Complex Emotion Recognition via Facial Expressions with Label Noises Self-Cure Relation Networks.

Current deep learning-based facial expression recognition mainly focused on the six basic human emotions and relied on large-scale and well-annotated data. For complex emotion recognition, such a large amount of data are not easy to obtain, and a high-quality annotation is even more difficult. Therefore, in this paper, we regard complex emotion recognition via facial expressions as a few-shot learning problem and introduce a metric-based few-shot model named self-cure relation networks (SCRNet), which is robust to label noises and is able to classify facial images of new classes of emotions by only few examples from each. Specifically, SCRNet learns a distance metric based on deep features abstracted by convolutional neural networks and predicts a query image's emotion category by computing relation scores between the query image and the few examples of each new class. To tackle the label noise problem, SCRNet gives corrected labels to noise data via class prototype stored in external memory during the meta-training phase. Experimenting on public datasets as well as on synthetic noise datasets demonstrates the effectiveness of our method.

Objective performance of emergency medical technicians in the use of mechanical cardiopulmonary resuscitation compared with subjective self-evaluation: a cross-sectional, simulation-based study.

OBJECTIVE: To evaluate the subjective and objective resuscitation performance of emergency medical technicians (EMTs) using mechanical cardiopulmonary resuscitation (MCPR) devices. DESIGN AND SETTING: This was a cross-sectional simulation-based study where participants installed the MCPR device on a training manikin. PARTICIPANTS: We assessed EMT-Intermediates (EMT-Is) and EMT-Paramedics (EMT-Ps) of the Emergency Medical Services (Ambulance) Division of the Taipei City Fire Department. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the gap between self-perceived (subjective) and actual (objective) no-flow time during resuscitation, which we hypothesised as statistically insignificant. The secondary outcome was the association between resuscitation performance and personal attributes like knowledge, attitude and self-confidence. RESULTS: Among 210 participants between 21 and 45 years old, only six were female. There were 144 EMT-Is and 66 EMT-Ps. During a simulated resuscitation lasting between four and a half and 5 min, EMTs had longer actual no-flow time compared with self-perceived no-flow time (subjective, 38 s; objective, 57.5 s; p value<0.001). This discrepancy could cause a 6.5% drop of the chest compression fraction in a resuscitation period of 5 min. Among the EMT personal factors, self-confidence was negatively associated with objective MCPR deployment performance (adjusted OR (aOR) 0.66, 95% CI 0.45 to 0.97, p=0.033) and objective teamwork performance (aOR 0.57, 95% CI 0.34 to 0.97, p=0.037) for EMT-Ps, whereas knowledge was positively associated with objective MCPR deployment performance (aOR 2.15, 95% CI 1.31 to 3.52, p=0.002) and objective teamwork performance (aOR 1.77, 95% CI 1.02 to 3.08, p=0.043) for EMT-Is. Moreover, regarding the self-evaluation of no-flow time, both self-satisfaction and self-abasement were associated with objectively poor teamwork performance. CONCLUSIONS: EMTs' subjective and objective performance was inconsistent during the MCPR simulation. Self-confidence and knowledge were personal factors associated with MCPR deployment and teamwork performance. Both self-satisfaction and self-abasement were detrimental to teamwork during resuscitation.

Low Cost Three-Dimensional Programmed Mini-Pump Used in PCR.

Programmed mini-pumps play a significant role in various fields, such as chemistry, biology, and medicine, to transport a measured volume of liquid, especially in the current detection of COVID-19 with PCR. In view of the cost of the current automatic pipetting pump being higher, which is difficult to use in a regular lab, this paper designed and assembled a three-dimensional programmed mini-pump with the common parts and components, such as PLC controller, motor, microinjector, etc. With the weighting calibration before and after pipetting operation, the error of the pipette in 10 µL (0.2%), 2 µL (1.8%), and 1 µL (5.6%) can be obtained. Besides, the contrast test between three-dimensional programmed mini-pump and manual pipette was conducted with the ORF1ab and pGEM-3Zf (+) genes in qPCR. The results proved that the custom-made three-dimensional programmed mini-pump has a stronger reproducibility compared with manual pipette (ORF1ab: 24.06 ± 0.33 vs. 23.50 ± 0.58, p = 0.1014; pGEM-3Zf (+): 11.83.06 ± 0.24 vs. 11.50 ± 0.34, p = 0.8779). These results can lay the foundation for the functional, fast, and low-cost programmed mini-pump in PCR or other applications for trace measurements.

Influence of advanced life support response time on out-of-hospital cardiac arrest patient outcomes in Taipei.

BACKGROUND: The association between out-of-hospital cardiac arrest patient survival and advanced life support response time remained controversial. We aimed to test the hypothesis that for adult, non-traumatic, out-of-hospital cardiac arrest patients, a shorter advanced life support response time is associated with a better chance of survival. We analyzed Utstein-based registry data on adult, non-traumatic, out-of-hospital cardiac arrest patients in Taipei from 2011 to 2015. METHODS: Patients without complete data, witnessed by emergency medical technicians, or with response times of ≥ 15 minutes, were excluded. We used logistic regression with an exposure of advanced life support response time. Primary and secondary outcomes were survival to hospital discharge and favorable neurological outcomes (cerebral performance category ≤ 2), respectively. Subgroup analyses were based on presenting rhythms of out-of-hospital cardiac arrest, bystander cardiopulmonary resuscitation, and witness status. RESULTS: A total of 4,278 cases were included in the final analysis. The median advanced life support response time was 9 minutes. For every minute delayed in advanced life support response time, the chance of survival to hospital discharge would reduce by 7% and chance of favorable neurological outcome by 9%. Subgroup analysis showed that a longer advanced life support response time was negatively associated with the chance of survival to hospital discharge among out-of-hospital cardiac arrest patients with shockable rhythm and pulse electrical activity groups. CONCLUSIONS: In non-traumatic, adult, out-of-hospital cardiac arrest patients in Taipei, a longer advanced life support response time was associated with declining odds of survival to hospital discharge and favorable neurologic outcomes, especially in patients presenting with shockable rhythm and pulse electrical activity.

Effect of Placement of a Supraglottic Airway Device vs Endotracheal Intubation on Return of Spontaneous Circulation in Adults With Out-of-Hospital Cardiac Arrest in Taipei, Taiwan: A Cluster Randomized Clinical Trial.

Importance: Prehospital advanced airway management with either initial endotracheal intubation (ETI) or initial supraglottic airway (SGA) insertion in patients with out-of-hospital cardiac arrest (OHCA) remains controversial. Objective: To compare the effectiveness of ETI and SGA in patients with nontraumatic OHCA. Design, Setting, and Participants: The Supraglottic Airway Device vs Endotracheal intubation (SAVE) trial was a multicenter cluster randomized clinical trial conducted in Taipei City, Taiwan. Individuals aged 20 years or older who experienced nontraumatic OHCA requiring advanced airway management and were treated by participating emergency medical service agencies were enrolled from November 11, 2016, to December 31, 2019. The final day of follow-up was February 19, 2020. Interventions: Four advanced life support ambulance teams were divided into 2 randomization clusters, with each cluster assigned to either ETI or SGA in a biweekly period. Main Outcomes and Measures: The primary outcome of the SAVE trial was sustained return of spontaneous circulation (ROSC) (≥2 hours) after resuscitation. Secondary outcomes included prehospital ROSC, survival to hospital discharge, and favorable neurologic outcome, defined as a cerebral performance category score less than or equal to 2. Prespecified subgroups and the association between time to advanced airways were explored. Per protocol and intention-to-treat analysis were performed. Results: A total of 936 patients (517 in the ETI group and 419 in the SGA group) were included in the primary analysis (median age, 77 [IQR, 62-85] years; 569 men [60.8%]). The first-attempt airway success rates were 77% with ETI (n = 413) and 83% with SGA (n = 360). Sustained ROSC was 26.9% (n = 139) in the ETI group vs 25.8% (n = 108) in the SGA group. The odds ratio of sustained ROSC was 1.02 (95% CI, 0.98-1.06) in the ETI group vs SGA group. The odds ratio of ETA vs SGA was 1.04 (95% CI, 1.02-1.07) for prehospital ROSC, 1.00 (95% CI, 0.94-1.06) for survival to hospital discharge, and 0.99 (95% CI, 0.94-1.03) for cerebral performance category scores less than or equal to 2. Conclusions and Relevance: In this randomized clinical trial, among patients with OHCA, initial airway management with ETI did not result in a favorable outcome of sustained ROSC compared with SGA device insertion. Trial Registration: ClinicalTrials.gov Identifier: NCT02967952.

Outcomes of out-of-hospital cardiac arrests after a decade of system-wide initiatives optimising community chain of survival in Taipei city.

OBJECTIVE: A strengthened chain of survival benefits patient outcomes after out-of-hospital cardiac arrest (OHCA).2 Over the past decade, the Taipei Fire Department (TFD) has continuously implemented system-wide initiatives on this issue.We hypothesised that for adult, non-trauma OHCA patients, the bundle of these system-wide initiatives are associated with better outcomes. METHODS: We conducted a registry-based, retrospective study to examine the association between consecutive system-level initiatives and OHCA survival on a two-yearly basis using trend analysis and multivariable logistic regression. The primary outcome was survival to hospital discharge (STHD) and favourable neurological status. RESULTS: We analysed 18,076 cases from 2008 to 2017. The numbers of two-yearly cases of OHCA with resuscitation attempts from 2008 to 2017 were 3,576, 3,456, 3,822, 3,811, and 3,411. There was a significant trend of improved STHD (Two-fold) and favourable neurological outcome (Six-fold) over the past decade. Similar trends were observed in the shockable and non-shockable groups. Considering the first 2 years as baseline, the odds of STHD and favourable neurological status in the end of the initiatives increased significantly after adjusting for universally recognised predictors for OHCA survival. CONCLUSION: For non-trauma adult OHCA in Taipei, continuous, multifaceted system-wide initiatives on the community chain of survival were associated with improved odds of STHD and favourable neurologic outcomes.

Advances in Filament Structure of 3D Bioprinted Biodegradable Bone Repair Scaffolds.

Conventional bone repair scaffolds can no longer meet the high standards and requirements of clinical applications in terms of preparation process and service performance. Studies have shown that the diversity of filament structures of implantable scaffolds is closely related to their overall properties (mechanical properties, degradation properties, and biological properties). To better elucidate the characteristics and advantages of different filament structures, this paper retrieves and summarizes the state of the art in the filament structure of the three-dimensional (3D) bioprinted biodegradable bone repair scaffolds, mainly including single-layer structure, double-layer structure, hollow structure, core-shell structure and bionic structures. The eximious performance of the novel scaffolds was discussed from different aspects (material composition, ink configuration, printing parameters, etc.). Besides, the additional functions of the current bone repair scaffold, such as chondrogenesis, angiogenesis, anti-bacteria, and anti-tumor, were also concluded. Finally, the paper prospects the future material selection, structural design, functional development, and performance optimization of bone repair scaffolds.

Detection and analysis of null alleles of amelogenin in gender identification.

In this study, we located eight samples with null alleles of amelogenin out of 10,750 cases, and discussed the influence in gender identification and forensic personal identification. Amelogenin was detected and retested by several autosomal STR kits and sex chromosomal STR kits, and the causes were analyzed by chromosome karyotype analysis and Y chromosome microdeletion detection if necessary. Suspected AMEL-X loss was observed in five samples, but no abnormality was detected in the X-STR loci. AMEL-X was recovered when samples were retested by other detection systems designed with different primers. One sample had AMEL-X and X-STR loci loss, and the karyotype was chimeric 45,X0[70]/46,X,+mar[13].Two male samples lost AMEL-Y fragment, and both of them lost DYS522-DYS570-DYS576 loci, but no abnormalities were found in the STS loci of SRY and AZF regions. Therefore, when carrying out gender identification by using amelogenin, it is essential to focus on null alleles of amelogenin. In especially, deal with the samples collected from the individuals who had chromosomal hereditary disorders(e.g. Turner Syndrome and Oligospermia / Azoospermia). In order to achieve this, laboratories should have various techniques to verify the null alleles of amelogenin and ensure accurate genotyping. Accurate genotyping of amelogenin and DNA database establishment are vital for personal identification.

Effect of Field Triage Training on Emergency Medical Technicians in Taipei City.

Injury is a leading cause of death among young adults. An accurately implemented fi led triage scheme (FTS) by emergency medical technicians (EMTs) is the first step for delivering right patients to the right hospital. However, the training effect of FTS on EMTs with different levels and backgrounds has scarcely been reported. We evaluated training effects of FTS among EMTs in Taipei. Standard FTS contains physiologic status, anatomical sites of injury, and mechanism of injury criteria. The intervention was a 30-minute lecture and pre-and-post tests, each containing five questions about trauma severity judgment (i.e., mechanism of injury [2 questions], anatomic sites of injury [2 questions], and physiological status [1 question]). The change in EMT accuracy was measured before and after training. Subgroup analyses were performed across EMTs with different levels and seniorities. From September 1, 2015 to March 31, 2016, 821 EMTs were enrolled, including 740 EMT-intermediates and 81 paramedics. Overall, EMT accuracy improved after the intervention in the intermediate (73.2% vs. 85.5%, p < 0.05) and paramedic (76.0% vs. 85.7%, p <0.01) groups. All trainees showed improvements in physiology and mechanism criteria, but paramedics showed decreased accuracy in anatomic criteria. The subgroup analysis showed that accuracy positively associated with prehospital care experience for major trauma cases 1 year before the training course, and the anatomical criterion accuracy was adversely associated with paramedic seniority. Field triage training can improve EMT accuracy for FTS. The anatomical aspect is more diffi cult to improve and should be emphasized in FTS training courses.

A prediction model for patients with emergency medical service witnessed out-of-hospital cardiac arrest.

BACKGROUND/PURPOSE: The study aim was to develop a model for predicting patients with emergency medical service (EMS) witnessed out-of-hospital cardiac arrest (OHCA). METHODS: We used fire-based EMS data from Taipei city to develop the prediction model. Patients included in this study were those who were initially alive, non-traumatic, and age ≧20 years. Data were extracted from electronic records of ambulance run sheets and an Utstein-style OHCA registry. The primary outcome (EMS-witnessed OHCA) was defined as cardiac arrest occurring during the service of emergency medical technicians before arrival at a receiving hospital. Area under the receiver operating characteristic curve (AUROC) and the Hosmer-Lemeshow (HL) test were used to examine discrimination and calibration. The point value system with Youden's J Index was used to find the optimal cut-off value. RESULTS: From 2011 to 2015, a total of 252,771 patients were included. Of them, 660 (0.26%) were EMS-witnessed OHCA. The model, including the predictors of male gender, respiratory rate≦10 cycles/min, heart rate <60 or ≧120 beats/min, systolic blood pressure <100 mmHg, level of consciousness, and oxygen saturation <94%, reached excellent discrimination with an AUROC of 0.94 [95% confidence interval (CI), 0.93-0.95] and excellent calibration (p = 0.42 for HL test) in a randomly selected derivation cohort. The results were comparable to those found in a validation cohort. The optimal cut-off value (≧13) of the tool demonstrated high sensitivity (87.84%) and specificity (86.20%). CONCLUSION: This newly developed prediction model will help identify high-risk patients with EMS-witnessed OHCA.

Using G-FAST to recognize emergent large vessel occlusion: a training program for a prehospital bypass strategy.

INTRODUCTION: The shorter the time between the onset of symptoms and reperfusion using endovascular thrombectomy, the better the functional outcome of patients. A training program was designed for emergency medical technicians (EMTs) to learn the gaze-face-arm-speech-time test (G-FAST) score for initiating a prehospital bypass strategy in an urban city. This study aimed to evaluate the effect of the training program on EMTs. METHODS: All EMTs in the city were invited to join the training program. The program consisted of a 30 min lecture and a 20 min video which demonstrated the G-FAST evaluation. The participants underwent tests before and after the program. The tests included (1) a questionnaire of knowledge, attitudes, confidence, and behaviors towards stroke care; and (2) watching 10 different scenarios in a video and answering questions, including eight sub-questions of G-FAST parameters, and choosing a suitable receiving hospital. RESULTS: In total, 1058 EMTs completed the training program. After the program, significant improvement was noted in knowledge, attitudes, and confidence, as well as scenario judgement. The performance of the EMTs in evaluating G-FAST criteria in comatose patients was relatively poor in the pre-test and improved significantly after the training course. Although the participants answered the G-FAST items correctly, they tended to overtriage the patients and refer them to higher-level hospitals. CONCLUSIONS: A short training program can improve the ability to identify stroke patients and choose a suitable receiving hospital. A future training program could put further emphasis on how to evaluate comatose patients and choose a suitable receiving hospital.

Reinforcing Mechanism of Reduced Graphene Oxide on Flexural Strength of Geopolymers: A Synergetic Analysis of Hydration and Chemical Composition.

With the development of nanotechnology, reduced graphene oxide (rGO) has been used to improve the flexural strength of geopolymers. However, the reinforcing mechanism of rGO nanosheets on the flexural strength of geopolymers remains unclear. Here, this reinforcing mechanism was investigated from the perspectives of hydration and chemical composition. The effect of the reduction degree on rGO-reinforced geopolymers was also studied using isothermal calorimetry (IC), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) tests. Results show that the hydration degree and flexural strength of geopolymers effectively increase due to rGO addition. After alkali reduction at a temperature of 60 °C, rGO nanosheets have maximum reinforcement on the flexural strength of geopolymers with an increment of 51.2%. It is attributed to the promotion of slag hydration, as well as the simultaneous formation of calcium silicate hydrate with low Ca/Si ratio (C-S-H(I)) and calcium aluminosilicate hydrate (C-A-S-H) phases due to the inhibiting effect of rGO nanosheets on Al substitution on the end-of-chain silicates of C-S-H and C-A-S-H gels. In addition, different reduction degrees have almost no effect on the chemical composition of rGO-reinforced geopolymers, while excessive reduction impairs the improving effect of rGO nanosheets on the hydration process and flexural strength of geopolymers due to significant structural defects.

Cord blood leptin DNA methylation levels are associated with macrosomia during normal pregnancy.

BACKGROUND: We previously demonstrated an association between placental leptin (LEP) methylation levels and macrosomia without gestational diabetes mellitus (non-GDM). This study further explored the association between LEP methylation in cord blood and non-GDM macrosomia. METHOD: We carried out a case-control study of 61 newborns with macrosomia (birth weight ≥4000 g) and 69 newborns with normal birth weight (2500-3999 g). Methylation in the LEP promoter region was mapped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RESULTS: Average cord blood LEP methylation levels were lower in macrosomia newborns than in control newborns (P < 0.001). Eleven CpG sites were associated with macrosomia. Multivariate logistic regression revealed that low LEP methylation levels [adjusted odds ratio (AOR) = 2.84, 95% confidence interval (CI): 1.72-4.17], high pre-pregnancy body mass index (AOR = 7.44, 95% CI: 1.99-27.75), long gestational age (AOR = 3.18, 95% CI: 1.74-5.79), high cord blood LEP concentration (AOR = 2.25, 95% CI: 1.34-3.77), and male newborn gender (AOR = 3.91, 95% CI: 1.31-11.69) significantly increased the risk of macrosomia. CONCLUSIONS: Lower cord blood LEP methylation levels and certain maternal and fetal factors are associated with non-GDM macrosomia.

Dynamic Mechanical Behavior of Fiber-Reinforced Seawater Coral Mortars.

Coral aggregate has been widely used for island construction because of its local availability. However, the addition of coral aggregate exaggerates the brittle nature of cement-based materials under dynamic loading. In this study, polyvinyl alcohol (PVA) fiber was used to improve dynamic mechanical behavior of seawater coral mortars (SCMs). The effects of coral aggregate and PVA fiber on the workability, static mechanical strengths, and dynamic mechanical behavior of fiber-reinforced SCMs were investigated. Results showed that the workability of the SCM decreased with increasing coral aggregate replacement rate and PVA fiber content. Mechanical strengths of the SCM increased with increasing PVA fiber content, but decreased with increasing coral aggregate replacement rate. Dynamic mechanical behavior at varying coral aggregate replacement rates was analyzed by combining dynamic mechanical analysis and micro-scale elastic modulus experiment. With increasing coral aggregate replacement rate, the storage modulus, loss factor, and elastic modulus of the interfacial transition zone in the SCM decreased. Nevertheless, with the incorporation of PVA fibers (1 vol.%), the storage modulus and loss factor were improved dramatically by 151.9 and 73.3%, respectively, compared with the reference group. Therefore, fiber-reinforced coral mortars have a great potential for use in island construction, owing to the excellent anti-vibrational performance.

The Effect of Successful Intubation on Patient Outcomes After Out-of-Hospital Cardiac Arrest in Taipei.

STUDY OBJECTIVE: The effect of out-of-hospital intubation in patients with out-of-hospital cardiac arrest remains controversial. The Taipei City paramedics are the earliest authorized to perform out-of-hospital intubation among Asian areas. This study evaluates the association between successful intubation and out-of-hospital cardiac arrest survival in Taipei. METHODS: We analyzed 6 years of Utstein-based registry data from nontrauma adult patients with out-of-hospital cardiac arrest who underwent out-of-hospital airway management including intubation, laryngeal mask airway, or bag-valve-mask ventilation. The primary analysis was intubation success on patient outcomes. The primary outcome was survival to discharge and the secondary outcomes included sustained return of spontaneous circulation and favorable neurologic survival. Sensitivity analysis was performed with intubation attempts rather than intubation success. Subgroup analysis of advanced life support-serviced districts was also performed. RESULTS: A total of 10,853 cases from 2008 to 2013 were analyzed. Among out-of-hospital cardiac arrest patients receiving airway management, successful intubation, laryngeal mask airway, and bag-valve-mask ventilation was reported in 1,541, 3,099, and 6,213 cases, respectively. Compared with bag-valve-mask device use, successful out-of-hospital intubation was associated with improved chances of sustained return of spontaneous circulation (adjusted odds ratio [aOR] 1.91; 95% confidence interval [CI] 1.66 to 2.19), survival to discharge (aOR 1.98; 95% CI 1.57 to 2.49), and favorable neurologic outcome (aOR 1.44; 95% CI 1.03 to 2.03). The results were comparable in sensitivity and subgroup analyses. CONCLUSION: In nontrauma adult out-of-hospital cardiac arrest in Taipei, successful out-of-hospital intubation was associated with improved odds of sustained return of spontaneous circulation, survival to discharge, and favorable neurologic outcome.

The effect of the number and level of emergency medical technicians on patient outcomes following out of hospital cardiac arrest in Taipei.

AIM: The effect of the number and level of on-scene emergency medical technicians (EMTs) on the outcomes of patients with out-of-hospital cardiac arrest (OHCA) remains unclear. We aimed to test the association between the number and level of EMTs and the outcomes of patients with OHCA. METHODS: We analysed Utstein-based registry data on OHCA in Taipei from 2011 to 2015. The eligible patients were adults, aged ≥20 years, with non-traumatic OHCA who underwent resuscitation attempts. The exposures were the total number of EMTs or the EMT-Paramedic (EMT-P) ratio >50%. The outcome of interest was survival to discharge. RESULTS: During study period, total 8262 OHCA cases were included, of which 1085 (13.1%) were approached by crews with an EMT-P ratio >50%. While an increase in the number of EMTs on-scene was not associated with better chances of survival (adjusted odds ratio [aOR] 0.98, 95% confidence interval [CI] 0.89-1.08), an EMT-P ratio >50% was significantly associated with improved outcome (aOR 1.36, 95% CI 1.06-1.76). Subgroup analyses showed that EMT-P >50% significantly benefited survival in witnessed OHCA cases with non-shockable rhythm (aOR 1.69, 95% CI 1.01-2.58). Survival was the highest among cases seen by four EMTs with an EMT-P ratio >50% (aOR 2.54, 95% CI 1.43-4.50). CONCLUSION: An on-scene EMT-P ratio >50% was associated with improved survival to discharge of OHCA cases, especially in those with witnessed, non-shockable rhythm. The presence of four EMTs with an EMT-P ratio >50% at the scene of OHCA was associated with the best outcome.

Nano-Silica Sol-Gel and Carbon Nanotube Coupling Effect on the Performance of Cement-Based Materials.

Carbon nanotubes (CNTs) have shown promise for improving the mechanical performance of cement composites through crack-bridging and frictional pull-out. The interactive behaviors between CNTs and cement matrix act are crucial in optimizing the reinforcement of CNTs in cement composites. This study investigates the effects of nano-silica (NS) sol-gel on the interactive behaviors of CNTs and the cement matrix through a series of experiments and analyses. UV-visible spectrometer results show that CNTs are well-dispersed in suspension and the addition of NS has a negligible effect on the stability of CNT dispersion. Calorimetry tests and dynamic mechanical analysis demonstrate the nucleation and frictional performance of CNTs in cement matrix, respectively. The paper shows that the physical adsorption of NS on the CNT surface could result in the acceleration of cement hydration. Morphology observation confirms that a denser interface between CNTs and cement hydrates is formed. Finally, the improved interaction between CNTs and cement hydrates leads to a substantial increase in friction between CNTs and the cement matrix under periodic loading. NS may act as an ideal admixture for improving both the interactive behaviors between CNTs and cement matrix and the damping properties of cement composite.

Influence of Ultrafine 2CaO·SiO2 Powder on Hydration Properties of Reactive Powder Concrete.

In this research, we assessed the influence of an ultrafine 2CaO·SiO2 powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM), mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength) with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO2. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO2 powder has the potential to improve the performance of a reactive powder cementitious system.

Investigation on the Mechanical Properties of a Cement-Based Material Containing Carbon Nanotube under Drying and Freeze-Thaw Conditions.

This paper aimed to explore the mechanical properties of a cement-based material with carbon nanotube (CNT) under drying and freeze-thaw environments. Mercury Intrusion Porosimetry and Scanning Electron Microscopy were used to analyze the pore structure and microstructure of CNT/cement composite, respectively. The experimental results showed that multi-walled CNT (MWCNT) could improve to different degrees the mechanical properties (compressive and flexural strengths) and physical performances (shrinkage and water loss) of cement-based materials under drying and freeze-thaw conditions. This paper also demonstrated that MWCNT could interconnect hydration products to enhance the performance of anti-microcracks for cement-based materials, as well as the density of materials due to CNT's filling action.

A randomized trial of compression first or analyze first strategies in patients with out-of-hospital cardiac arrest: results from an Asian community.

BACKGROUND: It is still under debate whether a period of cardiopulmonary resuscitation should be performed prior to rhythm analysis for defibrillation for out of hospital cardiac arrests (OHCA). This study compared outcomes of OHCA treated by "compression first" (CF) versus "analyze first" (AF) strategies in an Asian community with low rates of shockable rhythms. METHODS: This randomized trial was conducted in Taipei City between February 2008 and December 2009. Dispatches of suspected OHCA that activated advanced life support teams were randomized into the CF and AF strategies. Patients assigned to CF strategy received 10 cycles of CPR prior to analysis by automatic external defibrillator. The primary outcome was sustained (>2 h) return of spontaneous circulation (ROSC) and secondary outcome was survival to hospital discharge. RESULTS: We included 289 cases in the final analysis after exclusion by pre-specified criteria, 141 were allocated to CF strategy and 148 to AF strategy. Baseline characteristics were similar. Thirty-seven (26.2%) of those receiving CF strategy and 49 (33.1%) of the AF strategy achieved sustained ROSC (p=0.25). In a post-hoc analysis of patients who achieved ROSC, those that received CF strategy were more likely to be discharged alive from the hospital (16/37=43.2% vs. 11/49=22.4%, p=0.02). CONCLUSION: In this study population of low rates of shockable rhythms, there was no difference in ROSC for CF or AF strategies. Considering the EMS operation situations, a period of paramedic-administered CPR for up to 10 cycles prior to rhythm analysis could be a feasible strategy in this community.