Monitoring Prevalence and Persistence of Environmental Contamination by SARS-CoV-2 RNA in a Makeshift Hospital for Asymptomatic and Very Mild COVID-19 Patients

Objective: To investigate the details of environmental contamination status by SARS-CoV-2 in a makeshift COVID-19 hospital.Methods: Environmental samples were collected from a makeshift hospital. The extent of contamination was assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) for SARS-CoV-2 RNA from various samples.Results: There was a wide range of total collected samples contaminated with SARS-CoV-2 RNA, ranging from 8.47% to 100%. Results revealed that 70.00% of sewage from the bathroom and 48.19% of air samples were positive. The highest rate of contamination was found from the no-touch surfaces (73.07%) and the lowest from frequently touched surfaces (33.40%). The most contaminated objects were the top surfaces of patient cubic partitions (100%). The median Ct values among strongly positive samples were 33.38 (IQR, 31.69–35.07) and 33.24 (IQR, 31.33–34.34) for ORF1ab and N genes, respectively. SARS-CoV-2 relic RNA can be detected on indoor surfaces for up to 20 days.Conclusion: The findings show a higher prevalence and persistence in detecting the presence of SARS-CoV-2 in the makeshift COVID-19 hospital setting. The contamination mode of droplet deposition may be more common than contaminated touches

On constrained minimizers for Kirchhoff type equations with Berestycki-Lions type mass subcritical conditions

In this paper, for given mass m > 0 , we focus on the existence and nonexistence of constrained minimizers of the energy functional \begin{equation*} I(u): = \frac{a}{2}\int_{\mathbb{R}^3}\left|\nabla u\right|^2dx+\frac{b}{4}\left(\int_{\mathbb{R}^3}\left|\nabla u\right|^2dx\right)^2-\int_{\mathbb{R}^3}F(u)dx \end{equation*} on $S_m: = \left\{u\in H^1(\mathbb{R}^3):\, \|u\|^2_2 = m\right\},$where a, b > 0 and $F$ satisfies the almost optimal mass subcritical growth assumptions. We also establish the relationship between the normalized ground state solutions and the ground state to the action functional $I(u)-\frac{\lambda}{2}\|u\|_2^2$. Our results extend, nontrivially, the ones in Shibata (Manuscripta Math. 143 (2014) 221–237) and Jeanjean and Lu (Calc. Var. 61 (2022) 214) to the Kirchhoff type equations, and generalize and sharply improve the ones in Ye (Math. Methods. Appl. Sci. 38 (2015) 2603–2679) and Chen et al. (Appl. Math. Optim. 84 (2021) 773–806)

Neskončno mnogo rešitev s spremenljivim predznakom za probleme Kirchhoffovega tipa v R[sup]3

In this paper, we consider the following nonlinear Kirchhoff type problem: ▫begin{cases} - Big (a+b int_{mathbb{R}^3} |nabla u|^2 Big) Delta u + V(x)u = f(u), & text{in} quad mathbb{R}^3, \ u in H^1 (mathbb{R}^3), end{cases}▫ where ▫$a,b > 0$▫ are constants, the nonlinearity ▫$f$▫ is superlinear at infinity with subcritical growth and ▫$V$▫ is continuous and coercive. For the case when ▫$f$▫ is odd in ▫$u$▫ we obtain infinitely many sign-changing solutions for the above problem by using a combination of invariant sets method and the Ljusternik-Schnirelman type minimax method. To the best of our knowledge, there are only few existence results for this problem. It is worth mentioning that the nonlinear term may not be 4-superlinear at infinity, in particular, it includes the power-type nonlinearity ▫$|u|^{p-2}u$▫ with ▫$p in (2, 4]$▫.Obravnavamo naslednji nelinearni problem Kirchhoffovega tipa ▫begin{cases} - Big (a+b int_{mathbb{R}^3} |nabla u|^2 Big) Delta u + V(x)u = f(u), & text{in} quadmathbb{R}^3, \ u in H^1 (mathbb{R}^3), end{cases}▫ kjer sta ▫$a,b > 0$▫ konstanti, nelinearni člen ▫$f$▫ je superlinearen v neskončnosti, s subkritično rastjo, ▫$V$▫ pa je zvezna in vsiljena funkcija. V primeru, ko je ▫$f$▫ liha funkcija za ▫$u$▫, dobimo z uporabo kombinacije invariantnih množic in mini-maks metode Ljusternik-Schnirelmanovega tipa neskončno mnogo rešitev s spremenljivim predznakom za ta problem. Kolikor je nam znano, je bilo doslej najdenih le malo eksistenčnih rezultatov za ta problem. Velja omeniti, da nelinearni člen ni nujno 4-superlinearen v neskončnosti, konkretno vključuje nelinearnost potenčnega tipa ▫$|u|^{p-2}u$▫ za ▫$p$▫ iz intervala ▫$(2,4]$▫

Stability and Hydrocarbon/Fluorocarbon Sorption of a Metal-Organic Framework with Fluorinated Channels

The stabilities and hydrocarbon/fluorocarbon sorption properties of a zeolite-like metal-organic framework (MOF) Zn(hfipbb) with fluorinated channels has been studied. By the combination of thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD) measurements, we confirm that Zn(hfipbb) has exceptionally high hydrothermal and thermal stabilities. The adsorption behaviors of water and methanol by Zn(hfipbb) indicate that it is highly hydrophobic but with high adsorption of alcohols. Hexane and perfluorohexane adsorption measurements show that the fluorinated channels in Zn(hfipbb) have high affinity with hydrocarbon and fluorocarbon. The high fluorophilic nature of the channels and the high stability of the compound suggest its potential utility in practical separation applications

Resource Allocation in NOMA-Assisted Ambient Backscatter Communication System

This paper considers a non-orthogonal multiple access (NOMA)-assisted ambient backscatter communication (AmBC) system. To maximize the achievable sum rate (ASR) of the AmBC system, a joint optimization problem over a backscatter device (BD) grouping strategy, reflection coefficients, and decoding order is formulated, where the BD grouping strategy contains the number of BD groups and the BD allocation strategy. The BD grouping strategy, the reflection coefficients, and the decoding order are all intertwined, and the global search is extremely complex. As a result, we propose a four-step optimization algorithm. First, we give the closed-form optimal solution of the BD decoding order and reflection coefficient for a given grouping strategy. Then, for a given number of BD groups, we propose a low-complexity BD allocation strategy based on the complexity–performance trade-off. Finally, the number of BD groups with the largest ASR is selected as the global optimal number of BD groups. The simulation results show that the proposed four-step optimization algorithm is better than the benchmark solution

Fcc -> bcc -> hcp successive phase transformations in the strained ultrathin copper film: A molecular dynamic simulation study

The phase transformation behaviors of ultrathin Cu film under uniaxial tensile stress are investigated using molecular dynamic simulation. With the stress increasing, Cu film undergoes a successive phase transformation, i.e. firstly fcc -> bcc, then bcc -> hcp. The phase transformation process is very fast and thorough, i.e., all parents phase can transit into the new phase almost instantaneously. The crystallography mechanisms of two martensitic transformations are exactly corresponding to Bain and Burgers mechanism, respectively. By examining the formation conditions of such phase transformation in Cu film, we reveal that this fcc -> bcc -> hcp successive phase transformation will be subject to the very strict simulation conditions, namely stretching along [100] ( or [010], [001] ) direction, definitive tensile speed (1 x 10(10)/s), appropriate film thickness (0.7230-18.08 nm), low temperature (T <= 10 K), and continuous stretching process without any relaxation procedure

Development and implementation of a prognostic model for clear cell renal cell carcinoma based on heterogeneous TLR4 expression

Objective: Clear cell renal cell carcinoma (ccRCC) is the most common subtype among renal cell carcinomas and has the worst prognosis, originating from renal tubular epithelial cells. Toll-like receptor 4 (TLR4) plays a crucial role in ccRCC proliferation, infiltration, and metastasis. The aim of this study was to construct a prognostic scoring model for ccRCC based on TLR4 expression heterogeneity and to explore its association with immune infiltration, thereby providing insights for the treatment and prognostic evaluation of ccRCC. Methods: Using R software, a differential analysis was conducted on normal samples and ccRCC samples, and in conjunction with the KEGG database, a correlation analysis for the clear cell renal cell carcinoma pathway (hsa05211) was carried out. We observed the expression heterogeneity of TLR4 in the TCGA-KIRC cohort and identified its related differential genes (TRGs). Based on the expression levels of TRGs, consensus clustering was employed to identify TLR4-related subtypes, and further clustering heatmaps, principal component, and single-sample gene set enrichment analyses were conducted. Overlapping differential genes (ODEGs) between subtypes were analysed, and combined with survival data, univariate Cox regression, LASSO, and multivariate Cox regression were used to establish a prognostic risk model for ccRCC. This model was subsequently evaluated through ROC analysis, risk factor correlation analysis, independent prognostic factor analysis, and intergroup differential analysis. The ssGSEA model was employed to explore immune heterogeneity in ccRCC, and the performance of the model in predicting patient prognosis was evaluated using box plots and the oncoPredict software package. Results: In the TCGA-KIRC cohort, TLR4 expression was notably elevated in ccRCC samples compared to normal samples, correlating with improved survival in the high-expression group. The study identified distinct TLR4-related differential genes and categorized ccRCC into three subtypes with varied survival outcomes. A risk prognosis model based on overlapping differential genes was established, showing significant associations with immune cell infiltration and key immune checkpoints (PD-1, PD-L1, CTLA4). Additionally, drug sensitivity differences were observed between risk groups. Conclusion: In the TCGA-KIRC cohort, the expression of TLR4 in ccRCC samples exhibited significant heterogeneity. Through clustering analysis, we identified that the primary immune cells across subtypes are myeloid-derived suppressor cells, central memory CD4 T cells, and regulatory T cells. Furthermore, we successfully constructed a prognostic risk model for ccRCC composed of 17 genes. This model provides valuable references for the prognosis prediction and treatment of ccRCC patients

Resource Allocation in NOMA-Assisted Ambient Backscatter Communication System

This paper considers a non-orthogonal multiple access (NOMA)-assisted ambient backscatter communication (AmBC) system. To maximize the achievable sum rate (ASR) of the AmBC system, a joint optimization problem over a backscatter device (BD) grouping strategy, reflection coefficients, and decoding order is formulated, where the BD grouping strategy contains the number of BD groups and the BD allocation strategy. The BD grouping strategy, the reflection coefficients, and the decoding order are all intertwined, and the global search is extremely complex. As a result, we propose a four-step optimization algorithm. First, we give the closed-form optimal solution of the BD decoding order and reflection coefficient for a given grouping strategy. Then, for a given number of BD groups, we propose a low-complexity BD allocation strategy based on the complexity&ndash;performance trade-off. Finally, the number of BD groups with the largest ASR is selected as the global optimal number of BD groups. The simulation results show that the proposed four-step optimization algorithm is better than the benchmark solution

Contamination dynamics of personal protective equipment (PPE) by SARS-CoV-2 RNA in a makeshift hospital with COVID-19 positive occupants

Summary: Background: Personal protective equipment (PPE) helps protect healthcare workers (HCWs) from infection and prevents cross-contamination. Knowledge of the contamination dynamics of PPE during the management of COVID-19 patients in a makeshift hospital is limited. Aim: To describe the rate of SARS-CoV-2 contamination in PPE and to assess the change of contamination at different time points. Methods: HCWs were followed up for up to 4 hours with hourly collection of swab samples from PPE surfaces in a makeshift COVID-19 hospital setting. Swabs were tested using quantitative reverse transcription polymerase chain reaction (RT-qPCR) for SARS-CoV-2 RNA. Results: SARS-CoV-2 was detected on 50.9% of the 1620 swabbed samples from 9 different sites of full-body PPE worn by HCWs. The proportion of sites contaminated with SARS-CoV-2 RNA varied from 10.6% to 95.6%. Viral RNA was most frequently detected from the sole of the outer foot cover (95.6%) and least frequently on the face shield (10.6%). The median Ct values among positive samples were 34.20 (IQR, 32.61–35.22) and 34.05 (IQR, 32.20–35.39) for ORF1ab and N genes, respectively. The highest rate of contamination with SARS-CoV-2 RNA for the PPE swab samples was found after 3 hours of use. The positive rate of outer surface of HEPA filters from air supply device was 82.1% during the full capacity period of the makeshift hospital. Conclusion: A higher rate of contamination was identified at 3 hours after the entrance to the COVID-19 patient care area. Virus-containing aerosols were trapped in the HEPA filter of air supply equipment, representing a potential protective factor against infection to HCWs