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Introduction: Stress-induced volatile organic compounds (VOCs) that induce plant immunity bear potential for biocontrol. Here, we explore the potential of nonanal to enhance the seed yield of common bean (Phaseolus vulgaris) under open field conditions that are realistic for smallholder farmers. Methods and results: Using plastic cups with a nonanal-containing lanolin paste as low-cost dispensers, we observed that exposure of Flor de Junio Marcela (FJM) plants over 48h to airborne nonanal was followed by a 3-fold higher expression of pathogenesis-related (PR) genes PR1 and PR4. Both genes further increased their expression in response to subsequent challenge with the fungal pathogen Colletotrichum lindemuthianum. Therefore, we conclude that nonanal causes resistance gene priming. This effect was associated with ca. 2.5-fold lower infection rates and a 2-fold higher seed yield. Offspring of nonanal-exposed FJM plants exhibited a 10% higher emergence rate and a priming of PR1- and PR4-expression, which was associated with decreased infection by C. lindemuthianum and, ultimately, a ca. 3-fold increase in seed yield by anthracnose-infected offspring of nonanal-exposed plants. Seeds of nonanal-exposed and of challenged plants contained significantly more phenolic compounds (increase by ca 40%) and increased antioxidant and radical scavenging activity. Comparative studies including five widely used bean cultivars revealed 2-fold to 3-fold higher seed yield for nonanal-exposed plants. Finally, a cost-benefit analysis indicated a potential economic net profit of nonanal exposure for some, but not all cultivars. Outlook: We consider nonanal as a promising candidate for an affordable tool that allows low-income smallholder farmers to increase the yield of an important staple-crop without using pesticides [ABSTRACT FROM AUTHOR]

Aims Volatile organic compounds (VOCs) have an important function in plant growth-promoting rhizobacteria (PGPR) development and plant growth. This study aimed to identify VOCs of the PGPR strain, Stutzerimonas stutzeri NRCB010, and investigate their effects on NRCB010 biofilm formation, swarming motility, colonization, and tomato seedling growth. Methods and results Solid-phase microextraction and gas chromatography-mass spectrometry were performed to identify the VOCs produced during NRCB010 fermentation. A total of 28 VOCs were identified. Among them, seven (e.g. γ-valerolactone, 3-octanone, mandelic acid, 2-heptanone, methyl palmitate, S-methyl thioacetate, and 2,3-heptanedione), which smell well, are beneficial for plant, or as food additives, and without serious toxicities were selected to evaluate their effects on NRCB010 and tomato seedling growth. It was found that most of these VOCs positively influenced NRCB010 swarming motility, biofilm formation, and colonization, and the tomato seedling growth. Notably, γ-valerolactone and S-methyl thioacetate exhibited the most positive performances. Conclusion The seven NRCB010 VOCs, essential for PGPR and crop growth, are potential bioactive ingredients within microbial fertilizer formulations. Nevertheless, the long-term sustainability and replicability of the positive effects of these compounds across different soil and crop types, particularly under field conditions, require further investigation. [ABSTRACT FROM AUTHOR]

The study investigated the impact of intraspecific plant chemodiversity on plant growth and reproductive traits at both the plant and plot levels. It also aimed to understand how chemodiversity at stand level affects ecosystem functioning and plant–plant interactions. We describe a biodiversity experiment in which we manipulated intraspecific plant chemodiversity at the plot level using six different chemotypes of common tansy (Tanacetum vulgare L., Asteraceae). We tested the effects of chemotype identity and plot‐level chemotype richness on plant growth and reproductive traits and plot‐level headspace emissions. The study found that plant chemotypes differed in growth and reproductive traits and that traits were affected by the chemotype richness of the plots. Although morphological differences among chemotypes became less pronounced over time, reproductive phenology patterns persisted. Plot‐level trait means were also affected by the presence or absence of certain chemotypes in a plot, and the direction of the effect depended on the specific chemotype. However, chemotype richness did not lead to overyielding effects. Lastly, chemotype blends released from plant communities were neither richer nor more diverse with increasing plot‐level chemotype richness, but became more dissimilar as they became more dissimilar in their leaf terpenoid profiles. We found that intraspecific plant chemodiversity is crucial in plant–plant interactions. We also found that the effects of chemodiversity on plant growth and reproductive traits were complex and varied depending on the chemotype richness of the plots. This long‐term field experiment will allow further investigation into plant–insect interactions and insect community assembly in response to intraspecific chemodiversity. [ABSTRACT FROM AUTHOR]

This study focuses on the equilibrium adsorption of diethyl ketone, a VOC widely used in the printing industry, on activated carbon in a supercritical CO2 environment at pressures in the range of 10 MPa to 20 MPa and temperatures between 313 K and 353 K, which provides a wider range of equilibrium adsorption data for diethyl ketone under different pressure and temperature conditions and allows a comparative analysis with other ketone VOCs. It is found that the equilibrium adsorption of diethyl ketone on activated carbon exceeds that of methyl ethyl ketone, probably due to differences in their respective affinities for activated carbon and their different volatilities in a supercritical fluid context. The Dubinin-Astakhov model was used to interpret the data and showed an average relative deviation of approximately 3.8 % between modeled and observed values. Additional analysis of the model parameters influenced by CO2 density and VOC characteristics was performed to gain a better insight into the adsorption dynamics and to contribute to the design and improvement of the activated carbon regeneration process.

Background: From 2020 to 2023 many people around the world were forced to wear masks for large proportions of the day based on mandates and laws. We aimed to study the potential of face masks for the content and release of inanimate toxins. Methods: A scoping review of 1003 studies was performed (database search in PubMed/MEDLINE, qualitative and quantitative evaluation). Results: 24 studies were included (experimental time 17 min to 15 days) evaluating content and/or release in 631 masks (273 surgical, 228 textile and 130 N95 masks). Most studies (63%) showed alarming results with high micro- and nanoplastics (MPs and NPs) release and exceedances could also be evidenced for volatile organic compounds (VOCs), xylene, acrolein, per-/polyfluoroalkyl substances (PFAS), phthalates (including di(2-ethylhexyl)-phthalate, DEHP) and for Pb, Cd, Co, Cu, Sb and TiO2. Discussion: Of course, masks filter larger dirt and plastic particles and fibers from the air we breathe and have specific indications, but according to our data they also carry risks. Depending on the application, a risk-benefit analysis is necessary. Conclusion: Undoubtedly, mask mandates during the SARS-CoV-2 pandemic have been generating an additional source of potentially harmful exposition to toxins with health threatening and carcinogenic properties at population level with almost zero distance to the airways.

Large industrial emissions of volatile organic compounds (VOCs) from the petrochemical industry are a critical concern due to their potential carcinogenicity. VOC emissions vary in composition depending on the source and occur in mixtures containing compounds with varying degrees of toxicity. We proposed the use of carcinogenic equivalence (CEQ) and multivariate analysis to identify the major contributors to the carcinogenicity of VOC emissions. This method weights the carcinogenicity of each VOC by using a ratio of its cancer slope factor to that of benzene, providing a carcinogenic equivalence factor (CEF) for each VOC. We strategically selected a petrochemical industrial park in southern Taiwan that embodies the industry's comprehensive nature and serves as a representative example. The CEQs of different emission sources in three years were analyzed and assessed using principal component analysis (PCA) to characterize the major contributing sectors, vendors, sources, and species for the carcinogenicity of VOC emissions. Results showed that while the study site exhibited a 20.7 % (259.8 t) decrease in total VOC emissions in three years, the total CEQ emission only decreased by 4.5 % (15.9 t), highlighting a potential shift in the emitted VOC composition towards more carcinogenic compounds. By calculating CEQ followed by PCA, the important carcinogenic VOC emission sources and key compounds were identified. More importantly, the study compared three approaches: CEQ followed by PCA, PCA followed by CEQ, and PCA only. While the latter two methods prioritized sources based on emission quantities, potentially overlooking less abundant but highly carcinogenic compounds, the CEQ-first approach effectively identified vendors and sources with the most concerning cancer risks. This distinction underscores the importance of selecting the appropriate analysis method based on the desired focus. Our study highlighted how prioritizing CEQ within the analysis framework empowered the development of precise control measures that address the most carcinogenic VOC sources.

IntroductionThe study investigated the utilization of odor detection dogs to identify the odor profile of Staphylococcus aureus (S. aureus) biofilms in pure in vitro samples and in in vivo biosamples from animals and humans with S. aureus periprosthetic joint infection (PJI). Biofilms form when bacterial communities aggregate on orthopedic implants leading to recalcitrant infections that are difficult to treat. Identifying PJI biofilm infections is challenging, and traditional microbiological cultures may yield negative results even in the presence of clinical signs.MethodsDogs were trained on pure in vitro S. aureus biofilms and tested on lacrimal fluid samples from an in vivo animal model (rabbits) and human patients with confirmed S. aureus PJI.ResultsThe results demonstrated that dogs achieved a high degree of sensitivity and specificity in detecting the odor profile associated with S. aureus biofilms in rabbit samples. Preliminary results suggest that dogs can recognize S. aureus volatile organic compounds (VOCs) in human lacrimal fluid samples.DiscussionTraining odor detection dogs on in vitro S. aureus, may provide an alternative to obtaining clinical samples for training and mitigates biosecurity hazards. The findings hold promise for culture-independent diagnostics, enabling early disease detection, and improved antimicrobial stewardship. In conclusion, this research demonstrates that dogs trained on in vitro S. aureus samples can identify the consistent VOC profile of PJI S. aureus biofilm infections. The study opens avenues for further investigations into a retained VOC profile of S. aureus biofilm infection. These advancements could revolutionize infectious disease diagnosis and treatment, leading to better patient outcomes and addressing the global challenge of antimicrobial resistance.

Introduction: Outdoor air pollution has been considered the primary issueby scientists and environmentalists for decades. With the advancement of technology, the activities of human are shifting from outdoor to indoor, urging researchers to investigate the indoor environment. Theerefore, the focus of this study is to examine indoor air quality in the metropolitan of Lahore. Materials and methods: The Temtop M2000C and Temtop H3 Laser monitors were used to collect data on Particulate Matter (PM), Carbon dioxide (CO2) concentration, Total Volatile Organic Compounds (TVOC), and formaldehyde (HCHO). The concentration of air pollutants in nine indoor areas was measured for a specified time interval. The values of particulate matter are measured to find the impact of the outdoor environment on the indoor environment. Results: The maximum average values of the particulate matter PM2.5 and PM10 were 488.6 μg/m³ and 737.2 6 μg/m³, respectively, which reduced drastically after the rain to 219 μg/m³ and 340 μg/m³, respectively. The maximum values of PM2.5 and PM10 during coal burning outside the room were 997.6 μg/m³ and 999.9 μg/m³, respectively, far higher than the values during normal conditions. TVOC and HCHO were found within the prescribed limits. Conclusion: The outcomes of this study established a deep impact of the outdoor environment on the indoor environment and recommend air purifiers to reduce the level of pollutants in the indoor environment.

Truffle is an important food source for wild animals and a significant part of the ecosystem, indicating a healthy forest. With their unique aromas, truffles are also a crucial food source for humans. The volatile substances released by Tuber not only appeal to our sense of smell but also contribute to various biological activities. Different aromas result in different tastes; therefore, aroma is essential in defining the organoleptic properties and quality of underground fungi. This research aims to investigate according to the percentage the chemical components considering the habitat and mycorrhizal host tree species of naturally occurring summer truffle Tuber aestivum Vittad. and white truffle Tuber borchii Vittad. in Southwest Anatolia and Marmara regions. For this purpose, the aroma components of T. aestivum and T. borchii collected from two different regions were analyzed using the HS-SPME-GC/MS system. Accordingly, a total of 59 different compounds (volatile organic compounds) were identified, including 20 compounds in T. aestivum from Muğla, 13 compounds in T. aestivum from Kırklareli, 44 compounds in T. borchii from Muğla, and 33 compounds in T. borchii from Kırklareli, belonging to different classes of compounds. While terpenes such as limonene (37.62%), p-cymene (4.79%), and ß-pinene (4.12%) were major compounds in T. aestivum collected from Muğla, 2-octen-1-ol (46.78%), 1-octen-3-ol (40.44%), and 3-octanol (2.62%) predominantly constituted the aroma in T. aestivum from Kırklareli. The characteristic sulfur compounds commonly found in Tuber species were present in 42.19% of T. borchii collected from Kırklareli and 12.15% from Muğla. When comparing T. borchii grown in Kırklareli and Muğla, 3-methyl-4,5-dihydrothiophene (29.53% and 6.73%) pmethyl thiobenzaldehyde (2.75% and 5.42%), and methionine (9.91% in Kırklareli, not detected in Muğla) were found in different percentage rates. Based on the data obtained in this study, the classification of both Tuber species, with respect to their geographical origin, was determined using hierarchical cluster analysis (HCA). Accordingly, it is show that of the aroma of Tuber species of the chemical components and the aroma components to the formation should be cultivated after optimizing the ecological conditions that contribute to the symbiotic life of the plant species they provide. [ABSTRACT FROM AUTHOR]

The regeneration of spent activated carbon used to adsorb alkyl acetates, which are the main volatile organic compounds (VOCs) used in the printing industry, is important because of numerous economic and environmental factors. Regeneration by supercritical CO2 (scCO2) avoids the high temperatures associated with the commonly used thermal regeneration method, which may damage the activated carbon. However, previous studies cover only a limited range of operating conditions, and more extensive research is required for better understanding the scCO2 process. In this study, the adsorption equilibria of propyl acetate on activated carbon in scCO2 were investigated using the fixed-bed adsorption method at 313 K–353 K and 10 MPa–20 MPa. Our results agree with previous reports of other VOCs on the effect of temperature and pressure on adsorption equilibria. Furthermore, the Dubinin–Astakhov (DA) equation is used to correlate the measured data with an average relative deviation of 5.6%. Evidently, the adsorbed amounts of propyl acetate are higher than those of ethyl acetate but lower than those of butyl acetate, which can be attributed to their different volatilities in scCO2 and different affinities for the used adsorbent.

A method of preparing heated tobacco product aerosol condensate (HTPAC) was developed to expedite HTP toxicity evaluation, and the effectiveness was assessed. To prepare HTPAC, HTP aerosol was generated and collected using a Cambridge filter (particulate phase) and Dulbecco's phosphate buffered saline (DPBS; gaseous phase). The aerosol collected on the Cambridge filter was extracted using methanol, which was thereafter removed by nitrogen purging. The HTP aerosol residue was mixed with DPBS loaded with the collected HTP vapor, ultimately yielding HTPAC. Nicotine and formaldehyde, key harmful compounds in HTP aerosol, were detected in HTPAC (901 ± 224 and 22.2 ± 3.90 µg stick–1, respectively, comparable to those in HTP aerosol (990–1350 (nicotine) and 2.33–21.9 µg stick–1 (formaldehyde)). Propylene glycol and vegetable glycerin, which influence the amount of HTP aerosol, were detected at similar levels in HTPAC and HTP aerosol (propylene glycol = 616 ± 57.1 (HTPAC) and 320–630 µg stick–1 (aerosol) and vegetable glycerin = 2418 ± 224 (HTPAC) and 1667–4000 µg stick–1 (aerosol)). Known components of HTP aerosol (hydroxyacetone, acetic acid, triacetin, and 2-furanmethanol) were also detected in HTPAC. Consequently, HTPAC offers an effective method for concentrating harmful compounds found in HTP aerosols. This, in turn, facilitates comprehensive toxicity assessments, paving the way for guidelines ensuring the safe utilization of HTP.

A non-invasive optical fiber sensor for detecting volatile organic compounds (VOCs) as biomarkers of diabetes is proposed and experimentally demonstrated. It offers a low-cost and straightforward fabrication approach by implementing a one-step spray coating of a ZnO colloidal solution on a glass optical fiber. The structure of the optical fiber sensor is based on a single-mode fiber–coreless silica fiber–single-mode fiber (SMF-CSF-SMF) structure, where the CSF is the sensor region spliced between two SMFs. The ZnO layer of a higher refractive index coated over the sensing region improves the light interaction with the surrounding medium, leading to sensitivity enhancement. The optical properties, morphology, and elemental composition of the ZnO layer were analyzed. The sensing mechanism of the developed sensor is based on a wavelength interrogation technique showing wavelength shifts when the sensor is exposed to various VOC vapor concentration levels. Various concentrations of the three VOCs (including acetone, isopropanol, and ethanol) ranging from 20% to 100% were tested and analyzed. The sensor noticeably shows a significant response towards acetone vapor, with a better sensitivity of 0.162 nm/% vapor than for isopropanol (0.082 nm/% vapor) and ethanol (0.075 nm/% vapor) vapors. The high sensitivity and selectivity towards acetone, a common biomarker for diabetes, offers the potential for further development of this sensor as a smart healthcare system for monitoring diabetic conditions. [ABSTRACT FROM AUTHOR]

This work focuses on the possible application of gold nanoparticles on flexible cotton fabric as acetone- and ethanol-sensitive substrates by means of impedance measurements. Specifically, citrate- and polyvinylpyrrolidone (PVP)-functionalized gold nanoparticles (Au NPs) were synthesized using green and well-established procedures and deposited on cotton fabric. A complete structural and morphological characterization was conducted using UV–VIS and Fourier transform infrared (FT–IR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). A detailed dielectric characterization of the blank substrate revealed interfacial polarization effects related to both Au NPs and their specific surface functionalization. For instance, by entirely coating the cotton fabric (i.e., by creating a more insulating matrix), PVP was found to increase the sample resistance, i.e., to decrease the electrical interconnection of Au NPs with respect to citrate functionalized sample. However, it was observed that citrate functionalization provided a uniform distribution of Au NPs, which reduced their spacing and, therefore, facilitated electron transport. Regarding the detection of volatile organic compounds (VOCs), electrochemical impedance spectroscopy (EIS) measurements showed that hydrogen bonding and the resulting proton migration impedance are instrumental in distinguishing ethanol and acetone. Such findings can pave the way for the development of VOC sensors integrated into personal protective equipment and wearable telemedicine devices. This approach may be crucial for early disease diagnosis based on nanomaterials to attain low-cost/low-end and easy-to-use detectors of breath volatiles as disease markers. [ABSTRACT FROM AUTHOR]

All fungi emit mixtures of volatile organic compounds (VOCs) during growth. The qualitative and quantitative composition of these volatile mixtures vary with the species of fungus, the age of the fungus, and the environmental parameters attending growth. In nature, fungal VOCs are found as combinations of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, and are responsible for the characteristic odors associated with molds, mushrooms and yeasts. One of the single most common fungal volatiles is 1-octen-3-ol also known as "mushroom alcohol" or "matsutake alcohol." Many volatiles, including 1-octen-3-ol, serve as communication agents and display biological activity as germination inhibitors, plant growth retardants or promoters, and as semiochemicals ("infochemicals") in interactions with arthropods. Volatiles are understudied and underappreciated elements of the chemical lives of fungi. This review gives a brief introduction to fungal volatiles in hopes of raising awareness of the physiological importance of these gas phase fungal metabolites to encourage mycologists and other biologists to stop "throwing away the head space." • Filamentous fungi and yeasts are prolific producers of volatile organic compounds (VOCs). • Fungal VOCs are responsible for the characteristic odors associated with molds, mushrooms, and yeasts. • Molds growing in water damaged buildings release VOCs that may cause risks to human health. • Fungal VOCs can affect plant growth in positive and negative ways. • Trichoderma VOCs inhibit the growth of certain plant-pathogenic fungi and oomycetes. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are byproducts from metabolic pathways that can be detected in exhaled breath and have been reported as biomarkers for different diseases. The gold standard for analysis is gas chromatography–mass spectrometry (GC–MS), which can be coupled with various sampling methods. The current study aims to develop and compare different methods for sampling and preconcentrating VOCs using solid-phase microextraction (SPME). An in-house sampling method, direct-breath SPME (DB–SPME), was developed to directly extract VOCs from breath using a SPME fiber. The method was optimized by exploring different SPME types, the overall exhalation volume, and breath fractionation. DB–SPME was quantitatively compared to two alternative methods involving the collection of breath in a Tedlar bag. In one method, VOCs were directly extracted from the Tedlar bag (Tedlar–SPME) and in the other, the VOCs were cryothermally transferred from the Tedlar bag to a headspace vial (cryotransfer). The methods were verified and quantitatively compared using breath samples (n = 15 for each method respectively) analyzed by GC–MS quadrupole time-of-flight (QTOF) for compounds including but not limited to acetone, isoprene, toluene, limonene, and pinene. The cryotransfer method was the most sensitive, demonstrating the strongest signal for the majority of the VOCs detected in the exhaled breath samples. However, VOCs with low molecular weights, including acetone and isoprene, were detected with the highest sensitivity using the Tedlar–SPME. On the other hand, the DB–SPME was less sensitive, although it was rapid and had the lowest background GC–MS signal. Overall, the three breath-sampling methods can detect a wide variety of VOCs in breath. The cryotransfer method may be optimal when collecting a large number of samples using Tedlar bags, as it allows the long-term storage of VOCs at low temperatures (−80 °C), while Tedlar–SPME may be more effective when targeting relatively small VOCs. The DB-SPME method may be the most efficient when more immediate analyses and results are required. [ABSTRACT FROM AUTHOR]

SO2 is a preservative often used in the food industry, particularly in the wine industry. However, regulatory authorities and consumers have been strongly suggesting its reduction or even its replacement. In order to understand the impact of SO2 on the profiles of volatile organic compounds (VOCs) as well as amino acids (AAs), the aging of two white wines (one being a varietal and another being a blend) under identical conditions and in the presence of different doses of total SO2 was studied. After alcoholic fermentation (t = 0), either no SO2 was added (0 mg/L), or 30, 60, 90, or 120 mg/L of SO2 was applied. The samples under study were kept on fine lees for 3 months (t = 3). After 3 months (t = 6) and 9 months (t = 12), the wines were bottled and analyzed. For t = 0 and t = 3, the samples were submitted to HS-SPME-GC/MS for VOC analysis and LC-DAD for AA analysis. From the principal component analysis of the detected VOCs, it was observed that the blended wine in comparison with the varietal wine, was less impacted by the applied SO2 doses and aging time. From the AA profile, it was also observed in this study that maturation on fine lees resulted in an increase in the total concentration of AAs as would be expected. [ABSTRACT FROM AUTHOR]

Traditional large mass spectrometer has the advantages of high sensitivity and fast speed of analysis. However, because of its large size, it only can be used in professional labs generally. The miniature mass spectrometer has the advantages of lightweight and portable. Although some performances are sacrificed, the needs of the application field of on-site detection were met. The ion trap was used as the mass analyzer for miniature mass spectrometer, because of its good performance and small size. In this paper, two miniature mass spectrometers called “Brick-L” and “Brick-V” were introduced, which were based on the new technologies developed by our lab, including the quadrupole enhanced dipolar resonance ejection from the linear ion trap, the continuous atmospheric pressure interface, and the hybrid ion funnel. Both the miniature mass spectrometers had similar vacuum chamber structures and the same main components, such as ion funnel, mass analyzer and control circuit. The switch between Brick-V and Brick-L could be achieved by simply changing the front board of the chamber where the interface system is located, and it allowed the instruments to meet variable demands of on-site detection more easily. The difference was that the Brick-L required to be coupled with an atmospheric pressure ion source, and it could detect gas, liquid and solid samples. An UV lamp ion source was installed inside the Brick-V, which could detect volatile organic compounds (VOCs). The overall weight of the miniature mass spectrometers is about 20 kg, the size is 38 cm×23 cm×34 cm, the power consumption is 200 W, and they have the capability of MS2. The limits of detection (LODs) of cocaine and imatinib can reach 1 μg/L for Brick-L, and the resolution is more than 1 600. Brick-V can be used to identify fruits. Due to use the continuous atmospheric pressure interface, Brick-V has more resistant to pollution and shorter detection cycle time than the same type of miniature mass spectrometer using the photon ionization source. The two instruments are portable and easy to operate, which can be used in rapid on-site analysis and have good application prospects. [ABSTRACT FROM AUTHOR]

Styrene is a typical volatile organic compound (VOC) emitted from various sources that is considered hazardous due to its toxicity and strong odor. Many technologies have been developed to control VOCs, including plasma, catalytic, and thermal oxidation. In this study, styrene, one of the typical VOCs, was decomposed by ozone (O3) in laboratory and on-site systems. In a laboratory reactor, the styrene conversion efficiency in the reaction was determined under different temperatures, inlet styrene concentrations, and [O3]/[styrene] mole ratios. The styrene conversion efficiency decreased as the reaction temperature increased and was higher at higher mole ratios. A complete conversion was obtained in the laboratory system at room temperature, and 58.3% styrene conversion efficiency was achieved in the on-site system. [ABSTRACT FROM AUTHOR]

Many life-threatening diseases remain obscure in their early disease stages. Symptoms appear only at the advanced stage when the survival rate is poor. A non-invasive diagnostic tool may be able to identify disease even at the asymptotic stage and save lives. Volatile metabolites-based diagnostics hold a lot of promise to fulfil this demand. Many experimental techniques are being developed to establish a reliable non-invasive diagnostic tool; however, none of them are yet able to fulfil clinicians' demands. Infrared spectroscopy-based gaseous biofluid analysis demonstrated promising results to fulfil clinicians' expectations. The recent development of the standard operating procedure (SOP), sample measurement, and data analysis techniques for infrared spectroscopy are summarized in this review article. It has also outlined the applicability of infrared spectroscopy to identify the specific biomarkers for diseases such as diabetes, acute gastritis caused by bacterial infection, cerebral palsy, and prostate cancer. [ABSTRACT FROM AUTHOR]

Brown planthopper (BPH), a monophagous phloem feeder, consumes a large amount of photoassimilates in rice and causes wilting. A near-isogenic line 'TNG71-Bph45' was developed from the Oryza sativa japonica variety 'Tainung 71 (TNG71) carrying a dominant BPH-resistance locus derived from Oryza nivara (IRGC 102165) near the centromere of chromosome 4. We compared the NIL (TNG71-Bph45) and the recurrent parent to explore how the Bph45 gene confers BPH resistance. We found that TNG71-Bph45 is less attractive to BPH at least partially because it produces less limonene. Chiral analysis revealed that the major form of limonene in both rice lines was the L-form. However, both L- and D-limonene attracted BPH when applied exogenously to TNG71-Bph45 rice. The transcript amounts of limonene synthase were significantly higher in TNG71 than in TNG71-Bph45 and were induced by BPH infestation only in the former. Introgression of the Bph45 gene into another japonica variety, Tainan 11, also resulted in a low limonene content. Moreover, several dominantly acting BPH resistance genes introduced into the BPH-sensitive IR24 line compromised its limonene-producing ability and concurrently decreased its attractiveness to BPH. These observations suggest that reducing limonene production may be a common resistance strategy against BPH in rice. [ABSTRACT FROM AUTHOR]

Food contamination has long plagued agriculture, posing significant health risks to consumers. The use of volatile gases for food safety detection has proven highly effective, with composite gas sensors that leverage the two-dimensional material MXene exhibiting notable advancements in detecting various target gases. This paper reviews the progress of MXene-based composite gas sensors in the detection of food safety-related gases. The review begins by examining MXene material synthesis methods and then presents an overview of techniques aimed at enhancing MXene-based sensor detection capabilities. Recently, advancements in MXene composite gas sensors tailored for food safety gases have been highlighted. Finally, challenges encountered in gas-sensing applications of MXene-based composites are outlined, alongside predictions for their future development, aiming to offer insights for the application and advancement of intelligent gas sensors for target gases in food safety. [Display omitted] • Recent advances in MXene-based sensors for the detection of food-safety related gases are reviewed. • Synthesis methods of MXene materials and gas-sensitive performance enhancement strategies are discussed. • The potential trend toward high-performance MXene composite gas sensors for food safety detection is highlighted. • MXene nanocomposite sensors are a useful alternative to simplify food contamination analysis. [ABSTRACT FROM AUTHOR]

Infrared spectroscopy appears to be a promising analytical method for the metabolic analysis of breath. However, due to the presence of trace amounts in exhaled breath, the absorption strength of the metabolites remains extremely low. In such low detection limits, the nonlinear detection sensitivity of the infrared detector and electronic noise strongly modify the baseline of the acquired infrared spectra of breath. Fitting the reference molecular spectra with the baseline-modified spectral features of breath metabolites does not provide accurate identification. Therefore, baseline correction of the acquired infrared spectra of breath is the primary requirement for the success of breath-based infrared diagnosis. A selective spectral region-based, simple baseline correction method is proposed for the infrared spectroscopy of breath. [Display omitted] • VOCs in exhaled breath provide information about internal chemistry of the body. • IR spectroscopy is a promising technique for the identification of VOCs in breath. • Due to the presence of trace amount VOCs, in data processing, baseline looks distorted. • Proposed hierarchical correction method allows accurately identify and quantify VOCs. [ABSTRACT FROM AUTHOR]

Abstract Background Fibrotic Interstitial lung diseases (ILD) are a heterogeneous group of chronic lung diseases characterized by diverse degrees of lung inflammation and remodeling. They include idiopathic ILD such as idiopathic pulmonary fibrosis (IPF), and ILD secondary to chronic inflammatory diseases such as connective tissue disease (CTD). Precise differential diagnosis of ILD is critical since anti-inflammatory and immunosuppressive drugs, which are beneficial in inflammatory ILD, are detrimental in IPF. However, differential diagnosis of ILD is still difficult and often requires an invasive lung biopsy. The primary aim of this study is to identify volatile organic compounds (VOCs) patterns in exhaled air to non-invasively discriminate IPF and CTD-ILD. As secondary aim, the association between the IPF and CTD-ILD discriminating VOC patterns and functional impairment is investigated. Methods Fifty-three IPF patients, 53 CTD-ILD patients and 51 controls donated exhaled air, which was analyzed for its VOC content using gas chromatograph- time of flight- mass spectrometry. Results By applying multivariate analysis, a discriminative profile of 34 VOCs was observed to discriminate between IPF patients and healthy controls whereas 11 VOCs were able to distinguish between CTD-ILD patients and healthy controls. The separation between IPF and CTD-ILD could be made using 16 discriminating VOCs, that also displayed a significant correlation with total lung capacity and the 6 min’ walk distance. Conclusions This study reports for the first time that specific VOC profiles can be found to differentiate IPF and CTD-ILD from both healthy controls and each other. Moreover, an ILD-specific VOC profile was strongly correlated with functional parameters. Future research applying larger cohorts of patients suffering from a larger variety of ILDs should confirm the potential use of breathomics to facilitate fast, non-invasive and proper differential diagnosis of specific ILDs in the future as first step towards personalized medicine for these complex diseases.

Based on the current trend towards broad-bandwidth LED light spectra for basil productions in multi-tiered controlled-environment horticulture, a recently developed white broad-bandwidth LED light spectrum (400-780 nm) including far-red wavelengths with elevated red and blue light fractions was employed to cultivate basil. Four Ocimum basilicum L. cultivars (cv. Anise, cv. Cinnamon, cv. Dark Opal and cv. Thai Magic) were exposed to two different rising light intensity conditions (ILow and IHigh). In dependence of the individual cultivar-specific plant height increase over time, basil cultivars were exposed to light intensities increasing from ~ 100 to ~ 200 µmol m-2 s-1 under ILow, and from 200 to 400 µmol m-2 s-1 under IHigh (due to the exponential light intensity increases with decreasing proximity to the LED light fixtures). Within the first experiment, basils' morphological developments, biomass yields and time to marketability under both light conditions were investigated and the energy consumptions were determined to calculate the basils' light use efficiencies. In detail, cultivar-dependent differences in plant height, leaf and branch pair developments over time are described. In comparison to the ILow light conditions, IHigh resulted in accelerated developments and greater yields of all basil cultivars and expedited their marketability by 3-5 days. However, exposure to light intensities above ~ 300 µmol m-2 s-1 induced light avoidance responses in the green-leafed basil cultivars cv. Anise, cv. Cinnamon and cv. Thai Magic. In contrast, ILow resulted in consumerpreferred visual qualities and greater biomass efficiencies of the green-leafed basil cultivars and are discussed as a result of their ability to adapt well to low light conditions. Contrarily to the green-leafed cultivars, purple-leafed cv. Dark Opal developed insufficiently under ILow, but remained light-tolerant under IHigh, which is related to its high anthocyanin contents. In a second experiment, cultivars' volatile organic compound (VOC) contents and compositions over time were investigated. While VOC contents per gram of leaf dry matter gradually decreased in purple-leafed cv. Dark Opal between seedling stage to marketability, their contents gradually increased in the green cultivars. Regardless of the light treatment applied, cultivar-specific VOC compositions changed tremendously in a developmental stage-dependent manner. [ABSTRACT FROM AUTHOR]

Harmful volatile organic compounds (VOCs) are present in drinking water due to anthropogenic activities, such as oil refining (e.g., benzene) and disinfection (e.g., the so-called trihalomethanes, THMs). Gas chromatography (GC)-based techniques are widely applied for analysis of these compounds in the laboratory but have some throughput drawbacks due to sample preparation and the extended analysis time (due to chromatographic separation). Selected ion flow tube mass spectrometry (SIFT-MS) is a direct-injection mass spectrometry (DIMS) technique that has potential to reduce sample preparation and analysis times through direct analysis of aqueous headspace with no preconcentration, drying, or other water management. This study applies headspace-SIFT-MS to the analysis of benzene, related petroleum aromatics, and THMs to evaluate the potential for enhanced sample throughput for drinking water analysis (10 samples per hour). Headspace-SIFT-MS achieved a limit of quantitation (LOQ) of 0.1 to 0.2 μg L−1 for benzene, toluene, ethylbenzene and xylenes (BTEX), and 1 to 2 μg L−1 for the THMs. These LOQs achieve the current European Union and United States regulatory limits but are higher than modern GC methods. Therefore, the potential application of SIFT-MS is envisaged to lie in rapid screening in the laboratory, or field-based real-time monitoring. [ABSTRACT FROM AUTHOR]

Encapsulation of volatile organic compounds (VOCs) that could evaporate at a defined rate is of immense interest for application in emission reference materials (ERMs). Polyurethane/polyurea microcapsules with various VOC active ingredients (limonene, pinene, and toluene) were successfully produced by interfacial polymerization with Shirasu porous glass membrane emulsification in a size range between 10 and 50 μm. The effect of surfactant, VOC, monomer(s) type, and ratio has a great effect on the formulation process and morphology of capsules. The type of VOC played a significant role in the encapsulation efficiency. Due to the difference in vapor pressure and VOC/water interfacial tension, the formulation for encapsulation was optimized for each individual VOC. Furthermore, to achieve effective stability of the large droplets/capsules, a combination of ionic and nonionic surfactants was used. Optical and scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), were used to characterize the optimized microcapsules. The results showed that the obtained microcapsules exhibited a spherical shape and core-shell morphology and featured characteristic urethane-urea bonds. The amount of encapsulated VOC ranges between 54 and 7 wt %. The emission tests were performed with the help of the emission test chamber procedure (EN 16516). The limonene-loaded polyurethane/polyurea microcapsules show a change in emission rate of less than 10% within 14 days and can be considered as a potential candidate for use as an ERM.

Although odor is an important indicator of herbal medicine quality, an objective odor evaluation method remains undiscovered. Quantitative measurement using previous methods is complicated as Citrus Unshiu Peel (Chimpi) emits an odor when broken. To establish odor evaluation methods for herbal medicines using chimpi as an example, we developed a reproducible method for breaking samples and an objective odor evaluation method using an electronic nose (e-nose). First, an odor-emitting device (OED) was fabricated by modifying a pill cutter, which suppressed the spread of odor components into the room air while cutting the samples. The odor was emitted from chimpi with an OED and measured using an e-nose. The cut length was then measured. The sensor intensity was positively correlated with the cut length (r=0.840-0.927) in the same sample, and the intensity per unit length (INPULTH) calculated from the sensor intensity and cut length enables the comparison of the sensor intensity among different samples. In addition, average d-limonene emission level measured by GC-MS was positively correlated with average INPULTH (r=0.999), which suggests that this OED and e-nose method enables the comparison of the sensor intensity and d-limonene emissions. INPULTH also positively correlated with other seven monoterpenes such as p-cymene, β-myrcene, β-phellandrene, α-pinene, β-pinene, γ-terpinene, and α-terpinolene (r=0.701-0.865). Therefore, monoterpene content can be evaluated by measuring the odor in the same way as d-limonene. In conclusion, we developed a simple odor intensity evaluation method optimized for chimpi to establish an odor evaluation method for herbal medicines.

Accurate prediction of preterm birth is currently challenging, resulting in unnecessary maternal hospital admittance and fetal overexposure to antenatal corticosteroids. Novel biomarkers like volatile organic compounds (VOCs) hold potential for predictive, bed-side clinical applicability. In a proof of principle study, we aimed to assess the predictive potential of urinary volatile organic compounds in the identification of pregnant women at risk for preterm birth. Urine samples of women with a high risk for preterm birth (≧24 + 0 until 36 + 6 weeks) were collected prospectively and analyzed for VOCs using gas chromatography coupled with an ion mobility spectrometer (GS-IMS). Urinary VOCs of women delivering preterm were compared with urine samples of women with suspicion of preterm birth collected at the same gestation period but delivering at term. Additionally, the results were also interpreted in combination with patient characteristics, such as physical examination at admission, microbial cultures, and placental pathology. In our cohort, we found that urinary VOCs of women admitted for imminent preterm birth were not significantly different in the overall group of women delivering preterm vs. term. However, urinary VOCs of women admitted for imminent preterm birth and delivering between 28 + 0 until 36 + 6 weeks compared to women with a high risk for preterm birth during the same gestation period and eventually delivering at term (>37 + 0 weeks) differed significantly (area under the curve: 0.70). In addition, based on the same urinary VOCs, we could identify women with a confirmed chorioamnionitis (area under the curve: 0.72) and urinary tract infection (area under the curve: 0.97). In conclusion, urinary VOCs hold potential for non-invasive, bedside prediction of preterm birth and on the spot identification of intra-uterine infection and urinary tract infections. We suggest these observations are further explored in larger populations.

Based on the current trend towards broad-bandwidth LED light spectra for basil productions in multi-tiered controlled-environment horticulture, a recently developed white broad-bandwidth LED light spectrum (400-780 nm) including far-red wavelengths with elevated red and blue light fractions was employed to cultivate basil. Four Ocimum basilicum L. cultivars (cv. Anise, cv. Cinnamon, cv. Dark Opal and cv. Thai Magic) were exposed to two different rising light intensity conditions (ILow and IHigh). In dependence of the individual cultivar-specific plant height increase over time, basil cultivars were exposed to light intensities increasing from ~ 100 to ~ 200 µmol m-2 s-1 under ILow, and from 200 to 400 µmol m-2 s-1 under IHigh (due to the exponential light intensity increases with decreasing proximity to the LED light fixtures). Within the first experiment, basils’ morphological developments, biomass yields and time to marketability under both light conditions were investigated and the energy consumptions were determined to calculate the basils’ light use efficiencies. In detail, cultivar-dependent differences in plant height, leaf and branch pair developments over time are described. In comparison to the ILow light conditions, IHigh resulted in accelerated developments and greater yields of all basil cultivars and expedited their marketability by 3-5 days. However, exposure to light intensities above ~ 300 µmol m-2 s-1 induced light avoidance responses in the green-leafed basil cultivars cv. Anise, cv. Cinnamon and cv. Thai Magic. In contrast, ILow resulted in consumer-preferred visual qualities and greater biomass efficiencies of the green-leafed basil cultivars and are discussed as a result of their ability to adapt well to low light conditions. Contrarily to the green-leafed cultivars, purple-leafed cv. Dark Opal developed insufficiently under ILow, but remained light-tolerant under IHigh, which is related to its high anthocyanin contents. In a second experiment, cultivars’ volatile organic compound (VOC) contents and compositions over time were investigated. While VOC contents per gram of leaf dry matter gradually decreased in purple-leafed cv. Dark Opal between seedling stage to marketability, their contents gradually increased in the green cultivars. Regardless of the light treatment applied, cultivar-specific VOC compositions changed tremendously in a developmental stage-dependent manner.

A non-invasive optical fiber sensor for detecting volatile organic compounds (VOCs) as biomarkers of diabetes is proposed and experimentally demonstrated. It offers a low-cost and straightforward fabrication approach by implementing a one-step spray coating of a ZnO colloidal solution on a glass optical fiber. The structure of the optical fiber sensor is based on a single-mode fiber–coreless silica fiber–single-mode fiber (SMF-CSF-SMF) structure, where the CSF is the sensor region spliced between two SMFs. The ZnO layer of a higher refractive index coated over the sensing region improves the light interaction with the surrounding medium, leading to sensitivity enhancement. The optical properties, morphology, and elemental composition of the ZnO layer were analyzed. The sensing mechanism of the developed sensor is based on a wavelength interrogation technique showing wavelength shifts when the sensor is exposed to various VOC vapor concentration levels. Various concentrations of the three VOCs (including acetone, isopropanol, and ethanol) ranging from 20% to 100% were tested and analyzed. The sensor noticeably shows a significant response towards acetone vapor, with a better sensitivity of 0.162 nm/% vapor than for isopropanol (0.082 nm/% vapor) and ethanol (0.075 nm/% vapor) vapors. The high sensitivity and selectivity towards acetone, a common biomarker for diabetes, offers the potential for further development of this sensor as a smart healthcare system for monitoring diabetic conditions.

Plant volatiles play a major role in plant–insect interactions as defense compounds or attractants for insect herbivores. Recent studies have shown that endophytic fungi are also able to produce volatiles and this raises the question of whether these fungal volatiles influence plant–insect interactions. Here, we qualitatively investigated the volatiles released from 13 endophytic fungal species isolated from leaves of mature black poplar (Populus nigra) trees. The volatile blends of these endophytes grown on agar medium consist of typical fungal compounds, including aliphatic alcohols, ketones and esters, the aromatic alcohol 2-phenylethanol and various sesquiterpenes. Some of the compounds were previously reported as constituents of the poplar volatile blend. For one endophyte, a species of Cladosporium, we isolated and characterized two sesquiterpene synthases that can produce a number of mono- and sesquiterpenes like (E)-β-ocimene and (E)-β-caryophyllene, compounds that are dominant components of the herbivore-induced volatile bouquet of black poplar trees. As several of the fungus-derived volatiles like 2-phenylethanol, 3-methyl-1-butanol and the sesquiterpene (E)-β-caryophyllene, are known to play a role in direct and indirect plant defense, the emission of volatiles from endophytic microbial species should be considered in future studies investigating tree-insect interactions.

Most of the research on indoor air pollutants in the United Arab Emirates focus on the state before moving in. There are no studies on the evaluation and characteristics of Indoor Air Quality in living conditions. This study aims to obtain primary data by measuring the concentration of indoor hazardous chemical substances in apartment housings with different area characteristics and to identify the external and internal pollutants that affect them. As a methodology, a comparative analysis was conducted between residential (Business Bay) and industrial areas (Ras Al Khor) to investigate the indoor air pollutants level with the comparison of the outdoor environment, elapsed time after construction, finished materials, temperature, relative humidity, renovation, purchase of furniture and electric appliances, built-in closets, and air cleaning methods. The result showed that Benzene (C6H6), Toluene (C7H8), Ethylbenzene (C8H10), Xylene (C8H10), and Styrene (C8H8) were at a stable level. However, in the case of formaldehyde (HCHO), points exceeding or close to the WHO IAQ standard were found, suggesting that long-term attention is required. The differences between residential and industrial areas were marginal in terms of the size of the house, temperature and humidity, and the building materials. It was proven that the emission of indoor air pollutants from building materials lessened under 18 months after construction.

Volatile organic compounds (VOCs) are byproducts from metabolic pathways that can be detected in exhaled breath and have been reported as biomarkers for different diseases. The gold standard for analysis is gas chromatography–mass spectrometry (GC–MS), which can be coupled with various sampling methods. The current study aims to develop and compare different methods for sampling and preconcentrating VOCs using solid-phase microextraction (SPME). An in-house sampling method, direct-breath SPME (DB–SPME), was developed to directly extract VOCs from breath using a SPME fiber. The method was optimized by exploring different SPME types, the overall exhalation volume, and breath fractionation. DB–SPME was quantitatively compared to two alternative methods involving the collection of breath in a Tedlar bag. In one method, VOCs were directly extracted from the Tedlar bag (Tedlar–SPME) and in the other, the VOCs were cryothermally transferred from the Tedlar bag to a headspace vial (cryotransfer). The methods were verified and quantitatively compared using breath samples (n = 15 for each method respectively) analyzed by GC–MS quadrupole time-of-flight (QTOF) for compounds including but not limited to acetone, isoprene, toluene, limonene, and pinene. The cryotransfer method was the most sensitive, demonstrating the strongest signal for the majority of the VOCs detected in the exhaled breath samples. However, VOCs with low molecular weights, including acetone and isoprene, were detected with the highest sensitivity using the Tedlar–SPME. On the other hand, the DB–SPME was less sensitive, although it was rapid and had the lowest background GC–MS signal. Overall, the three breath-sampling methods can detect a wide variety of VOCs in breath. The cryotransfer method may be optimal when collecting a large number of samples using Tedlar bags, as it allows the long-term storage of VOCs at low temperatures (−80 °C), while Tedlar–SPME may be more effective when targeting relatively small VOCs. The DB-SPME method may be the most efficient when more immediate analyses and results are required.

SO2 is a preservative often used in the food industry, particularly in the wine industry. However, regulatory authorities and consumers have been strongly suggesting its reduction or even its replacement. In order to understand the impact of SO2 on the profiles of volatile organic compounds (VOCs) as well as amino acids (AAs), the aging of two white wines (one being a varietal and another being a blend) under identical conditions and in the presence of different doses of total SO2 was studied. After alcoholic fermentation (t = 0), either no SO2 was added (0 mg/L), or 30, 60, 90, or 120 mg/L of SO2 was applied. The samples under study were kept on fine lees for 3 months (t = 3). After 3 months (t = 6) and 9 months (t = 12), the wines were bottled and analyzed. For t = 0 and t = 3, the samples were submitted to HS-SPME-GC/MS for VOC analysis and LC-DAD for AA analysis. From the principal component analysis of the detected VOCs, it was observed that the blended wine in comparison with the varietal wine, was less impacted by the applied SO2 doses and aging time. From the AA profile, it was also observed in this study that maturation on fine lees resulted in an increase in the total concentration of AAs as would be expected.

The purge and trap gas chromatography-mass spectrometry (GC-MS) is established for the determination of 60 volatile organic compounds (VOC) in groundwater of enterprise land of key industries. The purge and trap conditions are optimized by selecting Watsons double-distilled water as blank water, ion and full scanning alternating mode for qualitative-quantitative analysis and determination of types and dosages of protective agent. The detection limit of the method is 0.3-1.2 µig/L, with the linear range of 0-250 µg/L, and correlation coefficient (R2) of 0.9907-0.9999. The spiked average recovery ofthree different concentrations are 87.2%-117%, with the relative standard deviation of 1.7% -9.7%, which is better than the quality control requirements of Technical Specifications on Quality Assurance and Control of Survey for Enterprise Land of Key Industries (Trial)" for VOCs in groundwater. The method adds test types of VOCs, with wide linear range and high sensitivity, suitable for rapid batch analysis of 60 VOCs in groundwater of enterprise land of various key industries. [ABSTRACT FROM AUTHOR]

Detection of volatile organic compound (VOC) vapors, which are known to have carcinogenic effects, is extremely important and necessary in many areas. In this work, the sensing properties of a cobalt phthalocyanine (CoPc) thin film at six different VOC vapors (methanol, ethanol, butanol, isopropyl alcohol, acetone, and ammonia) concentrations from 50 to 450 ppm are investigated. In this sense, it is observed that the interaction between the VOC vapors and the CoPc surface is not selective. It is shown that using machine learning algorithms the present sensor, which is poorly selective, can be transformed into a more efficient one with better detection ability. As a feature, 10 seconds of responses taken from the steady state region are used without any additional processing technique. Among classification algorithms, k-nearest neighbor (KNN) reaches the highest accuracy of 96.7%. This feature is also compared with the classical steady state response feature. Classification results indicate that the feature based on 10 seconds of responses taken from the steady state region is much better than that based on the classical steady state response feature. [ABSTRACT FROM AUTHOR]

There is a growing number of COVID-19 patients experiencing long-term symptoms months after their acute SARS-CoV-2 infection. Previous research proved dogs' ability to detect acute SARS-CoV-2 infections, but has not yet shown if dogs also indicate samples of patients with post-COVID-19 condition (Long COVID). Nine dogs, previously trained to detect samples of acute COVID-19 patients, were confronted with samples of Long COVID patients in two testing scenarios. In test scenario I (samples of acute COVID-19 vs. Long COVID) dogs achieved a mean sensitivity (for acute COVID-19) of 86.7% (95%CI: 75.4–98.0%) and a specificity of 95.8% (95%CI: 92.5–99.0%). When dogs were confronted with Long COVID and negative control samples in scenario IIa, dogs achieved a mean sensitivity (for Long COVID) of 94.4 (95%CI: 70.5–100.0%) and a specificity of 96.1% (95%CI: 87.6–100.0%). In comparison, when acute SARS-CoV-2 positive samples and negative control samples were comparatively presented (scenario IIb), a mean sensitivity of 86.9 (95%CI: 55.7–100.0%) and a specificity of 88.1% (95%CI: 82.7–93.6%) was attained. This pilot study supports the hypothesis of volatile organic compounds (VOCs) being long-term present after the initial infection in post-COVID-19 patients. Detection dogs, trained with samples of acute COVID-19 patients, also identified samples of Long COVID patients with a high sensitivity when presented next to samples of healthy individuals. This data may be used for further studies evaluating the pathophysiology underlying Long COVID and the composition of specific VOC-patterns released by SARS-CoV-2 infected patients throughout the course of this complex disease.

Biomedical detection dogs offer incredible advantages during disease outbreaks that are presently unmatched by current technologies, however, dogs still face hurdles of implementation due to lack of inter-governmental cooperation and acceptance by the public health community. Here, we refine the definition of a biomedical detection dog, discuss the potential applications, capabilities, and limitations of biomedical detection dogs in disease outbreak scenarios, and the safety measures that must be considered before and during deployment. Finally, we provide recommendations on how to address and overcome the barriers to acceptance of biomedical detection dogs through a dedicated research and development investment in olfactory sciences.

Background: Fibrotic Interstitial lung diseases (ILD) are a heterogeneous group of chronic lung diseases characterized by diverse degrees of lung inflammation and remodeling. They include idiopathic ILD such as idiopathic pulmonary fibrosis (IPF), and ILD secondary to chronic inflammatory diseases such as connective tissue disease (CTD). Precise differential diagnosis of ILD is critical since anti-inflammatory and immunosuppressive drugs, which are beneficial in inflammatory ILD, are detrimental in IPF. However, differential diagnosis of ILD is still difficult and often requires an invasive lung biopsy. The primary aim of this study is to identify volatile organic compounds (VOCs) patterns in exhaled air to non-invasively discriminate IPF and CTD-ILD. As secondary aim, the association between the IPF and CTD-ILD discriminating VOC patterns and functional impairment is investigated.Methods: Fifty-three IPF patients, 53 CTD-ILD patients and 51 controls donated exhaled air, which was analyzed for its VOC content using gas chromatograph- time of flight- mass spectrometry.Results: By applying multivariate analysis, a discriminative profile of 34 VOCs was observed to discriminate between IPF patients and healthy controls whereas 11 VOCs were able to distinguish between CTD-ILD patients and healthy controls. The separation between IPF and CTD-ILD could be made using 16 discriminating VOCs, that also displayed a significant correlation with total lung capacity and the 6 min' walk distance.Conclusions: This study reports for the first time that specific VOC profiles can be found to differentiate IPF and CTD-ILD from both healthy controls and each other. Moreover, an ILD-specific VOC profile was strongly correlated with functional parameters. Future research applying larger cohorts of patients suffering from a larger variety of ILDs should confirm the potential use of breathomics to facilitate fast, non-invasive and proper differential diagnosis of specific ILDs in the future as first step towards personalized medicine for these complex diseases. [ABSTRACT FROM AUTHOR]

Many life-threatening diseases remain obscure in their early disease stages. Symptoms appear only at the advanced stage when the survival rate is poor. A non-invasive diagnostic tool may be able to identify disease even at the asymptotic stage and save lives. Volatile metabolites-based diagnostics hold a lot of promise to fulfil this demand. Many experimental techniques are being developed to establish a reliable non-invasive diagnostic tool; however, none of them are yet able to fulfil clinicians’ demands. Infrared spectroscopy-based gaseous biofluid analysis demonstrated promising results to fulfil clinicians’ expectations. The recent development of the standard operating procedure (SOP), sample measurement, and data analysis techniques for infrared spectroscopy are summarized in this review article. It has also outlined the applicability of infrared spectroscopy to identify the specific biomarkers for diseases such as diabetes, acute gastritis caused by bacterial infection, cerebral palsy, and prostate cancer.