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Insect neural systems are a promising source of inspiration for new navigation algorithms, especially on low size, weight, and power platforms. There have been unprecedented recent neuroscience breakthroughs with Drosophila in behavioral and neural imaging experiments as well as the mapping of detailed connectivity of neural structures. General mechanisms for learning orientation in the central complex (CX) of Drosophila have been investigated previously; however, it is unclear how these underlying mechanisms extend to cases where there is translation through an environment (beyond only rotation), which is critical for navigation in robotic systems. Here, we develop a CX neural connectivity-constrained model that performs sensor fusion, as well as unsupervised learning of visual features for path integration; we demonstrate the viability of this circuit for use in robotic systems in simulated and physical environments. Furthermore, we propose a theoretical understanding of how distributed online unsupervised network weight modification can be leveraged for learning in a trajectory through an environment by minimizing orientation estimation error. Overall, our results may enable a new class of CX-derived low power robotic navigation algorithms and lead to testable predictions to inform future neuroscience experiments.

This article discusses how to create an interactive virtual training program at the intersection of neuroscience, robotics, and computer science for high school students. A four-day microseminar, titled Swarming Powered by Neuroscience (SPN), was conducted virtually through a combination of presentations and interactive computer game simulations, delivered by subject matter experts in neuroscience, mathematics, multi-agent swarm robotics, and education. The objective of this research was to determine if taking an interdisciplinary approach to high school education would enhance the students learning experiences in fields such as neuroscience, robotics, or computer science. This study found an improvement in student engagement for neuroscience by 16.6%, while interest in robotics and computer science improved respectively by 2.7% and 1.8%. The curriculum materials, developed for the SPN microseminar, can be used by high school teachers to further evaluate interdisciplinary instructions across life and physical sciences and computer science.

Insect neural systems are a promising source of inspiration for new algorithms for navigation, especially on low size, weight, and power platforms. There have been unprecedented recent neuroscience breakthroughs with Drosophila in behavioral and neural imaging experiments as well as the mapping of detailed connectivity of neural structures. General mechanisms for learning orientation in the central complex (CX) of Drosophila have been investigated previously; however, it is unclear how these underlying mechanisms extend to cases where there is translation through an environment (beyond only rotation), which is critical for navigation in robotic systems. Here, we develop a CX neural connectivity-constrained model that performs sensor fusion, as well as unsupervised learning of visual features for path integration; we demonstrate the viability of this circuit for use in robotic systems in simulated and physical environments. Furthermore, we propose a theoretical understanding of how distributed online unsupervised network weight modification can be leveraged for learning in a trajectory through an environment by minimizing of orientation estimation error. Overall, our results here may enable a new class of CX-derived low power robotic navigation algorithms and lead to testable predictions to inform future neuroscience experiments.SummaryAn insect neural connectivity-constrained model performs sensor fusion and online learning for orientation estimation.

Graph signal processing (GSP) is an emerging field developed for analyzing signals defined on irregular spatial structures modeled as graphs. Given the considerable literature regarding the resilience of infrastructure networks using graph theory, it is not surprising that a number of applications of GSP can be found in the resilience domain. GSP techniques assume that the choice of graphical Fourier transform (GFT) imparts a particular spectral structure on the signal of interest. We assess a number of power distribution systems with respect to metrics of signal structure and identify several correlates to system properties and further demonstrate how these metrics relate to performance of some GSP techniques. We also discuss the feasibility of a data-driven approach that improves these metrics and apply it to a water distribution scenario. Overall, we find that many of the candidate systems analyzed are properly structured in the chosen GFT basis and amenable to GSP techniques, but identify considerable variability and nuance that merits future investigation., Comment: 7 pages, 6 figures. Submitted to Resilience Week 2020

Nearly 600 articles were located in citation and keyword searches regarding the effects of humidity on comfort, health, and indoor environmental quality. Of these, around 70 articles reported the effects of low humidity (relative humidity ≤ 40%) and were analyzed in detail. Information in some categories was well chronicled, while other categories had significant knowledge gaps. Low humidity decreased house dust mite allergens. Due to different envelopes, generalizations could not be made for all bacteria and viruses. However, lower humidity increased virus survival for influenza. For comfort, low humidity had little effect on thermal comfort, but skin dryness, eye irritation, and static electricity increased as humidity decreased. For indoor environmental quality, low humidity had nonuniform effects on volatile organic compound emissions and perceived indoor air quality. Across many low humidity studies, ventilation rates and exposure times were noted as confounding variables. A majority of studies that ...

We examine the potential for low-intensity focused ultrasound to non-invasively produce small (< 1mm3) focal acoustic fields for precise brain stimulation near the skull. Our goal is to utilize transcranial ultrasonic neuromodulation to transform communications and immersive gaming experiences and to optimize neuromodulation applications in medicine. To begin evaluating possible hardware design strategies for engineering ultrasonic brain interfaces, in the present study we evaluated the skull transmission properties of longitudinal and shear waves as a function of incidence angle for 0–2 MHz. We also employed K-wave and time-reversal numerical simulations to further inspect waveform interactions with modeled layers. Timereversal focusing for single-layer and three-layer skull cases were simulated for three different bandwidth ranges (MHz): Broadband(0–2), 1 MHz(0.4–1.4), and 0.2 MHz(0.4–0.6). Broadband and 1 MHz bandwidths emulate the performance of micromachined or piezo membrane ultrasonic arrays, while 0.2 MHz bandwidth is representative of the performance of conventional piezoelectric ultrasonic transducer. We found the 3dB focal volume was ~0.6 mm for broadband and 1 MHz, with the latter showing a slightly larger sidelobe. In contrast, 0.2 MHz nearly doubled the size of the 3dB focal volume while producing prominent sidelobes. Our results provide initial confirmation that a broadband, ultrasonic, linear array can access the first 15 mm of the human brain, which contains circuitry essential to sensory processing including pre-motor and motor planning, somatosensory feedback, and visual attention. These areas are critical targets for providing haptic feedback via non-invasive neural stimulation.

Optical neuroimaging technologies aim to observe neural tissue structure and function by detecting changes in optical signals (scatter, absorption, etc…) that accompany a range of anatomical and functional properties of brain tissue. At present, there is a tradeoff between spatial and temporal resolution that is not currently optimized in a single imaging modality. This work focuses on filling the gap between the spatio-temporal resolutions of existing neuroimaging technologies by developing a coherent optics-based imaging system capable of extracting anatomical and functional information across a measurement volume by leveraging a coherent optics-based approach that provides both magnitude and phase information of the sample. We developed a digital holographic imaging (DHI) system capable of detecting these optical signals with a spatial resolution of better than 50 μm over a twenty-five mm2 field of view at sampling rates of 300 Hz and higher. The DHI system operates in the near-infrared (NIR) at 1064 nm, facilitating increased light penetration depths while minimizing contributions from overt changes in oxy- and deoxy-hemoglobin concentration present at shorter NIR wavelengths. This label-free imaging method detects intrinsic signals driven by tissue motion, allowing for innately spatio-temporally registered extraction of anatomical and functional signals in vivo. In this work, we present in vivo results from rat whisker barrel cortex demonstrating signals reflecting anatomical structure and tissue dynamics.

Lifelong mammalian male fertility is maintained through an intricate balance between spermatogonial proliferation and differentiation. DNA damage in spermatogonia, for instance caused by chemo- or radiotherapy, can induce cell cycle arrest or germ cell apoptosis, possibly resulting in male infertility. Spermatogonia are generally more radiosensitive and prone to undergo apoptosis than somatic cells. Among spermatogonial sub-types the response to DNA damage is differentially modulated; undifferentiated spermatogonia, including the spermatogonial stem cells (SSCs), are relatively radio-resistant, whereas differentiating spermatogonia are very radiosensitive. To investigate the molecular mechanisms underlying this difference, we used an in vitro system consisting of mouse male germline stem (GS) cells that can be induced to differentiate. Using RNA-sequencing analysis, we analyzed the response of undifferentiated and differentiating GS cells to ionizing radiation (IR). At the RNA expression level, both undifferentiated and differentiating GS cells showed a very similar response to IR. Protein localization of several genes found to be involved in either spermatogonial differentiation or radiation response was investigated using mouse testis sections. For instance, we found that the transcription factor PDX1 was specifically expressed in undifferentiated spermatogonia and thus may be a novel marker for these cells. Interestingly, also at the protein level, undifferentiated GS cells showed a more pronounced upregulation of p53 in response to IR than differentiating GS cells. The higher p53 protein level in undifferentiated spermatogonia may preferentially induce cell cycle arrest, thereby giving these cells more time to repair inflicted DNA damage and increase their radio-resistance.

The digitization of pollen grain images would permit the creation of a semi-automated system that could aid the expert palynologists in pollen classification. It would reduce cost and time-to-answer as well as improve analyst productivity. These issues are particularly critical in forensic applications. There are numerous factors that should be considered when establishing a digital database intended for semi-automated pollen classification. This paper explores a number of these issues through computer vision and machine learning assessments. The main topics evaluated are morphologically similar species-level classification, optimal training data size, how best to utilize three-dimensional data, accuracy changes due to the availability of metadata, i.e., fluctuations in analysts' confidence in taxa labeling, and using fossil data to classify modern data. This is the first known application of training on fossil data to classify modern taxa. Performances of 95.4% and 93.8% correct classification were achieved on two distinct sets of morphologically similar species-level data, surpassing previous records. We determined that a minimum of 5–10 training images per class was required to yield reasonable performance. Additionally, we established that all depth dimension slices associated with each grain were required to yield the best performance possible. Lastly, the error rate doubles due to decreasing analyst confidence and almost triples when using data from grains of varying ages, further solidifying the importance of comprehensive metadata.

The structural maintenance of chromosomes complex SMC5/6 is thought to be essential for DNA repair and chromosome segregation during mitosis and meiosis. To determine the requirements of the SMC5/6 complex during mouse spermatogenesis we combined a conditional knockout allele for Smc5, with four germ cell–specific Cre-recombinase transgenes, Ddx4-Cre, Stra8-Cre, Spo11-Cre, and Hspa2-Cre, to mutate Smc5 in spermatogonia, in spermatocytes before meiotic entry, during early meiotic stages, and during midmeiotic stages, respectively. Conditional mutation of Smc5 resulted in destabilization of the SMC5/6 complex. Despite this, we observed only mild defects in spermatogenesis. Mutation of Smc5 mediated by Ddx4-Cre and Stra8-Cre resulted in partial loss of preleptotene spermatocytes; however, spermatogenesis progresses and mice are fertile. Mutation of Smc5 via Spo11-Cre or Hspa2-Cre did not result in detectable defects of spermatogenesis. Upon exposure to gamma irradiation or etoposide treatment, each conditional Smc5 mutant demonstrated an increase in the number of enlarged round spermatids with multiple acrosomes and supernumerary chromosome content. We propose that the SMC5/6 complex is not acutely required for premeiotic DNA replication and meiotic progression during mouse spermatogenesis; however, when germ cells are challenged by exogenous DNA damage, the SMC5/6 complex ensures genome integrity, and thus, fertility.

Ultrasound (US) is recognized for its use in medical imaging as a diagnostic tool. As an acoustic energy source, US has become increasingly appreciated over the past decade for its ability to non-invasively modulate cellular activity including neuronal activity. Data obtained from a host of experimental models has shown that low-intensity US can reversibly modulate the physiological activity of neurons in peripheral nerves, spinal cord, and intact brain circuits. Experimental evidence indicates that acoustic pressures exerted by US act, in part, on mechanosensitive ion channels to modulate activity. While the precise mechanisms of action enabling US to both stimulate and suppress neuronal activity remain to be clarified, there are several advantages conferred by the physics of US that make it an appealing option for neuromodulation. For example, it can be focused with millimeter spatial resolutions through skull bone to deep-brain regions. By increasing our engineering capability to leverage such physical advantages while growing our understanding of how US affects neuronal function, the development of a new generation of non-invasive neurotechnology can be developed using ultrasonic methods.

The development of portable non-invasive brain computer interface technologies with higher spatio-temporal resolution has been motivated by the tremendous success seen with implanted devices. This talk will discuss efforts to overcome several major obstacles to viability including approaches that promise to improve spatial and temporal resolution. Optical approaches in particular will be highlighted and the potential benefits of both Blood-Oxygen Level Dependent (BOLD) and Fast Optical Signal (FOS) will be discussed. Early-stage research into the correlations between neural activity and FOS will be explored.

SMC complexes include three major classes: cohesin, condensin, and SMC5/6. However, the localization pattern and genetic requirements for the SMC5/6 complex during mammalian oogenesis had not previously been examined. In mouse oocytes, the SMC5/6 complex is enriched at the pericentromeric heterochromatin, and also localizes along chromosome arms during meiosis. The infertility phenotypes of females with a Zp3-Cre-driven conditional knockout (cKO) of Smc5 demonstrated that maternally expressed SMC5 protein is essential for early embryogenesis. Interestingly, protein levels of SMC5/6 complex components in oocytes decline as wild-type females age. When SMC5/6 complexes were completely absent in oocytes during meiotic resumption, homologous chromosomes failed to segregate accurately during meiosis I. Despite what appears to be an inability to resolve concatenation between chromosomes during meiosis, localization of topoisomerase II alpha to bivalents was not affected; however, localization of condensin along the chromosome axes was perturbed. Taken together, these data demonstrate that the SMC5/6 complex is essential for the formation of segregation-competent bivalents during meiosis I, and findings suggest that age-dependent depletion of the SMC5/6 complex in oocytes could contribute to increased incidence of oocyte aneuploidy and spontaneous abortion in aging females.

Air travel can rapidly transport infectious diseases globally. To facilitate the design of biosensors for infectious organisms in commercial aircraft, we characterized bacterial diversity in aircraft air. Samples from 61 aircraft high-efficiency particulate air (HEPA) filters were analyzed with a custom microarray of 16S rRNA gene sequences (PhyloChip), representing bacterial lineages. A total of 606 subfamilies from 41 phyla were detected. The most abundant bacterial subfamilies included bacteria associated with humans, especially skin, gastrointestinal and respiratory tracts, and with water and soil habitats. Operational taxonomic units that contain important human pathogens as well as their close, more benign relatives were detected. When compared to 43 samples of urban outdoor air, aircraft samples differed in composition, with higher relative abundance of Firmicutes and Gammaproteobacteria lineages in aircraft samples, and higher relative abundance of Actinobacteria and Betaproteobacteria lineages in outdoor air samples. In addition, aircraft and outdoor air samples differed in the incidence of taxa containing human pathogens. Overall, these results demonstrate that HEPA filter samples can be used to deeply characterize bacterial diversity in aircraft air and suggest that the presence of close relatives of certain pathogens must be taken into account in probe design for aircraft biosensors. Practical Implications A biosensor that could be deployed in commercial aircraft would be required to function at an extremely low false alarm rate, making an understanding of microbial background important. This study reveals a diverse bacterial background present on aircraft, including bacteria closely related to pathogens of public health concern. Furthermore, this aircraft background is different from outdoor air, suggesting different probes may be needed to detect airborne contaminants to achieve minimal false alarm rates. This study also indicates that aircraft HEPA filters could be used with other molecular techniques to further characterize background bacteria and in investigations in the wake of a disease outbreak.

Summary Epidemics of novel or re-emerging infectious diseases have quickly spread globally via air travel, as highlighted by pandemic H1N1 influenza in 2009 (pH1N1). Federal, state, and local public health responders must be able to plan for and respond to these events at aviation points of entry. The emergence of a novel influenza virus and its spread to the United States were simulated for February 2009 from 55 international metropolitan areas using three basic reproduction numbers (R0): 1.53, 1.70, and 1.90. Empirical data from the pH1N1 virus were used to validate our SEIR model. Time to entry to the U.S. during the early stages of a prototypical novel communicable disease was predicted based on the aviation network patterns and the epidemiology of the disease. For example, approximately 96% of origins (R0 of 1.53) propagated a disease into the U.S. in under 75 days, 90% of these origins propagated a disease in under 50 days. An R0 of 1.53 reproduced the pH1NI observations. The ability to anticipate the rate and location of disease introduction into the U.S. provides greater opportunity to plan responses based on the scenario as it is unfolding. This simulation tool can aid public health officials to assess risk and leverage resources efficiently.

Aims: To evaluate the feasibility of identifying viruses from aircraft cabin air, we evaluated whether respiratory viruses trapped by commercial aircraft air filters can be extracted and detected using a multiplex PCR, bead-based assay. Methods and Results: The ResPlex II assay was first tested for its ability to detect inactivated viruses applied to new filter material; all 18 applications of virus at a high concentration were detected. The ResPlex II assay was then used to test for 18 respiratory viruses on 48 used air filter samples from commercial aircraft. Three samples tested positive for viruses, and three viruses were detected: rhinovirus, influenza A and influenza B. For 33 of 48 samples, internal PCR controls performed suboptimally, suggesting sample matrix effect. Conclusion: In some cases, influenza and rhinovirus RNA can be detected on aircraft air filters, even more than 10 days after the filters were removed from aircraft. Significance and Impact of the Study: With protocol modifications to overcome PCR inhibition, air filter sampling and the ResPlex II assay could be used to characterize viruses in aircraft cabin air. Information about viruses in aircraft could support public health measures to reduce disease transmission within aircraft and between cities.

Rapid, chip-scale, and cost-effective single particle detection of biological agents is of great importance to human health and national security. We report real-time, high-throughput detection and sizing of individual, low-index polystyrene nanoparticles and H1N1 virus. Our widefield, common path interferometer detects nanoparticles and viruses over a very large sensing area, orders of magnitude larger than competing techniques. We demonstrate nanoparticle detection and sizing down to 70 nm in diameter. We clearly size discriminate nanoparticles with diameters of 70, 100, 150, and 200 nm. We also demonstrate detection and size characterization of hundreds of individual H1N1 viruses in a single experiment.

While the mechanisms of ultrasonic neurostimulation are still unknown, this method has been successfully shown on rodents from a variety of research groups. While the results are compelling, there has been limited work in characterizing the acoustic fields that are generated and ultimately delivered to the rodent brain which is important in order to determine the underlying neurostimulation mechanism. This presentation details some of the acoustical experimental design processes that are being undertaken at JHU/APL as well as our current progress in the rodent ultrasonic neurostimulation. The experimental design utilizes a complementary process of both simulation and experimentation verification to determine the expected delivered acoustic wave field. The simulation encompasses the full propagation path from the single element focused transducer, through an acoustic waveguide and skull, to the treatment location. This work uses a focused transducer with a center frequency of 0.5 MHz with several different waveguides that are characterized in our calibration tank with regards to intensity over space. Each of these waveguides is modeled and compared relative to the focal spot size and intensity delivered to the focal spot. These measurements are used to select an optimal waveguide which is used in the model to determine the expected performance of the full system. The presented results compare the performance of the waveguides and their impact on ultrasonic delivery to the rodent brain.While the mechanisms of ultrasonic neurostimulation are still unknown, this method has been successfully shown on rodents from a variety of research groups. While the results are compelling, there has been limited work in characterizing the acoustic fields that are generated and ultimately delivered to the rodent brain which is important in order to determine the underlying neurostimulation mechanism. This presentation details some of the acoustical experimental design processes that are being undertaken at JHU/APL as well as our current progress in the rodent ultrasonic neurostimulation. The experimental design utilizes a complementary process of both simulation and experimentation verification to determine the expected delivered acoustic wave field. The simulation encompasses the full propagation path from the single element focused transducer, through an acoustic waveguide and skull, to the treatment location. This work uses a focused transducer with a center frequency of 0.5 MHz with several different...

A transmission-based surface plasmon resonance (SPR) sensor for label-free detection of protein-carbohydrate and protein-protein binding proximate to a perforated gold surface is demonstrated. An SPR instrument makes real-time measurements of the resonant wavelength and/or the resonant angle of incidence of transmitted light; both are influenced by the presence of proteins at the gold surface-liquid interface. Ethylene glycol solutions with known refractive indexes were used to calibrate the instrument. A paired polarization-sensitive detector achieved an overall detection resolution of ~ 6.6 times 10-5 refractive index units (RIU). Proof of principle experiments was performed with concanavalin A (Con A) binding to gold-adsorbed ovomucoid and anti-bovine serum albumin (BSA) binding to gold-adsorbed BSA.

The use of pollen grain analysis for forensic geo-historical location has been explored for several decades, yet it is not widely adopted in the United States. We confirmed significant improvement in geographic precision, i.e., from 2.5×107 to 1.2×105 km2, by simultaneously applying flowering plant data from four different taxa at the genus and species levels. Moreover, when we calculated precision using collected pollen data, we found that co-occurring, pairwise genus-level distinctions based on expert-provided indicator taxa resulted in average precision values of 4° and 4.5° in latitude and longitude, respectively - corresponding to roughly 1.8×105 km2. We also applied computer vision techniques to identify morphologically similar pollen grains, which resulted in grain-identification error rates of 2.18% and 6.24% at the genus and species levels, respectively, surpassing previously published records. Collectively, our results demonstrate that algorithmic identification of species-specific pollen morphology, founded on established computer vision techniques, when combined with species-level pollen distribution, has the potential to revolutionize the scope, accuracy, and precision of forensic geographic attribution.

Background Collection of exhaled breath samples for the analysis of inflammatory biomarkers is an important area of research aimed at improving our ability to diagnose, treat and understand the mechanisms of chronic pulmonary disease. Current collection methods based on condensation of water vapor from exhaled breath yield biomarker levels at or near the detection limits of immunoassays contributing to problems with reproducibility and validity of biomarker measurements. In this study, we compare the collection efficiency of two aerosol-to-liquid sampling devices to a filter-based collection method for recovery of dilute laboratory generated aerosols of human cytokines so as to identify potential alternatives to exhaled breath condensate collection. Methodology/Principal Findings Two aerosol-to-liquid sampling devices, the SKC® Biosampler and Omni 3000™, as well as Teflon® filters were used to collect aerosols of human cytokines generated using a HEART nebulizer and single-pass aerosol chamber setup in order to compare the collection efficiencies of these sampling methods. Additionally, methods for the use of Teflon® filters to collect and measure cytokines recovered from aerosols were developed and evaluated through use of a high-sensitivity multiplex immunoassay. Our results show successful collection of cytokines from pg/m3 aerosol concentrations using Teflon® filters and measurement of cytokine levels in the sub-picogram/mL concentration range using a multiplex immunoassay with sampling times less than 30 minutes. Significant degradation of cytokines was observed due to storage of cytokines in concentrated filter extract solutions as compared to storage of dry filters. Conclusions Use of filter collection methods resulted in significantly higher efficiency of collection than the two aerosol-to-liquid samplers evaluated in our study. The results of this study provide the foundation for a potential new technique to evaluate biomarkers of inflammation in exhaled breath samples.

Microbial culture is exemplified by the Petri dish, a tool that (one century after its invention) still remains one of the “gold standards” for microbiological analysis. However, current trends towards automation, massively paralleled assays, and miniaturization (as well as the observation that we still cannot culture most microorganisms), suggest that new ideas in microbial culture are required. In the Petri dish, nutrient containing agar is typically used as the matrix on which microorganisms are cultured. However, new materials such as nanofibres and nanoporous materials may be better choices as supporting matrixes. Further, emerging techniques in microengineering and the fabrication of low cost materials are helping to create new porous disposables that are of sufficiently low cost that they may be used in the routine microbiology laboratory. These disposables are in turn allowing the development of novel miniature culture methods to take place, methods such as microchemostats, cages for growing microorganisms, and “habitats on a chip”. One particularly useful porous ceramic is Porous Aluminium Oxide (PAO), which can be utilized to generate highly subdivided culture chips that possess up to one million separate, miniaturized, growth areas. Indeed, this material has applications in microbiological diagnostics, microbiological research and industrial microbiology. In this chapter, the applications, advantages, and limitations of porous matrixes and accompanying culture chips will be examined. It is expected that these advances will yield significant improvements in microbial culture when compared to the classical Petri dish.

The spread of infectious disease via commercial airliner travel is a significant and realistic threat. To shed some light on the feasibility of detecting airborne pathogens, a sensor integration study has been conducted and computational investigations of contaminant transport in an aircraft cabin have been performed. Our study took into consideration sensor sensitivity as well as the time-to-answer, size, weight and the power of best available commercial off-the-shelf (COTS) devices. We conducted computational fluid dynamics simulations to investigate three types of scenarios: (1) nominal breathing (up to 20 breaths per minute) and coughing (20 times per hour); (2) nominal breathing and sneezing (4 times per hour); and (3) nominal breathing only. Each scenario was implemented with one or seven infectious passengers expelling air and sneezes or coughs at the stated frequencies. Scenario 2 was implemented with two additional cases in which one infectious passenger expelled 20 and 50 sneezes per hour, respectively. All computations were based on 90 minutes of sampling using specifications from a COTS aerosol collector and biosensor. Only biosensors that could provide an answer in under 20 minutes without any manual preparation steps were included. The principal finding was that the steady-state bacteria concentrations in aircraft would be high enough to be detected in the case where seven infectious passengers are exhaling under scenarios 1 and 2 and where one infectious passenger is actively exhaling in scenario 2. Breathing alone failed to generate sufficient bacterial particles for detection, and none of the scenarios generated sufficient viral particles for detection to be feasible. These results suggest that more sensitive sensors than the COTS devices currently available and/or sampling of individual passengers would be needed for the detection of bacteria and viruses in aircraft.

We propose an interferometric technique to detect and size low-index nanoparticles with radius smaller than 100nm. The method offers sensitive detection and identification of pathogens such as viruses based on the size information.

Recent biological terrorism threats and outbreaks of microbial pathogens clearly emphasize the need for biosensors that can quickly and accurately identify infectious agents. The majority of rapid biosensors generate detectable signals when a molecular probe in the detector interacts with an analyte of interest. Analytes may be whole bacterial or fungal cells, virus particles, or specific molecules, such as chemicals or protein toxins, produced by the infectious agent. Peptides and nucleic acids are most commonly used as probes in biosensors because of their versatility in forming various tertiary structures. The interaction between the probe and the analyte can be detected by various sensor platforms, including quartz crystal microbalances, surface acoustical waves, surface plasmon resonance, amperometrics, and magnetoelastics. The field of biosensors is constantly evolving to develop devices that have higher sensitivity and specificity, and are smaller, portable, and cost-effective. This mini review discusses recent advances in peptide-dependent rapid biosensors and their applications as well as relative advantages and disadvantages of each technology.

The early and late components of the event-related potential (ERP) Old–New effect are well characterized with respect to long-term memory, and have been associated with processes of familiarity and recollection, respectively. Now, using a short-term memory paradigm with verbal and nonverbal stimuli, we explored the way that these two components respond to variation in recency and stimulus type. We found that the amplitude of the early component (or frontal N400, FN400) showed Old–New effects only for verbal stimuli and increased with recency. In contrast, the later component (or late positive component, LPC) showed Old–New effects across a range of stimulus types and did not scale with recency. These results are consistent with the way that these same ERP components have been characterized in long-term memory, supporting the idea that some of the same processes underlie long- and short-term item recognition.

The spread of disease via commercial airliner travel is a significant and realistic threat. To shed some light on the feasibility of detecting airborne pathogens a sensor integration study has been conducted in this work in addition to computational investigations of the contaminant transport in an aircraft cabin. Our sensor study took into consideration the sensor sensitivity as well as the size, weight and power of commercial off the shelf devices. The computational fluid dynamic simulations were implemented for investigating extreme coughing and sneezing scenarios. The principle finding was that the contaminant concentration is relatively low when compared to the sensitivity available in current state of the art devices. Therefore, this study proposes a novel device/method to detect existence of pathogens. Moreover, it concludes that a collector is also required.

Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3) proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG) protein. Previous studies in mouse have shown that there is one SMC1 protein (SMC1β), two α-kleisins (RAD21L and REC8) and one STAG protein (STAG3) that are meiosis-specific. During meiosis, homologous chromosomes must recombine with one another in the context of a tripartite structure known as the synaptonemal complex (SC). From interaction studies, it has been shown that there are at least four meiosis-specific forms of cohesin, which together with the mitotic cohesin complex, are lateral components of the SC. STAG3 is the only meiosis-specific subunit that is represented within all four meiosis-specific cohesin complexes. In Stag3 mutant germ cells, the protein level of other meiosis-specific cohesin subunits (SMC1β, RAD21L and REC8) is reduced, and their localization to chromosome axes is disrupted. In contrast, the mitotic cohesin complex remains intact and localizes robustly to the meiotic chromosome axes. The instability of meiosis-specific cohesins observed in Stag3 mutants results in aberrant DNA repair processes, and disruption of synapsis between homologous chromosomes. Furthermore, mutation of Stag3 results in perturbation of pericentromeric heterochromatin clustering, and disruption of centromere cohesion between sister chromatids during meiotic prophase. These defects result in early prophase I arrest and apoptosis in both male and female germ cells. The meiotic defects observed in Stag3 mutants are more severe when compared to single mutants for Smc1β, Rec8 and Rad21l, however they are not as severe as the Rec8, Rad21l double mutants. Taken together, our study demonstrates that STAG3 is required for the stability of all meiosis-specific cohesin complexes. Furthermore, our data suggests that STAG3 is required for structural changes of chromosomes that mediate chromosome pairing and synapsis, DNA repair and progression of meiosis., Author Summary Meiosis is a specialized cell division required for the formation of gametes (sperm and egg). Early in meiosis, the chromosome pairs that we inherit from our mother and father become linked and genetic material is exchanged. This is a remarkable process as every gamete that we make is unique, and the unison between a sperm and egg will create a new individual that harbors novel combinations of characteristics from each parents' family tree. Linkage and genetic exchange between chromosomes is facilitated by a linear protein scaffold structure. A group of protein complexes known as cohesins are a key component of the protein scaffold. To date, there are 4 meiosis-specific cohesin complexes identified. Only one cohesin component known as STAG3 is represented in all meiosis-specific cohesins. We mutated the gene that encodes for STAG3 in mouse and discovered that it results in meiotic failure and absence of gametes. From careful analysis we have determined that STAG3 is required for the stability of meiosis-specific cohesins, which ensure that chromosomes are paired and genetic material is exchanged. Our findings imply that abnormalities in human STAG3 will give rise to chromosome defects, infertility and gonad atrophy.

Nanocrescent-like structures have become important surface enhanced Raman scattering structures because instead of relying on a few nanometer gap inter-particle plasmonic coupling to achieve local field enhancement, intra-particle plasmonic coupling between the cavity modes and the tip edges are utilized to achieve high local field enhancement at the tips. Our fabrication approach creates 'nanotorch' structures with controllable cavity rim opening and deterministic orientation to yield uniform Raman measurements, consisting of three-dimensional upright-oriented nanocrescent structures resting on nanopillars. Each structure serves as a single SERS substrate. We demonstrate that a nanotorch with a smaller rim opening results in a higher enhancement factor compare to one with a larger opening. More importantly, the uniformity of all the analysed Raman modes of adsorbed benzenethiol is better than 80% due to the consistent, upright orientation of each single nanotorch SERS substrate, paving the way for practical implementation of SERS detection.

An analytical expression of spectral sensitivity derived from a surface plasmon polariton dispersion relation for a two-dimensional nanohole array surface plasmon polariton resonance sensor is presented. The sensitivity of the nanohole array sensor depends on the periodicity of the array and the order of the excited surface plasmon polariton modes. The analytical expression is further confirmed by rigorous electromagnetic simulation and validated by experimental results. Real-time monitoring of protein-protein specific bonding is performed to demonstrate the integrated microfluidic nanohole array surface plasmon resonance biosensor.

A surface plasmon resonance biosensor based on two-dimensional metallic nanohole array is presented. The resonance is narrowed by a crossed polarizer-analyzer pair. Protein specific bindings are used to demonstrate real-time label-free microfluidic packaged sensor.