Containment Facilities Research Articles

Inactivation of African Swine Fever Virus by reagents commonly used in containment laboratories

Rapid and effective virus inactivation is an essential step for safe diagnostic testing and for research and vaccine development using infectious viruses. We characterised the reduction of African Swine Fever Virus (ASFV) infectivity using Virkon™ S (Lanxess) 1% w/v disinfectant, FACS™ Lysing buffer (BD), and AVL™ buffer (Qiagen), using porcine cell culture. No virus was detected following a 30 s 20:1 v/v mixing ratio of Virkon™ S 1% with high titre ASFV, supporting its effective use as a laboratory surface disinfectant. FACS™ Lysing and AVL™ buffers also inactivated ASFV, permitting safe removal of treated infected samples from high containment facilities.

Numerical Analysis on the Flow and Stability of Vertical Hydraulic Barrier at Offshore Containment Facility

Preventing leakage and structural stability of vertical barrier at offshore containment facilities are very important. Two-dimensional numerical analysis were performed to evaluate seepage and flow characteristics regarding to different embedded depths and hydraulic permeability of vertical barrier. In addition, stress and displacement at corner of vertical barrier were evaluated by using 3-dimensional numerical analysis. The effluent flux in the case of vertical barrier with insufficient embedded depth was significantly increased by 200 ~ 240 times compared with the case of embedded barrier in low permeable clay layer. The effluent flux was increased by 4.5 and 45 times according to 10 and 100 times increase of hydraulic permeability of vertical barrier, respectively. The seepage and flow analysis results imply that the most important factor to prevent leakage is to embed the vertical barrier in low permeable layer. The 3-dimensional stress and displacement analysis results showed small displacement but large moment and shear stress at the corner of vertical barrier. Therefore, the stiffness and strength at the corner of vertical barrier compared with other parts should be increased to secure stability of vertical barrier at offshore disposal facilities. Keywords: offshore containment facility, waste disposal, vertical hydraulic barrier, PLAXIS

Evaluation of Efficacy about Disinfectants in Biological Containment Facilities

Evaluation of Efficacy about Disinfectants in Biological Containment Facilities

Evaluation of Efficacy about Disinfectants in Biological Containment Facilities

Evaluation of Efficacy about Disinfectants in Biological Containment Facilities

Adaptation of Research Infrastructure to Meet the Priorities of Global Public Health.

The rise of SARS-CoV-2 has resulted in the urgent need to unlock the mechanisms behind the disease it causes, COVID-19, and to develop countermeasures. As a result, there has been a massive push to study the virus and to test potential candidate vaccines, therapeutics, and antivirals. This has caused a rush at many institutions to switch research priorities to contribute to knowledge about the virus and COVID-19. This means that biosafety professionals have been tasked with figuring out how to conduct research with a novel pathogen safely and securely, often without the requisite knowledge and experience to safely assess the risk. Due to the similarity to another coronavirus, SARS-CoV, many biosafety professionals use the risk mitigation measures for this virus as a starting point. Research with live SARS-CoV-2 requires biosafety level 3 (BSL-3) high containment with additional risk mitigation measures, such as specialized training, engineering controls, personal protective equipment, and health monitoring as well as being mindful of the communication complexities of an ever-connected world. Analyzing human samples, developing diagnostics tests, studying downstream metabolites or proteins, or conducting immunology assays may be performed in a BSL-2 facility with enhanced practices depending upon an institution's risk assessment and risk tolerance. Globally, there are regional differences in high containment laboratories and what is studied in each facility. It is unknown if high-containment laboratory capacity in the United States meets or exceeds the national need or if they can be operated safely (Kingsbury, 2009). In addition, not all BSL-3 facilities are created equal and some do not have the optimal safeguards in place for conducting research with pathogens of pandemic potential. The Government Accountability Office (GAO) previously determined the absence of national standards for high containment laboratory design, construction, commissioning, operations, and maintenance raised concerns and increased the risk of laboratory accidents [US Government Accountability Office (GAO), 2013]. Some BSL-3 laboratories are built for specific purposes and others are built with a limited scope of use. Others are designed in an attempt to anticipate all future uses. More often than not, BSL-3 laboratories are value-engineered due to the high costs of construction, daily-operations, upkeep, and maintenance. Organizations do not want to overspend for features they might not use even though they might need them later on. As a result, there are a limited number of BSL-3 high containment facilities in the United States capable of conducting live SARS-COV-2 research safely and securely, especially with animal models. In addition, not all researchers have the training and expertise to work inside of BSL-3 laboratories. Training programs vary greatly depending on the structure and expertise of the trainer and the previous experiences of researchers. Due to the different designs and resulting standard operating procedures (SOPs), often the training from one facility is not necessarily applicable to another. Although the principles and practices behind biosafety and biosecurity are the same regardless of the design, individuals must demonstrate competency in conducting experiments and the laboratory SOPs before working unescorted. In addition, the COVID-19 pandemic is an ever-evolving situation, and as a result, public health guidance is changing frequently. Currently, there is a greater risk of researchers being exposed to SARS-CoV-2 in the community than from working in the laboratory. In combination, these factors present a challenging environment for biosafety professionals who facilitate research and ensure it is being performed in a safe and secure manner. It takes the entire institutional infrastructure—including but not limited to compliance and safety departments, facilities and maintenance personnel, oversight committees, information technology and security, and media relations—to ensure the research can be brought online swiftly and with limited hindrance in the most effective way possible.

Determination of mechanical and hydraulic properties of polyacrylamide-added bentonite-sand mixtures

Bentonite-sand mixtures are typically used in engineering applications such as cutoff walls for waste containment facilities or barriers in landfills and freshwater reservoirs. However, low or reduced mechanical and hydraulic performance of a bentonite-sand mixture might result in the failure of the engineering structure. In order to enhance the mechanical and hydraulic properties of a bentonite-sand mixture, an anionic and a cationic polyacrylamides with a content of 1, 2, 5, 10, and 15% respectively were added to the bentonite-sand mixtures. The polyacrylamides used in this study were water-soluble synthetic polymers with high molecular weights. They had enhanced flocculation capability when coming into contact with soil and water. Standard Proctor compaction, consolidated-drained direct shear, unconfined compression, falling-head permeability, and free swell tests were performed on the bentonite-sand mixtures that had different bentonite contents. Test results indicated that cohesion, unconfined compressive strength, maximum dry unit weight, and swell index increased while internal frictional angle, permeability, and optimum water content decreased as a result of the polyacrylamide addition. The rate of change was much higher when the polyacrylamide content was increased up to 2%. The performance of the anionic polyacrylamide was found to be slightly better than that of the cationic polyacrylamide in terms of both strength and permeability. In conclusion, 2% anionic polyacrylamide addition resulted in a sufficient increase in the shear and compressive strength, a slight increase in the swell index, and a sufficient decrease in the permeability of the bentonite-sand mixtures.

Mapping of Ug99 stem rust resistance in Canadian durum wheat

Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), has potential to cause major yield losses in durum wheat. Development of durum cultivars with improved resistance to stem rust is a sustainable option for effective control of this disease. This study was conducted to identify genomic regions associated with resistance to Ug99-derived Pgt races using a doubled haploid (DH) mapping population produced from a cross between the resistant experimental line A9919-BY5C and the moderately susceptible cultivar ‘Strongfield’. The parents and DH lines were phenotyped for adult plant disease severity and infection response at Njoro, Kenya, for four years, and for seedling reaction to race TTKSK in a containment facility near Morden, Canada. Composite interval mapping using 612 SNP and DArT markers indicated four significant QTL for resistance to stem rust on chromosomes 1B, 4A, 5B, and 6A. A major and stable QTL from A9919-BY5C was identified on the short arm of chromosome 6A (6AS), which accounted for 71% of variation explained for seedling resistance and up to 46% for field resistance. This QTL mapped near the Sr8 locus and may be Sr8155B1, or a novel gene at the same location. Another QTL for adult plant resistance from A9919-BY5C was mapped on chromosome 1B that explained up to 14% of the phenotypic variation and likely is Sr14. Two minor QTL were identified in ‘Strongfield’ on chromosomes 4A and 5B that were inconsistent over years. Markers associated with the 6AS and 1B QTL can be used to proactively stack resistance to Ug99-derived races of Pgt into Canadian durum wheat.

Unsaturated hydraulic conductivity of compacted bio-cemented lateritic soil in municipal solid waste containment application

Most engineering infrastructures, including municipal solid waste containment facilities, are situated in unsaturated zone. The use of chemical additives for soil improvement has been linked to the adverse environmental issues being experienced globally. Research into more sustainable methods of soil improvement has led to the discovery of a novel and innovative method known as microbial induced calcite precipitation (MICP). Lateritic soil was treated with stepped Sporosarcina pasteurii (S. pasteurii) suspension density up to 2.40 x 109 cells/ml at moulding water content (MWC) -2, 0 and +2 % relative to optimum moisture content (OMC) before compaction using Reduced British Standard light (RBSL), British Standard light (BSL), West African Standard (WAS) or Intermediate and British Standard heavy (BSH) energies. Compacted specimens were saturated with cementation reagent in three cycles with 1/3rd pore volume at 6 hours’ interval to induce calcite precipitation at an ambient laboratory temperature of 24±2°C. The soil-water characteristics curves (SWCC) of the specimens were determined using pressure plate extractor over a pressure range of 10-1500 kPa. Unsaturated hydraulic conductivity values were predicted for the S. pasteurii suspension densities considered using Brooks-Corey, van Genuchten as well as Fredlund and Xing curve fitting prediction models. Results show that the unsaturated hydraulic conductivity values of specimens prepared at lower, MWC relative to OMC were generally higher than at higher MWC regardless of compactive efforts and S. pasteurii suspension densities considered. The Brooks-Corey model gave the best predicted unsaturated hydraulic conductivity values which fit the requirements for waste containment facilities over the matric suction range and S. pasteurii suspension densities considered, than the van Genuchten and Fredlund – Xing, when compared with measured values.

Optimised Method for the Production and Titration of Lentiviral Vectors Pseudotyped with the SARS-CoV-2 Spike

The use of recombinant lentivirus pseudotyped with the coronavirus Spike protein of SARS-CoV-2 would circumvent the requirement of biosafety-level 3 (BSL-3) containment facilities for the handling of SARS-CoV-2 viruses. Herein, we describe a fast and reliable protocol for the transient production of lentiviruses pseudotyped with SARS-CoV-2 Spike (CoV-2 S) proteins and green fluorescent protein (GFP) reporters. The virus titer is determined by the GFP reporter (fluorescent) expression with a flow cytometer. High titers (>1.00 E+06 infectious units/ml) are produced using codon-optimized CoV-2 S, harboring the prevalent D614G mutation and lacking its ER retention signal. Enhanced and consistent cell entry is achieved by using permissive HEK293T/17 cells that were genetically engineered to stably express the SARS-CoV-2 human receptor ACE2 along with the cell surface protease TMPRSS2 required for efficient fusion. For the widespread use of this protocol, its reagents have been made publicly available.Graphic abstract:Production and quantification of lentiviral vectors pseudotyped with the SARS-CoV-2 Spike glycoprotein, [摘要]使用SARS-CoV-2 冠状病毒 Spike 蛋白假型重组慢病毒将规避生物安全级别 3 (BSL-3) 收容设施对处理 SARS-CoV-2 病毒的要求。在此，我们描述了一种快速可靠的协议，用于瞬时生产SARS-CoV-2 Spike (CoV-2 S) 蛋白和绿色荧光蛋白 (GFP) 报告基因假型的慢病毒。病毒滴度由流式细胞仪的 GFP 报告基因（荧光）表达确定。使用密码子优化的 CoV-2 S 产生高滴度（> 1.00 E+06 感染单位/ml），含有普遍的 D614G 突变并且缺乏其 ER 保留信号。通过使用经过基因改造的许可 HEK293T/17 细胞，可稳定表达 SARS-CoV-2 人类受体 ACE2 以及有效融合所需的细胞表面蛋白酶 TMPRSS2，从而增强且一致的细胞进入。为了广泛使用该协议，其试剂已公开可用。 图文摘要： 生产和慢病毒载体的量化假与所述SARS-CoV的-2刺突糖蛋白 [背景]对 SARS-CoV-2 病毒的研究因难以生产和操作需要生物安全 3 级 (BSL-3) 实验室的活病毒而受到阻碍。使用活病毒的另一种方法是使用用SARS-CoV-2 Spike 蛋白假型化的重组慢病毒。伪型病毒载体是研究与包膜病毒相关的生物过程（例如病毒进入和免疫反应）的非常强大的工具。假型病毒颗粒由一种病毒的包膜糖蛋白和另一种病毒的复制缺陷核心组成。这允许有缺陷的核心依赖于目标细胞进入的假型包膜，从而允许调查 SARS-CoV-2 感染和相关的血清学反应。Spike 是一种 I 型融合跨膜蛋白，以异源二聚体的冠状三聚体形式在病毒颗粒表面表达。在宿主细胞中，前体糖蛋白被蛋白水解由裂解弗林蛋白酶在multibasic S1 / S2位点，产生含有所述受体的胞外亚基（S1）构成的二聚体-结合结构域，其非共价地附接到一个跨膜亚基（S2）负责病毒融合和随后的细胞进入（Hoffmann等，2020a；Peacock等，2020）。尖峰是必要的和足够的通过首先结合其诱导膜融合和进入细胞的人类受体，ACE2（hACE2），接着通过靶细胞中的蛋白水解裂解蛋白酶，如跨膜蛋白酶丝氨酸2（TMPRSS2） （霍夫曼等人。, 2020b; Walls等人, 2020) 。因此，Spike 已被证明是 COVID-19 恢复期患者血清中中和抗体的主要目标（Chen等人，2020 年；Ju等人，2020 年；Pinto等人，2020 年）。从不同的冠状病毒穗已经成功地假在不同的非复制能力的病毒（卡内尔等人，2017年; Grehan 。等人，2015年;严等人，2007;福祉。等，2005） 。因此，不同的病毒载体已被假从SARS-CoV的-2与钉，包括VSV （Letko 。等人，2020;啮。等人，2020），HIV （区等人，2020;吴，2020） ，和MLV （平托等人，2020;昆兰。等人，2020）基于用于neutrali矢量ž通货膨胀测定，已报道相关联与活菌株。然而，伪矢量制备的详细协议已不被用于广泛的应用说明。在此，我们描述了一种快速和可靠的协议用于生产一个自失活的慢病毒载体假型与SARS-CoV的-2的刺突糖蛋白，表达增强的绿色荧光蛋白（eGFP的）作为一个感染的标志物。该协议采用在HEK293T / 17细胞的三质粒转染下列质粒：（我）质粒表达HIV-1的慢病毒基因的gag ，POL ，REV ，和TAT ：（ii）编码自失活转移载体的eGFP下源自脾病灶形成病毒（SFFV）的内部病毒启动子；(iii)在巨细胞病毒 (CMV) 启动子下编码密码子优化的 Spike 的质粒，有或没有普遍的 D614G 突变（Korber等人，2020），其 ER 保留信号（氨基酸残基 1255 至 1273）被删除为它已被证明可以增强表面表达（Ou等人，2020 年）。然后通过对稳定表达 hACE2 和 TMPRSS2 的基因工程 HEK293T/17 细胞的感染性测定来量化产生的载体（补充图 1 ）。这些细胞已存放在美国国家生物标准与控制研究所的 Covid-19 相关研究试剂 ( CFAR #101008)的存储库中，以供广泛使用。

Molecular tool for monitoring the safety of Aedes (Stegomyia) aegypti Rockefeller rearing in arthropod containment facilities

The interest in and use of Aedes (Stegomyia) aegypti (Linnaeus) (Diptera: Culicidae) insectary lines increased in most laboratories around the world since the recognition of the transmission of human and animal pathogens by this mosquito species, resulting in further scientific research on tropical diseases and vectors, and the development of chemical and biological products for mosquito populations control. In recent years, approaches to mosquito populations reduction have focused on new technologies that include the release of Wolbachia-infected lines, genetically modified vector and insects subjected to radiation in the Sterile Insect Technique. In order to evaluate some of these techniques, it is essential to count with wild A. aegypti populations and the reference strain, accurately identified, maintained under laboratory conditions. This work proposes a new tool to monitor possible exchanges between reference mosquito strain and wild native populations of A. aegypti in neighboring areas, or between different lines in the same insectary. We aligned and compared ND5 gene fragments of A. aegypti from diverse sources, finding a region with putative Single Nucleotide Polymorphisms between individuals of Rockefeller (Rock) strain and different wild A. aegypti populations. These polymorphic sites in the molecular marker, allowed us to discriminate Rock reference strain from the wild A. aegypti haplotypes found in the southeast of Argentina and bordering areas with Brazil, Uruguay and Paraguay, and it can be useful as a tool for regulatory entities of mosquito insectaries at different Arthropod Containment Levels.

Development of container laboratories in response to COVID-19

A silver lining has emerged from the current COVID-19 pandemic that medical laboratory services across the Pacific have benefitted by. The pressures of COVID-19 exposed numerous deficiencies in our healthcare systems with a particular spotlight beamed onto national diagnostic testing capabilities. Consequently, laboratory services have been thrust into the centre of attention in biosecurity issues and become a high priority focus in the drive to ensure performance accuracy and diagnostic capacity is realised. Resources have been directed to ensure laboratories are prepared and responsive to early detection, but also prepared and ready for the recovery stages when borders re-open and new generation tourists are screened. An exciting development to come out of these uncertain times is the growing popularity of mobile laboratory facilities housed in shipping containers. They provide a convenient, cheap and timely solution to smaller Pacific Island nations by greatly enhancing their molecular technology platforms and containment facilities all in one box. A collaborated effort from Pacific partnership organisations has been instrumental in accelerating the establishment of these novel laboratory units and help address the need for testing facilities in geographically isolated sites.

Optimised Method for the Production and Titration of Lentiviral Vectors Pseudotyped with the SARS-CoV-2 Spike.

The use of recombinant lentivirus pseudotyped with the coronavirus Spike protein of SARS-CoV-2 would circumvent the requirement of biosafety-level 3 (BSL-3) containment facilities for the handling of SARS-CoV-2 viruses. Herein, we describe a fast and reliable protocol for the transient production of lentiviruses pseudotyped with SARS-CoV-2 Spike (CoV-2 S) proteins and green fluorescent protein (GFP) reporters. The virus titer is determined by the GFP reporter (fluorescent) expression with a flow cytometer. High titers (>1.00 E+06 infectious units/ml) are produced using codon-optimized CoV-2 S, harbouring the prevalent D614G mutation and lacking its ER retention signal. Enhanced and consistent cell entry is achieved by using permissive HEK293T/17 cells that were genetically engineered to stably express the SARS-CoV-2 human receptor ACE2 along with the cell surface protease TMPRSS2 required for efficient fusion. For the widespread use of this protocol, its reagents have been made publicly available. Graphic abstract: Production and quantification of lentiviral vectors pseudotyped with the SARS-CoV-2 Spike glycoprotein.

Bioshield: Linking Bioscience, Biosecurity and Strategic Plan for Biodefense in Pandemics

Biological threats, whether intentional, unintentional or natural are considered most dangerous hazards worldwide, seriously affecting the health system and global economy. In 21st century where scientists were busy to create superhuman, COVID-19 outbreak spread to 212 countries, struck the world and we found ourselves ill equipped as international comity to defeat the virus. The economic, health and political foundation were shacked globally and exposed the global health security system due to poor implementations of the policy guidelines. Similarly, Pakistan being an endemic region for emerging and reemerging infectious diseases, encountered badly by numerous different outbreaks in past. Pakistan share border with China, India, Iran and Afghanistan and increase influx of travelers through both air and land route puts Pakistan at high risk to the infectious agents. In 21st century the game of bio warfare cannot be eliminated and pose significant challenges to the security. Countries who learned from past like Korea, China with best preparedness readiness and response tackled the situation as they have best biosecurity, biorisk management system. Biosecurity as biodefense against outbreaks, pandemics, biological warfare and bioterrorism has been underestimated in developing countries like Pakistan and therefore need to highlight the urgency at national level to cope with any future outbreaks. Risk assessment, and mitigation strategies through collaborative work should need to adopt by stakeholders for strategic plan of biosecurity. Better means to protect military, health care workers operating in difficult environment are also needed. A national biosecurity system in response to outbreaks, prioritizing the emergency R&D in diagnostics, establishing high containment facilities, vaccination should be initiated. Moreover, a permanent national defense force or bio-umbrella on biosecurity should be established to shield the country from biological, chemical, nuclear and radiological threat agents. National Biological Defense Program (NBDP) should be initiated to train and protect military personnel against wide range of biological threat.

A Human-Like Dual-Forklift Collaborative Mechanism for Container Handling

At present, container handling facilities are huge in size, low in automation, and complicated to operate, which are not suitable for applications in the limited spaces. Inspired by humans’ flexible collaboration when carrying a heavy and large object, in this article we devise a novel dual-forklift collaborative mechanism to address this problem. Specifically, we design a turn lock and hydraulic lifting structure to enable a rigid connection between each forklift and the target container, deploy a four-wheel steering structure in each forklift for omnidirectional motion, and construct a novel vision system by leveraging both RGB camera and time-of-flight depth camera. Furthermore, to provide visual feedback to the controller such that the dual forklift can connect, lift, and handle the container successfully, we devise a coarse-to-fine container detection and corner junction location model. Experiments demonstrate that our model outperforms representative models in terms of both precision and efficiency. Besides, the designed dual-forklift system can accomplish the handling tasks at narrow spaces, confirming its practical value in industrial applications.

X-ray inactivation of RNA viruses without loss of biological characteristics

In the event of an unpredictable viral outbreak requiring high/maximum biosafety containment facilities (i.e. BSL3 and BSL4), X-ray irradiation has the potential to relieve pressures on conventional diagnostic bottlenecks and expediate work at lower containment. Guided by Monte Carlo modelling and in vitro 1-log10 decimal-reduction value (D-value) predictions, the X-ray photon energies required for the effective inactivation of zoonotic viruses belonging to the medically important families of Flaviviridae, Nairoviridae, Phenuiviridae and Togaviridae are demonstrated. Specifically, it is shown that an optimized irradiation approach is attractive for use in a multitude of downstream detection and functional assays, as it preserves key biochemical and immunological properties. This study provides evidence that X-ray irradiation can support emergency preparedness, outbreak response and front-line diagnostics in a safe, reproducible and scalable manner pertinent to operations that are otherwise restricted to higher containment BSL3 or BSL4 laboratories.

52 Alterations of fecal microbiome characteristics by dietary soy isoflavone ingestion in growing pigs infected with porcine reproductive and respiratory syndrome virus

Abstract Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically-important disease and ingestion of soy isoflavones (ISF) may benefit PRRSV-infected pigs due to demonstrated anti-inflammatory and anti-viral properties. The objective of this study was to quantify long-term effects of ISF consumption on fecal microbiome characteristics under disease challenge. In total, 96 weaned barrows were group-housed in a BSL-2 containment facility and allotted to 1 of 3 experimental treatments that were maintained throughout the wean-to-finish study: non-infected pigs receiving an ISF-devoid control diet (NC, n=24), and infected pigs receiving either the control diet (PC, n=36) or that supplemented with total ISF in excess of 1,600 mg/kg (ISF, n=36) (Table 1). Following a 7-day adaptation, pigs were inoculated intranasally with either a sham-control (PBS) or live PRRSV (1×105 TCID50/mL, strain NADC20). Fecal samples were collected from 48 individual pigs at pre-infection (-2 days post-inoculation, DPI), peak-infection (10 DPI), and post-infection (144 DPI) time-points and extracted DNA was used for 16S bacterial rRNA sequencing. Differences in bacterial communities among diet groups were evaluated using UniFrac distance matrices (weighted and unweighted) in QIIME. All other data were analyzed by one-way ANOVA performed on transformed data using R. Across all time-points, only minimal differences were observed due to ISF alone. At 10 DPI, PRRSV infection reduced Prevotella 9 genera abundance from approximately 20% to less than 10%, but the specific function of this variety in pigs is unclear. The most notable finding was decreased relative abundance of Actinobacteria at 144 DPI between non-infected and infected treatments (P < 0.05), which is consistent with various dysbioses observed in other disease models. Our findings indicate that differences present were mainly due to PRRSV infection and not strongly influenced by ISF ingestion, which implies previously observed performance benefits conferred by dietary ISF are not likely due to changes in microbiome composition.

Monitoring SARS-CoV-2 decontamination by dry heat and ultraviolet treatment with a swine coronavirus as a surrogate

SummaryThe critical need for reliable methods to validate decontamination protocols for personal protective equipment (PPE) for re-use during the SARS-CoV-2 pandemic is limited by the need for specialized containment facilities to handle the virus. Hence, we have herein validated the use of a swine coronavirus as a surrogate, and tested the effectiveness of dry heat and ultraviolet (UV) rays for PPE decontamination. Exposure of experimentally contaminated N95 masks and hospital gowns to 60°C for 20 min, and UVC at 1800 mJ/cm2 resulted in a 4-log reduction and inactivation of the surrogate virus. This study provides a novel alternative to validate PPE reprocessing methods.

Development of expansive soil geopolymer binders for use in waste containment facility

Waste containment facilities require liners and covers for safe waste disposal, which can be efficiently achieved using robust green technologies. In the present study, a systematic approach was adopted towards the development of reliable expansive soil geopolymers suitable for waste containment application. Various factors that influence geopolymerisation were considered including the precursor type (PT), precursor content, liquid alkali hydroxide type (LT), activator-to-precursor ratio (A/P) and method of preparation. Multiresponse optimisation for permeability, volumetric shrinkage and unconfined compressive strength was executed to achieve soil geopolymers that satisfy the regulatory requirement as hydraulic barrier materials. This was done using a robust experimental design and the utility concept to prescribe a framework for achieving reliable soil geopolymers. The results obtained show that significant interactions between the factors (PT × LT) and (PT × A/P) affected the response characteristics and consequently the soil geopolymer performance. The aptness of the multiresponse optimisation was confirmed at 95% confidence interval, which revealed that the developed soil geopolymers can be used in waste containment facility under certain conditions. Evidence of the geopolymerisation process was clarified using microstructural analyses. Scanning electron microscopy and energy-dispersive spectroscopy supported the formation of N–A–S–H and K–A–S–H gels. Moreover, diffraction patterns for new minerals such as muscovite and crystobalite were formed, with the disappearance of clay minerals. The presence of aluminosilicate gel binding systems was revealed by Fourier transform infrared spectroscopy. The participation of clay minerals in the geopolymerisation distinguishes the developed expansive soil geopolymer from the conventional geopolymers developed for concrete applications.

Polymer microarrays rapidly identify competitive adsorbents of virus-like particles

The emergence of SARS-CoV-2 highlights the global need for platform technologies to enable the rapid development of diagnostics, vaccines, treatments, and personal protective equipment (PPE). However, many current technologies require the detailed mechanistic knowledge of specific material-virion interactions before they can be employed, for example, to aid in the purification of vaccine components or in the design of a more effective PPE. Here, we show that an adaption of a polymer microarray method for screening bacterial-surface interactions allows for the screening of polymers for desirable material-virion interactions. Nonpathogenic virus-like particles including fluorophores are exposed to the arrays in an aqueous buffer as a simple model of virions carried to the surface in saliva/sputum. Competitive binding of Lassa and Rubella virus-like particles is measured to probe the relative binding properties of a selection of copolymers. This provides the first step in the development of a method for the discovery of novel materials with promise for viral binding, with the next being development of this method to assess absolute viral adsorption and assessment of the attenuation of the activity of live virus, which we propose would be part of a material scale up step carried out in high containment facilities, alongside the use of more complex media to represent biological fluids.

Flipping the substrate preference of Hazara virus ovarian tumour domain protease through structure-based mutagenesis.

Nairoviruses are arthropod-borne viruses with a nearly global geographical distribution. Several are known causative agents of human disease, including Crimean-Congo hemorrhagic fever virus (CCHFV), which has a case fatality rate that can exceed 30%. Nairoviruses encode an ovarian tumour domain protease (OTU) that can suppress the innate immune response by reversing post-translational modifications by ubiquitin (Ub) and/or interferon-stimulated gene product 15 (ISG15). As a result, the OTU has been identified as a potential target for the development of CCHFV therapeutics. Despite sharing the same general fold, nairoviral OTUs show structural and enzymatic diversity. The CCHFV OTU, for example, possesses activity towards both Ub and ISG15, while the Hazara virus (HAZV) OTU interacts exclusively with Ub. Virology studies focused on the OTU have mostly been restricted to CCHFV, which requires BSL-4 containment facilities. Although HAZV has been proposed as a BSL-2 alternative, differences in the engagement of substrates by CCHFV and HAZV OTUs may present complicating factors when trying to model one using the other. To understand the molecular underpinnings of the differences in activity, a 2.78 Å resolution crystal structure of HAZV OTU bound to Ub was solved. Using structure-guided site-directed mutagenesis, HAZV OTUs were engineered with altered or eliminated deubiquitinase activity, including one with an exclusive activity for ISG15. Additionally, analysis of the structure yielded insights into the difference in inhibition observed between CCHFV and HAZV OTUs with a Ub-based inhibitor. These new insights present opportunities to utilize HAZV as a model system to better understand the role of the OTU in the context of infection.