Sensor systems,electronic tongues and electronic noses,for the monitoring of biotechnological processes

Production of biofuel is based on the conversion by microorganisms of complex organic substrates into the methane or ethanol, which are consequently used as energy sources. Real time monitoring of the fermented media composition is of paramount for the effectiveness of the whole process. However, despite the fact that products worth billions of dollars are produced through fermentation processes annually, analytical instruments used for these processes’ monitoring remain relatively primitive. Established laboratory techniques produce exhaustive information about media composition but analysis is often quite time-consuming, expensive, requires skilled personnel and hardly can be automated. Lack of on-line sensors for the fermentation monitoring is commonly stressed in the literature. One of the techniques particularly suitable for this purpose is chemical sensors. Such features as low prices, relatively simple instrumentation, minimal sample preparation and easy automation of measurements make chemical sensors an attractive tool for industrial process control. However, practical use of chemical sensors in complex media is often hindered by their insufficient selectivity. For example, only pH and oxygen probes are routinely used in bio-reactors. One of the emerging approaches permitting to overcome the selectivity problems is the use of systems instead of discrete sensors. Such systems for liquid and gas analysis were named electronic tongues and electronic noses correspondingly. They are capable to perform both quantitative analysis (components’ concentrations) and classification or recognition of multicomponent media. This review presents recent achievements in the R&D and applications of electronic tongues and noses to the monitoring of biotechnological processes. JIMB-2008: BioEnergy—Special issue.     

Inspirational airflow patterns in deviated noses: a numerical study

This study attempts to evaluate the effects of deviation of external nose to nasal airflow patterns. Four typical subjects were chosen for model reconstruction based on computed tomography images of undeviated, S-shaped deviated, C-shaped deviated and slanted deviated noses. To study the hypothetical influence of deviation of external nasal wall on nasal airflow (without internal blockage), the collapsed region along the turbinate was artificially reopened in all the three cases with deviated noses. Computational fluid dynamics simulations were carried out in models of undeviated, original deviated and reopened nasal cavities at both flow rates of 167 and 500 ml/s. The shape of the anterior nasal roof was found to be collapsed on one side of the nasal airways in all the deviated noses. High wall shear stress region was found around the collapsed anterior nasal roof. The nasal resistances in cavities with deviated noses were considerably larger than healthy nasal cavity. Patterns of path-line distribution and wall shear stress distribution were similar between original deviated and reopened models. In conclusion, the deviation of an external nose is associated with the collapse of one anterior nasal roof. The crooked external nose induced a larger nasal resistance compared to the undeviated case, while the internal blockage of the airway along the turbinates further increased it.     

Detection and identification of fungal species by electronic nose technology: A systematic review

A rapid and effective identification of fungal species is essential for numerous applications, and electronic nose systems are being proposed as suitable alternatives to currently available fungi identification techniques. Hence, the present review aims to unveil all published information concerning fungi identification by electronic nose systems.A systematic review of the literature was conducted according to the PRISMA guidelines. A total of 16 articles met the inclusion criteria and were included in the analysis. The results of the reviewed studies demonstrated that effective detection of fungi was possible through sensor-based electronic nose systems, which may actually function as a mycotoxin screening tool for several applications.The obtained results suggest that the sensor-based electronic nose systems may not only screen different fungi genera, but also identify the associated species. This technology has already been experimented in several fields, from food industry to clinical practice.By summarizing these results, the present review may accelerate the standardization of electronic noses in fungi detection and discrimination, allowing a faster and more efficient screening of samples.     

Exhaled breath volatile alterations in pregnancy assessed with electronic nose

Context: Pregnancy-linked accelerated metabolism and oxidative stress may alter the exhaled volatile compound pattern (“breathprint”). Electronic noses can distinguish “breathprints” associated with different disorders.

Objective: This is the first study assessing alterations in “breathprint” during gestation.

Material and methods: 130 women participated in our study (78 pregnant vs. 52 non-pregnant). Breath samples were processed by an electronic nose and analyzed using principal component analysis.

Results: Significant differences were found in exhaled breath pattern between pregnant and non-pregnant women (p?=?0.001).

Conclusion: Pregnancy-induced changes in exhaled gases need to be considered when pregnant women with respiratory disorders carry out breath tests.     

嗅球僧帽细胞具有编码气味空间信息的能力

刺激源的方位是刺激的重要特性之一.行为学的研究发现,动物能够利用气味到达左右鼻腔的时间差和强度差信息对气味方位进行感知,但作为嗅觉系统第一神经中枢的嗅球,是否具有利用两侧鼻间差信息对气味方位进行编码的能力一直受到质疑.为探讨该问题,在本研究中通过比较嗅球中84个僧帽细胞对同侧气味刺激、对侧气味刺激以及对侧气味刺激略先于同侧气味刺激时的反应,发现有29个僧帽细胞可被同侧气味所兴奋,其中18个虽然对对侧气味刺激不反应,但对侧气味的存在却能显著降低其对同侧气味刺激的反应.另外,50个僧帽细胞在只给予同侧或对侧气味刺激时不反应,但其中11个在对侧刺激略先于同侧刺激的方式给出气味时,表现出明显的兴奋性反应.我们的研究结果一方面提示僧帽细胞具有编码气味到达两个鼻腔的时间差,或气味源位置信息的能力;另一方面也表明对侧刺激不仅能对同侧嗅球僧帽细胞产生抑制效应,还可能存在目前还不明确的机制而产生兴奋效应.     

创新型单手操作新生儿复苏器的研制

该复苏器操作简便、安全。只要把面罩盖住新生儿口鼻,用一只手即可对手泵吸球进行加压给氧。加压过高时能排余气并发声报警,避免发生气胸,提高抢救效果。另外,该手泵吸球可一物两用,按瘪后将长嘴放人新生儿口内或鼻孔口,放松时可吸羊水等黏液。节约原材料,降低成本,大有利于新生儿窒息复苏的推广普及。     

Fruit Volatile Analysis Using an Electronic Nose

Numerous and diverse physiological changes occur during fruit ripening, including the development of a specific volatile blend that characterizes fruit aroma. Maturity at harvest is one of the key factors influencing the flavor quality of fruits and vegetables¹. The validation of robust methods that rapidly assess fruit maturity and aroma quality would allow improved management of advanced breeding programs, production practices and postharvest handling. Over the last three decades, much research has been conducted to develop so-called electronic noses, which are devices able to rapidly detect odors and flavors^2-4. Currently there are several commercially available electronic noses able to perform volatile analysis, based on different technologies. The electronic nose used in our work (zNose, EST, Newbury Park, CA, USA), consists of ultra-fast gas chromatography coupled with a surface acoustic wave sensor (UFGC-SAW). This technology has already been tested for its ability to monitor quality of various commodities, including detection of deterioration in apple⁵; ripeness and rot evaluation in mango⁶; aroma profiling of thymus species⁷; C₆ volatile compounds in grape berries⁸; characterization of vegetable oil⁹ and detection of adulterants in virgin coconut oil¹⁰. This system can perform the three major steps of aroma analysis: headspace sampling, separation of volatile compounds, and detection. In about one minute, the output, a chromatogram, is produced and, after a purging cycle, the instrument is ready for further analysis. The results obtained with the zNose can be compared to those of other gas-chromatographic systems by calculation of Kovats Indices (KI). Once the instrument has been tuned with an alkane standard solution, the retention times are automatically converted into KIs. However, slight changes in temperature and flow rate are expected to occur over time, causing retention times to drift. Also, depending on the polarity of the column stationary phase, the reproducibility of KI calculations can vary by several index units¹¹. A series of programs and graphical interfaces were therefore developed to compare calculated KIs among samples in a semi-automated fashion. These programs reduce the time required for chromatogram analysis of large data sets and minimize the potential for misinterpretation of the data when chromatograms are not perfectly aligned.We present a method for rapid volatile compound analysis in fruit. Sample preparation, data acquisition and handling procedures are also discussed.     

The bioelectronic nose and tongue using olfactory and taste receptors: Analytical tools for food quality and safety assessment

Food intake is the primary method for obtaining energy and component materials in the human being. Humans evaluate the quality of food by combining various facets of information, such as an item of food's appearance, smell, taste, and texture in the mouth. Recently, bioelectronic noses and tongues have been reported that use human olfactory and taste receptors as primary recognition elements, and nanoelectronics as secondary signal transducers. Bioelectronic sensors that mimic human olfaction and gustation have sensitively and selectively detected odor and taste molecules from various food samples, and have been applied to food quality assessment. The portable and multiplexed bioelectronic nose and tongue are expected to be used as next-generation analytical tools for rapid on-site monitoring of food quality. In this review, we summarize recent progress in the bioelectronic nose and tongue using olfactory and taste receptors, and discuss the potential applications and future perspectives in the food industry.     

Electronic sensory systems for taste and odour monitoring in water – Developments and limitations

Taste and odour causingchemicals in drinking water supplies can bedetected and identified using a variety ofanalytical techniques and sensory methods.Currently limitations exist in applying thesetechniques and methods to the continuousmonitoring of taste and odour episodes.Electronic sensory systems so called``electronic noses' using non-specific gassensors could offer a rapid and relative simpletechnique for continuous monitoring of waterquality. Laboratory and field-based continuouswater monitoring showed that introducedpollutants such as 2-chlorophenol and geosmincould be detected by a sensor array, howeverthe detection limits were significant higherthan the odour threshold concentrations (OTC)for the respective compounds. The conditioningof the monitoring system in a temperaturecontrolled environment for on-line headspacegeneration and transfer reduced the impact ofenvironmental fluctuations on the sensorresponse profiles. At present, a sensor arraybased monitoring system could be applied to theintake protection of taste and odour causingcompounds in water supplies with a minimum OTCof 10 ppm.     

Detailed and abstract phase-locked attractor network models of early olfactory systems

Across species, primary olfactory centers show similarities both in their cellular organization and their types of olfactory information coding. In this article, we consider an excitatory-inhibitory spiking neural network as a model of early olfactory systems (antennal lobe for insects, olfactory bulb for vertebrates). In line with experimental results, we show that, in our network, odor-like stimuli evoke synchronization of excitatory cells, phase-locked to the oscillations of the local field potential. As revealed by a mathematical analysis, the phase-locking probability of excitatory cells is given by an inverted-U function and the firing probability of inhibitory cells is well described by a sigmoid function. These neural response functions are used to reduce the spiking model to a more abstract model with discrete-time dynamics (oscillatory cycles) and binary-state neurons (phase-locked or not). An iterative map, built for explaining the dynamics of the binary model, reveals that it converges to fixed point attractors similar to those obtained with the spiking model. This result is consistent with odor-specific attractors found in recent experimental studies. It also provides insights for designing bio-inspired olfactory associative memories applicable for data analysis in electronic noses.     

Early detection of bacterial diseases in apple plants by analysis of volatile organic compounds profiles and use of electronic nose

DNA‐based protocols are the standard methods for the diagnosis of infected plant material. Nevertheless, these methods are time‐consuming and require trained personnel, with an efficacy depending on the sampling procedure. In comparison, recognition methods based on volatile compounds emissions are less precise, but allow a non‐destructive mass screening of bulk samples, and may be implemented to steer molecular diagnosis. In this study, the analysis of volatile compounds is used for the discrimination of fire blight (Erwinia amylovora) and blossom blight (Pseudomonas syringae pv. syringae) on apple propagation material. Possible marker compounds were identified by gas chromatography–mass spectroscopy (GC‐MS) and proton transfer reaction‐time of flight‐mass spectroscopy (PTR‐ToF‐MS). In addition, two commercial electronic noses were used for diagnosis. After a preliminary validation in vitro, a diagnostic protocol was successfully developed to scale up to real nursery conditions on cold stored, asymptomatic dormant plants.     

Electronic noses and disease diagnostics

Rapid developments in sensor technology have facilitated the production of devices--known as electronic noses--that can detect and discriminate the production profiles of volatile compounds from microbial infections in situ. Such qualitative and semi-quantitative approaches could have a significant role in the early diagnosis and detection of microbial diseases. Using artificial intelligence and web-based knowledge systems, electronic noses might also have a valuable role in monitoring disease epidemiology.     

Lateralized memory storage and crossed inhibition during odor processing by Limax

After odor conditioning intact Limax maximus and injecting LY into their haemocoel, labeled groups of neurons are found in either the right or left procerebral lobe but never in both procerebral lobes. This suggests that a competitive interaction occurs between right and left odor processing pathways of which the procerebral lobe is a part. We use the nerve discharge in the external peritentacular nerve evoked by applying a puff of conditioned odor to the nose to document crossed inhibition between left and right odor processing pathways. Responses in the external peritentacular nerve evoked by stimulating one superior nose with a conditioned odor are strongly lateralized as responses occur only on the stimulated side. Stimulating both superior noses simultaneously with the same conditioned odor yields responses in both external peritentacular nerves that resemble the sum of responses to unilateral stimulation. Simultaneously stimulating both superior noses, each with a different conditioned odor, leads to strong inhibition of both external peritentacular nerve responses. The crossed inhibition is also evident if both superior and inferior noses on the same side are stimulated simultaneously. A lateral inhibitory mechanism, situated postsynaptic to odor recognition, appears to inhibit external peritentacular nerve responses if the two noses receive conflicting sensory inputs. Accepted: 14 December 1999     

Bio-Benchmarking of Electronic Nose Sensors

Background

Electronic noses, E-Noses, are instruments designed to reproduce the performance of animal noses or antennae but generally they cannot match the discriminating power of the biological original and have, therefore, been of limited utility. The manner in which odorant space is sampled is a critical factor in the performance of all noses but so far it has been described in detail only for the fly antenna.

Methodology

Here we describe how a set of metal oxide (MOx) E-Nose sensors, which is the most commonly used type, samples odorant space and compare it with what is known about fly odorant receptors (ORs).

Principal Findings

Compared with a fly''s odorant receptors, MOx sensors from an electronic nose are on average more narrowly tuned but much more highly correlated with each other. A set of insect ORs can therefore sample broader regions of odorant space independently and redundantly than an equivalent number of MOx sensors. The comparison also highlights some important questions about the molecular nature of fly ORs.

Conclusions

The comparative approach generates practical learnings that may be taken up by solid-state physicists or engineers in designing new solid-state electronic nose sensors. It also potentially deepens our understanding of the performance of the biological system.     

Bioelectronic nose and its application to smell visualization

There have been many trials to visualize smell using various techniques in order to objectively express the smell because information obtained from the sense of smell in human is very subjective. So far, well-trained experts such as a perfumer, complex and large-scale equipment such as GC-MS, and an electronic nose have played major roles in objectively detecting and recognizing odors. Recently, an optoelectronic nose was developed to achieve this purpose, but some limitations regarding the sensitivity and the number of smells that can be visualized still persist. Since the elucidation of the olfactory mechanism, numerous researches have been accomplished for the development of a sensing device by mimicking human olfactory system. Engineered olfactory cells were constructed to mimic the human olfactory system, and the use of engineered olfactory cells for smell visualization has been attempted with the use of various methods such as calcium imaging, CRE reporter assay, BRET, and membrane potential assay; however, it is not easy to consistently control the condition of cells and it is impossible to detect low odorant concentration. Recently, the bioelectronic nose was developed, and much improved along with the improvement of nano-biotechnology. The bioelectronic nose consists of the following two parts: primary transducer and secondary transducer. Biological materials as a primary transducer improved the selectivity of the sensor, and nanomaterials as a secondary transducer increased the sensitivity. Especially, the bioelectronic noses using various nanomaterials combined with human olfactory receptors or nanovesicles derived from engineered olfactory cells have a potential which can detect almost all of the smells recognized by human because an engineered olfactory cell might be able to express any human olfactory receptor as well as can mimic human olfactory system. Therefore, bioelectronic nose will be a potent tool for smell visualization, but only if two technologies are completed. First, a multi-channel array-sensing system has to be applied for the integration of all of the olfactory receptors into a single chip for mimicking the performance of human nose. Second, the processing technique of the multi-channel system signals should be simultaneously established with the conversion of the signals to visual images. With the use of this latest sensing technology, the realization of a proper smell-visualization technology is expected in the near future.     

Recent advances in electronic and bioelectronic noses and their biomedical applications

Significant effort has been made in the development of an artificial nose system for various applications. Advances in sensor technology have facilitated the development of high-performance electronic and bioelectronic noses. Numerous articles describe the advantages of artificial nose systems for biomedical applications. Recent advances in the development of electronic and bioelectronic noses and their biomedical applications are reviewed in this article.     

Molecular-biological characteristics of rubella virus strains isolated in St. Petersburg

In the surveillance of the incidence of rubella in the northwestern region of Russia, an analysis was conducted of swabs from the noses and pharynxes of 37 patients with rubella treated in Solovev District Military Clinical Hospital No. 442. To isolate the virus, the RK-13 cell line was used, in total 22 strains were allocated. The strains of the Rubella virus isolated in St. Petersburg during the 2007 outbreak belong to the 1E genotype. In the culture of RK-13 cells, changes of cellular morphogenesis and the formation of replicative complexes, as well as the shells of virions of rubella viruses, were detected.     

A study of cephalo-facial measurements from age 20 to 80 in Jat-Sikh and Bania females of Punjab (India)

The sample consists of 502 Jat-Sikh and 510 Bania females ranging in age from 20 to 80 years. Most of the measurements of head and face have shown a trend of increase up to fifth or sixth decade followed by a decrease, with intermittent fluctuations. Nose length and nose breadth have shown a trend of continuous increase up to the last age group. But this increase or decrease observed for these measurements during successive age-groups is significant only in few age-groups. On an average, the Jat-Sikh females possess significantly bigger heads, however some measurements like bigonial breadth, morphological upper facial length and nose breadth are significantly larger in Banias. The head is generally dolichocephal, with broad upper face and medium jugo-mandibular index in both the communities. The maximum frequency of Jat-Sikh females possess leptorhinae noses, whereas in Banias there is a transition from leptorhinae to mesorhinae noses.     

Oral immunization with a replication-deficient recombinant vaccinia virus protects mice against influenza.

Mice immunized with two intragastrically administered doses of a replication-deficient recombinant vaccinia virus containing the hemagglutinin and nucleoprotein genes from H1N1 influenza virus developed serum anti-H1 immunoglobulin G (IgG) antibody that completely protected the lungs from challenge with H1N1. Almost all of the mice given two intragastric doses also developed mucosal anti-H1 IgA antibody, and those with high anti-H1 IgA titers had completely protected noses. Intramuscular injection of the vaccine protected the lungs but not the noses from challenge. We also found that the vaccine enhanced recovery from infection caused by a shifted (H3N2) influenza virus, probably through the induction of nucleoprotein-specific cytotoxic T-lymphocyte activity. A replication-deficient, orally administered, enteric-coated, vaccinia virus-vectored vaccine might safely protect humans against influenza.     

鼻的活体测量与观察

本文对九江地区汉族成年男女,共计950例(男467例,女483例),进行鼻的活体测量与活体观察。结果表明:男、女不仅在鼻的形态上有明显差异,而且外鼻各径亦存在显著差异。本文还对这些差异进行了初步讨论,分析了该地区鼻型特点,并且与国外一些民族鼻型资料进行分析比较,初步确定本地区鼻型属于狭鼻型。