Low Transmission Rate Research Articles

Impact of Citric Acid on the Structure, Barrier, and Tensile Properties of Esterified/Cross-Linked Potato Peel-Based Films and Coatings

The valorization of potato peel side streams for food packaging applications, especially for the substitution of current petrochemical-based oxygen barrier solutions such as EVOH, is becoming increasingly important. Therefore, potato peel-based films and coatings (on PLA) were developed containing 10–50% (w/w potato peel) citric acid (CA). To determine the impact of CA concentration on the structure and physicochemical properties of cast films and coatings, ATR-FTIR spectroscopy, moisture adsorption isotherms, tensile properties, light transmittance, oxygen permeability, carbon dioxide transmission rate, and water vapor transmission rate measurements were performed. The results indicate that an increase in CA concentration from 10% to 30% increased esterification/cross-linking and resulted in minimal values for the oxygen permeability (0.08 cm3 m−2 d−1 bar−1) at 50% RH and water vapor transmission rate (1.6 g m−2 d−1) at 50% → 0% RH, whereas an increase from 30% to 50% increased free CA concentration and resulted in increased flexibility, indicating that CA functioned as a plasticizer within the film/coating at higher concentrations. Overall, potato peel-based coatings containing CA showed comparable barrier properties to EVOH. We assume that an extensive industrial purification or fractionation of potato peel, which was not carried out in this study, could lead to even lower transmission rates.

Brain-Computer Interface Application in Recognition and Regulation of Emotion

This paper investigates the application of Brain-Computer Interface (BCI) technology in the realms of emotion recognition and regulation. BCI technology facilitates direct communication between the brain and external devices, offering significant promise for improving human-environment interactions, particularly with regard to the identification and modulation of emotional states. By analyzing brain signals, such as electroencephalography, this study classifies emotions based on widely recognized models, including Ekmans model and the Russell circumplex model. To enhance the precision of emotion classification, machine learning algorithms, such as support vector machines and neural networks, are utilized. Moreover, this study explores BCIs potential in emotion regulation, focusing on neurofeedback and brain stimulation methods like transcranial direct current stimulation, which have shown therapeutic potential, particularly for disorders related to emotional dysregulation. Additionally, the paper delves into the integration of BCI with virtual reality to create immersive environments conducive to emotional therapy. Despite its considerable potential, BCI technology faces obstacles such as low data transmission rates and the complexities associated with user training. Nonetheless, the integration of BCI technology within Industry 4.0 frameworks holds promising opportunities for optimizing human-machine interactions and improving workplace safety.

Prevalence and factors associated with placental malaria in Lira District, Northern Uganda: a cross-sectional study

BackgroundMalaria has a stable perennial transmission across Uganda. Placental malaria is associated with adverse maternal, fetal, and neonatal outcomes. The factors associated with placental malaria are poorly understood in the study setting. The aim of the study was to assess the prevalence of placental malaria and to determine its associated factors among parturient women in Lira District, Uganda.MethodsThis was a cross-sectional study among 366 pregnant women who delivered at Lira Regional Referral Hospital. Data were collected from December 2018 to February 2019 using an interviewer-administered questionnaire. The variables were socio-demographic, obstetric characteristics, and malaria preventive practices. Standard Diagnostic Bioline Rapid Diagnostic Tests were used to detect placental malaria present in placental blood. Microscopy was used to quantify the grade of placental malaria parasitaemia. Logistic regression was used to assess factors associated with placental malaria.ResultsThe mean age of the participants was 25.34 years (standard deviation [SD] 5.73). The prevalence of placental malaria was [4.4% (16/366) 95% CI (2.5 to 7.0)]. Of these, only 7/16 were positive on microscopy, with 2/7 having moderate parasitemia and 5/7 having mild parasitaemia. Women aged less than 20 years [AOR 3.48, 95% CI (1.13 to 10.72)], and those not taking iron supplements during pregnancy [AOR = 3.55, 95% CI (1.02 to 12.31)] were associated with an increased likelihood of having placental malaria.ConclusionThe prevalence of placental malaria was low in this setting. This may have reflected the low malaria transmission rates following intensive indoor residual spraying. Placental malaria infection was associated with younger age and not taking iron supplements during pregnancy. Public health measures need to scale up and emphasise adherence to malaria preventive measures during pregnancy especially among teenage mothers.

Reversible Photo-Responsive Hydrophobic Coating Synthesized from Lignin-Derivable Molecules on Nanocellulose Films for Packaging Applications.

Paper-based packaging can offer a sustainable replacement for plastics. However, paper provides a poor barrier to water, oxygen and moisture. This study presents a novel renewable lignocellulosic composite made from a hydrophobic photo-reversible coating deposited onto a cellulose nanofiber film that has improved barrier properties and can be reprocessed. Diglycerol and lignin-derivable aldehyde were reacted to form a tetra-functional monomer with photo-responsive unsaturated double bonds that can be converted to covalent cyclobutane rings to create reversibly crosslinkable network upon UV-irradiation. The photo-responsive compound was applied as a thin coating of thickness 2.7±0.4 μm over cellulose nanofiber (CNF) films of thickness 80±19 μm. The surface of the coated films became hydrophobic with a contact angle (CA) of 93.1±1.7° and displayed a low water vapour transmission rate (WVTR) of 16±2 g/m2/day vs. 30.7±1.5° CA and 81±11 g/m2/day WVTR for uncoated CNF films. The coated film is also oleophobic, an attractive feature for food packaging applications. The reversible photo-reaction enables the crosslinked covalent network to be broken down to unsaturated double bonds once exposed to a higher-energy UV irradiation, allowing reprocessing and recycling. The novel coating was developed using a sustainable green synthesis method (process simple E factor 0.9).

Water Vapor-Impermeable AlON/HfOx Bilayer Films Deposited by Hybrid High-Power Impulse Magnetron Sputtering/Radio-Frequency Magnetron Sputtering Processes.

Water vapor-impermeable AlON/HfOx bilayer films were constructed through a hybrid high-power impulse magnetron sputtering (HiPIMS) and radio-frequency magnetron sputtering process (RFMS), applied as an encapsulation of flexible electronics such as organic photovoltaics. The deposition of monolithic and amorphous AlON films through HiPIMS was investigated by varying the duty cycles from 5% to 20%. At an accelerated test condition, 60 °C, and 90% relative humidity, a 100 nm thick monolithic AlON film prepared using a duty cycle of 20% exhibited a low water vapor transmission rate (WVTR) of 0.0903 g m-2 day-1 after testing for 336 h. Furthermore, after introducing a nanocrystalline HfOx film through RFMS, a 214 nm thick AlON/HfOx bilayer film reached the lowest WVTR of 0.0126 g m-2 day-1.

Extending The Calendar Life of Fiber Lithium-Ion Batteries to 200 Days with Ultra-High Barrier Polymer Tubes.

Scalable fiber lithium-ion batteries (FLIBs) have garnered significant attention due to huge potential applications in wearable technology. However, their widespread applications have been limited by inadequate cycle and calendar life, primarily due to the high permeability of the encapsulation layer to water vapor in ambient air. To address this challenge, an ultra-high barrier composite tube is developed by blending polytrifluorochloroethylene (PCTFE) with organically modified montmorillonite (OMMT) for the continuous packaging of FLIBs. Due to the high crystallinity (≈40.21%) and small free volume (103.443 Å3), the PCTFE tube exhibited a low water vapor transmission rate (WVTR) of 0.123 mgday-1pkg-1. Furthermore, through the melt extrusion, OMMT with its plate-like morphology are fully exfoliated and dispersed within the PCTFE matrix. This created more complex pathways for water, increasing the diffusion path length and thereby reducing WVTR to 0.006 mgday-1pkg-1. This innovation enabled an ultra-long calendar life of 200 days and cycle life of 870 cycles for FLIBs, with over 80% capacity retention in ambient air. Additionally, 2%OMMT-PCTFE-FLIBs exhibited excellent flexibility, retaining an impressive 85.31% capacity after 10000 bending cycles. This research presents a simple yet effective approach to enhance the lifetime and practicality of FLIBs through building a high-performance polymer-based encapsulation layer.

Enhanced wound healing with biogenic zinc oxide nanoparticle-incorporated carboxymethyl cellulose/polyvinylpyrrolidone nanocomposite hydrogels.

Contemporary wound dressings lack antibacterial properties, exhibit a low water vapour transmission rate, and demonstrate inadequate porosity. In order to overcome these limitations, scientists have employed water hyacinth to produce carboxymethyl cellulose (CMC). CMC/PVP nanocomposite films containing biogenic zinc oxide nanoparticles (nZnOs) were synthesised using cost effective solution-casting technique. As the proportion of nZnOs in the film increased, swelling and water permeability decreased, whereas mechanical stability improved. Dynamic light scattering testing and transmission electron microscopy confirmed that the particle size was around 50.7 nm. Field emission scanning electron microscopy (FESEM) images showed that nZnOs were distributed uniformly in the polymer matrix. Cell viability against Vero cells was greater than 94%, and a substantial zone of inhibition against S. aureus and E. coli bacteria was observed. Wounds of albino mice were treated with CMC/PVP and CMC/PVP/nZnO (6%) nanocomposite hydrogels and healed in 20 and 12 days, respectively, as demonstrated by wound healing assay and histological staining. In vitro and in vivo studies revealed that the novel nanocomposite hydrogels exhibit improved cell viability and wound healing features. Therefore, they could be exploited as promising skin wound dressing materials.

Transmission Coil Group Shaping for Wireless Magnetic Induction MISO Communication System

Abstract Magnetic induction communication is a technology that utilizes magnetic field variations to transmit information. Compared to traditional electromagnetic wave communication, magnetic induction communication performs excellently in environments where electromagnetic waves are difficult to propagate, such as underwater and in soil. However, the current transmission rate of magnetic induction communication is relatively low. The magnetic induction MISO communication system addresses the issue of low transmission rates in cross-medium communication. However, it overlooks the impact of the transmission coil group arrangement on transmission rates. This paper investigates the effect of the transmission coil group arrangement on communication performance and proposes an arc-shaped magnetic induction MISO communication system. The transmission rate performance is analyzed, and the impact of the angle between the transmitting and receiving coils on the reception rate is studied. An expression for the channel gain increment is provided, along with its variation trend with the angle. When the position of the receiving coil is fixed, the expression yields the maximum increment of the shaped channel gain. Simulation results demonstrate that the data transmission rate of the shaped system is approximately 10% higher than that of the unshaped system.

Innovating a EVOH composite coating towards outstanding H2 barrier and anti-corrosion properties

Concerning the mitigating leakage and hydrogen-induced embrittlement during the conveyance of hydrogen (H2), we have developed an innovative dual-layer composite coating that exhibits exceptional hydrogen gas barrier properties and good resistance to corrosion. Using a bottom-top approach combining hot pressing with spin-coating techniques, the bottom Ethylene-vinyl alcohol copolymer (EVOH) layer with glass flakes (GF) serves as an effective hydrogen gas barrier and the top fluorosilicone resin (FSR) layer with composite nanofiller possesses good corrosion resistance, ensuring the functional integrity of the EVOH layer. The composite coating shows an exemplary low hydrogen gas transmission rate (H2 GTR) value of 2.858 cm3/(m2·24 h·0.1 MPa), representing a substantial decrease of 99.98 % compared to the FSR coating and 15 times more effective than commercial gas barrier films. Moreover, even after a 90-day immersion in 3.5 wt% NaCl solution, the coating maintains an impressive impedance at 0.01 Hz (|Z|0.01 Hz) of 1.0 × 1011 Ω·cm2. The composite coating is exposed to 2 MPa hydrogen for 7 days, and we find that it still sustains outstanding hydrogen gas barrier and anti-corrosion properties.

Pioneering high barrier packaging for pressure assisted thermal sterilization of low-acid food products

Pressure-assisted thermal sterilization (PATS) utilizes flexible packaging with low oxygen and water vapor transmission rates (OTRs, WVTRs). In this study, pouches made from metal oxide (MO)-coated (A–D) and ethylene vinyl alcohol (EVOH)-containing (E, F) multilayer films were filled with water and mashed potatoes (MP), preheated at 98 ± 0.5 °C for 10 min, and processed using a pilot-scale high-pressure processing machine (HPP) at 600 ± 5 MPa for 300 s. The initial vessel temperature and the fluid medium were 90 °C, and during processing, the temperature of the fluid medium increased to approximately 120 °C. After processing, the water-filled pouches were emptied, refilled with a novel oxygen indicator, and stored at 40 ± 0.2 °C for 80 days. The MP-filled pouches were stored at 49 ± 1 °C for 60 days. MO-coated film D contained fewer defects, had ultra-low OTRs and WVTRs, showed insignificant (p > 0.05) moisture absorption and changes in crystallinity after PATS processing, and exhibited minimal color change in both the oxygen indicator and the packaged MP during the 60 days of storage. The ultra-high barrier of film D could be attributed to the presence of multiple AlOx-coated PET layers that successfully prevented oxygen ingress, even after exposure to high temperature and pressure conditions during PATS processing. Among the EVOH-based structures, the Film F showed a 22.3 % lower OTR than Film E (p < 0.05), due to a 16.7 % greater EVOH-layer thickness, despite having a lower overall thickness than Film E. Overall, this study can assist packaging manufacturers in designing and developing high-barrier flexible packaging suitable for in-package, shelf-stable food products.

Genitourinary tumors and liver transplantation: A comprehensive review.

Liver transplantation is as a crucial therapeutic option for patients with end-stage liver disease, but the persistent organ shortage emphasizes a need to explore unconventional donor sources, including individuals with a history of malignancies. This review investigates the viability of liver donation from individuals with current or past genitourinary malignancies, focusing on renal, prostate and urinary bladder cancers. The rising incidence of urogenital malignancies among potential donors is thought to result from increasing donor age. Analysis of transmission risks reveals low rates of donor-derived cancer transmission, particularly for early-stage renal and prostate cancers. Recipients with a history of genitourinary malignancy pose complex challenges regarding post-transplant immunosuppression and cancer recurrence. Nonetheless, the evidence suggests acceptable outcomes can be achieved with careful patient selection and tailored management strategies. Recommendations for pre-transplant evaluation and post-transplant surveillance are discussed, highlighting the need for individualized approaches in this patient population. Further prospective studies are warranted to refine guidelines and optimize outcomes in liver transplantation for patients with genitourinary malignancies.

Managing the largest school-based COVID-19 outbreak: insights and mitigation strategies

The COVID-19 pandemic, caused by SARS-CoV-2, has significantly impacted educational environments due to their role in community transmission. Early reports indicated low transmission rates in schools, but subsequent studies showed variability, including significant outbreaks like the one in Israel. This study investigates a large COVID-19 outbreak in a boarding school in Brazil, analyzing transmission dynamics and the effectiveness of control measures such as mass testing and isolation. A total of 291 individuals from the school community were tested, revealing an overall infection rate of 64.6%. Initial cases were identified through antigen testing, followed by extensive RT-qPCR testing. Mass testing and timely isolation of infected individuals significantly reduced transmission rates. Whole-genome sequencing was performed on seven positive samples, and environmental contamination was confirmed, with 11 of 35 surface samples testing positive for SARS-CoV-2. The outbreak was controlled within 30 days through rigorous testing, isolation, and environmental disinfection. The study emphasizes the importance of mass testing, including asymptomatic individuals, and highlights the role of environmental contamination in transmission. The findings contribute to understanding COVID-19 outbreaks in educational settings and provide practical insights into managing future outbreaks through comprehensive testing and control strategies. These results may guide policymakers and public health officials in improving pandemic response measures in similar environments.

Finite-time adaptive fuzzy event-triggered control for nonlinear time-delay system with input quantization via command filter

This paper investigates the problem of finite-time adaptive fuzzy event-triggered control for a class of uncertain nonlinear systems with input quantization. The nonlinear systems under consideration contain unmodeled dynamics and time-varying delays. Fuzzy logic systems are used to handle unknown nonlinear terms. Additionally, finite-time filters are introduced to solve the problem of “explosion of complexity” as well as to ensure that the derivative of the virtual controller can be approximated in finite time. The Lyapunov–Krasovskii function is used to handle time-varying delays. The hysteresis quantizer is used to ensure adequate precision when there is a low transmission rate requirement. The control strategy combines event-triggered mechanisms and quantization technology to ensure that all signals of the closed-loop system remain bounded in finite time. Finally, two examples are included to demonstrate the effectiveness of the proposed controller.

Understanding Climate Variability and Malaria Transmission in West Africa: Case Studies, Regional Insights, and Future Directions

Climate variability plays a crucial role in malaria transmission in West Africa. Variable temperature, rainfall, and humidity patterns in diverse climatic zones, such as tropical rainforests and semi-arid regions, significantly influence mosquito breeding sites and transmission rates. Tropical rainforests experience high transmission rates due to consistent rainfall and humidity, while savanna regions experience seasonal peaks. Semi-arid regions with limited rainfall and extreme temperatures show lower but variable transmission rates. Temperature fluctuations affect the development and survival of Anopheles mosquitoes and malaria parasites. Rising temperatures can extend transmission seasons and spread the disease to unaffected areas. Rainfall patterns affect breeding site availability, with heavy rains increasing breeding sites and droughts reducing mosquito populations. Humidity influences mosquito survival and parasite development. Extreme weather events, such as cyclones and floods, exacerbate malaria transmission by increasing breeding sites and damaging infrastructure. Socioeconomic factors, including urbanization, land use changes, and economic instability, also interact with climate variability to impact malaria dynamics. The review highlights the need for integrated malaria control strategies that incorporate climate considerations, including enhanced surveillance, climate-resilient infrastructure, and community engagement. Future research should address knowledge gaps regarding the interaction between climate variables and malaria transmission, and the socioeconomic impacts of climate change on malaria dynamics. By tailoring control strategies to specific climatic and socio-economic contexts, stakeholders can better manage malaria risks and improve health outcomes across West Africa. Keywords: Climate, Variability, Malaria, Transmission, West Africa, Case Studies.

A study on preparation of low-cost environment-friendly self-assembled nanocellulose membrane from waste paper

In the context of green development, different types of waste paper were used in this study to prepare environment-friendly nanocellulose membrane by using different pretreatment processes. The results showed that all nanocellulose membranes had a novel microscopic composite morphology: nanocellulose fibers in the middle were tightly arranged and had a certain direction, while nanocellulose fibers at the edge were arranged randomly. Moreover, the type of waste paper affected the formation and property of nanocellulose membranes deeply compared with the pretreatment process. Nanocellulose membrane prepared from office waste paper had a high transmittance (50.8 %) and low oxygen transmission rate (1.548·10−3/cm3mm/(m2·d·KPa)) while that prepared from waste corrugated paper had a high yield (50.63 %), high folding number (81 times), and low water vapor transmission rate (1550.24 g·m−2·day−1). Meanwhile, nanocellulose membrane prepared without any deinking treatment had a significant performance advantage in terms of water vapor barrier and folding resistance. Therefore, in actual application, deinking treatment can be selectivity omitted, which will simplify the preparation process flow and reduce the production cost of nanocellulose membrane. Furthermore, in order to satisfy different application requirements, the appropriate raw materials and treatment processes can be chosen to prepare nanocellulose membranes with different properties. This study provides a simple and low-cost way to prepare high-performance environment-friendly self-assembled nano membrane material, and also achieves the high value utilization of waste paper, which has a certain ecological, economic, and social benefits.

Impact on the incorporation of metals in physicochemical and antimicrobial properties in films based on arrowroot starcha

New biodegradable packaging has been developed from renewable sources, mainly of vegetable origin. Arrowroot starch has been recently used to produce high-quality biodegradable films capable of behaving well when incorporating oils, extracts, metal, and metal nanocomposites. The study aimed to verify the impact of incorporating metals in the sulfate and chloride forms in a biopolymeric matrix from arrowroot starch in terms of biodegradability, physicochemical and microbiological parameters. Different arrowroot films were produced to incorporate solutions with a concentration of 1 Mol L-1 of sulfate and chloride metals. The action of biodegradability in soil, UV transmittance, and visible light were observed in UV-Vis spectrophotometry and antimicrobial action on Escherichia coli, Staphylococcus aureus, Salmonella serovar Typhimurium, and Salmonella serovar Enteritidis. Good results were obtained, such as biodegradability time between 81.70 to 100 % (30 days), a low transmission rate of UV radiation and visible light between 250 to 890 nm, high capacity for bacterial inhibition between 22.08 to 10.05 mm for E. coli, among 25.59 to 11.10 mm for S. aureus, between 22.14 to 11.66 mm for S. serovar Typhimurium and between 21.11 to 8.26 mm for S. serovar Enteritidis. It is concluded that the biodegradable films of arrowroot starch incorporated with metals showed potential in all the evaluated tests, thus characterizing possible new products for different uses, such as low time available in the environment, preservation of the characteristics of special products, and antimicrobial capacity.

FPGA-based SPI serial communication

With advances in computer and IoT technology, the realization of the Internet of Everything is just around the corner. Synchronous serial bus communication with simple, high-speed interfaces and easy implementation will become a key player in the electronics industry. However, due to factors such as I/O resources, timing constraints, and register resources, general microcontrollers have various problems. The serial bus communication of I/O simulation has a low transmission rate and cannot achieve true full duplex communication. SPI is a standard for serial transmission introduced by Motorola in the United States. It is a high-speed, full-duplex, synchronous communication bus. Peripheral chips with SPI interface are abundant and widely used. This design uses Verilog HDL language to describe the function, based on the FPGA platform, verifies the SPI serial communication protocol, and realizes the serial communication between the sender and the receiver. SPI has important research significance for enhancing the stability of inter-device communication, improving communication speed and transmission security in the future.

Easy-to-design wide stop-band multi-layer metamaterial filter based on symmetrical modified circular resonators for terahertz communication applications and electromagnetic interference shielding

Terahertz filters represent an essential element in modern communications system engineering. Designing a stopband filter with unique electrical qualities remains a relatively complicated task to achieve. In this context, the present paper suggests an easy-to-design bandstop filter to exploit it in terahertz communications and electromagnetic interference (EMI) shielding. The proposed filter is based on the multi-layer metamaterials stacking technique; it is constituted by a five-layer metal-insulator-metal-insulator-metal (MIMIM) microstructure. The two dielectric layers in polyimide with the three metallic layers in gold represent a total thickness of 43 μm. Each metallic layer is represented by a modified metamaterial resonator (MTMR) of the same symmetrical circular shape. The filter cell dimensions are optimized as 120 × 120 μm2 to have the desired stopband feature. The electrical qualities of the proposed filter have been analyzed by the finite element method (FEM) via the ANSYS high-frequency structure simulator software (HFSS). Through the simulation outcomes, salient filter features were highlighted. A wide −20 dB bandwidth of the order of 1.062 THz centered at 1.872 THz with a low transmission rate in the stopband which is less than 0.87 %, a significant square ratio of 0.86 and a relative bandwidth of around 57 %. Moreover, the absorption rate of the stopband has reached more than 97 % with excellent flat-top characteristics. To give more credibility to our results, we have presented a parametric analysis that included several components. In addition, the designed filter was insensitive to the polarization angle thanks to the symmetrical metamaterial resonators. Based on all these results and due to the simplicity of its design combined with all these unique features, our filter can be a prominent contender in the field of THz communications. It can be also required for terahertz imaging and EMI shielding.

How women living with HIV in the UK manage infant-feeding decisions and vertical transmission risk – a qualitative study

BackgroundThe World Health Organization (WHO) recommends that women with HIV breastfeed for a minimum of one year. In contrast, across high-income countries, HIV and infant-feeding guidelines recommend exclusive formula feeding if parents want to avoid all risk of postpartum transmission. However, recently these guidelines (including in the United Kingdom (UK)) increasingly state that individuals with HIV should be supported to breast/chest feed if they meet certain criteria; such as an undetectable maternal HIV viral load and consent to additional clinical monitoring. Between 600 and 800 pregnancies are reported annually in women with HIV in the UK, with low rates of vertical transmission (0.22%). Informed infant-feeding decision-making requires clinical support. Currently, little research addresses how individuals with HIV in high-income countries navigate infant-feeding decisions with their clinical teams and familial and social networks, and the resources needed to reach an informed decision.MethodsSemi-structured remote interviews were conducted between April 2021 – January 2022 with UK-based individuals with a confirmed HIV diagnosis who were pregnant or one-year postpartum. Using purposive sampling, pregnant and postpartum participants were recruited through NHS HIV clinics, community-based organisations and snowballing. Data were analysed thematically and organised using NVivo 12.ResultsOf the 36 cisgender women interviewed, 28 were postpartum. The majority were of Black African descent (n = 22) and born outside the UK. The majority of postpartum women had chosen to formula feed. Women’s decision-making regarding infant-feeding was determined by (1) information and support; (2) practicalities of implementing medical guidance; (3) social implications of infant-feeding decisions.ConclusionThe evolution of UK HIV and infant-feeding guidelines are not reflected in the experiences of women living with HIV. Clinicians’ emphasis on reducing the risk of vertical transmission, without adequately considering personal, social and financial concerns, prevents women from making fully informed infant-feeding decisions. For some, seeking advice beyond their immediate clinical team was key to feeling empowered in their decision. The significant informational and support need among women with HIV around their infant-feeding options must be addressed. Furthermore, training for and communication by healthcare professionals supporting women with HIV is essential if women are to make fully informed decisions.

Development of an Ion Mobility Spectrometer Based on a Pulsed Photoelectric Effect Ionization Source.

Ion mobility spectrometry (IMS) is a compact and sensitive trace gas analysis instrument that ionizes the sample into ions for detection. Typically, an ion gate is used to cut the continuous ion beam into ion packets for separation and detection. However, commonly used ion gates suffer from complex structures or low ion transmission rates, making the gateless IMS a viable alternative. In this study, an IMS based on a pulsed photoelectric effect ionization source was designed. The photoelectrons were generated by irradiating a photoelectric material with a back-illuminated pulsed xenon lamp. This allows for low-energy photoelectron generation and the production of simple reactant ions (O2-(H2O)n) and thus negative product ions. The photoelectron current generated by this ionization source was analyzed, which can reach an intensity of a few microamperes and can be converted into an ion signal exceeding 10 nA. The introduction of the pulsed photoelectric effect ionization source makes it possible to generate separate ion packets and complete ion injection when a constant electric field is maintained in the ionization region. And with an assisted pulsed electric field in the ionization region, the resolving power of the system can be effectively improved to 1.85 times that of the constant electric field. The IMS developed in this study was used for the detection of common volatile hazardous chemicals, yielding effective results. The detection limit for phenol was below 1 ppb, and the dynamic response range exceeded 1 order of magnitude, which implies the potential applications of this IMS to detect substances with high electron affinity, such as explosives detection in public safety.