We extend a result of Lieb [‘On the lowest eigenvalue of the Laplacian for the intersection of two domains’, Invent. Math.74(3) (1983), 441–448] to the fractional setting. We prove that if A and B are two bounded domains in $\mathbb R^N$ and $\lambda _s(A)$ , $\lambda _s(B)$ are the lowest eigenvalues of $(-\Delta )^s$ , $0<s<1$ , with Dirichlet boundary conditions, there exists some translation $B_x$ of B such that $\lambda _s(A\cap B_x)< \lambda _s(A)+\lambda _s(B)$ . Moreover, without the boundedness assumption on A and B, we show that for any $\varepsilon>0$ , there exists some translation $B_x$ of B such that $\lambda _s(A\cap B_x)< \lambda _s(A)+\lambda _s(B)+\varepsilon .$

Acute myocarditis is one of the common complications of coronavirus disease 2019 (COVID-19) with a relatively high case fatality. Here reported is a fulminant case of a 42-year-old previously healthy woman with cardiogenic shock and refractory cardiac arrest due to COVID-19-induced myocarditis who received veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) after 120 minutes of cardiopulmonary resuscitation (CPR). This is the first adult case of cardiac arrest due to COVID-19-induced myocarditis supported by ECMO that fully recovered with normal neurological functions. The success of the treatment course with full recovery emphasized the potential role of ECMO in treating these patients.

Herein, we propose a convenient method to enable pretreatment of target objects using digital holographic microscopy (DHM). As a test sample, we used diatom frustules (Nitzschia sp.) as the target objects. In the generally used sample preparation method, the frustule suspension is added dropwise onto a glass substrate or into a glass chamber. While our work confirms good observation of purified frustules using the typical sample preparation method, we also demonstrate a new procedure to observe unseparated structures of frustules prepared by baking them on a mica surface. The baked frustules on the mica surface were transferred to a glass chamber with 1% sodium dodecyl sulfate solution. In this manner, the unseparated structures of the diatom frustules were clearly observed. Furthermore, metal-coated frustules prepared by sputtering onto them on a mica surface were also clearly observed using the same procedure. Our method can be applied for the observation of any target object that is pretreated on a solid surface. We expect our proposed method to be a basis for establishing DHM techniques for microscopic observations of biomaterials.

One of the three Critically Endangered and endemic primate species in Viet Nam, Delacour's langur Trachypithecus delacouri, is restricted to the north of the country. The largest remaining population is in Van Long Nature Reserve, Ninh Binh Province, and the second largest is in nearby Kim Bang Protection Forest, Ha Nam Province, with other populations believed to be too small for recovery. The population in Van Long has been well studied but the status of that of Kim Bang has not previously been adequately evaluated. To address this, a survey was conducted during 10 August–7 October 2018. In total, we recorded 13 groups comprising a total of at least 73 individuals, almost doubling the highest number reported in previous studies. We documented six new groups in Lien Son and Ba Sao communes in Kim Bang. Our findings indicate there is a high likelihood that Delacour's langur population in Kim Bang will recover and could be important for the long-term conservation of this Critically Endangered species. However, immediate and appropriate conservation measures need to be implemented to protect the population from major anthropogenic threats, namely poaching and habitat destruction, detected during our survey.

We explore the possibility of combining a knowledge-based reduced order model (ROM) with a reservoir computing approach to learn and predict the dynamics of chaotic systems. The ROM is based on proper orthogonal decomposition (POD) with Galerkin projection to capture the essential dynamics of the chaotic system while the reservoir computing approach used is based on echo state networks (ESNs). Two different hybrid approaches are explored: one where the ESN corrects the modal coefficients of the ROM (hybrid-ESN-A) and one where the ESN uses and corrects the ROM prediction in full state space (hybrid-ESN-B). These approaches are applied on two chaotic systems: the Charney–DeVore system and the Kuramoto–Sivashinsky equation and are compared to the ROM obtained using POD/Galerkin projection and to the data-only approach based uniquely on the ESN. The hybrid-ESN-B approach is seen to provide the best prediction accuracy, outperforming the other hybrid approach, the POD/Galerkin projection ROM, and the data-only ESN, especially when using ESNs with a small number of neurons. In addition, the influence of the accuracy of the ROM on the overall prediction accuracy of the hybrid-ESN-B is assessed rigorously by considering ROMs composed of different numbers of POD modes. Further analysis on how hybrid-ESN-B blends the prediction from the ROM and the ESN to predict the evolution of the system is also provided.

In this study, we investigate the intial value problem (IVP) for a time-fractional fourth-order equation with nonlinear source terms. More specifically, we consider the time-fractional biharmonic with exponential nonlinearity and the time-fractional Cahn–Hilliard equation. By using the Fourier transform concept, the generalized formula for the mild solution as well as the smoothing effects of resolvent operators are proved. For the IVP associated with the first one, by using the Orlicz space with the function $\Xi (z)={\textrm {e}}^{|z|^{p}}-1$ and some embeddings between it and the usual Lebesgue spaces, we prove that the solution is a global-in-time solution or it shall blow up in a finite time if the initial value is regular. In the case of singular initial data, the local-in-time/global-in-time existence and uniqueness are derived. Also, the regularity of the mild solution is investigated. For the IVP associated with the second one, some modifications to the generalized formula are made to deal with the nonlinear term. We also establish some important estimates for the derivatives of resolvent operators, they are the basis for using the Picard sequence to prove the local-in-time existence of the solution.

The ocean is a central site of escape, danger, and rescue for refugees. It is also a place where oceanic humanitarianism is enacted. In histories of refugee migration, the combination of the ocean, weather, and climate in determining the fate of refugees has not been adequately examined. This article provides a critical analysis of a Vietnamese refugee boat journey in 1982, to demonstrate the paradoxical nature of the ocean as both a site of danger and saviour. Conventional historical methodologies alone cannot capture the complex role of the ocean and the weather in determining boat refugee journeys and rescues. Interdisciplinary research between historians and ocean engineers provides new evidence and understanding of how the ocean and weather influences the outcomes of refugees seeking asylum by boat. Numerical model predictions of sea state and ship motion – which enables the vessel's journey in past environmental conditions to be understood – integrated within historical analysis contributes to a fuller and more complex understanding of the nexus between environmental conditions and forced migration journeys. Ocean engineering produces a scientific narrative that historians can use, alongside oral histories and other sources, to theorize the ocean as an active agent.

In hot environments, collagen, which is normally targeted when radiocarbon (14C) dating bone, rapidly degrades. With little other skeletal material suitable for 14C dating, it can be impossible to obtain dates directly on skeletal materials. A small amount of carbonate occurs in hydroxyapatite, the mineral phase of bone and tooth enamel, and has been used as an alternative to collagen. Unfortunately, the mineral phase is often heavily contaminated with exogenous carbonate causing 14C dates to underestimate the true age of a sample. Although tooth enamel, with its larger, more stable crystals and lower porosity, is likely to be more robust to diagenesis than bone, little work has been undertaken to investigate how exogenous carbonate can be effectively removed prior to 14C dating. Typically, acid is used to dissolve calcite and etch the surface of the enamel, but it is unclear which acid is most effective. This study repeats and extends earlier work using a wider range of samples and acids and chelating agents (hydrochloric, lactic, acetic and propionic acids, and EDTA). We find that weaker acids remove carbonate contaminants more effectively than stronger acids, and acetic acid is the most effective. However, accurate dates cannot always be obtained.

We study the fractional parabolic Lichnerowicz equation

$$ \begin{align*} v_t+(-\Delta)^s v=v^{-p-2}-v^p \quad\mbox{in } \mathbb R^N\times\mathbb R \end{align*} $$

$p>0$

$ 0<s<1 $

$p>1$

$0<p\leq 1$

$$ \begin{align*} (-\Delta)^s u=u^{-p-2}-u^p \quad\mbox{in }\mathbb R^N \end{align*} $$

$p>0$

$0<s<1$

ABSTRACT IMPACT: Human exhaled breath is rich in metabolomic content that represents pulmonary function and gas exchange with blood, which can provide insights into an individual’s state of health. OBJECTIVES/GOALS: Human exhaled breath is rich in metabolomic content that represents pulmonary function and gas exchange with blood. It contains a mixture of compounds that offer insight into an individual’s state of health. Here, we present two novel non-invasive breath sampling devices for use in basic medical practice. METHODS/STUDY POPULATION: The two breath samplers have a disposable mouthpiece, a set of inhale and exhale one-way flap valves to allow condensation of exhaled breath only, and a saliva filter. The housing is constructed out of Teflon®, a chemically inert material to reduce chemical absorbance. The first device condenses exhaled breath into a frozen condensate using dry ice pellets and the other is a miniaturized design that liquifies exhaled breath on a condenser surface with micropatterned features on a cooling plate. Both designs have individual strategic and analytical advantages: frozen exhaled breath condensate (EBC) has high retention of analytes and sample volume; EBC collected in liquid phase offers facilitated sample collection and device portability. RESULTS/ANTICIPATED RESULTS: We investigated if breath aerosol size distribution affects the types or abundances of metabolites. We modified the geometry of the first device to redirect aerosol trajectories based on size. The trapping of larger aerosols increases with filter length, thus altering the aerosol size distribution although no significant changes in the metabolite profiles were found. With the miniaturized device, metabolite abundances were measured in a small cohort of healthy control and mild asthmatic subjects. Differences among subjects were found, as well as main differences between control and asthmatic groups. All analyses of EBC were performed with liquid chromatography - mass spectrometry. Inflammatory suppression found in asthmatic subjects can be explained by prescribed daily use of inhaled corticosteroids. DISCUSSION/SIGNIFICANCE OF FINDINGS: Breath collection devices can be used in intensive care units, outpatient clinics, workplaces, and at home. EBC analysis has been used to monitor asthma and chronic obstructive pulmonary disease. It can be applied to infectious respiratory diseases (e.g. influenza, COVID-19) and for monitoring environmental and occupational chemical exposures.

Background: Pertussis continues to be an important health issue in Vietnam despite infant vaccination programs. In Vietnam, the incidence rates of pertussis per 100,000 population rose from 0.09 in 2014 to 0.33 in 2015 and to 0.58 in 2017. Macrolides, especially erythromycin, are the treatment of choice. However, erythromycin-resistant cases, caused by transition at A2047G position in 23S rRNA, have been reported in the region. Few data are available on antimicrobial resistance in Bordetella pertussis to guide treatment in Vietnam. We report antimicrobial susceptibility of the circulating strains in southern Vietnam during 2015–2017. Methods: Tracheal aspirates from 263 suspected pertussis cases were subject to multiplex real-time PCR to identify B. pertussis and Bordetella spp. Samples were cultured on Regan Lowe agar with 10% sheep blood containing cephalexin (40 µg/mL) and incubated at 37°C for 10 days. The antimicrobial susceptibilities to erythromycin, azithromycin, clarithromycin, and trimethoprim/sulfamethoxazole were determined using the disc diffusion method (CLSI-2017) on Regan Lowe and Mueller Hinton agar. Erythromycin minimum inhibitory concentrations (MICs) were determined using an E-test. The results were recorded after days 3 and 7 of incubation. Sequencing of the 23S rRNA gene was performed to detect mutations conferring macrolide resistance. Results: Of 263 cases, 119 were positive for B. pertussis (45.2%) by real-time PCR, and 15 of 263 strains (5.7%) were successfully cultured. All 15 isolates were susceptible to macrolides and no heterogeneous phenotype was recorded after 7 days; erythromycin MICs were ≤0.094 µg/mL (Fig. 1). We observed no difference in results generated on Regan Lowe and Mueller Hinton media. However, for testing trimethoprim/sulfamethoxazole, results on were superior, as those on Regan Lowe media were unclear. Sequencing of 23S rRNA identified no mutations known to confer macrolide resistance. Conclusions: None of 15 B. pertussis isolates tested were nonsusceptible to erythromycin and macrolides. Similarly, no mutation at the erythromycin-binding site in the 23S rRNA gene was identified. The low isolation rate of B. pertussis by culture means that few positive specimens were tested for antimicrobial susceptibility. To overcome this limitation, detection of resistance directly from clinical specimens needs to be investigated. Ongoing screening for B. pertussis and antimicrobial susceptibility is recommended to support efforts to control the spread of this respiratory tract infection agent.

Funding: None

Disclosures: None

Background: Antibiotic overuse has led to increasing rates of antibiotic resistant infections and unnecessary antibiotic costs. Clinical pharmacists can play a key role in optimizing appropriate use of antimicrobials and reducing antimicrobial resistance. However, the role of clinical pharmacists in antimicrobial stewardship is new and not well established in Viet Nam. Objective: We evaluated the use of clinical pharmacists for improved antimicrobial prescribing. Methods: We assembled an antibiotic stewardship program (ASP) team consisting of a clinical pharmacist and a specialist in infection prevention and control in a 60-bed medical intensive care unit (MICU) at Hue Central Hospital in central Viet Nam. During January–September 2018, the ASP team collected baseline antibiotic prescribing days of therapy (DOT) for all antibiotics administered in the MICU. Then, from October 2018 through June 2019, the ASP team reviewed daily positive clinical bacterial cultures and susceptibility results for all patients present in the MICU. They reviewed medical charts, including antimicrobial prescriptions, during week days and only if patient was still in the ICU at the time of ASP rounds. The team recommended changes to antibiotic therapy verbally to physicians and left the decision to change antibiotic therapy to their discretion. The ASP team documented whether their recommendations were accepted or rejected. Statistical significance was determined using the Student t test. Results: The ASP team reviewed 160 medical charts and made 169 ASP recommendations: 122 (72%) to continue current treatment; 24 (14%) to monitor drug levels or obtain diagnostic tests; 10 (6%) to discontinue therapy; 6 (4%) to de-escalate therapy; 5 (3%) to adjust doses; and 2 (1%) to broaden therapy. Only 8 of the recommended changes (5%) were declined by the clinicians. The average monthly DOT for all types of antibiotics declined significantly from 2,213 to 1,681 (24% decrease; P = .04). Reductions in DOT for the most common broad-spectrum antibiotics included colistin from 303 to 276 (P = .75); imipenem-cilastatin 434 to 248 (P = .06); doripenem 150 to 144 (P = .85). Piperacillin-tazobactam increased from 122 to 142 (P = 0.75). Conclusions: We demonstrated that daily review of cultures and antibiotic use decreased overall antibiotic prescribing. Given that few recommendations included discontinuation of therapy, ASP rounds likely raised awareness for clinicians to optimize antibiotic use.

Funding: None

Disclosures: None

Background: Whooping cough is a serious respiratory illness in infants caused by Bordetella pertussis. In spite of the vaccination program, the incidence rates of whooping cough per 100,000 population in Vietnam increased from 0.33 in 2015 to 0.58 in 2017. If this represents a pertussis resurgence, contributors may include pathogen adaptation, the spread of specific variants, vaccine failure, and failure to effectively treat cases and contacts. There has been little research in Vietnam on B. pertussis strains. Therefore, we investigated the molecular epidemiology of circulating B. pertussis strains in Southern Vietnam by applying multilocus sequence typing (MLST) for 7 housekeeping genes and 4 antigenic determinant genes as components in the acellular vaccine including prn, ptxP, ptxS1, and fim3. Methods: DNA was extracted from 15 isolates collected from 263 case patients during 2015–2017 and was subject to MLST using primers and cycling conditions from the Bordetella pubMLST website (www.Pubmlst.org/Bordetella/). The products were analyzed using BioEdit version 7.2.5 software and then were aligned and compared to reference sequences of each genotype in the database. The evolutionary relationship among sequence types (STs) from housekeeping genes was performed as a minimum spanning tree via the goeBURST algorithm, whereas the correlation of different variants from 4 antigenic determinant genes was built up and clarified with phylogenetic trees based on the UPGMA method by MEGA 7 program. Results: The 15 isolates were all classified as ST2 (100%) by MLST of housekeeping genes, and they belonged to a common global clonal group (Fig. 1). Sequencing of antigenic determinant genes prn2 – ptxP3 – ptxS1-1 – fim3-1 determined that all were identical to each another and the reference sequences (Fig. 2). Conclusions:B. pertussis isolates circulating in Southern Vietnam appeared to be the same as the common global strain. Few isolates were available for testing; therefore, continued surveillance is important to confirm these findings and to monitor population changes over time.

Funding: None

Disclosures: None

This study contributes to a growing literature body of studies aimed at explaining socio-economic-related health inequality in non-communicable diseases (NCDs), with a focus on older people who are commonly affected by socio-economic gradient in later life. It identifies factors associated with self-reported NCDs and examines socio-economic-related health inequality in self-reported NCDs between rural and urban Vietnamese older people. This cross-sectional study utilised data from the Viet Nam Ageing Survey. A sample of 2,682 older people aged 60 and over (urban = 703, rural = 1,979) was analysed. Concentration indices were computed to measure socio-economic inequalities in self-reported NCDs. Concentration index decomposition analysis was performed to determine the relative contributions of the determinants to explaining those inequalities. Significant socio-economic inequalities in self-reported NCDs favouring the rich were found, in which the degree of inequality was more pronounced in urban areas than in their rural counterparts. Household wealth and social health insurance were the main drivers contributing to increased socio-economic inequalities in self-reported NCDs in urban and rural areas, respectively. Among disadvantaged groups, older people living alone, with lowest wealth and with social health insurance had highest probability of reporting at least one NCD for both areas. Public policies aimed at narrowing wealth gaps and expanding and improving principle roles of social health insurance should prioritise the most disadvantaged groups in order to achieve health equality.

Our research proposes ‘mixed legal transplant’ as a new concept in theories of legal transplantation. While the concept of legal transplantation is real, the phenomenon is much more complicated than what is often depicted and discussed by the academic community. In modern times, legal transplantation is often an informed reception by independent sovereign nations or people of two or more sets of rules from different jurisdictions, rather than a simplistic and passive reception of rules from one country to another. Using Vietnam as a case study, this article analyzes the deliberate consideration of two different models of precedent in the civil and common law traditions by Vietnamese lawmakers, and their choice of a mixed legal transplant in the hope that it would be best suited to the needs of a socialist country in transition. Its methods and results, however, are still in doubt and have been criticized as possibly creating uncertainty due to their structural incoherence. This article therefore concludes by proposing recommendations based on legal tradition to correct the misuse of the mixed legal transplant in Vietnam, and we hope that these recommendations can serve as a model for other countries.

In engineering applications, it is pretty often to have domain heat source involved inside. This article proposes an approach using the boundary element method to study thermal stresses in 3D anisotropic solids when internal domain heat source is involved. As has been well noticed, thermal effect will give rise to a volume integral, where its direct evaluation will need domain discretization. This shall definitely destroy the most distinctive notion of the boundary element method that only boundary discretization is required. The present work presents an analytical transformation of the volume integral in the boundary integral equation due to the presence of internal volume heat source. For simplicity, distribution of the heat source is modeled by a quadratic function. When needed, the formulations can be further extended to treat higher-ordered volume heat sources. Indeed, the present work has completely restored the boundary discretization feature of the boundary element method for treating 3D anisotropic thermoelasticity involving volume heat source.