to increase vaccine uptake in this population group.

A large common-source outbreak of norovirus gastroenteritis in a hotel in Singapore, 2012.

An outbreak of gastroenteritis affected 453 attendees (attack rate 28·5%) of six separate events held at a hotel in Singapore. Active case detection, case-control studies, hygiene inspections and microbial analysis of food, environmental and stool samples were conducted to determine the aetiology of the outbreak and the modes of transmission. The only commonality was the food, crockery and cutlery provided and/or handled by the hotel's Chinese banquet kitchen. Stool specimens from 34 cases and 15 food handlers were positive for norovirus genogroup II. The putative index case was one of eight norovirus-positive food handlers who had worked while they were symptomatic. Several food samples and remnants tested positive for Escherichia coli or high faecal coliforms, aerobic plate counts and/or total coliforms, indicating poor food hygiene. This large common-source outbreak of norovirus gastroenteritis was caused by the consumption of contaminated food and/or contact with contaminated crockery or cutlery provided or handled by the hotel's Chinese banquet kitchen.

Impact of pharmacist-involved collaborative care on the clinical, humanistic and cost outcomes of high-risk patients with type 2 diabetes (IMPACT): a randomized controlled trial.

WHAT IS KNOWN AND OBJECTIVE: With the increasing prevalence of diabetes, the physician-centred model is challenged to deliver holistic care in Asia. Diabetes may be managed effectively within a multidisciplinary collaborative care model; however, evidence on its effectiveness in Asian patients is lacking. Therefore, the primary objective was to evaluate the clinical outcomes of multidisciplinary collaborative care vs physician-centred care in diabetes. The secondary objectives were to evaluate humanistic and economic outcomes among the two types of care. METHODS: This 6-month prospective, open-label, parallel-arm, randomized, controlled study was conducted at four outpatient healthcare institutions. High-risk patients aged ≥21 years with uncontrolled type 2 diabetes, polypharmacy and comorbidities were included. Patients with type 1 diabetes or those who were unable to communicate independently were excluded. The control arm received usual care with referrals to nurses and dietitians as needed. The intervention arm (multidisciplinary collaborative care) was followed up with pharmacists regularly, in addition to receiving the usual care. The primary outcomes included HbA1c, systolic blood pressure, low-density lipoprotein and triglycerides. The secondary outcomes included scores from the Problem Areas in Diabetes (PAID) and the Diabetes Treatment Satisfaction Questionnaires (DTSQ), and diabetes-related health service utilization rates and costs. RESULTS AND DISCUSSION: Of 411 eligible patients, 214 and 197 patients were randomized into the intervention and control arms, respectively. At 6 months, 141 patients in the intervention arm (65.9%) and 189 patients in the control arm (95.9%) completed the study. Mean HbA1c reduced from 8.6%±1.5% at baseline to 8.1%±1.3% at 6 months in the intervention arm (P=.04), with up to mean HbA1c improvement of 0.8% in patients with greater levels of uncontrolled glycemia. Whereas the mean HbA1c in the control arm remained unchanged (8.5%±1.4%) throughout the 6-month period. Improvements in PAID and DTSQ scores, reduction in physician workload and an average cost savings of US$91.01 per patient were observed in the intervention arm over 6 months. WHAT IS NEW AND CONCLUSIONS: The positive clinical, humanistic and economic outcomes highlighted the value of multidisciplinary collaborative care for Asian diabetic patients, thereby supporting the effectiveness of this approach in managing chronic diseases.

Newly diagnosed end stage kidney disease in a single centre in Sabah.

AIM: To study the epidemiology, clinical characteristics, vascular access, and the short term survival of ESRD patients initiated on dialysis from Hospital Queen Elizabeth (HQE). BACKGROUND: The number of patients with ESRD is increasing in Sabah, Malaysia. Most patients present late and some live in remote areas with difficult access to healthcare services. Many therefore present with potentially fatal complications. METHODS: All the newly confirmed ESRD patients who were initiated on renal replacement therapy (RRT) from 1 January to 31 December 2014 were included. The basic epidemiological and clinical data were collected. They were divided into three groups: Group 1 - those known to the medical service and had been prepared properly for the initiation of RRT; Group 2 - those known to the medical service, but were not prepared for the RRT; Group 3 - those with undiagnosed CKD. Outcome is mainly survival at 3rd, 6th, 9th and 12th month. RESULTS: There were 249 ESRD patients. 153 (61.4%) were male. The average age was 53.3 (range 12 - 83). The main cause of ESRD was diabetic nephropathy (128 patients, 51.4%). Most patients were started on RRT with a catheter (74.3%), 47 patients (18.9%) with a fistula, and 17 patients (6.8%) with a Tenckhoff catheter. 185 (74.3%) patients were not prepared properly (Group 2 - 66.3%, and Group 3 - 8.0%). The survival for 249 patients were 86.3% at 6 months, 77.9% at 12 months. Group 2 has the worst survival (81.9% at 6 months, 71.1% at 12 months). CONCLUSIONS: Our data showed that most patients (74.3%) were started on dialysis in an unplanned manner with poor survival. A comprehensive and well-supported predialysis programme is needed.

Amyotrophic lateral sclerosis and motor neuron syndromes in Asia.

While the past 2 decades have witnessed an increasing understanding of amyotrophic lateral sclerosis (ALS) arising from East Asia, particularly Japan, South Korea, Taiwan and China, knowledge of ALS throughout the whole of Asia remains limited. Asia represents >50% of the world population, making it host to the largest patient cohort of ALS. Furthermore, Asia represents a diverse population in terms of ethnic, social and cultural backgrounds. In this review, an overview is presented that covers what is currently known of ALS in Asia from basic epidemiology and genetic influences, through to disease characteristics including atypical phenotypes which manifest a predilection for Asians. With the recent establishment of the Pan-Asian Consortium for Treatment and Research in ALS to facilitate collaborations between clinicians and researchers across the region, it is anticipated that Asia and the Pacific will contribute to unravelling the uncertainties in ALS.

Prevalence of diphtheria and tetanus antibodies among adults in Singapore: a national serological study to identify most susceptible population groups.

BACKGROUND: In view of waning antitoxin titres over time after the last vaccine dose against diphtheria and tetanus, we determined the immunity levels in adults to identify most susceptible groups for protection in Singapore. METHODS: Our study involved residual sera from 3293 adults aged 18-79 who had participated in a national health survey in 2010. IgG antibody levels were determined using commercial enzyme-linked immunosorbent assay. RESULTS: Overall, 92.0% (95% confidence interval [CI]: 91.1-92.9%) had at least basic protection against diphtheria (antibody levels ≥0.01 IU/ml), while 71.4% (95% CI: 69.8-72.9%) had at least short-term protection against tetanus (antibody levels >0.1 IU/ml). The seroprevalence declined significantly with age for both diseases; the drop was most marked in the 50- to 59-year age group for diphtheria and 60- to 69-year age group for tetanus. There was a significant difference in seroprevalence by residency for diphtheria (92.8% among Singapore citizens versus 87.1% among permanent residents; P = 0.001). The seroprevalence for tetanus was significantly higher among males (83.2%) than females (62.4%) (P < 0.0005). CONCLUSIONS: It may be of value to consider additional vaccination efforts to protect older adults at higher risk for exposure against diphtheria and tetanus, particularly those travelling to areas where diphtheria is endemic or epidemic.

Cross-sectional study on knowledge of chronic kidney disease among medical outpatient clinic patients.

BACKGROUND: Chronic kidney disease (CKD) is a major health concern worldwide. There are limited studies which look into the actual knowledge level of CKD among the general population both locally and internationally. This study aims to assess the knowledge level of CKD among patients in a secondary hospital in Malaysia. METHODS: Consecutive sampling of patients attending the Medical Outpatient Clinic was performed in this crosssectional study. Respondents were given self-administered questionnaires which contain questions on demographic characteristics and knowledge on CKD. RESULTS: Out of 300 respondents, 78.6% (n=236) of the respondents completed the questionnaire. Majority of respondents (73.7%, n=174) scored less than 4 out of 7 marks on knowledge on CKD. Respondents who were younger, males, having higher education status, professionals/executives and earned higher monthly income were more likely to have a higher mean knowledge score of CKD. Respondents who have heard of CKD were also significantly associated with higher mean knowledge score of CKD. CONCLUSION: The study findings suggest that our Malaysian population is still inadequately informed on CKD, especially those who are at risk of developing CKD and its complications, and also among those of the lower socioeconomic group. In order for successful primary and secondary prevention of CKD, more importance should be placed on increasing awareness on CKD among these atrisk groups.

An updated Asia Pacific Consensus Recommendations on colorectal cancer screening.

OBJECTIVE: Since the publication of the first Asia Pacific Consensus on Colorectal Cancer (CRC) in 2008, there are substantial advancements in the science and experience of implementing CRC screening. The Asia Pacific Working Group aimed to provide an updated set of consensus recommendations. DESIGN: Members from 14 Asian regions gathered to seek consensus using other national and international guidelines, and recent relevant literature published from 2008 to 2013. A modified Delphi process was adopted to develop the statements. RESULTS: Age range for CRC screening is defined as 50-75 years. Advancing age, male, family history of CRC, smoking and obesity are confirmed risk factors for CRC and advanced neoplasia. A risk-stratified scoring system is recommended for selecting high-risk patients for colonoscopy. Quantitative faecal immunochemical test (FIT) instead of guaiac-based faecal occult blood test (gFOBT) is preferred for average-risk subjects. Ancillary methods in colonoscopy, with the exception of chromoendoscopy, have not proven to be superior to high-definition white light endoscopy in identifying adenoma. Quality of colonoscopy should be upheld and quality assurance programme should be in place to audit every aspects of CRC screening. Serrated adenoma is recognised as a risk for interval cancer. There is no consensus on the recruitment of trained endoscopy nurses for CRC screening. CONCLUSIONS: Based on recent data on CRC screening, an updated list of recommendations on CRC screening is prepared. These consensus statements will further enhance the implementation of CRC screening in the Asia Pacific region.

Recurrent spontaneous subdural hematoma secondary to immune thrombocytopenia in a patient with overlap syndrome.

Patients with autoimmune connective tissue disease may manifest as overlap syndrome with features of systemic lupus erythematosus (SLE), systemic sclerosis, rheumatoid arthritis and myositis. Those presenting with active SLE can present with immune thrombocytopenia (IT) and may be complicated with subdural hematoma which, though rare, is potentially life-threatening. We report here a patient with overlap syndrome who had recurrent spontaneous subdural hematoma due to severe thrombocytopenia which did not respond to corticosteroids and azathioprine. Her platelet count became normal with three doses of low-dose intravenous cyclophosphamide (IV CYC) given at 3-weekly intervals. She remained in remission with maintenance therapy with azathioprine.