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An increase in the prevalence of allergic rhinitis (AR) worldwide presents a significant burden to the health care system. An initiative was started in Europe designated as Allergic Rhinitis and Its Impact on Asthma (ARIA) to develop internationally applicable guidelines by utilising an evidence-based approach to address this crucial issue. The efforts are directed at empowerment of patients for self-management, the use of digital mobile technology to complement and personalise treatment, and establishment of real-life integrated care pathways (ICPs). This guideline includes aspects of patients' and health care providers' management and covers the main areas of treatment for AR. The model provides better real-life health care than the previous traditional models. This review summarises the ARIA next-generation guideline in the context of the Malaysian health care system.

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PURPOSE: The setting regarding the ideal timing for deep inferior epigastric perforator flap (DIEP) reconstruction remains unclear. Immediate breast reconstruction (IBR) is performed at the same time as mastectomy, while delayed breast reconstruction (DBR) is performed at any time after mastectomy except immediately. We compared both strategies to assess whether IBR or DBR should be performed to reduce postoperative adverse events. METHODS: A systematic review of PubMed, Embase, Medline, Cochrane, and Web of Science was conducted, aiming at articles comparing the recipient site outcomes of IBR versus DBR with DIEP. We used the Mantel-Haenszel method with a fixed effects model. Results were expressed as the OR with a 95% CI. RESULTS: Two retrospective and two prospective studies were identified involving 5784 DIEPs (1744 immediate and 4040 delayed). We showed a significant difference in favor of IBR for wound healing issues (OR = 0.57, 95% CI 0.41, 0.77; p = 0.0003). However, no significant differences for hematoma, infection, fat necrosis, partial flap loss, and total flap loss rate were seen. CONCLUSIONS: Despite variability in the choice of the ideal time for breast reconstruction and outcomes reported among studies, immediate DIEP surgery appears to be a reliable setting with less delayed healing issues.

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It is generally accepted that material inhomogeneity causes stress concentrations at the interface and thus reduces the overall strength of a composite. To overcome this reduction in strength, some groups experimented on coating the nanoinclusions with a layer of rubbery material, aiming for higher energy absorption. However, representative volume element (RVE) nanocomposite models, established with randomly distributed core-shell nanoparticles and single nanoparticle cells, show that the enhancement in strength observed in some experiments remains elusive computationally. By including a pre-existing crack in the matrix of the RVE, the stress concentration at the crack tip is reduced for cases where the nanoparticle and precrack are aligned away from the loading direction. This suggests that stress concentrations around inherent defects in materials can sometimes be reduced by adding nanoparticles to improve material strength. The effect is reversed if the crack and nanoparticle are aligned towards the loading direction. Parametric studies were also carried out in terms of the relative stiffness of the nanoparticle to the matrix and crack length. Validation tests were performed on 3D RVEs with an elliptical crack as the initial defect, and the results match with the 2D findings.

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Glass-Fiber-Reinforced Polymer (GFRP) laminates are widely used in the automotive and marine industries such as auto bodies and boat hulls. Decreasing the weight and improving the reparability of GFRP parts will cut down material usage, fuel consumption and repair costs. This study shows a bio-inspired helicoidal stacking configuration that significantly improves the impact performance and fiber damage resistance of GFRP laminates. For similar impact performance in terms of perforation energy, the helicoidal GFRP laminate is 20% lighter than the conventional quasi-isotropic GFRP laminate. Upon impact, delaminations and matrix splits link-up and grow extensively throughout the helicoidal laminate. This effectively reduces fiber damage and improves impact performance. Because helicoidal GFRP laminates are resistant to fiber damage and composite healing agents can effectively repair non-fiber damage, embedding healing agents into helicoidal GFRP results in lightweight, inexpensive and healable laminates.

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Nonnegative matrix factorization (NMF) is a linear dimensionality reduction technique for analyzing nonnegative data. A key aspect of NMF is the choice of the objective function that depends on the noise model (or statistics of the noise) assumed on the data. In many applications, the noise model is unknown and difficult to estimate. In this paper, we define a multi-objective NMF (MO-NMF) problem, where several objectives are combined within the same NMF model. We propose to use Lagrange duality to judiciously optimize for a set of weights to be used within the framework of the weighted-sum approach, that is, we minimize a single objective function which is a weighted sum of the all objective functions. We design a simple algorithm based on multiplicative updates to minimize this weighted sum. We show how this can be used to find distributionally robust NMF (DR-NMF) solutions, that is, solutions that minimize the largest error among all objectives, using a dual approach solved via a heuristic inspired from the Frank-Wolfe algorithm. We illustrate the effectiveness of this approach on synthetic, document and audio data sets. The results show that DR-NMF is robust to our incognizance of the noise model of the NMF problem.

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Mortality risk is a major concern to patients who have just been discharged from the intensive care unit (ICU). Many studies have been directed to construct machine learning models to predict such risk. Although these models are highly accurate, they are less amenable to interpretation and clinicians are typically unable to gain further insights into the patients' health conditions and the underlying factors that influence their mortality risk. In this paper, we use patients' profiles extracted from the MIMIC-III clinical database to construct risk calculators based on different machine learning techniques such as logistic regression, decision trees, random forests, k-nearest neighbors and multilayer perceptrons. We perform an extensive benchmarking study that compares the most salient features as predicted by various methods. We observe a high degree of agreement across the considered machine learning methods; in particular, age, blood urea nitrogen level and the indicator variable - whether the patient is discharged from the cardiac surgery recovery unit are commonly predicted to be the most salient features for determining patients' mortality risks. Our work has the potential to help clinicians interpret risk predictions.

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In vitro 3D cell models have been accepted to better recapitulate aspects of in vivo organ environment than 2D cell culture. Currently, the production of these complex in vitro 3D cell models with multiple cell types and microenvironments remains challenging and prone to human error. Here, a versatile ink comprising a 4-arm poly(ethylene glycol) (PEG)-based polymer with distal maleimide derivatives as the main ink component and a bis-thiol species as the activator that crosslinks the polymer to form the hydrogel in less than a second is reported. The rapid gelation makes the polymer system compatible with 3D bioprinting. The ink is combined with a novel drop-on-demand 3D bioprinting platform, designed specifically for producing 3D cell cultures, consisting of eight independently addressable nozzles and high-throughput printing logic for creating complex 3D cell culture models. The combination of multiple nozzles and fast printing logic enables the rapid preparation of many complex 3D cell cultures comprising multiple hydrogel environments in one structure in a standard 96-well plate format. The platform's compatibility for biological applications is validated using pancreatic ductal adenocarcinoma cancer (PDAC) and human dermal fibroblast cells with their phenotypic responses controlled by tuning the hydrogel microenvironment.

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Effectiveness of knee braces remains to be identified. Therefore, the purpose of this study was to investigate the effectiveness of bilateral single-hinged knee bracing in knee osteoarthritis (OA) using finite element (FE) method. A three-dimensional FE model consisted of main model (knee-brace structure) and submodel (strap-muscle system) was developed. The submodel was used to convert the elastic strap-muscle interaction into an equivalent stiffness value required by the main model. Adding 100 N · mm/rad torsion spring to the brace with 5 kPa strap pressure lowered maximum von Mises stress in the knee OA components at a flexion angle greater than or equal to 90°. Separately, employing 10% brace pre-tension to the brace with 5 kPa strap pressure started to reduce stresses at a flexion angle of 70°. The configuration involving a combination of 10% brace pre-tension and 300 N · mm/rad torsion spring with 30 kPa strap tightness produced stress reduction over the entire range from 0° to 100° flexion angle. The basic bilateral single-hinged knee brace has shown to reduce stresses in the knee OA at high flexion angles only. Compared to the torsion spring, the brace pre-tension has shown to provide more significant benefits (i.e. stress reduction at lower flexion angles). The most sophisticated effects were achieved when the torsion spring was used in combination with the brace pre-tension. These two features can be potentially used for the development of an active knee brace if they can be modulated at different flexion angles or during the gait cycle.

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The purpose of this study was to determine stress envelopes for an intact tibiofemoral joint and to study how they vary with knee loading, external-internal rotation, varus-valgus rotation and cartilage degradation (osteoarthritis) using the finite element method. The envelopes were presented in terms of knee flexion angle. The maximum von Mises stress for all tibiofemoral joint components increased with increasing the axial compressive force magnitude. Menisci exhibited the highest magnitude of maximum von Mises stress as compared to the femoral and tibial cartilages. In a range of flexion angles between 0° and 100°, the medial meniscus exhibited the highest maximum von Mises stress than the lateral meniscus and the stress in medial meniscus tended to increase with increasing the flexion angle. External-internal and varus-valgus rotations changed the stress distribution: higher stress on lateral compartment but lower stress on medial compartment, and conversely. The internal rotation provided more extreme effect than the external rotation. For the knee osteoarthritis, cartilage degradation (early stage) caused maximum von Mises stress to increase on the intact menisci revealing that knee osteoarthritis could also cause meniscal tear. The late osteoarthritis caused the maximum von Mises stress to increase on the calcified cartilage and subchondral bone.

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The excellent mechanical properties of carbon nanofibers bring promise for energy-related applications. Through in silico studies and continuum elasticity theory, here we show that the ultra-thin carbon nanothreads-based bundles exhibit a high mechanical energy storage density. Specifically, the gravimetric energy density is found to decrease with the number of filaments, with torsion and tension as the two dominant contributors. Due to the coupled stresses, the nanothread bundle experiences fracture before reaching the elastic limit of any individual deformation mode. Our results show that nanothread bundles have similar mechanical energy storage capacity compared to (10,10) carbon nanotube bundles, but possess their own advantages. For instance, the structure of the nanothread allows us to realize the full mechanical energy storage potential of its bundle structure through pure tension, with a gravimetric energy density of up to 1.76 MJ kg-1, which makes them appealing alternative building blocks for energy storage devices.

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We revisit the distributed hypothesis testing (or hypothesis testing with communication constraints) problem from the viewpoint of privacy. Instead of observing the raw data directly, the transmitter observes a sanitized or randomized version of it. We impose an upper bound on the mutual information between the raw and randomized data. Under this scenario, the receiver, which is also provided with side information, is required to make a decision on whether the null or alternative hypothesis is in effect. We first provide a general lower bound on the type-II exponent for an arbitrary pair of hypotheses. Next, we show that if the distribution under the alternative hypothesis is the product of the marginals of the distribution under the null (i.e., testing against independence), then the exponent is known exactly. Moreover, we show that the strong converse property holds. Using ideas from Euclidean information theory, we also provide an approximate expression for the exponent when the communication rate is low and the privacy level is high. Finally, we illustrate our results with a binary and a Gaussian example.

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This paper attempts to develop a modified chemical percolation devolatilization (M-CPD) model that can include heat transfer, primary pyrolysis and the secondary cracking reactions of volatiles together to describe the pyrolysis of waste scrap tyre chip, as well as to examine the influence of operating conditions on the scrap tyre pyrolysis product yields. Such a study has yet to be conducted in the past, thereby leading to a large knowledge gap failing to understand the pyrolysis of the coarse feedstock appropriately. To validate the developed model, a number of operating parameters including reactor configurations, carrier gas compositions (argon and argon blended with CO2 and/or steam), scrap tyre chip size (0.5-15.0 mm), terminal pyrolysis temperature (400-800 °C) and heating rate (10 °C/min and 110 °C/min) were examined in a lab-scale fixed-bed pyrolyser, with a particular focus on the secondary cracking extents of the liquid tar. Through both experimental investigation and modelling approach, it was found that significant secondary cracking extent occurred upon the increase in the feedstock size, heating rate and residence time. Upon the fast pyrolysis, the average temperature gap between the centres of the coarse particle and reactor wall could reach a maximum of 115 °C for the tyre chips of 6-15 mm. Consequently, its primary volatiles underwent the secondary cracking reaction at an overall extent of 17% at a terminal temperature of 600 °C and a fast heating rate of 110 °C/min. Consequently, the yield of light gases including methane was increased remarkably. The flow rate of inert carrier gas was also influential in the secondary cracking, in which a maximum tar yield (54 wt%) was reached at a carrier gas flow rate of 1.5  L/min. This indicates the occurrence of secondary cracking has been largely minimised. At a pyrolysis temperature of 600 °C, the addition of CO2 in the carrier gas had an insignificant effect on the product yield distribution under the slow heating scheme. In contrast, the addition of steam resulted in a slight increase of carbon monoxide, presumably due to the occurrence of gasification reaction.

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Herein is presented a proof-of-concept study of protease sensing that combines nontoxic silicon quantum dots (SiQDs) with Förster resonance energy transfer (FRET). The SiQDs serve as the donor and an organic dye as the acceptor. The dye is covalently attached to the SiQDs using a peptide linker. Enzymatic cleavage of the peptide leads to changes in FRET efficiency. The combination of interfacial design and optical imaging presented in this work opens opportunities for use of nontoxic SiQDs relevant to intracellular sensing and imaging.

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Vibro-acoustic modulation (VAM) is a form of a non-destructive testing technique used in nonlinear acoustic methods for the detection of defects. It comprises of exciting the structure with a dual frequency sinusoidal signal and studying the interaction of this wave with the underlying defect. In this work a theoretical study on the mechanics of VAM is presented for a generic material body. The roles of different types of defect on the response of the material are analyzed. The theoretical analysis shows the origins of the nonlinear frequencies in the form of higher harmonics and sidebands commonly observed in the output response of VAM excitation. In addition, the analysis provides insights on the relationships between the magnitudes of the nonlinear responses and those of the input vibrations, and on the physical origins of the nonlinear responses. For a physical visualization of the nonlinear vibrations associated with the theory a finite element analysis of VAM is also performed. The model looks into the plausibility of using VAM for the mapping of damage in physical structures. The model is also used to investigate the effects of the defect size and defect depth on the nonlinear mechanism of VAM.

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Blast-induced traumatic brain injury has been on the rise in recent years because of the increasing use of improvised explosive devices in conflict zones. Our study investigates the response of a helmeted human head subjected to a blast of 1 atm peak overpressure, for cases with and without a standard polycarbonate (PC) face shield and for face shields comprising of composite PC and aerogel materials and with lateral edge extension. The novel introduction of aerogel into the laminate face shield is explored and its wave-structure interaction mechanics and performance in blast mitigation is analysed. Our numerical results show that the face shield prevented direct exposure of the blast wave to the face and help delays the transmission of the blast to reduce the intracranial pressures (ICPs) at the parietal lobe. However, the blast wave can diffract and enter the midface region at the bottom and side edges of the face shield, resulting in traumatic brain injury. This suggests that the bottom and sides of the face shield are important regions to focus on to reduce wave ingress. The laminated PC/aerogel/PC face shield yielded higher peak positive and negative ICPs at the frontal lobe, than the original PC one. For the occipital and temporal brain regions, the laminated face shield performed better than the original. The composite face shield with extended edges reduced ICP at the temporal lobe but increases ICP significantly at the parietal lobe, which suggests that a greater coverage may not lead to better mitigating effects.

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Carbon fibres have attracted interest from both the scientific and engineering communities due to their outstanding physical properties. Here we report that recently synthesized ultrathin diamond nanothread not only possesses excellent torsional deformation capability, but also excellent interfacial load-transfer efficiency. Compared with (10,10) carbon nanotube bundles, the flattening of nanotubes is not observed in diamond nanothread bundles, which leads to a high-torsional elastic limit that is almost three times higher. Pull-out tests reveal that the diamond nanothread bundle has an interface transfer load of more than twice that of the carbon nanotube bundle, corresponding to an order of magnitude higher in terms of the interfacial shear strength. Such high load-transfer efficiency is attributed to the strong mechanical interlocking effect at the interface. These intriguing features suggest that diamond nanothread could be an excellent candidate for constructing next-generation carbon fibres.

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The current study aims to investigate the effectiveness of two different designs of helmet interior cushion, (Helmet 1: strap-netting; Helmet 2: Oregon Aero foam-padding), and the effect of the impact directions on the helmeted head during ballistic impact. Series of ballistic impact simulations (frontal, lateral, rear, and top) of a full-metal-jacketed bullet were performed on a validated finite element head model equipped with the two helmets, to assess the severity of head injuries sustained in ballistic impacts using both head kinematics and biomechanical metrics. Benchmarking with experimental ventricular and intracranial pressures showed that there is good agreement between the simulations and experiments. In terms of extracranial injuries, top impact had the highest skull stress, still without fracturing the skull. In regard to intracranial injuries, both the lateral and rear impacts generally gave the highest principal strains as well as highest shear strains, which exceed the injury thresholds. Off-cushion impacts were found to be at higher risk of intracranial injuries. The study also showed that the Oregon Aero foam pads helped to reduce impact forces. It also suggested that more padding inserts of smaller size may offer better protection. This provides some insights on future's helmet design against ballistic threats.

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Linear ultrasonics methods based on the principle of reflection, transmission, dissipation of sound waves have been traditionally used to detect delaminations in composite structures. However, when the delamination is in very early stages such that it is almost closed, or closed due to a compressive load, the linear methods may fail to detect such cases of delaminations. Nonlinear acoustics/ultrasonics have shown potential to identify damages in composite structures which are difficult to detect using conventional linear ultrasonic methods. The nonlinear method involves exciting the structure with a sinusoidal signal of certain (or multiple) frequency and observing the vibrations of the structure. The vibrations of the damage region differ significantly from intact regions and can be used to identify the damage. However due to the complex and varying nature of the nonlinear phenomena created by the interaction between the exciting signal and the damage, there are many variables at play which can lead to success or failure of the method. While experiments lead to the establishment of the method to be used as a damage detection technique, numerical simulations can help to explain the various phenomena associated with nonlinearity. This work presents a quick approach to model the nonlinear behavior caused by closed delaminations. The model is validated with a previously available approach for nonlinear vibrations modeling and a comparison is made between the two. The local nature of the nonlinearity enables to map out the area of damage in the structure. Additionally, a few parametric studies are performed to study the effect of various parameters related to the nonlinear phenomenon.

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As a potential building block for the next generation of devices/multifunctional materials that are spreading in almost every technology sector, one-dimensional (1D) carbon nanomaterial has received intensive research interests. Recently, a new ultra-thin diamond nanothread (DNT) has joined this palette, which is a 1D structure with poly-benzene sections connected by Stone-Wales (SW) transformation defects. Using large-scale molecular dynamics simulations, we found that this sp(3) bonded DNT can transition from brittle to ductile behaviour by varying the length of the poly-benzene sections, suggesting that DNT possesses entirely different mechanical responses than other 1D carbon allotropes. Analogously, the SW defects behave like a grain boundary that interrupts the consistency of the poly-benzene sections. For a DNT with a fixed length, the yield strength fluctuates in the vicinity of a certain value and is independent of the "grain size". On the other hand, both yield strength and yield strain show a clear dependence on the total length of DNT, which is due to the fact that the failure of the DNT is dominated by the SW defects. Its highly tunable ductility together with its ultra-light density and high Young's modulus makes diamond nanothread ideal for the creation of extremely strong three-dimensional nano-architectures.