An acidic microenvironment in Tuberculosis increases extracellular matrix degradation by regulating macrophage inflammatory responses.

Mycobacterium tuberculosis (M.tb) infection causes marked tissue inflammation leading to lung destruction and morbidity. The inflammatory extracellular microenvironment is acidic, however the effect of this acidosis on the immune response to M.tb is unknown. Using RNA-seq we show that acidosis produces system level transcriptional change in M.tb infected human macrophages regulating almost 4000 genes. Acidosis specifically upregulated extracellular matrix (ECM) degradation pathways with increased expression of Matrix metalloproteinases (MMPs) which mediate lung destruction in Tuberculosis. Macrophage MMP-1 and -3 secretion was increased by acidosis in a cellular model. Acidosis markedly suppresses several cytokines central to control of M.tb infection including TNF-α and IFN-γ. Murine studies demonstrated expression of known acidosis signaling G-protein coupled receptors OGR-1 and TDAG-8 in Tuberculosis which are shown to mediate the immune effects of decreased pH. Receptors were then demonstrated to be expressed in patients with TB lymphadenitis. Collectively, our findings show that an acidic microenvironment modulates immune function to reduce protective inflammatory responses and increase extracellular matrix degradation in Tuberculosis. Acidosis receptors are therefore potential targets for host directed therapy in patients.

Review of the current TB human infection studies for use in accelerating TB vaccine development: A meeting report.

Tools to evaluate and accelerate tuberculosis (TB) vaccine development are needed to advance global TB control strategies. Validated human infection studies for TB have the potential to facilitate breakthroughs in understanding disease pathogenesis, identify correlates of protection, develop diagnostic tools, and accelerate and de-risk vaccine and drug development. However, key challenges remain for realizing the clinical utility of these models, which require further discussion and alignment amongst key stakeholders. In March 2023, the Wellcome Trust and the International AIDS Vaccine Initiative (IAVI) convened international experts involved in developing both TB and Bacillus Calmette-Guerin (BCG) human infection studies (including mucosal and intradermal challenge routes) to discuss the status of each of the models and the key enablers to move the field forward. This report provides a summary of the presentations and discussion from the meeting. Discussions identified key issues, including demonstrating model validity, to provide confidence for vaccine developers, which may be addressed through demonstration of known vaccine effects, e.g. BCG vaccination in specific populations, and by comparing results from field efficacy and human infection studies. The workshop underscored the importance of establishing safe and acceptable studies in high-burden settings, and the need to validate more than one model to allow for different scientific questions to be addressed as well as to provide confidence to vaccine developers and regulators around use of human infection study data in vaccine development and licensure pathways.

Mammalian lectin arrays for screening host-microbe interactions.

Many members of the C-type lectin family of glycan-binding receptors have been ascribed roles in the recognition of microorganisms and serve as key receptors in the innate immune response to pathogens. Other mammalian receptors have become targets through which pathogens enter target cells. These receptor roles have often been documented with binding studies involving individual pairs of receptors and microorganisms. To provide a systematic overview of interactions between microbes and the large complement of C-type lectins, here we developed a lectin array and suitable protocols for labeling of microbes that could be used to probe this array. The array contains C-type lectins from cow, chosen as a model organism of agricultural interest for which the relevant pathogen-receptor interactions have not been previously investigated in detail. Screening with yeast cells and various strains of both Gram-positive and -negative bacteria revealed distinct binding patterns, which in some cases could be explained by binding to lipopolysaccharides or capsular polysaccharides, but in other cases they suggested the presence of novel glycan targets on many of the microorganisms. These results are consistent with interactions previously ascribed to the receptors, but they also highlight binding to additional sugar targets that have not previously been recognized. Our findings indicate that mammalian lectin arrays represent unique discovery tools for identifying both novel ligands and new receptor functions.

Invasive mechanical ventilation using a bilevel PAP ST device in a healthy swine model.

PURPOSE: The Coronavirus Disease 2019 (COVID-19) pandemic may cause an acute shortage of ventilators. Standard noninvasive bilevel positive airway pressure devices with spontaneous and timed respirations (bilevel PAP ST) could provide invasive ventilation but evidence on their effectiveness in this capacity is limited. We sought to evaluate the ability of bilevel PAP ST to effect gas exchange via invasive ventilation in a healthy swine model. METHODS: Two single limb respiratory circuits with passive filtered exhalation were constructed and evaluated. Next, two bilevel PAP ST devices, designed for sleep laboratory and home use, were tested on an intubated healthy swine model using these circuits. These devices were compared to an anesthesia ventilator. RESULTS: We evaluated respiratory mechanics, minute ventilation, oxygenation, and presence of rebreathing for all of these devices. Both bilevel PAP ST devices were able to control the measured parameters. There were noted differences in performance between the two devices. Despite these differences, both devices provided effective invasive ventilation by controlling minute ventilation and providing adequate oxygenation in the animal model. CONCLUSIONS: Commercially available bilevel PAP ST can provide invasive ventilation with a single limb respiratory circuit and in-line filters to control oxygenation and ventilation without significant rebreathing in a swine model. Further study is needed to evaluate safety and efficacy in clinical disease models. In the setting of a ventilator shortage during the COVID-19 pandemic, and in other resource-constrained situations, these devices may be considered as an effective alternative means for invasive ventilation.

A randomized, placebo-controlled trial using a novel PAP delivery platform to treat patients with OSA and comorbid PTSD.

PURPOSE: Positive airway pressure (PAP) adherence is poor in comorbid OSA/PTSD. SensAwake™ (SA) is a wake-sensing PAP algorithm that lowers pressure when wake is detected. We compared auto-PAP (aPAP) with and without SA for comorbid OSA/PTSD. METHODS: Prospective, randomized crossover study comparing aPAP to aPAP + SA. We enrolled patients with OSA/PTSD who were PAP naïve. Four weeks after randomization, the patients were crossed over to the alternate treatment group, with final follow-up at eight weeks. Sleep questionnaires (ESS, ISI, FSS, and FOSQ-10) were assessed at baseline and follow-up. RESULTS: We enrolled 85 patients with OSA/PTSD. aPAP reduced AHI to < 5/h in both groups. Our primary endpoint, average hours of aPAP adherence (total) after 4 weeks, was significantly increased in the SA group in our intention-to-treat (ITT) analysis (ß = 1.13 (95% CI 0.16-2.1); p = 0.02), after adjustment for ESS differences at baseline. After adjustment for ESS, SA (ITT analysis) also showed significant improvement in percentage of nights used for ≥ 4 h (ß = 14.9 (95% CI 1.02-28.9); p = 0.04). There were trends toward an increase in percentage nights used total (ß = 17.4 (95% CI - 0.1 to 34.9); p = 0.05), average hours of aPAP adherence (nights used) (ß = 1.04 (95% CI - 0.07 to 2.1); p = 0.07), and regular use (OR = 7.5 (95% CI 0.9-64.7); p = 0.07) after adjustment for ESS at baseline. After adjustment for ESS and days to cross over, SA by actual assignment did not show any effect on adherence variables. The ESS, ISI, FSS, and FOSQ-10 all showed significant improvements with PAP, but there were no differences in the magnitude of improvement in any score between groups. CONCLUSIONS: Adherence to aPAP may be improved with the addition of SA and deserves further study. SA is as effective as standard aPAP for normalizing the AHI and improving sleep-related symptoms. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT02549508 https://clinicaltrials.gov/ct2/show/NCT02549508?term=NCT02549508&rank=1 "Comparison Study Using APAP With and Without SensAwake in Patients With OSA and PTSD".

Cranial and ventricular size following shunting or endoscopic third ventriculostomy (ETV) in infants with aqueductal stenosis: further insights from the International Infant Hydrocephalus Study (IIHS).

PURPOSE: The craniometrics of head circumference (HC) and ventricular size are part of the clinical assessment of infants with hydrocephalus and are often utilized in conjunction with other clinical and radiological parameters to determine the success of treatment. We aimed to assess the effect of endoscopic third ventriculostomy (ETV) and shunting on craniometric measurements during the follow-up of a cohort of infants with symptomatic triventricular hydrocephalus secondary to aqueductal stenosis. METHODS: We performed a post hoc analysis of data from the International Infant Hydrocephalus Study (IIHS)-a prospective, multicenter study of infants (< 24 months old) with hydrocephalus from aqueductal stenosis who were treated with either an ETV or shunt. During various stages of a 5-year follow-up period, the following craniometrics were measured: HC, HC centile, HC z-score, and frontal-occipital horn ratio (FOR). Data were compared in an analysis of covariance, adjusting for baseline variables including age at surgery and sex. RESULTS: Of 158 enrolled patients, 115 underwent an ETV, while 43 received a shunt. Both procedures led to improvements in the mean HC centile position and z-score, a trend which continued until the 5-year assessment point. A similar trend was noted for FOR which was measured at 12 months and 3 years following initial treatment. Although the values were consistently higher for ETV compared with shunt, the differences in HC value, centile, and z-score were not significant. ETV was associated with a significantly higher FOR compared with shunting at 12 months (0.52 vs 0.44; p = 0.002) and 3 years (0.46 vs 0.38; p = 0.03) of follow-up. CONCLUSION: ETV and shunting led to improvements in HC centile, z-score, and FOR measurements during long-term follow-up of infants with hydrocephalus secondary to aqueductal stenosis. Head size did not significantly differ between the treatment groups during follow-up, however ventricle size was greater in those undergoing ETV when measured at 1 and 3 years following treatment.

Platelets Regulate Pulmonary Inflammation and Tissue Destruction in Tuberculosis.

RATIONALE: Platelets may interact with the immune system in tuberculosis (TB) to regulate human inflammatory responses that lead to morbidity and spread of infection. OBJECTIVES: To identify a functional role of platelets in the innate inflammatory and matrix-degrading response in TB. METHODS: Markers of platelet activation were examined in plasma from 50 patients with TB before treatment and 50 control subjects. Twenty-five patients were followed longitudinally. Platelet-monocyte interactions were studied in a coculture model infected with live, virulent Mycobacterium tuberculosis (M.tb) and dissected using qRT-PCR, Luminex multiplex arrays, matrix degradation assays, and colony counts. Immunohistochemistry detected CD41 (cluster of differentiation 41) expression in a pulmonary TB murine model, and secreted platelet factors were measured in BAL fluid from 15 patients with TB and matched control subjects. MEASUREMENTS AND MAIN RESULTS: Five of six platelet-associated mediators were upregulated in plasma of patients with TB compared with control subjects, with concentrations returning to baseline by Day 60 of treatment. Gene expression of the monocyte collagenase MMP-1 (matrix metalloproteinase-1) was upregulated by platelets in M.tb infection. Platelets also enhanced M.tb-induced MMP-1 and -10 secretion, which drove type I collagen degradation. Platelets increased monocyte IL-1 and IL-10 and decreased IL-12 and MDC (monocyte-derived chemokine; also known as CCL-22) secretion, as consistent with an M2 monocyte phenotype. Monocyte killing of intracellular M.tb was decreased. In the lung, platelets were detected in a TB mouse model, and secreted platelet mediators were upregulated in human BAL fluid and correlated with MMP and IL-1ß concentrations. CONCLUSIONS: Platelets drive a proinflammatory, tissue-degrading phenotype in TB.

Characterising resuscitation promoting factor fluorescent-fusions in mycobacteria.

BACKGROUND: Resuscitation promoting factor proteins (Rpfs) are peptidoglycan glycosidases capable of resuscitating dormant mycobacteria, and have been found to play a role in the pathogenesis of tuberculosis. However, the specific roles and localisation of each of the 5 Rpfs in Mycobacterium tuberculosis remain mostly unknown. In this work our aim was to construct fluorescent fusions of M. tuberculosis Rpf proteins as tools to investigate their function. RESULTS: We found that Rpf-fusions to the fluorescent protein mCherry are functional and able to promote cell growth under different conditions. However, fusions to Enhanced Green Fluorescent Protein (EGFP) were non-functional in the assays used and none were secreted into the extracellular medium, which suggests Rpfs may be secreted via the Sec pathway. No specific cellular localization was observed for either set of fusions using time-lapse video microscopy. CONCLUSIONS: We present the validation and testing of five M. tuberculosis Rpfs fused to mCherry, which are functional in resuscitation assays, but do not show any specific cellular localisation under the conditions tested. Our results suggest that Rpfs are likely to be secreted via the Sec pathway. We propose that such mCherry fusions will be useful tools for the further study of Rpf localisation, individual expression, and function.

Abusive Injuries Are Worse Than Vehicular Injuries: Should We Refocus Prevention?

OBJECTIVES: The objective of this study was to compare the injury severity and outcome of motor vehicle and nonaccidental traumatic injuries and examine trends in mortality rates over time. METHODS: We reviewed data from 2005 to 2013 from a level 1 pediatric trauma center including demographics, injury severity, and outcomes. Primary outcomes of interest were mortality rates and hospital length of stay. RESULTS: Injury severity scores were significantly worse for nonaccidental traumas (NATs) (P < 0.001) compared with motor vehicle collisions and motor pedestrian collisions. Nonaccidental traumas were also found to have significantly longer length of stay and higher fatality rates (P < 0.001). Significant differences were also found for the types of injuries sustained for head, extremity, trunk, and other injuries (P < 0.001), and for internal injuries (P < 0.01. Admission rates also dropped for both motor vehicle collisions and motor pedestrian collisions across the 9-year period (P < 0.001) but remained stable for NATs. CONCLUSION: In this study population, more severe injuries, higher mortality rates, and longer hospital stays were observed in pediatric NAT compared with those sustained through vehicular means. Furthermore, we observed statistically significant declines in motor vehicle-related injuries compared with NAT.

Psychological masochism: A systematic review of the literature on conflicts, defenses, and motives.

OBJECTIVE: Our aim was to conduct a systematic review of the literature on psychological masochism to identify hypotheses for examination in clinical studies. METHOD: We identified defenses, conflicts, and motives using standardized measures in 23 psychoanalytic papers. RESULTS: Three primary and three secondary subtypes of masochism emerged in the literature. Overall Gratification Inhibition (subtype I.1) was the "healthiest" form, associated with higher developmental level motives and neurotic defenses. The Global Conflict (I.2) was the least healthy form of masochism, consistent with personality disorder. It was associated with early developmental level motives and immature defenses, including depressive defenses, often associated with depression. Dominant Other (I.3) represented masochistic attachment problems, associated with early developmental level motives, object-related, image-distorting defenses, and narcissism. Of the secondary types, Separation-Abandonment (II.1) reflected object-related defenses, and separation-related motives. Rejection of Others (II.2) represented a sadistic-narcissistic form, associated with image-distorting and disavowal defenses, with both early and later developmental level motives. Finally, Sexual Pleasure vs. Guilt (II.3) was associated with autistic fantasy, and both early and later developmental level motives, suggesting a distinct traumatic origin and representing the juncture of sexual and psychological masochism. CONCLUSIONS: Analysts described six distinguishable types of masochism. Future studies should examine their validity.

Deciphering the metabolic response of Mycobacterium tuberculosis to nitrogen stress.

A key component to the success of Mycobacterium tuberculosis as a pathogen is the ability to sense and adapt metabolically to the diverse range of conditions encountered in vivo, such as oxygen tension, environmental pH and nutrient availability. Although nitrogen is an essential nutrient for every organism, little is known about the genes and pathways responsible for nitrogen assimilation in M. tuberculosis. In this study we have used transcriptomics and chromatin immunoprecipitation and high-throughput sequencing to address this. In response to nitrogen starvation, a total of 185 genes were significantly differentially expressed (96 up-regulated and 89 down regulated; 5% genome) highlighting several significant areas of metabolic change during nitrogen limitation such as nitrate/nitrite metabolism, aspartate metabolism and changes in cell wall biosynthesis. We identify GlnR as a regulator involved in the nitrogen response, controlling the expression of at least 33 genes in response to nitrogen limitation. We identify a consensus GlnR binding site and relate its location to known transcriptional start sites. We also show that the GlnR response regulator plays a very different role in M. tuberculosis to that in non-pathogenic mycobacteria, controlling genes involved in nitric oxide detoxification and intracellular survival instead of genes involved in nitrogen scavenging.

Unnatural amino acid analogues of membrane-active helical peptides with anti-mycobacterial activity and improved stability.

OBJECTIVES: The emergence of MDR-TB, coupled with shrinking antibiotic pipelines, has increased demands for new antimicrobials with novel mechanisms of action. Antimicrobial peptides have increasingly been explored as promising alternatives to antibiotics, but their inherent poor in vivo stability remains an impediment to their clinical utility. We therefore systematically evaluated unnatural amino acid-modified peptides to design analogues with enhanced anti-mycobacterial activities. METHODS: Anti-mycobacterial activities were evaluated in vitro and intracellularly against drug-susceptible and MDR isolates of Mycobacterium tuberculosis using MIC, killing efficacy and intracellular growth inhibition studies. Toxicity profiles were assessed against mammalian cells to verify cell selectivity. Anti-mycobacterial mechanisms were investigated using microfluidic live-cell imaging with time-lapse fluorescence microscopy and confocal laser-scanning microscopy. RESULTS: Unnatural amino acid incorporation was well tolerated without an appreciable effect on toxicity profiles and secondary conformations of the synthetic peptides. The modified peptides also withstood proteolytic digestion by trypsin. The all d-amino acid peptide, i(llkk)2i (II-D), displayed superior activity against all six mycobacterial strains tested, with a 4-fold increase in selectivity index as compared with the unmodified l-amino acid peptide in broth. II-D effectively reduced the intracellular bacterial burden of both drug-susceptible and MDR clinical isolates of M. tuberculosis after 4 days of treatment. Live-cell imaging studies demonstrated that II-D permeabilizes the mycobacterial membrane, while confocal microscopy revealed that II-D not only permeates the cell membrane, but also accumulates within the cytoplasm. CONCLUSIONS: Unnatural amino acid modifications not only decreased the susceptibility of peptides to proteases, but also enhanced mycobacterial selectivity.

Small phase pattern 2D beam steering and a single LCOS design of 40 1 × 12 stacked wavelength selective switches.

Two-dimensional beam steering by small, square, phase patterns as small as 50 × 50 pixels on a phase-only liquid crystal on silicon (LCOS) device is experimentally verified as suitable for the application of wavelength selective switches (WSSs), in terms of the diffraction efficiency and steering accuracy. This enables a proposed highly functional and versatile stacked switch architecture, where 40 independent 1 × 12 WSSs can be realised on a single 4k LCOS device. They can be configured to support a 1 × N WSSs with N≤144, or an N × N wavelength crossconnect with N≤12.

Association of allergy/immunology and obstructive sleep apnea.

Obstructive sleep apnea (OSA) is characterized by repetitive upper airway collapse that results in nonrefreshing sleep, excessive daytime sleepiness, and, ultimately, adverse consequences on quality of life, the cardiovascular system, and neurocognitive performance. OSA has traditionally been linked to body habitus (obesity and increased neck circumference), racial demographics, alcohol, tobacco, and sedative use. Numerous other conditions are linked to OSA, which may have clinical relevance. Specifically, asthma and nasal obstructive syndromes, e.g., rhinitis, have been shown to be risk factors. This review used the anatomic homogeneity of the upper and lower airways as an explanation for the inflammatory conditions that underlie and interrelate rhinitis, asthma, and OSA. There is strong evidence that both immunoglobulin Emediated and irritant-induced inflammation in either airway location play a significant role in all three (OSA, rhinitis, and asthma). We highlighted pathophysiologic, chemical, and cellular factors that explain the distinct relationship among OSA, asthma, and rhinitis, with emphasis for increased provider vigilance of the other syndromes when a patient is diagnosed with either entity.

The Extracellular Matrix Regulates Granuloma Necrosis in Tuberculosis.

A central tenet of tuberculosis pathogenesis is that caseous necrosis leads to extracellular matrix destruction and bacterial transmission. We reconsider the underlying mechanism of tuberculosis pathology and demonstrate that collagen destruction may be a critical initial event, causing caseous necrosis as opposed to resulting from it. In human tuberculosis granulomas, regions of extracellular matrix destruction map to areas of caseous necrosis. In mice, transgenic expression of human matrix metalloproteinase 1 causes caseous necrosis, the pathological hallmark of human tuberculosis. Collagen destruction is the principal pathological difference between humanised mice and wild-type mice with tuberculosis, whereas the release of proinflammatory cytokines does not differ, demonstrating that collagen breakdown may lead to cell death and caseation. To investigate this hypothesis, we developed a 3-dimensional cell culture model of tuberculosis granuloma formation, using bioelectrospray technology. Collagen improved survival of Mycobacterium tuberculosis-infected cells analyzed on the basis of a lactate dehydrogenase release assay, propidium iodide staining, and measurement of the total number of viable cells. Taken together, these findings suggest that collagen destruction is an initial event in tuberculosis immunopathology, leading to caseous necrosis and compromising the immune response, revealing a previously unappreciated role for the extracellular matrix in regulating the host-pathogen interaction.

Dorsal striatum mediates cognitive control, not cognitive effort per se, in decision-making: An event-related fMRI study.

OBJECTIVE: Whether the dorsal striatum (DS) mediates cognitive control or cognitive effort per se in decision-making is unclear given that these effects are highly correlated. As the cognitive control requirements of a neuropsychological task intensify, cognitive effort increases proportionately. We implemented a task that disentangled cognitive control and cognitive effort to specify the particular function DS mediates in decision-making. METHODS: Sixteen healthy young adults completed a number Stroop task with simultaneous blood-oxygenation-level-dependent response (BOLD) measurement using functional magnetic resonance imaging. Participants selected the physically larger number of a pair of single-digit integers. Discriminating smaller versus larger physical size differences between a number pair requires greater cognitive effort, but does not require greater cognitive control. We also investigated the effect of conflict between the physical and numerical dimensions of targets (e.g., 2 6). Selections in this incongruent case are more cognitively effortful and require greater cognitive control to suppress responding to the irrelevant dimension. Enhancing cognitive effort or cognitive control demands increases errors and response times. Despite similar behavioural profiles, our aim was to determine whether DS mediates cognitive control or simply indexes cognitive effort, using the same data set. RESULTS: As expected, behavioural interference effects occurred for both enhanced cognitive control and/or cognitive effort conditions. Despite similar degrees of behavioural interference, DS BOLD signal only correlated with interference arising due to increased cognitive control demands in the incongruent case. DS was not preferentially activated for discriminations of smaller relative to larger physical size differences between number pairs, even when using liberal statistical criteria. However, our incongruent and physical size effects conjointly activated regions related to effortful processing (e.g., anterior cingulate cortex). INTERPRETATION: We interpret these findings as support for the increasingly accepted notion that DS mediates cognitive control specifically and does not simply index cognitive effort per se.

Investigation of the high rates of extrapulmonary tuberculosis in Ethiopia reveals no single driving factor and minimal evidence for zoonotic transmission of Mycobacterium bovis infection.

BACKGROUND: Ethiopia, a high tuberculosis (TB) burden country, reports one of the highest incidence rates of extra-pulmonary TB dominated by cervical lymphadenitis (TBLN). Infection with Mycobacterium bovis has previously been excluded as the main reason for the high rate of extrapulmonary TB in Ethiopia. METHODS: Here we examined demographic and clinical characteristics of 953 pulmonary (PTB) and 1198 TBLN patients visiting 11 health facilities in distinct geographic areas of Ethiopia. Clinical characteristics were also correlated with genotypes of the causative agent, Mycobacterium tuberculosis. RESULTS: No major patient or bacterial strain factor could be identified as being responsible for the high rate of TBLN, and there was no association with HIV infection. However, analysis of the demographic data of involved patients showed that having regular and direct contact with live animals was more associated with TBLN than with PTB, although no M. bovis was isolated from patients with TBLN. Among PTB patients, those infected with Lineage 4 reported "contact with other TB patient" more often than patients infected with Lineage 3 did (OR = 1.6, CI 95% 1.0-2.7; p = 0.064). High fever, in contrast to low and moderate fever, was significantly associated with Lineage 4 (OR = 2.3; p = 0.024). On the other hand, TBLN cases infected with Lineage 4 tended to get milder symptoms overall for the constitutional symptoms than those infected with Lineage 3. CONCLUSIONS: The study suggests a complex role for multiple interacting factors in the epidemiology of extrapulmonary TB in Ethiopia, including factors that can only be derived from population-based studies, which may prove to be significant for TB control in Ethiopia.

Design of a low-cost and compact 1 × 5 wavelength-selective switch for access networks.

This paper describes the design, modeling, construction, and testing of a low-cost and compact (80 mm×50 mm) 1×5 wavelength-selective switch. The core beam-deflecting element of the switch is a nematic liquid crystal on silicon spatial light modulator. The switch is designed for coarse wavelength-division multiplexing wavelengths in order to bring the benefit of a low-cost, compact, and robust switching design toward the customer end in the access network. During the system development stage, a single optomechanical assembly was designed and prototyped using the three-dimensional printing technology. The experimental results show an insertion loss of -13.8±1.4 dB and a worst-case scenario crosstalk level of -24.8 dB. Approaches for enhancing the performance of the switch are analyzed and discussed.

Pixel-level fringing-effect model to describe the phase profile and diffraction efficiency of a liquid crystal on silicon device.

We propose a fringing-effect model based on the experimentally measured phase response across the phase transition region of a liquid crystal on silicon (LCOS) device. The measured phase profile in the phase transition region is characterized by a scaled error function of the flyback width. The flyback width can be determined by a cubic function of the phase depth between neighboring pixels. This dependence of the flyback width on the phase depth is explained by a linear rotation model of the liquid crystal director. The simulated diffraction efficiency based on the fringing-effect model shows a close agreement with the experimental measurement.

Cell electrospinning: an in vitro and in vivo study.

Cell electrospinning and aerodynamically assisted bio-threading are novel bioplatforms for directly forming large quantities of cell-laden scaffolds for creating living sheets and vessels in three-dimensions. The functional biological architectures generated will be useful in both the laboratory and the clinic.