Typical Laboratory Environment Research Articles

Persistent pollution of genetic materials in a typical laboratory environment

From the onset of coronavirus disease (COVID-19) pandemic, there are concerns regarding the disease spread and environmental pollution of biohazard since studies on genetic engineering flourish and numerous genetic materials were used such as the nucleic acid test of the severe acute respiratory syndrome coronavirus (SARS-CoV-2). In this work, we studied genetic material pollution in an institute during a development cycle of plasmid, one of typical genetic materials, with typical laboratory settings. The pollution source, transmission routes, and pollution levels in laboratory environment were examined. The Real-Time quantitative- Polymerase Chain Reaction results of all environmental mediums (surface, aerosol, and liquid) showed that a targeted DNA segment occurred along with routine experimental operations. Among the 79 surface and air samples collected in the genetic material operation, half of the environment samples (38 of 79) are positive for nucleic acid pollution. Persistent nucleic acid contaminations were observed in all tested laboratories and spread in the public area (hallway). The highest concentration for liquid and surface samples were 1.92 × 108 copies/uL and 5.22 × 107 copies/cm2, respectively. Significant amounts of the targeted gene (with a mean value of 74 copies/L) were detected in the indoor air of laboratories utilizing centrifuge devices, shaking tables, and cell homogenizers. Spills and improper disposal of plasmid products were primary sources of pollution. The importance of establishing designated experimental zones, employing advanced biosafety cabinets, and implementing highly efficient cleaning systems in laboratories with lower biosafety levels is underscored. SYNOPSISSTATEMENT. Persistent environmental pollutions of genetic materials are introduced by typical experiments in laboratories with low biosafety level.

Unraveling the Prominent Existence of Trace Metals in Photocatalysis: Exploring Iron Impurity Effects.

Metal impurities can complicate the identification of active catalyst species in transition metal catalysis and electrocatalysis, potentially leading to misleading findings. This study investigates the influence of metal impurities on photocatalysis. Specifically, the photocatalytic reaction of inert alkanes using chlorides without the use of an external photocatalyst was studied, achieving successful C(sp3)-H functionalization. The observations reveal that Fe and Cu impurities are challenging to avoid in a typical laboratory environment and are prominently present in normal reaction systems, and iron impurities play a dominant role in the aforementioned apparent 'metal-free' reaction. Additionally, iron exhibits significantly higher catalytic activity compared to Cu, Ce, and Ni at low metal concentrations in the photocatalytic C(sp3)-H functionalization using chlorides. Considering the widespread presence of Fe and Cu impurities in typical laboratory environments, this study serves as a reminder of their involvement in reaction processes.

Coriolis force compensation and laser beam delivery for 100-m baseline atom interferometry

The Coriolis force is a significant source of systematic phase errors and dephasing in atom interferometry and is often compensated by counter-rotating the interferometry laser beam against Earth's rotation. We present a novel method for performing Coriolis force compensation for long-baseline atom interferometry, which mitigates atom-beam misalignment due to beam rotation, an effect which is magnified by the long lever arm of the baseline length. The method involves adjustment of the angle of the interferometer beam prior to a magnifying telescope, enabling the beam to pivot around a tunable position along the interferometer baseline. By tuning the initial atom kinematics and adjusting the angle with which the interferometer beam pivots about this point, we can ensure that the atoms align with the center of the beam during the atom optics laser pulses. This approach will be used in the MAGIS-100 atom interferometer and could also be applied to other long-baseline atom interferometers. An additional challenge associated with long baseline interferometry is that since long-baseline atom interferometers are often located outside of typical laboratory environments, facilities constraints may require lasers to be housed in a climate-controlled room a significant distance away from the main experiment. Nonlinear effects in optical fibers restrict the use of fiber-based transport of the high-power interferometry beam from the laser room to the experiment. We present the design of and prototype data from a laser transport system for MAGIS-100 that maintains robustness against alignment drifts despite the absence of a long fiber.

Disentangling the sources of ionizing radiation in superconducting qubits

Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and gamma -rays emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly and operation of state-of-the-art superconducting qubits. We present a GEANT-4 based simulation to predict the rate of impacts and the amount of energy released in a qubit chip from each of the mentioned sources. We finally propose mitigation strategies for the operation of next-generation qubits in a radio-pure environment.

Designing Optimal Loop, Saddle, and Ellipse-Based Magnetic Coils by Spherical Harmonic Mapping

Adaptable, low-cost, coils designed by carefully selecting the arrangements and geometries of simple primitive units are used to generate magnetic fields for diverse applications. These extend from magnetic resonance and fundamental physics experiments to active shielding of quantum devices including magnetometers, interferometers, clocks, and computers. However, finding optimal arrangements and geometries of multiple primitive structures is time-intensive and it is challenging to account for additional constraints, e.g. optical access, during the design process. Here, we demonstrate a general method to find these optimal arrangements. We encode specific symmetries into sets of loops, saddles, and cylindrical ellipses and then solve exactly for the magnetic field harmonics generated by each set. By combining these analytic solutions using computer algebra, we can use numerical techniques to efficiently map the landscape of parameters and geometries which the coils must satisfy. Sets of solutions may be found which generate desired target fields accurately while accounting for complexity and size restrictions. We demonstrate this approach by employing simple configurations of loops, saddles, and cylindrical ellipses to design target linear field gradients and compare their performance with designs obtained using conventional methods. A case study is presented where three optimized arrangements of loops, designed to generate a uniform axial field, a linear axial field gradient, and a quadratic axial field gradient, respectively, are hand-wound around a low-cost, 3D-printed coil former. These coils are used to null the magnetic background in a typical laboratory environment, reducing the magnitude of the axial field along the central half of the former’s axis from (7.8 ± 0.3) μT (mean ± st. dev.) to (0.11 ± 0.04) μT.

Transformation of Sequential Hospital and Outpatient Laboratory Data into Between-Day Reference Change Values.

Serial differences between intrapatient consecutive measurements can be transformed into Taylor series of variation vs time with the intersection at time = 0 (y0) equal to the total variation (analytical + biological + preanalytical). With small preanalytical variation, y0, expressed as a percentage of the mean, is equal to the variable component of the reference change value (RCV) calculation: (CVA2 + CVI2)1/2. We determined the between-day RCV of patient data for 17 analytes and compared them to healthy participants' RCVs. We analyzed 653 consecutive days of Dartmouth-Hitchcock Roche Modular general chemistry data (4.2 million results: 60% inpatient, 40% outpatient). The serial patient values of 17 analytes were transformed into 95% 2-sided RCV (RCVAlternate), and 3 sets of RCVhealthy were calculated from 3 Roche Modular analyzers' quality control summaries and CVI derived from biological variation (BV) studies using healthy participants. The RCVAlternate values are similar to RCVhealthy derived from known components of variation. For sodium, chloride, bicarbonate calcium, magnesium, phosphate, alanine aminotransferase, albumin, and total protein, the RCVs are equivalent. As expected, increased variation was found for glucose, aspartate aminotransferase, creatinine, and potassium. Direct bilirubin and urea demonstrated lower variation. Our RCVAlternate values integrate known and unknown components of analytic, biologic, and preanalytic variation, and depict the variations observed by clinical teams that make medical decisions based on the test values. The RCVAlternate values are similar to the RCVhealthy values derived from known components of variation and suggest further studies to better understand the results being generated on actual patients tested in typical laboratory environments.

Development of an Off-Grid Solar-Powered Autonomous Chemical Mini-Plant for Producing Fine Chemicals.

Photochemistry using inexhaustible solar energy is an eco‐friendly way to produce fine chemicals outside the typical laboratory or chemical plant environment. However, variations in solar irradiation conditions and the need for an external energy source to power electronic components limits the accessibility of this approach. In this work, a chemical solar‐driven “mini‐plant” centred around a scaled‐up luminescent solar concentrator photomicroreactor (LSC‐PM) was built. To account for the variations in solar irradiance at ground level and passing clouds, a responsive control system was designed that rapidly adapts the flow rate of the reagents to the light received by the reaction channels. Supplying the plant with solar panels, integrated into the module by placing it behind the LSC to utilize the transmitted fraction of the solar irradiation, allowed this setup to be self‐sufficient and fully operational off‐grid. Such a system can shine in isolated environments and in a distributed manufacturing world, allowing to decentralize the production of fine chemicals.

Applying Virtual Reality to Audiovisual Speech Perception Tasks in Children.

Purpose The primary purpose of this study was to explore the efficacy of using virtual reality (VR) technology in hearing research with children by comparing speech perception abilities in a typical laboratory environment and a simulated VR classroom environment. Method The study included 48 final participants (40 children and eight young adults). The study design utilized a speech perception task in conjunction with a localization demand in auditory-only (AO) and auditory-visual (AV) conditions. Tasks were completed in simulated classroom acoustics in both a typical laboratory environment and in a virtual classroom environment accessed using an Oculus Rift head-mounted display. Results Speech perception scores were higher for AV conditions over AO conditions across age groups. In addition, interaction effects of environment (i.e., laboratory environment and VR classroom environment) and visual accessibility (i.e., AV vs. AO) indicated that children's performance on the speech perception task in the VR classroom was more similar to their performance in the laboratory environment for AV tasks than it was for AO tasks. AO tasks showed improvement in speech perception scores from the laboratory to the VR classroom environment, whereas AV conditions showed little significant change. Conclusion These results suggest that VR head-mounted displays are a viable research tool in AV tasks for children, increasing flexibility for audiovisual testing in a typical laboratory environment.

Towards High-Performance Wireless Control: $10^{-7}$ Packet Error Rate in Real Factory Environments

To meet the extremely low latency constraints of industrial wireless control in critical applications, the wireless high-performance scheme (WirelessHP) has been introduced as a promising solution. The proposed design showed great improvements in terms of latency, but its performance in terms of reliability have not been fully tested yet. While traditional wireless systems achieve high reliability through packet retransmissions, this would impair the latency, and an approach based on channel coding is preferable in industrial applications. In this paper, a set of packet error rate (PER) tests is performed by applying concatenated Reed Solomon and convolutional codes to the WirelessHP physical layer, using a demonstrator based on a universal software radio peripheral platform. The effectiveness of channel coding to achieve $10^{-7}$ level PER without retransmissions is shown in typical laboratory and factory environments.

A Novel Passive Indoor Localization Method by Fusion CSI Amplitude and Phase Information.

With the rapid development of wireless network technology, wireless passive indoor localization has become an increasingly important technique that is widely used in indoor location-based services. Channel state information (CSI) can provide more detailed and specific subcarrier information, which has gained the attention of researchers and has become an emphasis in indoor localization technology. However, existing research has generally adopted amplitude information for eigenvalue calculations. There are few research studies that have used phase information from CSI signals for localization purposes. To eliminate the signal interference existing in indoor environments, we present a passive human indoor localization method named FapFi, which fuses CSI amplitude and phase information to fully utilize richer signal characteristics to find location. In the offline stage, we filter out redundant values and outliers in the CSI amplitude information and then process the CSI phase information. A fusion method is utilized to store the processed amplitude and phase information as a fingerprint database. The experimental data from two typical laboratory and conference room environments were gathered and analyzed. The extensive experimental results demonstrate that the proposed algorithm is more efficient than other algorithms in data processing and achieves decimeter-level localization accuracy.

Production of Hymenolepis diminuta in the Laboratory: An Old Research Tool with New Clinical Applications.

Hymenolepis diminuta, the rat tapeworm, was first described in 1819 by Rudolphi and was studied extensively in several laboratories during the mid to latter part of the twentieth century. More recently, the primary use of the organism had been for educational purposes. The organisms require an intermediate insect host to complete their life cycle, making them non-transmissible to other rats or to humans under typical laboratory or educational environments. The organisms effectively colonize rats, but not humans or mice, and are easily maintained in laboratory. They are, with exceedingly rare exceptions, benign (e.g., nonparasitic) in humans, mice, and laboratory rats. Although the benign character of the helminth makes it ideal for educational purposes, the fact that no pathology is associated with colonization has led to decreased interest in the H. diminuta as a model for modern research where efforts are largely motivated by interests in medicine and health. However, more recently work with the "biota alteration" model of inflammatory disease has established that reintroduction of helminths into Western society, a practice often referred to as "helminthic therapy," is potentially a way of lowering inflammation without compromising immune function. For this effort, the lack of pathology and benign nature of the organism makes H. diminuta an ideal subject for study. In this chapter, we describe production of H. diminuta using laboratory rats and introduction of the organisms into laboratory mice as a model for their effects in humans.

Influence of curing temperature and stress conditions on mechanical properties of cementing paste backfill

Cemented paste backfill (CPB) has been observed to achieve greater cemented strength when cured in situ compared with equivalent mixes cured and tested in a laboratory environment. This is in part due to the development of effective stress and generation of elevated temperatures by exothermic cement hydration reactions occurring during curing in a typical underground stope environment. This differs from curing in typical laboratory environments, where little or no effective stresses are generated and curing occurs under constant-temperature conditions. This paper outlines the development, calibration, and testing of a temperature-controlled hydration cell that provides closer representation of in situ conditions by controlling the rate and final amount of specimen temperature increase, in addition to curing under effective stress. The temperature-controlled hydration cell was used to examine the effect of curing under combined effective stress and temperature conditions on the development of small-strain stiffness over a 7 day curing period and the unconfined compressive strength at the end of this period. Curing with both elevated temperature and effective stress was found to significantly increase the mechanical properties of CPB compared with curing at elevated effective stress or ambient temperatures alone.

An examination of speech reception thresholds measured in a simulated reverberant cafeteria environment

Objective: There is increasing demand in the hearing research community for the creation of laboratory environments that better simulate challenging real-world listening environments. The hope is that the use of such environments for testing will lead to more meaningful assessments of listening ability, and better predictions about the performance of hearing devices. Here we present one approach for simulating a complex acoustic environment in the laboratory, and investigate the effect of transplanting a speech test into such an environment. Design: Speech reception thresholds were measured in a simulated reverberant cafeteria, and in a more typical anechoic laboratory environment containing background speech babble. Study sample: The participants were 46 listeners varying in age and hearing levels, including 25 hearing-aid wearers who were tested with and without their hearing aids. Results: Reliable SRTs were obtained in the complex environment, but led to different estimates of performance and hearing-aid benefit from those measured in the standard environment. Conclusions: The findings provide a starting point for future efforts to increase the real-world relevance of laboratory-based speech tests.

High Repeatability of Anti-Predator Responses and Resting Metabolic Rate in a Beetle

Measures of repeatability are essential for understanding behavioral consistency and individual differences in behavior, i.e. animal personalities. We studied anti-predator responses of the yellow mealworm beetle (Tenebrio molitor) and performed behavioral tests in plastic containers representing a typical laboratory environment of T. molitor. Behavioral tests were repeated in Eppendorf test tubes where we also measured resting metabolic rate (RMR). Results show that the response latency to a threatening/startling stimulus, and the total time spent in the state of tonic immobility, correlated across the tests. The behavioral responses were repeatable and RMR covaried phenotypically with personality: we found a negative correlation between response latency time and time spent immobile, a positive correlation between response latency and RMR, and a negative correlation between RMR and total time spent immobile. These correlations were also similar across trials performed in the Eppendorf test tubes and the plastic containers.

B114 Proficiency Testing As a Quality Assessment Methodology in Acid Fast Bacilli Microscopy

Background: In 2009, The National Tuberculosis and Leprosy Control Program in Nigeria developed standardized panels for assessing laboratory proficiency in Tuberculosis (TB) smear microscopy. Laboratories supported by the Institute of Human Virology (IHV) – AIDSRelief project periodically conduct external quality assurance evaluation following this national protocol. Staff proficiency at 10 facilities was assessed in May 2012 as a measure of the quality of the IHV laboratory support model. Methodology: Each hospital received 15 slides of known, but blinded results ranging from negative to 3+ of the Acid Fast Bacilli. Laboratory personnel stained and examined the slides under their typical laboratory environment without supervision. Results were sent to the IHV Laboratory Specialist for comparison with the panel results. Results: Overall, 81% (12/22) microscopists passed scoring > 80%. Two microscopists recorded no error. Errors were detected in 31% of the 147 panel tests conducted. Low false negatives constituted 50% of the errors (23/46), where few or scanty bacilli were undetected. Others include Quantification errors (9/46; 20%) where bacilli were detected in incorrect quantities, high false negatives (6/46; 13%), where negative slides were falsely identified as highly positive (1+, 2+ and 3+), high false positives (4/46; 9%) where positive slides were falsely identified as negative and low false positives (4/46; 9%) from false identification of negative slides as scantily positive. Conclusion: These results suggest that a continuous staff competency improvement strategy through refresher trainings and standardization of AFB microscopy methodologies will be needed to have quality assured TB laboratory diagnosis.

Experimental UWB Propagation Channel Path Loss and Time-Dispersion Characterization in a Laboratory Environment

The knowledge of the propagation channel properties is an important issue for a successful design of ultrawideband (UWB) communication systems enabling high data rates in short-range applications. From an indoor measurement campaign carried out in a typical laboratory environment, this paper analyzes the path loss and time-dispersion properties of the UWB channel. Values of the path loss exponent are derived for the direct path and for a Rake receiver structure, examining the maximum multipath diversity gain when anallRake (ARake) receiver is used. Also, the relationship between time-dispersion parameters and path loss is investigated. The UWB channel transfer function (CTF) was measured in the frequency domain over a channel bandwidth of 7.5 GHz in accordance with the UWB frequency range (3.1–10.6 GHz).

Amplifier development for multiplexed cryogenic detectors

We make some considerations on the question of driving the cable from the cryogenic stage of refrigerators to the room temperature, in the case of multiplexed detector array systems where a high total Shannon information capacity is required. We have constructed large SQUID arrays for the purpose, some of which exhibit lower than 5 × 10−8 Φ0 Hz−1/2 flux noise at 4.2 K and do not require magnetic shielding in a typical laboratory environment. The option of using class-D amplifiers to reduce the cryogenic heat load is briefly reviewed.

Face adaptation effects show strong and long-lasting transfer from lab to more ecological contexts

A review on recent experiments on figural face aftereffects reveals that adaptation effects in famous faces can last for hours up to days. Such adaptations seem to be highly reliable regarding test–retest designs as well as regarding the generalizability of adaptation across different adaptation routines and adaptations toward different kinds of facial properties. However, in the studies conducted so far, adaptation and the subsequent test phase were carried out in typical laboratory environments. Under these circumstances, it cannot be ruled out that the observed effects are, in fact, episodic learn–test compatibility effects. To test for ecological validity in adaptation effects we used an adaptation paradigm including environmental and social properties that differed between adaptation and test phase. With matched samples (n1 = n2 = 54) we found no main effects of experimental setting compatibility resulting from varying where the tests where conducted (environmental condition) nor any interaction with effects of stimulus compatibility resulting from varying stimulus similarity between adaptation and test phase using the same picture, different pictures of the same person, or different persons (transfer). This indicates that these adaptation effects are not artificial or merely lab-biased effects. Adaptation to face stimuli may document representational adaptations and tuning mechanisms that integrate new visual input in a very fast, reliable, and sustainable way.

Accurate Phase-Based Ranging Measurements for Backscatter RFID Tags

Short-distance, millimeter-level ranging based on backscatter RF tags remains a challenge today. We propose a composite dual-frequency continuous-wave and continuous-wave (DFCW/CW) radar system for localization of backscatter RF tags. The coarse DFCW range result is used to correct the cycle ambiguity of the more accurate CW range result. A minimum mean square error (MMSE)-based method is employed to combine the DFCW and CW ranging data, given spectrum constraints. The composite radar concept is demonstrated with a custom 5.8-GHz backscatter RF tag system in a typical indoor laboratory environment with a strong line-of-sight (LOS). Results show that the MMSE technique can resolve the CW cycle ambiguity for a moving tag and results in a range error of approximately 1 mm after an acquisition period.

Assessing a novel room temperature DNA storage medium for forensic biological samples

The ability to properly collect, analyze and preserve biological stains is important to preserving the integrity of forensic evidence. Stabilization of intact biological evidence in cells and the DNA extracts from them is particularly important since testing is generally not performed immediately following collection. Furthermore, retesting of stored DNA samples may be needed in casework for replicate testing, confirmation of results, and to accommodate future testing with new technologies. A novel room temperature DNA storage medium, SampleMatrix™ (SM; Biomatrica, Inc., San Diego, CA), was evaluated for stabilizing and protecting samples. Human genomic DNA samples at varying amounts (0.0625–200 ng) were stored dry in SM for 1 day to 1 year under varying conditions that included a typical ambient laboratory environment and also through successive freeze–thaw cycles (3 cycles). In addition, spiking of 1–4× SM into samples prior to analysis was performed to determine any inhibitory effects of SM. Quantification of recovered DNA following storage was determined by quantitative PCR or by agarose gel electrophoresis, and evaluation of quantitative peak height results from multiplex short tandem repeat (STR) analyses were performed to assess the efficacy of SM for preserving DNA. Results indicate no substantial differences between the quality of samples stored frozen in liquid and those samples maintained dry at ambient temperatures protected in SM. For long-term storage and the storage of low concentration samples, SM provided a significant advantage over freezer storage through higher DNA recovery. No detectable inhibition of amplification was observed at the recommended SM concentration and complete profiles were obtained from genomic DNA samples even in the presence of higher than recommended concentrations of the SM storage medium. The ability to stabilize and protect DNA from degradation at ambient temperatures for extended time periods could have tremendous impact in simplifying and improving sample storage conditions and requirements. The current work focuses on forensics analysis; however this technology is applicable to all endeavors requiring storage of DNA.