Multicenter Evaluation of the Cepheid Xpert Xpress SARS-CoV-2/Flu/RSV Test.

With the approach of respiratory virus season in the Northern Hemisphere, clinical microbiology and public health laboratories will need rapid diagnostic assays to distinguish severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from influenza virus and respiratory syncytial virus (RSV) infections for diagnosis and surveillance. In this study, the clinical performance of the Xpert Xpress SARS-CoV-2/Flu/RSV test (Cepheid, Sunnyvale, CA, USA) for nasopharyngeal swab specimens was evaluated in four centers: Johns Hopkins Medical Microbiology Laboratory, Northwell Health Laboratories, NYC Public Health Laboratory, and Los Angeles County/University of Southern California (LAC+USC) Medical Center. A total of 319 nasopharyngeal swab specimens, positive for SARS-CoV-2 (n = 75), influenza A virus (n = 65), influenza B virus (n = 50), or RSV (n = 38) or negative (n = 91) by the standard-of-care nucleic acid amplification tests at each site, were tested using the Cepheid panel test. The overall positive percent agreement for the SARS-CoV-2 target was 98.7% (n = 74/75), and the negative agreement was 100% (n = 91), with all other analytes showing 100% total agreement (n = 153). Standard-of-care tests to which the Cepheid panel was compared included the Cepheid Xpert Xpress SARS-CoV-2, Cepheid Xpert Xpress Flu/RSV, GenMark ePlex respiratory panel, BioFire respiratory panel 2.1 and v1.7, DiaSorin Simplexa COVID-19 Direct, and Hologic Panther Fusion SARS-CoV-2 assays. The Xpert Xpress SARS-CoV-2/Flu/RSV test showed high sensitivity and accuracy for all analytes included in the test. This test will provide a valuable clinical diagnostic and public health solution for detecting and differentiating SARS-CoV-2, influenza A and B virus, and RSV infections during the current respiratory virus season.

Extremum Seeking Control for Model-Free Auto-Tuning of Powered Prosthetic Legs.

This paper proposes an extremum seeking controller (ESC) for simultaneously tuning the feedback control gains of a knee-ankle powered prosthetic leg using continuous-phase controllers. Previously, the proportional gains of the continuous-phase controller for each joint were tuned manually by trial-and-error, which required several iterations to achieve a balance between the prosthetic leg tracking error performance and the user's comfort. In this paper, a convex objective function is developed, which incorporates these two goals. We present a theoretical analysis demonstrating that the quasi-steady-state value of the objective function is independent of the controller damping gains. Furthermore, we prove the stability of error dynamics of continuous-phase controlled powered prosthetic leg along with ESC dynamics using averaging and singular perturbation tools. The developed cost function is then minimized by ESC in real-time to simultaneously tune the proportional gains of the knee and ankle joints. The optimum of the objective function shifts at different walking speeds, and our algorithm is suitably fast to track these changes, providing real-time adaptation for different walking conditions. Benchtop and walking experiments verify the effectiveness of the proposed ESC across various walking speeds.

An In Vitro Enrichment Strategy for Formulating Synergistic Synbiotics.

Research on the role of diet on gut and systemic health has led to considerable interest toward identifying novel therapeutic modulators of the gut microbiome, including the use of prebiotics and probiotics. However, various host responses have often been reported among many clinical trials. This is in part due to competitive exclusion as a result of the absence of ecological niches as well as host-mediated constraints via colonization resistance. In this research, we developed a novel in vitro enrichment (IVE) method for isolating autochthonous strains that can function as synergistic synbiotics and overcome these constraints. The method relied on stepwise in vitro fecal fermentations to enrich for and isolate Bifidobacterium strains that ferment the prebiotic xylooligosaccharide (XOS). We subsequently isolated Bifidobacterium longum subsp. longum CR15 and then tested its establishment in 20 unique fecal samples with or without XOS. The strain was established in up to 18 samples but only in the presence of XOS. Our findings revealed that the IVE method is suitable for isolating potential synergistic probiotic strains that possess the genetic and biochemical ability to ferment specific prebiotic substrates. The IVE method can be used as an initial high-throughput screen for probiotic selection and isolation prior to further characterization and in vivo tests.IMPORTANCE This study describes an in vitro enrichment method to formulate synergistic synbiotics that have potential for establishing autochthonous strains across multiple individuals. The rationale for this approach-that the chance of survival of a bacterial strain is improved by providing it with its required resources-is based on classic ecological theory. From these experiments, a human-derived strain, Bifidobacterium longum subsp. longum CR15, was identified as a xylooligosaccharide (XOS) fermenter in fecal environments and displayed synergistic effects in vitro The high rate of strain establishment observed in this study provides a basis for using synergistic synbiotics to overcome the responder/nonresponder phenomenon that occurs frequently in clinical trials with probiotic and prebiotic interventions. In addition, this approach can be applied in other protocols that require enrichment of specific bacterial populations prior to strain isolation.

Continuous-Phase Control of a Powered Knee-Ankle Prosthesis: Amputee Experiments Across Speeds and Inclines.

Control systems for powered prosthetic legs typically divide the gait cycle into several periods with distinct controllers, resulting in dozens of control parameters that must be tuned across users and activities. To address this challenge, this paper presents a control approach that unifies the gait cycle of a powered knee-ankle prosthesis using a continuous, user-synchronized sense of phase. Virtual constraints characterize the desired periodic joint trajectories as functions of a phase variable across the entire stride. The phase variable is computed from residual thigh motion, giving the amputee control over the timing of the prosthetic joint patterns. This continuous sense of phase enabled three transfemoral amputee subjects to walk at speeds from 0.67 to 1.21 m/s and slopes from -2.5 to +9.0 deg. Virtual constraints based on task-specific kinematics facilitated normative adjustments in joint work across walking speeds. A fixed set of control gains generalized across these activities and users, which minimized the configuration time of the prosthesis.

Toward Unified Control of a Powered Prosthetic Leg: A Simulation Study.

This brief presents a novel control strategy for a powered knee-ankle prosthesis that unifies the entire gait cycle, eliminating the need to switch between controllers during different periods of gait. A reduced-order Discrete Fourier Transformation (DFT) is used to define virtual constraints that continuously parameterize periodic joint patterns as functions of a mechanical phasing variable. In order to leverage the provable stability properties of Hybrid Zero Dynamics (HZD), hybrid-invariant Bézier polynomials are converted into unified DFT virtual constraints for various walking speeds. Simulations of an amputee biped model show that the unified prosthesis controller approximates the behavior of the original HZD design under ideal scenarios and has advantages over the HZD design when hybrid invariance is violated by mismatches with the human controller. Two implementations of the unified virtual constraints, a feedback linearizing controller and a more practical joint impedance controller, produce similar results in simulation.

Air-Abrasive Disinfection of Implant Surfaces in a Simulated Model of Periimplantitis.

INTRODUCTION: This in vitro study aimed to evaluate the ability of air-powder abrasion to decontaminate dental implants. MATERIALS AND METHODS: Twenty-six implants were inoculated with a Streptococcus sanguinis biofilm media in a novel periimplantitis defect model. Six implants served as controls, and 20 implants were disinfected with either the Cavitron JET Plus or the AIR-FLOW PERIO air-powder abrasion units. Residual bacteria were cultured, and colony forming units (CFUs) were totaled at 24 hours. RESULTS: As expected, negative control implant cultures showed no evidence of viable bacteria. Bacterial growth was observed on all positive control cultures, whereas only 15% of the experimental cultures displayed evidence of viable bacteria. The average CFU per streak for the positive control was 104 compared with a maximum of 10 and 4 CFUs for the Cavitron JET Plus and AIR-FLOW PERIO, respectively. There was a 99.9% reduction in bacteria for both air-powder abrasion instruments. CONCLUSION: Air-powder abrasion is an effective technique for the decontamination of dental implants, and the Cavitron JET Plus and AIR-FLOW PERIO are equally successful at eliminating viable bacteria from implant surfaces.

Junctional adhesion molecule A promotes epithelial tight junction assembly to augment lung barrier function.

Epithelial barrier function is maintained by tight junction proteins that control paracellular fluid flux. Among these proteins is junctional adhesion molecule A (JAM-A), an Ig fold transmembrane protein. To assess JAM-A function in the lung, we depleted JAM-A in primary alveolar epithelial cells using shRNA. In cultured cells, loss of JAM-A caused an approximately 30% decrease in transepithelial resistance, decreased expression of the tight junction scaffold protein zonula occludens 1, and disrupted junctional localization of the structural transmembrane protein claudin-18. Consistent with findings in other organs, loss of JAM-A decreased ß1 integrin expression and impaired filamentous actin formation. Using a model of mild systemic endoxotemia induced by i.p. injection of lipopolysaccharide, we report that JAM-A(-/-) mice showed increased susceptibility to pulmonary edema. On injury, the enhanced susceptibility of JAM-A(-/-) mice to edema correlated with increased, transient disruption of claudin-18, zonula occludens 1, and zonula occludens 2 localization to lung tight junctions in situ along with a delay in up-regulation of claudin-4. In contrast, wild-type mice showed no change in lung tight junction morphologic features in response to mild systemic endotoxemia. These findings support a key role of JAM-A in promoting tight junction homeostasis and lung barrier function by coordinating interactions among claudins, the tight junction scaffold, and the cytoskeleton.

EGFR-targeted Chimeras of Pseudomonas ToxA released into the extracellular milieu by attenuated Salmonella selectively kill tumor cells.

Tumor-targeted Salmonella VNP20009 preferentially replicate within tumor tissue and partially suppress tumor growth in murine tumor models. These Salmonella have the ability to locally induce apoptosis when they are in direct contact with cancer cells but they lack significant bystander killing, which may correlate with their overall lack of antitumor activity in human clinical studies. In order to compensate for this deficiency without enhancing overall toxicity, we engineered the bacteria to express epidermal growth factor receptor (EGFR)-targeted cytotoxic proteins that are released into the extracellular milieu. In this study, we demonstrate the ability of the Salmonella strain VNP20009 to produce three different forms of the Pseudomonas exotoxin A (ToxA) chimeric with a tumor growth factor alpha (TGFα) which results in its producing culture supernatants that are cytotoxic and induce apoptosis in EGFR positive cancer cells as measured by the tetrazolium dye reduction, and Rhodamine 123 and JC-10 mitochondrial depolarization assays. In addition, exchange of the ToxA REDLK endoplasmic reticulum retention signal for KDEL and co-expression of the ColE3 lysis protein resulted in an overall increased cytotoxicity compared to the wild type toxin. This approach has the potential to significantly enhance the antitumor activity of VNP20009 while maintaining its previously established safety profile. Biotechnol. Bioeng. 2016;113: 2698-2711. © 2016 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc.

Detection of Marteilia refringens infecting the European flat oyster Ostrea edulis and the dwarf oyster Ostrea stentina in southern Portugal and Spain.

In the present study, Marteilia sp. was detected by histological examination and in situ hybridisation in Ostrea edulis and Ostrea stentina collected in southern Iberian Peninsula. Marteilia refringens DNA was detected by PCR in O. edulis (collected in southern Portugal) and O. stentina (collected in southern Spain and Portugal). Sequencing analysis revealed the presence of M. refringens type O in O. edulis, and type O and M in O. stentina. This is the first confirmed detection of M. refringens in Portugal and the first report on the occurrence of M. refringens infecting O. stentina in Europe.

Controlling Dielectric Film Defects to Increase the Breakdown Voltage of Conductive Polymer Solid Capacitors.

Aluminum solid polymer capacitors are promising devices for the increased demand for power electronics applications. Nonetheless, the low breakdown voltage of commercially available catalysts (∼100 V) limits their applications. In this study, a hydroxide-film-covered high-purity aluminum was anodized at 700 V in boric acid at 85 °C, and the effect of a second hot water immersion (posthydration treatment) after anodizing on the breakdown voltage was studied as a possible future treatment to enhance the withstand voltages of solid electrolytic capacitors. The dielectric breakdown voltage of the anodized aluminum with a PEDOT:PSS coating was ∼500 V, being ∼200 V less than the anodizing voltage; however, the dielectric breakdown voltage was increased above 700 V by introducing the posthydration treatment due to the formation of a nanovoid layer above the dielectric alumina film. Our research suggests that the highly dispersed nanovoids incorporated with PEDOT:PSS avoid the current concentration at some local regions, effectively increasing the dielectric breakdown voltage. The posthydration treatment increased the leakage current by introducing physical defects in the dielectric film. However, the leakage current was reduced by a voltage sweep below the breakdown voltage after the PEDOT:PSS coating or a second anodizing process before the coating, keeping the breakdown voltage above 600 V. A promising processing route to obtain aluminum solid capacitors with high withstand voltage (600 V) found in our research is, first, dipping in hot water; second, anodizing at 700 V; then a second hot water treatment; and a second anodizing at 400 V, which keeps the capacitance invariable with a breakdown voltage enhanced.

Tryptophanase Expressed by Salmonella Halts Breast Cancer Cell Growth In Vitro and Inhibits Production of Immunosuppressive Kynurenine.

Tryptophan is an essential amino acid required for tumor cell growth and is also the precursor to kynurenine, an immunosuppressive molecule that plays a role in limiting anticancer immunity. Tryptophanase (TNase) is an enzyme expressed by different bacterial species that converts tryptophan into indole, pyruvate and ammonia, but is absent in the Salmonella strain VNP20009 that has been used as a therapeutic delivery vector. We cloned the Escherichia coli TNase operon tnaCAB into the VNP20009 (VNP20009-tnaCAB), and were able to detect linear production of indole over time, using Kovács reagent. In order to conduct further experiments using the whole bacteria, we added the antibiotic gentamicin to stop bacterial replication. Using a fixed number of bacteria, we found that there was no significant effect of gentamicin on stationary phase VNP20009-tnaCAB upon their ability to convert tryptophan to indole over time. We developed a procedure to extract indole from media while retaining tryptophan, and were able to measure tryptophan spectrophotometrically after exposure to gentamicin-inactivated whole bacterial cells. Using the tryptophan concentration equivalent to that present in DMEM cell culture media, a fixed number of bacteria were able to deplete 93.9% of the tryptophan in the culture media in 4 h. In VNP20009-tnaCAB depleted tissue culture media, MDA-MB-468 triple negative breast cancer cells were unable to divide, while those treated with media exposed only to VNP20009 continued cell division. Re-addition of tryptophan to conditioned culture media restored tumor cell growth. Treatment of tumor cells with molar equivalents of the TNase products indole, pyruvate and ammonia only caused a slight increase in tumor cell growth. Using an ELISA assay, we confirmed that TNase depletion of tryptophan also limits the production of immunosuppressive kynurenine in IFNγ-stimulated MDA-MB-468 cancer cells. Our results demonstrate that Salmonella VNP20009 expressing TNase has improved potential to stop tumor cell growth and reverse immunosuppression.

Identifying a Upper-Limb Phase-Dependent Variable under Perturbations for Powered Prosthesis Arm Control.

This paper investigates upper-limb kinematic reaching responses during a mechanical perturbation to understand interjoint arm coordination used towards powered prosthesis control development. Common prosthesis arm controllers use electromyography sensors with data-driven models to decode muscle activation signals in controlling prosthesis joint movements. However, these control approaches produce non-natural, discrete movements with no guarantee the controller can react to unexpected disturbances during continuous task motion. Determining a continuous phase-dependent variable for measuring a human's progression during reaching can derive a time-invariant kinematic function to control the prosthesis joint in a natural, continuous manner. A perturbation experimental study was conducted across three participants in evaluating the shoulder and elbow joint kinematics to examine the existence of a phase shift during reaching. Experimental results demonstrated the effects of arm proximal-distal interjoint coordination that validated the proposed mechanical phase variable of the shoulder used in parameterizing elbow joint kinematic for reaching. This could allow for a continuous phase-based control strategy that can handle disturbances to achieve arm reaching in prosthesis control.

The Future of Synbiotics: Rational Formulation and Design.

Synbiotics, mixtures of live microbes and substrates selectively utilized by host organisms, are of considerable interest due to their ability to improve gastrointestinal health. However, formulating synbiotics remains challenging, due in part, to the absence of rational strategies to assess these products for synbiotic activities prior to clinical trials. Currently, synbiotics are formulated as either complementary or synergistic. Complementary synbiotics are made by combining probiotics and prebiotics, with each component acting independently and with the combination shown to provide a clinical health benefit. Most commercial synbiotics as well as those used in clinical trials have been of the complementary type. In contrast, synergistic synbiotics require that the added microbe is specifically stimulated or it's persistence or activity are enhanced by the cognate substrate. Although several innovative examples have been described in the past few years based on this principle, in practice, relatively few synbiotic studies have tested for synergism. In this review, selected recent examples of complementary and synergistic synbiotics and the rationale for their formulation will be described. In addition, pre-clinical experimental approaches for identifying combinations that provide a basis for satisfying the requirements for synergism will be discussed.

SARS-CoV-2 cycle threshold (Ct) values predict future COVID-19 cases.

AIM: Anticipating local surges in COVID-19 cases has predominantly been based on observation of increasing cases. We sought to determine if temporal trends in SARS-CoV-2 Cycle threshold (Ct) values from clinical testing were predictive of future cases. METHODS: Data were collected from a large, safety-net hospital in Los Angeles, California. Ct values for all SARS-CoV-2 detections by the GeneXpert system (Cepheid) between October 2020 to March 2021 were analyzed. RESULTS: A total of 2,114 SARS-CoV-2-positive samples were included. Cases increased dramatically in December 2020, peaking the first week of January, before returning to pre-surge numbers by mid-February. Ct values fell during this same period, with values in December and January (25.6 ± 7.8 and 27±7.9, respectively) significantly lower than those of the other months (30±9.3 to 37.7 ± 6.3). Average weekly Ct values for all patients negatively correlated with the number of tests run two weeks in the future (r= -0.74, p<0.0001), whereas Ct values for asymptomatic patients negatively correlated most strongly with total number of tests performed one month later (r= -0.88, p<0.0001). Predictive modeling using these Ct values correctly predicted whether cases would increase or decrease 65% of the time for a subsequent surge (May-July 2021). CONCLUSIONS: During the largest COVID-19 surge in Los Angeles to date, we observed significantly lower Ct values (representing higher levels of viral RNA) suggesting that increased transmission of COVID-19 was temporarily associated with higher viral loads. Decreasing Ct values appear to be a leading indicator for predicting future COVID-19 cases, which can facilitate improved hospital-level surge planning.

2-Bromo-2-methyl-N-(4-nitro-phen-yl)propanamide.

The title compound, C(10)H(11)BrN(2)O(3), exhibits a small twist between the amide residue and benzene ring [the C-N-C-C torsion angle = 12.7 (4)°]. The crystal structure is stabilized by weak N-H⋯O, C-H⋯Br and C-H⋯O inter-actions. These lead to supra-molecular layers in the bc plane.

2-Bromo-N-(2-hy-droxy-5-methyl-phen-yl)-2-methyl-propanamide.

In the title mol-ecule, C(11)H(14)BrNO(2), there is twist between the mean plane of the amide group and the benzene ring [the C-N-C-C torsion angle is -172.1 (2)°]. The amide H atom forms an intra-molecular hydrogen bond with the Br atom. In the crystal, inter-molecular O-H⋯O and weak C-H⋯O hydrogen bonds link mol-ecules into a chain along [100].

2-Bromo-2-methyl-N-p-tolyl-propanamide.

In the title mol-ecule, C(11)H(14)BrNO, there is twist between the mean plane of the amide group and the benzene ring [C(=O)-N-C C torsion angle = -31.2 (5)°]. In the crystal, inter-molecular N-H⋯O and weak C-H⋯O hydrogen bonds link mol-ecules into chains along [100]. The methyl group H atoms are disordered over two sets of sites with equal occupancy.

2-Bromo-N-(4-chloro-phen-yl)-2-methyl-propanamide.

In the title mol-ecule, C(10)H(11)BrClNO, there is a twist between the mean plane of the amide group and the benzene ring [C(=O)-N-C-C torsion angle = -27.1 (3)°]. In the crystal, inter-molecular N-H⋯O and weak C-H⋯O hydrogen bonds link the mol-ecules into chains along [010].

Advanced glycation endproducts and rat dental implant osseointegration.

Advanced glycation endproducts (AGEs) are a diverse group of molecular adducts formed in environments high in reducing sugars that accumulate with aging and in diabetes. This study tests the hypothesis that AGEs inhibit the stabile osseointegration of dental implants through tissue interactions that interfere with bone turnover and compromise the biomechanical properties at the bone-implant interface. Maxillary first molars were extracted from 32 rats and allowed to heal for 4 weeks. Titanium implants (1 mm x 3 mm) were placed in the healed sockets of 2 groups of 16 rats consisting of 8 rats injected 3 times/wk for 1 month with AGE (prepared from glucose and lysine) and 8 rats injected with vehicle as a control. AGE injections continued for an additional 14 or 28 days before sacrifice. X-ray images, blood, and tissues were collected to examine bone/implant contact ratio, serum pyridinoline ([PYD] a collagen breakdown marker), osteocalcin ([OSC] a bone formation marker), and for immunohistochemistry with antibodies to AGE and the bone turnover-marker protein matrix metalloproteinase1. Compared with the AGE-treated groups, the controls showed significantly higher bone/implant contact at both 14- and 28-day time points. PYD (P < .05) and OSC (trend) levels from controls showed decreases at 28 days when compared with AGE-treated groups. Immunohistochemistry with AGE-specific and bone turnover marker antibodies showed stronger staining associated with the implant/tissue interface in AGE-treated rats. Our studies indicate an association between AGE and inhibition of bone turnover, suggesting that the formation of AGE in high glycemic conditions, such as diabetes, may contribute to a slower rate of osseointegration that negatively affects implant stability.

A Phase Variable Approach for Improved Rhythmic and Non-Rhythmic Control of a Powered Knee-Ankle Prosthesis.

Although there has been recent progress in control of multi-joint prosthetic legs for rhythmic tasks such as walking, control of these systems for non-rhythmic motions and general real-world maneuvers is still an open problem. In this article, we develop a new controller that is capable of both rhythmic (constant-speed) walking, transitions between speeds and/or tasks, and some common volitional leg motions. We introduce a new piecewise holonomic phase variable, which, through a finite state machine, forms the basis of our controller. The phase variable is constructed by measuring the thigh angle, and the transitions in the finite state machine are formulated through sensing foot contact along with attributes of a nominal reference gait trajectory. The controller was implemented on a powered knee-ankle prosthesis and tested with a transfemoral amputee subject, who successfully performed a wide range of rhythmic and non-rhythmic tasks, including slow and fast walking, quick start and stop, backward walking, walking over obstacles, and kicking a soccer ball. Use of the powered leg resulted in clinically significant reductions in amputee compensations for rhythmic tasks (including vaulting and hip circumduction) when compared to use of the take-home passive leg. In addition, considerable improvements were also observed in the performance for non-rhythmic tasks. The proposed approach is expected to provide a better understanding of rhythmic and non-rhythmic motions in a unified framework, which in turn can lead to more reliable control of multi-joint prostheses for a wider range of real-world tasks.