Mock Specimens Research Articles

A multi-center evaluation of a novel IVF cryostorage device in an active clinical setting

The objective of this study was to evaluate the function, and usability of a novel automated software-guided cryostorage system in an active IVF laboratory setting. The investigational device (ID) was installed at 3 IVF laboratories (sites: α, β, and γ). A total of 15 embryologists were trained to use the ID. Mock patient specimens containing mirrored live patient data were handled using the ID. Temperature readings were recorded every minute. Successful identification, storage, and retrieval of mock patient specimens by the ID were evaluated. To assess an LN2 pressure builder, the frequency of use and events of workflow interruption were logged. Student’s t-test was used to determine statistical significance. The ID was in active use for 164 days total. During this time, 329 mock patient egg and embryo cohorts were handled by the ID. The mean ± SD temperatures during active use were: α, − 176.57 ± 1.83 °C; β, − 178.21 ± 2.75 °C; γ, − 178.98 ± 1.74 and did not differ significantly. The highest recorded temperatures were: α, − 165.14 °C; β, − 157.41 °C; γ, − 164.45 °C. A total of 1064 automation transactions on 409 specimen vessels were performed. Data was managed on 1501 eggs and embryos. The ID did not lose or misplace any specimen data or vessels, and no mock specimen was exposed to a detrimental (> − 150 °C) temperature excursion. Over the 25 LN2 pressure builder usages during 99 total days, there was 1 occurrence where usage interrupted workflow due to a lack of LN2 pressure. The ID has advantages over the current manual-based cryostorage systems, including radio frequency identification (RFID) tracking, automation of manual tasks, and software guidance to ensure accurate specimen storage and retrieval. The results of this study indicate that the ID can be integrated into active IVF laboratories.

Target-enriched sequencing enables accurate identification of bloodstream infections in whole blood

Bloodstream infections are within the top ten causes of death globally, with a mortality rate of up to 70%. Gold standard blood culture testing is time-consuming, resulting in delayed, but accurate, treatment. Molecular methods, such as RT-qPCR, have limited targets in one run. We present a new Ampliseq detection system (ADS) combining target amplification and next-generation sequencing for accurate identification of bacteria, fungi, and antimicrobial resistance determinants directly from blood samples. In this study, we included removal of human genomic DNA during nucleic acid extraction, optimized the target sequence set and drug resistance genes, performed antimicrobial resistance profiling of clinical isolates, and evaluated mock specimens and clinical samples by ADS. ADS successfully identified pathogens at the species-level in 36 h, from nucleic acid extraction to results. Besides pathogen identification, ADS can also present drug resistance profiles. ADS enabled detection of all bacteria and accurate identification of 47 pathogens. In 20 spiked samples and 8 clinical specimens, ADS detected at least 92.81% of reads mapped to pathogens. ADS also showed consistency with the three culture-negative samples, and correctly identified pathogens in four of five culture-positive clinical blood specimens. This Ampliseq-based technology promises broad coverage and accurate pathogen identification, helping clinicians to accurately diagnose and treat bloodstream infections.

Brazilian disk compression testing of plastic-bonded idoxuridine mock explosive

ABSTRACT Recently, there has been increased interest in developing new inert surrogate materials, or “mocks,” for plastic-bonded explosives (PBX). Idoxuridine (IDOX) has similar density and mechanical behavior to the explosive HMX, and formulated plastic-bonded IDOX showed promise for emulating the HMX-based PBX 9501 in preliminary mechanical experiments. Several improvements to the manufacture of plastic-bonded IDOX have been made and are characterized here by Brazilian Disk testing. Compression tests were performed on these disk specimens under quasi-static loading conditions and at three different temperatures, , , and . The full-field deformation over the sample surface during the compression was obtained using the optical digital image correlation (DIC) technique. In this article, we summarize the Brazilian disk compression test results of the 2020 batch of IDOX mock specimens. We present the overall response, as well as the local deformation measurement. We discuss in detail, the sequence of deformation events occurring in the disk specimen during the compression process. Elastic constants, including shear modulus, Young’s modulus, and Poisson’s ratio, of the IDOX mock material, are extracted from the Brazilian disk compression test data. Finally, we compare the Brazilian disk compression test results with the data obtained from the baseline PBX 9501, tested in 2007, as well as the data from a previous batch of IDOX mock material tested in 2017. We hope that such comparisons would point out the path of improvement for the formulation and pressing of the new IDOX mock.

COVID-19 and the differential dilemma

The conundrums of choosing candidate genes, via differential expression between treated and mock specimens, are tackled by Ghandikota et al. in this issue of Patterns in their efforts to tease out genetic patterns that are characteristic of coronavirus disease 2019 (COVID-19) outcomes.

AlphaLISA for detection of staphylococcal enterotoxin B free from interference by protein A

Staphylococcal enterotoxin B (SEB) is an important enterotoxin which is a major reason for food poisoning and a potential biologic agent. Hence, rapid and accurate detection is very important. An amplified luminescent proximity homogeneous assay (AlphaLISA) for SEB detection was established here. Its performance was evaluated on mock specimen and culture supernatant. Its free from the effect of protein A was compared with ELISA. Results showed that the linear range for SEB detection was 25 pg/mL to 25 ng/mL. The detection limitation is 25 pg/mL in buffer and 50 pg/mL in specimen respectively. There was no cross-reaction with other classical SEs or botulinum toxin. AlphaLISA was also tolerant to the matrix of sample and showed good repeatability. The inter-assay coefficient of variation (CV) and intra-assay CV were<10% for buffer and mock specimens, respectively. Besides AlphaLISA detection was free of the interference of protein A (which is the obstacle for immune-based detection of SEs in Staphylococcus aureus culture supernatants): this feature is very important for food-poisoning confirmation caused by SEB contamination. These data suggest that the AlphaLISA established here is well suited for SEB detection in food samples and S. aureus culture supernatants.

Automated direct screening for resistance of Gram-negative blood cultures using the BD Kiestra WorkCell.

Early detection of resistance in sepsis due to Gram-negative organisms may lead to improved outcomes by reducing the time to effective antibiotic therapy. Traditional methods of resistance detection require incubation times of 18 to 48h to detect resistance. We have utilised automated specimen processing, digital imaging and zone size measurements in conjunction with direct disc susceptibility testing to develop a method for the rapid screening of Gram-negative blood culture isolates for resistance. Positive clinical blood cultures with Gram-negative organisms were prospectively identified and additional resistant mock specimens were prepared. Broth was plated and antibiotic-impregnated discs (ampicillin, ceftriaxone, piperacillin-tazobactam, meropenem, ciprofloxacin, gentamicin) were added. Plates were incubated, digitally imaged and zone sizes were measured using the BD Kiestra WorkCell laboratory automation system. Minimum, clinically useful, incubation times and optimised zone size cut-offs for resistance detection were determined. We included 187 blood cultures in the study. At 5h of incubation, >90% of plates yielded interpretable results. Using optimised zone size cut-offs, the sensitivity for resistance detection ranged from 87 to 100%, while the specificity ranged from 84.7 to 100%. The sensitivity and specificity for piperacillin-tazobactam resistance detection was consistently worse than for the other agents. Automated direct disc susceptibility screening is a rapid and sensitive tool for resistance detection in Gram-negative isolates from blood cultures for most of the agents tested.

Comparison of multiplex PCR hybridization-based and singleplex real-time PCR-based assays for detection of low prevalence pathogens in spiked samples

Molecular diagnostic devices are increasingly finding utility in clinical laboratories. Demonstration of the effectiveness of these devices is dependent upon comparing results from clinical samples tested with the new device to an alternative testing method. The preparation of mock clinical specimens will be necessary for the validation of molecular diagnostic devices when a sufficient number of clinical specimens is unobtainable. Examples include rare pathogens, some of which are pathogens posing a biological weapon threat. Here we describe standardized steps for developers to follow for the culture and quantification of three organisms used to spike human whole blood to create mock specimens. The three organisms chosen for this study were the Live Vaccine Strain (LVS) of Francisella tularensis, surrogate for a potential biothreat pathogen, Escherichia coli, a representative Gram-negative bacterium and Babesia microti (Franca) Reichenow Peabody strain, representing a protozoan parasite. Mock specimens were prepared with blood from both healthy donors and donors with nonspecific symptoms including fever, malaise, and flu-like symptoms. There was no significant difference in detection results between the two groups for any pathogen. Testing of the mock samples was compared on two platforms, Target Enriched Multiplex-PCR (TEM-PCR™) and singleplex real-time PCR (RT-PCR). Results were reproducible on both platforms. The reproducibility demonstrated by obtaining the same results between two testing methods and between healthy and symptomatic mock specimens, indicates the standardized methods described for creating the mock specimens are valid and effective for evaluating diagnostic devices.

Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10mm in cubic for an acceptable measurement time, i.e. 10min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access measurement of the texture and the amount of retained austenite.

Standardized methods to generate mock (spiked) clinical specimens by spiking blood or plasma with cultured pathogens.

To demonstrate standardized methods for spiking pathogens into human matrices for evaluation and comparison among diagnostic platforms. This study presents detailed methods for spiking bacteria or protozoan parasites into whole blood and virus into plasma. Proper methods must start with a documented, reproducible pathogen source followed by steps that include standardized culture, preparation of cryopreserved aliquots, quantification of the aliquots by molecular methods, production of sufficient numbers of individual specimens and testing of the platform with multiple mock specimens. Results are presented following the described procedures that showed acceptable reproducibility comparing in-house real-time PCR assays to a commercially available multiplex molecular assay. A step by step procedure has been described that can be followed by assay developers who are targeting low prevalence pathogens. The development of diagnostic platforms for detection of low prevalence pathogens such as biothreat or emerging agents is challenged by the lack of clinical specimens for performance evaluation. This deficit can be overcome using mock clinical specimens made by spiking cultured pathogens into human matrices. To facilitate evaluation and comparison among platforms, standardized methods must be followed in the preparation and application of spiked specimens.

赤外線サーモグラフィを用いたコンクリート材の内部剥離の深さ評価

In recent years, accidents resulting from spalling of concrete have been reported frequently due to the aging of concrete structures; thus, the detection of internal delamination, which is often the main factor of them, has become an important issue. Inspection technique using infrared thermography, while capable of searching over a wide region remotely without touching, still has room for improvement in terms of the accuracy of the delamination detection. In this research, a focus is placed particularly on the identification of the delamination depth. Measuring the surface temperature rise during the heating of specimens' surface with an infrared camera, a technique to identify the delamination depth is proposed based on one-dimensional non-steady heat conduction model. Experiments with mock specimens demonstrated that the evaluated delamination depths showed a good agreement with the actual ones when the heat flow can be approximated to be one-dimensional.

Detection of Streptococcus pneumoniae from Different Types of Nasopharyngeal Swabs in Children

BackgroundA better understanding of the epidemiology of nasopharyngeal carriage of Streptococcus pneumoniae is important to assess the impact of vaccination and the pathogenesis of pneumococcal disease. We compared the recovery of S. pneumoniae from nylon flocked, Dacron and rayon swabs.MethodsThe recovery of S. pneumoniae from mocked specimens using flocked, Dacron and rayon swabs were compared by culture. The yield from paired nasopharyngeal (NP) samples obtained from healthy children sampled with flocked and Dacron swabs was also determined using culture and lytA-targeted real-time polymerase chain reaction (qPCR).ResultsUsing mock specimen, the percentage recovery of S. pneumoniae ATCC 49619 (serotype 19F) strain from the flocked swabs was 100%, while it was 41% from Dacron swabs and 7% from rayon swabs. Similar results were observed for S. pneumoniae serotypes 1 and 5. S. pneumoniae was cultured from 18 of 42 (43%) paired NP samples from the healthy children (median age 8 [interquartile range (IQR) 5–16] months). The median number of colony-forming units (CFU) recovered from flocked swabs was two-fold higher (8.8×104 CFU/mL [IQR, 2.0×102 – 4.0×105 CFU/mL]) than Dacron swabs (3.7×104 CFU/mL [IQR, 4.0×102–3.2×105 CFU/mL], p = 0.17). Using lytA-targeted qPCR from paired NP samples, the median copy number of S. pneumoniae detected from flocked swabs was significantly higher than from Dacron swabs (3.0×105 genome copies/mL [IQR, 1.3×102−1.8×106] vs. 9.3×104 genome copies/mL [IQR, 7.0×101−1.1×106]; p = 0.005).ConclusionFlocked swabs released more S. pneumoniae compared to both Dacron and rayon swabs from mock specimens. Similarly, higher bacterial loads were detected by qPCR from flocked swabs compared with Dacron swabs from healthy children.

Development of a magnetic sensor system for predictive IASCC diagnosis on stainless steels in a nuclear reactor

The authors previously reported that magnetic flux leakage d ata, measured using a flux gate (FG) sensor, showed a correlation with the irradiation-assisted stress corros ion cracking (IASCC) susceptibility of neutron-irradiate d austenitic stainless alloys. This paper presents a study conducted to develop a diagnostic system that can detect IASCC precursors in stainless steels by measuring the magnetic properties of the material. The eddy current method and alternating current (AC) magnetization method were used, as these will be more practical for use in actual reactors. Probes were developed for these measurement methods, providing sufficient tolerance for en vironments in nuclear reactors. An attempt was also made to improve spatial resolution by manufacturing a smaller probe. A sensor system was designed for remote control, performance tests were conducted by measuring neutron-irradiated specimens and mock specimens, and magnetic data were evaluated by comparing the IASCC susceptibility of the specimens. It was proved that the sensor system developed in this study is capable of detecting IASCC precursors. Further developments necessary for application in actual nuclear reactors and the mechanism of correlation between magnetic properties and IASCC susceptibility were also discussed. Many of the problems experienced in existing light water reactors (LWR) are caused by damage to structural materials. Stress corrosion cracking (SCC) and irradiation-assisted SCC (IASCC) of structural materials have been especially serious problems, and it has not been possible to predict these in the reactor design process. These problems will become more significant when existing reactors start to age from now on, and when advanced reactors are operated and structural materials are used in more severe irradiation environments in future. It is therefore import ant to develop diagnostic techniques that can

No Association between Polyomaviruses and Primary Central Nervous System Lymphomas of HIV-Seronegative and HIV-Positive Patients

No Association between Polyomaviruses and Primary Central Nervous System Lymphomas of HIV-Seronegative and HIV-Positive Patients

Pooling of urine specimens for PCR testing: a cost saving strategy for Chlamydia trachomatis control programmes.

OBJECTIVES: To evaluate pooling of first catch urine (FCU) specimens as a cost effective strategy for chlamydia testing. METHODS: Mock specimens were pooled with and without dilution to determine optimal...

Abstract, conclusions and summaries

The functions of the Abstract, Conclusions and Summary sections in engineering and scientific reports and papers are compared and contrasted. Each is found to serve a specific purpose and not to be interchangeable with the others. As an illustration mock specimens of these sections are developed and compared for Shakespeare's Othello.