Search

Different neurodegenerative conditions can have complex, overlapping clinical presentations that make accurate diagnosis during life very challenging. For this reason, confirmation of the clinical diagnosis still requires postmortem verification. This is particularly relevant for clinical trials of novel therapeutics where it is important to ascertain what disease- and/or pathology-modifying effects the therapeutics have had. Furthermore, it is important to confirm that patients in the trial had the correct clinical diagnosis as this will have a major bearing on the interpretation of trial results. Here we present a simple protocol for pathological assessment of neurodegenerative changes., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Mixed reality has been used in trauma and emergency medicine simulation for more than a decade. As mixed reality potential in trauma simulation continues to expand, so too does the need to validate it as a surrogate for real-life emergency scenarios. Validation of these simulations can occur by measuring fidelity, or the degree to which a computing system can reproduce real-world experiences. After performing a literature review, we determined that most fidelity assessments of trauma and emergency simulations focus on how the user subjectively experiences the simulation. Although subjective user assessment is an important component of determining fidelity, we pose an introductory three-part framework that may assess mixed reality trauma simulation more adequately., Materials and Methods: A literature review was conducted using Google Scholar, PubMed, and the Uniformed Services University PowerER search database. Relevant articles were assessed to identify how studies measured fidelity in trauma simulation. We then designed the three-part framework to aid researchers in assessing the fidelity of mixed reality trauma simulations., Results: The domains we determined to best assess mixed reality emergency simulation are as follows:1. Continue assessing fidelity via subjective user assessments. This allows the researcher to know how real the simulation looked and felt to the user based on their individual report.2. Determine whether the trauma simulation changes the medical decision-making capacity of the user. If the user's decision-making capacity changes with a stress-inducing trauma simulation versus a non-stress-inducing simulation, then the stress-inducing trauma environment would be approaching greater fidelity.3. Study the domain of our newly proposed concept: physiologic fidelity. We define physiologic fidelity as the degree to which the simulation elicits a measurable, autonomic response independent of observed emotion or perceived affect. Recreating objective autonomic arousal may be the best way to ensure a trauma simulation reaches fidelity., Conclusion: We propose a methodology to assess mixed reality trauma simulation fidelity. Once fidelity is more fully known to the researcher and the simulation user, adjustments can be made to approach reality more closely. Improved simulators may enrich the preparedness of both junior and senior learners for real-life emergencies. We believe assessing the three domains using the Wide Area Virtual Experience at the Val G. Hemming simulation center in Bethesda, MD, will validate mixed reality-trauma simulators as invaluable surrogates for real-life emergency scenarios and ultimately contribute to improved clinical outcomes for clinicians and their patients., (© The Association of Military Surgeons of the United States 2022. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Benign prostatic hyperplasia (BPH) is common in the ageing male. Clinical manifestations like retention impact on a patient's quality of life. Alterations in androgen activity at the androgen receptor complex level in the prostate contribute to prostatic hyperplasia with the highest incidence occurring in males in their 70's. There remains a paucity of cases in young males who develop acute urinary retention secondary to BPH. We present a case of a 27-year-old male who developed acute urinary retention secondary to BPH who required a Holmium Laser Enucleation of his Prostate (HOLEP)., Case Description: A 27 year old man was admitted in acute urinary retention. BPH was diagnosed via way of radiological imaging and histological assessment. After pre-operative sperm banking and suprapubic catheterisation, the patient underwent a HOLEP. He had biochemically confirmed hypogonadotrophic hypogonadism which was at odds with his muscular, physical appearance. Total testosterone levels had fluctuated following admission suggesting an exogenous substance was interfering with the hypothalamic-pituitary-gonadal axis but he denied exogenous steroid use., Result: The patient successfully passed his voiding trial on the second post-operative day and remained catheter free. Post-operative uroflowmetry and sexual function remain unknown as patient disengaged with follow up., Conclusion: HOLEP prostatectomy is a safe and effective way of managing BPH in younger patients following sperm banking and assessment by endocrinology.

Because cells vary in thickness and in biomechanical properties, the use of a constant force trigger during atomic force microscopy (AFM) stiffness mapping produces a varied nominal strain that can obfuscate the comparison of local material properties. In this study, we measured the biomechanical spatial heterogeneity of ovarian and breast cancer cells by using an indentation-dependent pointwise Hertzian method. Force curves and surface topography were used together to determine cell stiffness as a function of nominal strain. By recording stiffness at a particular strain, it may be possible to improve comparison of the material properties of cells and produce higher contrast representations of cell mechanical properties. Defining a linear region of elasticity that corresponds to a modest nominal strain, we were able to clearly distinguish the mechanics of the perinuclear region of cells. We observed that, relative to the lamelopodial stiffness, the perinuclear region was softer for metastatic cancer cells than their nonmetastatic counterparts. Moreover, contrast in the strain-dependent elastography in comparison to conventional force mapping with Hertzian model analysis revealed a significant stiffening phenomenon in the thin lamellipodial region in which the modulus scales inversely and exponentially with cell thickness. The observed exponential stiffening is not affected by relaxation of cytoskeletal tension, but finite element modeling indicates it is affected by substrate adhesion. The novel cell mapping technique explores cancer cell mechanical nonlinearity that results from regional heterogeneity, which could help explain how metastatic cancer cells can show soft phenotypes while simultaneously increasing force generation and invasiveness., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Alpha-synuclein (aSyn) is a pre-synaptic monomeric protein that can form aggregates in neurons in Parkinson's disease (PD), Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB), and in oligodendrocytes in multiple system atrophy (MSA). Although aSyn in astrocytes has previously been described in PD, PDD and DLB, the biochemical properties and topographical distribution of astrocytic aSyn have not been studied in detail. Here, we present a systematic investigation of aSyn astrocytic pathology using an expanded antibody toolset covering the entire sequence and key post-translational modifications (PTMs) of aSyn in Lewy body disorders (LBDs) and in MSA. Astrocytic aSyn was detected in the limbic cortical regions of LBDs but were absent in main pathological regions of MSA. The astrocytic aSyn was revealed only with antibodies against the mid N-terminal and non-amyloid component (NAC) regions covering aSyn residues 34-99. The astroglial accumulations were negative to canonical aSyn aggregation markers, including p62, ubiquitin and aSyn pS129, but positive for phosphorylated and nitrated forms of aSyn at Tyrosine 39 (Y39), and not resistant to proteinase K. Our findings suggest that astrocytic aSyn accumulations represent a major part of aSyn pathology in LBDs and possess a distinct sequence and PTM signature that is characterized by both N- and C-terminal truncations and modifications at Y39. This is the first description that aSyn accumulations are made solely from N- and C-terminally cleaved aSyn species and the first report demonstrating that astrocytic aSyn is a mixture of Y39 phosphorylated and nitrated species. These observations underscore the importance of systematic characterization of aSyn accumulations in different cell types to capture the aSyn pathological diversity in the brain. Our findings combined with further studies on the role of astrocytic pathology in the progression of LBDs can pave the way towards identifying novel disease mechanisms and therapeutic targets., (© 2022. The Author(s).)

A compressible numerical model is applied for three-dimensional (3-D) gravity wave (GW) packets undergoing momentum deposition, self-acceleration (SA), breaking, and secondary GW (SGW) generation in the presence of highly-structured environments enabling thermal and/or Doppler ducts, such as a mesospheric inversion layer (MIL), tidal wind (TW), or combination of MIL and TW. Simulations reveal that ducts can strongly modulate GW dynamics. Responses modeled here include reflection, trapping, suppressed transmission, strong local instabilities, reduced SGW generations, higher altitude SGW responses, and induced large-scale flows. Instabilities that arise in ducts experience strong dissipation after they emerge, while trapped smaller-amplitude and smaller-scale GWs can survive in ducts to much later times. Additionally, GW breaking and its associated dynamics enhance the local wind along the GW propagation direction in the ducts, and yield layering in the wind field. However, these dynamics do not yield significant heat transport in the ducts. The failure of GW breaking to induce stratified layers in the temperature field suggests that such heat transport might not be as strong as previously assumed or inferred from observations and theoretical assessments. The present numerical simulations confirm previous finding that MIL generation may not be caused by the breaking of a transient high-frequency GW packet alone., (© 2022. The Authors.)

The correlation between cardiovascular disease and iron deficiency anemia (IDA) is well documented but poorly understood. Using a multi-disciplinary approach, we explore the hypothesis that the biophysical alterations of red blood cells (RBCs) in IDA, such as variable degrees of microcytosis and decreased deformability may directly induce endothelial dysfunction via mechanobiological mechanisms. Using a combination of atomic force microscopy and microfluidics, we observed that subpopulations of IDA RBCs (idRBCs) are significantly stiffer and smaller than both healthy RBCs and the remaining idRBC population. Furthermore, computational simulations demonstrated that the smaller and stiffer idRBC subpopulations marginate toward the vessel wall causing aberrant shear stresses. This leads to increased vascular inflammation as confirmed with perfusion of idRBCs into our "endothelialized" microfluidic systems. Overall, our multifaceted approach demonstrates that the altered biophysical properties of idRBCs directly lead to vasculopathy, suggesting that the IDA and cardiovascular disease association extends beyond correlation and into causation., Competing Interests: The authors declare no competing interests., (© 2022 The Author(s).)

Objective: Up to one-third of patients with Parkinson's disease (PD) experience visual hallucinations (VHs). Lewy bodies are sparse in the visual cortices and seem unlikely to explain the hallucinations. Some neuroimaging studies have found that perfusion is reduced in the occipital lobe in individuals with VHs. Recent work has suggested that decreased cholinergic input may directly lead to the decreased perfusion. The investigators hypothesized that individuals with PD and VHs would have biochemical evidence of reduced microvascular perfusion and reduced cholinergic activity in areas of the brain that process visual images., Methods: Tissue from Brodmann's area (BA) 18 and BA 19 was obtained from a well-characterized cohort matched for age, gender, and postmortem interval in 69 individuals (PD without VHs, N=11; PD without dementia plus VHs N=10, N=10; PD with dementia plus VHs, N=16; and control subjects, N=32). Von Willebrand factor, vascular endothelial growth factor A, and myelin-associated glycoprotein:proteolipid protein-1 (MAG:PLP1) ratio-a measure of tissue oxygenation relative to metabolic demand, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), choline acetyltransferase, and α-synuclein-were quantified by enzyme-linked immunosorbent assay. The primary outcome was the MAG:PLP1 ratio., Results: There was no biochemical evidence of chronic hypoperfusion in PD, although microvessel density was decreased in ventral BA 18 and BA 19. There was no between-group difference in BChE in either dorsal BA 18 or BA 19. AChE concentration was reduced in individuals with PD compared with control subjects in dorsal and ventral BA 18 and dorsal BA 19, and it was increased in ventral BA 19. These changes were most marked in the PD plus VHs group., Conclusions: These results suggest that changes in cholinergic activity rather than chronic hypoperfusion may underlie VHs in PD.

Regeneration of skeletal muscle after volumetric injury is thought to be impaired by a dysregulated immune microenvironment that hinders endogenous repair mechanisms. Such defects result in fatty infiltration, tissue scarring, chronic inflammation, and debilitating functional deficits. Here, we evaluated the key cellular processes driving dysregulation in the injury niche through localized modulation of sphingosine-1-phosphate (S1P) receptor signaling. We employ dimensionality reduction and pseudotime analysis on single cell cytometry data to reveal heterogeneous immune cell subsets infiltrating preclinical muscle defects due to S1P receptor inhibition. We show that global knockout of S1P receptor 3 (S1PR3) is marked by an increase of muscle stem cells within injured tissue, a reduction in classically activated relative to alternatively activated macrophages, and increased bridging of regenerating myofibers across the defect. We found that local S1PR3 antagonism via nanofiber delivery of VPC01091 replicated key features of pseudotime immune cell recruitment dynamics and enhanced regeneration characteristic of global S1PR3 knockout. Our results indicate that local S1P receptor modulation may provide an effective immunotherapy for promoting a proreparative environment leading to improved regeneration following muscle injury., (© 2020 Wiley Periodicals LLC.)

Volumetric muscle loss (VML) injuries after extremity trauma results in an important clinical challenge often associated with impaired healing, significant fibrosis, and long-term pain and functional deficits. While acute muscle injuries typically display a remarkable capacity for regeneration, critically sized VML defects present a dysregulated immune microenvironment which overwhelms innate repair mechanisms leading to chronic inflammation and pro-fibrotic signaling. In this series of studies, we developed an immunomodulatory biomaterial therapy to locally modulate the sphingosine-1-phosphate (S1P) signaling axis and resolve the persistent pro-inflammatory injury niche plaguing a critically sized VML defect. Multiparameter pseudo-temporal 2D projections of single cell cytometry data revealed subtle distinctions in the altered dynamics of specific immune subpopulations infiltrating the defect that were critical to muscle regeneration. We show that S1P receptor modulation via nanofiber delivery of Fingolimod (FTY720) was characterized by increased numbers of pro-regenerative immune subsets and coincided with an enriched pool of muscle stem cells (MuSCs) within the injured tissue. This FTY720-induced priming of the local injury milieu resulted in increased myofiber diameter and alignment across the defect space followed by enhanced revascularization and reinnervation of the injured muscle. These findings indicate that localized modulation of S1P receptor signaling via nanofiber scaffolds, which resemble the native extracellular matrix ablated upon injury, provides great potential as an immunotherapy for bolstering endogenous mechanisms of regeneration following VML injury., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 San Emeterio, Hymel, Turner, Ogle, Pendleton, York, Olingy, Liu, Lim, Sulchek, Warren, Mortensen, Qiu, Jang, Willett and Botchwey.)

High-throughput antibody sequencing allows in-depth insights into human antibody repertoires. To investigate the characteristics of antibody repertoires in patients with chronic HBV infection, we performed Illumina sequencing and IMGT/HighV-QUEST analysis of B lymphocytes from healthy adults and the HBV carriers with high or low level of viral replication. The comparative study revealed high levels of similarity between the IgM and IgG repertoires of the HBV carriers and the healthy adults, including the somatic mutations in V regions, the average CDR3 length, and the occurrence of junctional modifications. Nevertheless, the diversity of the unique clones decreased and some clusters of unique clones expanded in the IgM repertoire of chronic HBV carriers (CHB) compared with healthy adults (HH) and inactive HBV carriers (IHB). Such difference in clone diversity and expansion was not observed in the IgG repertoires of the three populations. More shared antibody clones were found between the IgM repertoires of IHB and HH than that found between CHB and HH (7079 clones vs. 2304 clones). Besides, the biased used IGHD genes were IGHD2-2 and IGHD3-3 in CHB library but were IGHD3-10 and IGHD3-22 in IHB and HH library. In contrast, for IgG repertories, the preferred used VDJ genes were similar in all the three populations. These results indicated that low level of serum HBV might not induce significant changes in BCR repertoires, and high level of HBV replication could have more impacts on IgM repertories than IgG repertoires. Taken together, our findings provide a better understanding of the antibody repertoires of HBV chronically infected individuals., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Hong, Wang, Huang, Hong, Liu, Li, Liu, Su, Wang, Wang and Ying.)

The diagonal band of Broca (DBB) contains the second largest cholinergic cell group in the human brain, known as the nucleus of the vertical limb of the DBB (nvlDBB). It has major projections to the hippocampus, but it is often underinvestigated, partly due to its ill-defined anatomical boundaries and hence the difficulty of reliable sampling. In this chapter, we have reviewed the historical literature to reestablish the anatomy of the nvlDBB, distinguishing it from neighboring basal forebrain cholinergic nuclei. Although varying degrees of neuronal loss in the nvlDBB have been reported in a range of neurological disorders, and in the aged brain, the significant nvlDBB cholinergic neuronal loss reported in Lewy body dementias is of particular interest. Retrograde tracer study in rodents has demonstrated reciprocal connections between the DBB and the hippocampal CA2 subfield, an area particularly susceptible to Lewy pathologies. Previous functional studies have demonstrated that the nvlDBB is particularly involved in memory retrieval, a cognitive domain severely affected in Lewy body disorders. Based on these observations, we propose an anatomical and functional connection between the cholinergic component of the nvlDBB (Ch2) and the hippocampal CA2., (Copyright © 2021 Elsevier B.V. All rights reserved.)

There is a great need for high-throughput protein purification to produce protein molecules for research and therapeutics. Although there have been significant advancements made in automated multi-step chromatography and preparative in-process design-of-experiment (DOE) capabilities in commercial fast performance liquid chromatography (FPLC) instruments, almost all commercial FPLCs rely on a binary buffer mixing system, which hinders automated buffer preparation. Nevertheless, current-generation FPLCs are equipped with a quaternary mixer designed for limited in-line buffer preparation and preparative pH scouting DOE experiments. We decided to leverage the quaternary mixing capability by extending and re-programming AkTA Avant's quaternary valve into an automated in-process buffer preparation system to simplify automated purification requiring complex washing steps. We accomplished this by using two extra inlet valves, a sample valve, and versatile valve to split inputs of the quaternary valve into software-selectable stock solutions of pH buffers, salts, eluents, and additives. We also devised a new flow scheme to perform automated two-step chromatography using only one versatile valve. This was accomplished by using only stock parts and software to facilitate reproduction. To demonstrate the versatility and capability of the system, we purified a transmembrane protein that requires a detergent to stay soluble and needs an in-column, high-salt washing step to achieve high purity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Binary expression systems like the LexA-LexAop system provide a powerful experimental tool kit to study gene and tissue function in developmental biology, neurobiology, and physiology. However, the number of well-defined LexA enhancer trap insertions remains limited. In this study, we present the molecular characterization and initial tissue expression analysis of nearly 100 novel StanEx LexA enhancer traps, derived from the StanEx 1 index line. This includes 76 insertions into novel, distinct gene loci not previously associated with enhancer traps or targeted LexA constructs. Additionally, our studies revealed evidence for selective transposase-dependent replacement of a previously-undetected KP element on chromosome III within the StanEx 1 genetic background during hybrid dysgenesis, suggesting a molecular basis for the over-representation of LexA insertions at the NK7.1 locus in our screen. Production and characterization of novel fly lines were performed by students and teachers in experiment-based genetics classes within a geographically diverse network of public and independent high schools. Thus, unique partnerships between secondary schools and university-based programs have produced and characterized novel genetic and molecular resources in Drosophila for open-source distribution, and provide paradigms for development of science education through experience-based pedagogy., (Copyright © 2019 Kockel et al.)

Although the precise neuropathological substrates of cognitive decline in Parkinson's disease (PD) remain elusive, it has long been regarded that pathology in the CA2 hippocampal subfield is characteristic of Lewy body dementias, including dementia in PD (PDD). Early non-human primate tracer studies demonstrated connections from the nucleus of the vertical limb of the diagonal band of Broca (nvlDBB, Ch2) to the hippocampus. However, the relationship between Lewy pathology of the CA2 subfield and cholinergic fibres has not been explored. Therefore, in this study, we investigated the burden of pathology in the CA2 subsector of PD cases with varying degrees of cognitive impairment and correlated this with the extent of septohippocampal cholinergic deficit. Hippocampal sections from 67 PD, 34 PD with mild cognitive impairment and 96 PDD cases were immunostained for tau and alpha-synuclein, and the respective pathology burden was assessed semi-quantitatively. In a subset of cases, the degree of CA2 cholinergic depletion was quantified using confocal microscopy and correlated with cholinergic neuronal loss in Ch2. We found that only cases with dementia have a significantly greater Lewy pathology, whereas cholinergic fibre depletion was evident in cases with mild cognitive impairment and this was significantly correlated with loss of cholinergic neurons in Ch2. In addition, multiple antigen immunofluorescence demonstrated colocalisation between cholinergic fibres and alpha-synuclein but not tau pathology. Such specific Lewy pathology targeting the cholinergic system within the CA2 subfield may contribute to the unique memory retrieval deficit seen in patients with Lewy body disorders, as distinct from the memory storage deficit seen in Alzheimer's disease.

In the original version of this Article, the concentration of boric acid buffer for the SDS clearing solution was given incorrectly as '1 M sodium borate' and should have read '0.2 M boric acid'. Also, the composition of PBST incorrectly read '1% Triton X-100 (vol/vol) and 0.1% sodium azide (wt/vol)' and should have read '0.1% Triton X-100 (vol/vol) and 0.01% sodium azide (wt/vol)'. Further, the pH of the OPTIClear solution was not stated, and should have read 'with a pH between 7 to 8 adjusted with hydrochloric acid'. These errors have been corrected in both the PDF and HTML versions of the Article.

Top-illuminated PIN and modified uni-traveling carrier (MUTC) photodiodes based on InGaAs/InAlAs/InP were epitaxially grown on Si templates. Photodiodes with 30-μm diameter have dark currents as low as 10 nA at 3 V corresponding to a dark current density of only 0.8 mA/cm 2 . The responsivity, 3-dB bandwidth, output power and third-order output intercept point (OIP3) were 0.79 A/W, 9 GHz, 2.6 dBm and 15 dBm, respectively.

Modern clearing techniques for the three-dimensional (3D) visualisation of neural tissue microstructure have been very effective when used on rodent brain but very few studies have utilised them on human brain material, mainly due to the inherent difficulties in processing post-mortem tissue. Here we develop a tissue clearing solution, OPTIClear, optimised for fresh and archival human brain tissue, including formalin-fixed paraffin-embedded material. In light of practical challenges with immunostaining in tissue clearing, we adapt the use of cresyl violet for visualisation of neurons in cleared tissue, with the potential for 3D quantification in regions of interest. Furthermore, we use lipophilic tracers for tracing of neuronal processes in post-mortem tissue, enabling the study of the morphology of human dendritic spines in 3D. The development of these different strategies for human tissue clearing has wide applicability and, we hope, will provide a baseline for further technique development.

Different neurodegenerative conditions can have complex, overlapping clinical presentations that make accurate diagnosis during life very challenging. For this reason, confirmation of the clinical diagnosis still requires postmortem verification. This is particularly relevant for clinical trials of novel therapeutics where it is important to ascertain what disease and/or pathology modifying effects the therapeutics have had. Furthermore, it is important to confirm that patients in the trial actually had the correct clinical diagnosis as this will have a major bearing on the interpretation of trial results. Here we present a simple protocol for pathological assessment of neurodegenerative changes.

Pichia pastoris is a highly successful recombinant protein expression system due to its ability to quickly generate large quantities of recombinant proteins in simple media. P. pastoris has been used to successfully generate milligram quantities of many important human membrane proteins, including G-protein coupled receptors, ion channels, and transporters, which are becoming increasingly important therapeutic targets. Despite these successes, protein expression in P. pastoris is still cumbersome due to a need to change growth media from glycerol media to methanol induction media, which minimizes inhibition of the AOX1 promoter by residual glycerol. Taking advantage of this behavior of the AOX1 promoter, we developed Buffered extra-YNB Glycerol Methanol (BYGM) auto-induction media (100 mM potassium phosphate pH 6.0, 2.68% w/v YNB, 0.4% v/v glycerol, 0.5% v/v methanol, and 8 × 10 -5 % w/v biotin) which not only simplified the protein expression process, but also optimized protein expression levels in P. pastoris. We successfully used this auto-induction method to overexpress the target in both Mut S and Mut + strains. Moreover, we show that this method can facilitate screening high-expressing clones, as well as enable parallel protein production in P. pastoris., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Several pathologic conditions of the heart lead to cardiac structural remodelling. Given the high density and the opaque nature of the myocardium, deep three dimensional (3D) imaging is difficult to achieve and structural analysis of pathological myocardial structure is often limited to two dimensional images and of thin myocardial sections. Efficient methods to obtain optical clearing of the tissue for 3D visualisation are therefore needed. Here we describe a rapid, simple and versatile Free-of-Acrylamide SDS-based Tissue Clearing (FASTClear) protocol specifically designed for cardiac tissue. With this method 3D information regarding collagen content, collagen localization and distribution could be easily obtained across a whole 300 µm-thick myocardial slice. FASTClear does not induce structural or microstructural distortion and it can be combined with immunostaining to identify the micro- and macrovascular networks. In summary, we have obtained decolorized myocardial tissue suitable for high resolution 3D imaging, with implications for the study of complex cardiac tissue structure and its changes during pathology.

We present measurements of relative intensity noise versus various levels of optical feedback for 1.3 μm quantum dot lasers epitaxially grown on silicon for the first time. A systematic comparison is made with heterogeneously integrated 1.55 μm quantum well lasers on silicon. Our results indicate up to 20 dB reduced sensitivity of the quantum dot lasers on silicon compared to the quantum wells.

High performance III-V lasers at datacom and telecom wavelengths on on-axis (001) Si are needed for scalable datacenter interconnect technologies. We demonstrate electrically injected quantum dot lasers grown on on-axis (001) Si patterned with {111} v-grooves lying in the [110] direction. No additional Ge buffers or substrate miscut was used. The active region consists of five InAs/InGaAs dot-in-a-well layers. We achieve continuous wave lasing with thresholds as low as 36 mA and operation up to 80°C.

We demonstrate the first electrically pumped continuous-wave (CW) III-V semiconductor lasers epitaxially grown on on-axis (001) silicon substrates without offcut or germanium layers, using InAs/GaAs quantum dots as the active region and an intermediate GaP buffer between the silicon and device layers. Broad-area lasers with uncoated facets achieve room-temperature lasing with threshold current densities around 860  A/cm 2 and 110 mW of single-facet output power for the same device. Ridge lasers designed for low threshold operations show maximum lasing temperatures up to 90°C and thresholds down to 30 mA.

Na lidar can measure vertical wind and temperature at high temporal and vertical resolutions, enough to resolve gravity wave perturbations. Heat flux due to dissipating gravity waves is an important quantity that can be derived from such perturbations. When lidar signals are high, a photomultiplier tube (PMT) used to count incoming photons may suffer from the saturation effect, and its output count is not linearly related to incoming photon counts. Corrections to this effect can be measured in a laboratory setting but may have large errors at high count rates. We show that the errors in the PMT correction can cause significant bias in the heat flux calculation due to the inherent correlation between wind and temperature errors. Using the measurements made by Na lidar at the Andes Lidar Observatory with Hamamatsu PMTs, we developed a calibration procedure to remove such PMT correction errors from laboratory measurements. By applying the revised PMT correction curve we demonstrated that the heat flux bias can be removed through this procedure.

The biomechanical behavior of tissues under mechanical stimulation is critically important to physiological function. We report a combined experimental and modeling study of bioengineered 3D smooth muscle microtissues that reveals a previously unappreciated interaction between active cell mechanics and the viscoplastic properties of the extracellular matrix. The microtissues' response to stretch/unstretch actuations, as probed by microcantilever force sensors, was dominated by cellular actomyosin dynamics. However, cell lysis revealed a viscoplastic response of the underlying model collagen/fibrin matrix. A model coupling Hill-type actomyosin dynamics with a plastic perfectly viscoplastic description of the matrix quantitatively accounts for the microtissue dynamics, including notably the cells' shielding of the matrix plasticity. Stretch measurements of single cells confirmed the active cell dynamics, and were well described by a single-cell version of our model. These results reveal the need for new focus on matrix plasticity and its interactions with active cell mechanics in describing tissue dynamics.

We report comparison of lasing dynamics in InAs quantum dot (QD) micro-disk lasers (MDLs) monolithically grown on V-groove patterned and planar Si (001) substrates. TEM characterizations reveal abrupt interfaces and reduced threading dislocations in the QD active regions when using the GaAs-on-V-grooved-Si template. The improved crystalline quality translates into lower threshold power in the optically pumped continuous-wave MDLs. Concurrent evaluations were also made with devices fabricated simultaneously on lattice-matched GaAs substrates. Lasing behaviors from 10 K up to room temperature have been studied systematically. The analyses spotlight insights into the optimal epitaxial scheme to achieve low-threshold lasing in telecommunication wavelengths on exact Si (001) substrates.

Three-dimensional visualization of intact tissues is now being achieved by turning tissues transparent. CLARITY is a unique tissue clearing technique, which features the use of detergents to remove lipids from fixed tissues to achieve optical transparency. To preserve tissue integrity, an acrylamide-based hydrogel has been proposed to embed the tissue. In this study, we examined the rationale behind the use of acrylamide in CLARITY, and presented evidence to suggest that the omission of acrylamide-hydrogel embedding in CLARITY does not alter the preservation of tissue morphology and molecular information in fixed tissues. We therefore propose a novel and simplified workflow for formaldehyde-fixed tissue clearing, which will facilitate the laboratory implementation of this technique. Furthermore, we have investigated the basic tissue clearing process in detail and have highlighted some areas for targeted improvement of technologies essential for the emerging subject of three-dimensional histology.

Direct integration of high-performance laser diodes on silicon will dramatically transform the world of photonics, expediting the progress toward low-cost and compact photonic integrated circuits (PICs) on the mainstream silicon platform. Here, we report, to the best of our knowledge, the first 1.3 μm room-temperature continuous-wave InAs quantum-dot micro-disk lasers epitaxially grown on industrial-compatible Si (001) substrates without offcut. The lasing threshold is as low as hundreds of microwatts, similar to the thresholds of identical lasers grown on a GaAs substrate. The heteroepitaxial structure employed here does not require the use of an absorptive germanium buffer and/or dislocation filter layers, both of which impede the efficient coupling of light from the laser active regions to silicon waveguides. This allows for full compatibility with the extensive silicon-on-insulator (SOI) technology. The large-area virtual GaAs (on Si) substrates can be directly adopted in various mature in-plane laser configurations, both optically and electrically. Thus, this demonstration represents a major advancement toward the commercial success of fully integrated silicon photonics.

Introduction: Depletion of cholinergic neurons within the nucleus basalis of Meynert (nbM) is thought to contribute to the development of cognitive impairments in both Alzheimer's disease (AD) and Lewy body disorders (LBD). It has been reported that, in late stage AD, a network of fibres that contain the neuropeptide galanin displays significant hypertrophy and 'hyperinnervates' the surviving cholinergic neurons. Galanin is considered as a highly inducible neuroprotective factor and in AD this is assumed to be part of a protective tissue response. The aim of this study was to determine if a similar galanin upregulation is present in the nbM in post-mortem tissue from patients with LBD. Gallatin immunohistochemistry was carried out on anterior nbM sections from 76 LBD cases (27 PD, 15 PD with mild cognitive impairment (MCI), 34 PD with dementia (PDD) and 4 aged-matched controls. Galaninergic innervation of cholinergic neurons was assessed on a semi-quantitative scale., Results: The LBD group had significantly higher galaninergic innervation scores (p = 0.016) compared to controls. However, this difference was due to increased innervation density only in a subgroup of LBD cases and this correlated positively with choline acetyltransferase-immunopositive neuron density., Conclusion: Galanin upregulation within the basal forebrain cholinergic system in LBD, similar to that seen in AD, may represent an intrinsic adaptive response to neurodegeneration that is consistent with its proposed roles in neurogenesis and neuroprotection.

This paper describes an approach to actuate magnetically arrays of microtissue constructs for long-term mechanical conditioning and subsequent biomechanical measurements. Each construct consists of cell/matrix material self-assembled around a pair of flexible poly(dimethylsiloxane) (PDMS) pillars. The deflection of the pillars reports the tissues' contractility. Magnetic stretching of individual microtissues via magnetic microspheres mounted on the cantilevers has been used to elucidate the tissues' elastic modulus and response to varying mechanical boundary conditions. This paper describes the fabrication of arrays of micromagnetic structures that can transduce an externally applied uniform magnetic field to actuate simultaneously multiple microtissues. These structures are fabricated on silicon-nitride coated Si wafers and contain electrodeposited Ni bars. Through-etched holes provide optical and culture media access when the devices are mounted on the PDMS microtissue scaffold devices. Both static and AC forces (up to 20 μN on each microtissue) at physiological frequencies are readily generated in external fields of 40 mT. Operation of the magnetic arrays was demonstrated via measurements of elastic modulus and dynamic stiffening in response to AC actuation of fibroblast populated collagen microtissues.

It has been well established that neuronal loss within the cholinergic nucleus basalis of Meynert (nbM) correlates with cognitive decline in dementing disorders such as Alzheimer's disease (AD). Friedrich Lewy first observed his eponymous inclusion bodies in the nbM of postmortem brain tissue from patients with Parkinson's disease (PD) and cell loss in this area can be at least as extensive as that seen in AD. There has been confusion with regard to the terminology and exact localisation of the nbM within the human basal forebrain for decades due to the diffuse and broad structure of this "nucleus". Also, while topographical projections from the nbM have been mapped out in subhuman primates, no direct clinicopathological correlations between subregional nbM and cortical pathology and specific cognitive profile decline have been performed in human tissue. Here, we review the evolution of the term nbM and the importance of standardised nbM sampling for neuropathological studies. Extensive review of the literature suggests that there is a caudorostral pattern of neuronal loss within the nbM in AD brains. However, the findings in PD are less clear due to the limited number of studies performed. Given the differing neuropsychiatric and cognitive deficits in Lewy body-associated dementias (PD dementia and dementia with Lewy bodies) as compared to AD, we hypothesise that a different pattern of neuronal loss will be found in the nbM of Lewy body disease brains. Understanding the functional significance of the subregions of the nbM could prove important in elucidating the pathogenesis of dementia in PD.

The objectives of the study were to evaluate the effect of intravenous contrast in the dosimetry of helical tomotherapy and RapidArc treatment for head and neck cancer and determine if it is acceptable during the computed tomography (CT) simulation to acquire only CT with contrast for treatment planning of head and neck cancer. Overall, 5 patients with head and neck cancer (4 men and 1 woman) treated on helical tomotherapy were analyzed retrospectively. For each patient, 2 consecutive CT scans were performed. The first CT set was scanned before the contrast injection and secondary study set was scanned 45 seconds after contrast. The 2 CTs were autoregistered using the same Digital Imaging and Communications in Medicine coordinates. Tomotherapy and RapidArc plans were generated on 1 CT data set and subsequently copied to the second CT set. Dose calculation was performed, and dose difference was analyzed to evaluate the influence of intravenous contrast media. The dose matrix used for comparison included mean, minimum and maximum doses of planning target volume (PTV), PTV dose coverage, and V45Gy, V30Gy, and V20Gy organ doses. Treatment planning on contrasted images generally showed a lower dose to both organs and target than plans on noncontrasted images. The doses for the points of interest placed in the organs and target rarely changed more than 2% in any patient. In conclusion, treatment planning using a contrasted image had insignificant effect on the dose to the organs and targets. In our opinion, only CT with contrast needs to be acquired during the CT simulation for head and neck cancer. Dose calculations performed on contrasted images can potentially underestimate the delivery dose slightly. However, the errors of planning on a contrasted image should not affect the result in clinically significant way., (Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)

cGMP-dependent protein kinase (PKG)-interacting proteins (GKIPs) mediate cellular targeting of PKG isoforms by interacting with their leucine zipper (LZ) domains. These interactions prevent aberrant signaling cross-talk between different PKG isotypes. To gain detailed insight into isotype-specific GKIP recognition by PKG, we analyzed the type II PKG leucine zipper domain and found that residues 40-83 dimerized and specifically interacted with Rab11b. Next, we determined a crystal structure of the PKG II LZ-Rab11b complex. The PKG II LZ domain presents a mostly nonpolar surface onto which Rab11b docks, through van der Waals interactions. Contact surfaces in Rab11b are found in switch I and II, interswitch, and the β1/N-terminal regions. This binding surface dramatically differs from that seen in the Rab11 family of interacting protein complex structures. Structural comparison with PKG Iα and Iβ LZs combined with mutagenic analysis reveals that GKIP recognition is mediated through surface charge interactions., (© 2014 by The American Society for Biochemistry and Molecular Biology, Inc.)

Valid, reliable, responsive and practical outcome measures are essential for treatment planning and outcome assessment. This study aimed to examine the measurement properties of Modified Rivermead Mobility Index (MRMI) and Modified Functional Ambulation Classification (MFAC) in Chinese stroke patients. The content validity, responsiveness, predictive validity, test-retest reliability, internal consistency and factor structure of the MRMI were examined. The content validity, discriminative power and inter-rater agreement of the MFAC were investigated. A total of 456 Chinese stroke patients were recruited. Evidence of good content validity, high responsiveness, adequate predictive validity, excellent test-retest reliability with 1.3-point as minimum detectable change in 95% confidence interval, high internal consistency and unidimensionality was obtained for the MRMI. Good content validity, sufficient discriminative power and excellent inter-rater agreement were demonstrated for the MFAC. Both the MRMI and MFAC have good to excellent measurement properties and are recommended as routine outcome measures for Chinese stroke patients.

Background: We evaluated the anatomic location of the external anal sphincter (EAS) to pelvic bony landmarks related to 3-dimensional conformal radiotherapy (3DRT) and studied the dosimetric coverage of the EAS in patients undergoing neoadjuvant chemoradiation for rectal cancer., Methods: Sixty-four consecutive rectal cancer patients treated with neoadjuvant chemoradiation were included. All patients were treated in a prone position on a bellyboard by 3DRT. The inferior border of the RT fields was at least 3-5 cm inferior to the gross tumorous volume (GTV) or at the inferior border of the obturator foramen (IBOF), whichever was more inferior. The EAS was contoured and dose distributions were determined using dose-volume histograms., Results: In 53 out of 64 cases (82.8%), the EAS was completely inferior to the IBOF. In the remaining 11 cases, the EAS was either overlapping the IBOF (10 cases; 15.6%) or completely superior to the IBOF (1 case; 1.7%). The average mean dose delivered to the EAS was 2795 cGy. Lower mean doses were delivered to the EAS when the center of the EAS was located more distant from the GTV., Conclusions: Meticulous planning to define the inferior border of the RT field is recommended to avoid irradiating the EAS.

Aims: Within a clinical trial population, direct thrombin inhibition using bivalirudin in patients undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) is associated with a reduction in mortality and major bleeding compared to heparin/glycoprotein IIb/IIIa receptor inhibition (GPI), but a higher incidence of acute stent thrombosis (ST), particularly in the absence of pre-procedural heparin. The safety and efficacy of bivalirudin in an all-comer, real-world primary PCI setting is unknown., Methods and Results: 968 consecutive STEMI patients (mean age 63 years, 72% male, 42% anterior STEMI, 3.7% cardiogenic shock) undergoing primary PCI with bivalirudin as the recommended anticoagulation, and with heparin/GPI (abciximab) as an alternative, were prospectively followed. Bivalirudin was administered as a bolus, high-dose procedural infusion and, unlike the HORIZONS-AMI trial, as a low-dose infusion for four hours post-PCI. Additional heparin was not routinely given. Mortality, major adverse cardiovascular events (MACE), major bleeding and ST were assessed at 30 days. Initial antithrombotic therapy was bivalirudin in 885 patients (91%), of whom 123 (13.9%) received additional antithrombin therapy, and 114 (11.8%) "bail-out" GPI. Outcomes for bivalirudin-treated patients were; mortality 5.2%, MACE 7.5%, major bleeding 3.8%. The incidence of acute ST was 1.0%, including in the absence of additional heparin (1.2%). Most cases of acute ST (7/9) occurred in the first four hours post-PCI. There was no significant difference in outcomes between patients treated with bivalirudin versus heparin/GPI., Conclusions: Routine use of bivalirudin in a real-world primary PCI population was associated with good 30-day outcomes. Acute stent thrombosis was infrequent, even without additional heparin. A continued low-dose infusion of bivalirudin did not appear to offer protection against very early stent thrombosis.

Objectives: Emotional distress, including depression, is an important issue for cancer patients and their families. Guidelines recommend the use of antidepressant drugs (ADs) for the management of depression in cancer. This study explores the views of oncology professionals about the inclusion of ADs in treatment plans., Design: Semi-structured interview study. Data were analysed using framework analysis., Setting: A specialist cancer centre and six district general hospitals across the Yorkshire Cancer Network., Participants: 18 randomly selected professionals from lung, breast, urology and colorectal cancer teams: oncologists (n=8), surgeons (n=3), clinical nurse specialists (n=2) and ward nurses (n=5)., Results: Three main themes emerged relating to professionals' attitudes, knowledge and behaviour. Positive attitudes were primarily expressed by nurses. However, negative views were expressed about the potential for over-reliance on ADs, and their use constituting 'giving in'. Doctors reported a lack of confidence in the use of and knowledge about ADs with an associated reluctance to prescribe. The general practitioner (GP) was regarded as the most appropriate professional to prescribe ADs., Conclusions: Cancer professionals highlighted a need for training in the appropriate use of ADs. Further, this research suggests that negative attitudes towards antidepressants may be a factor in their exclusion from treatment plans. The GP is seen to have a key prescribing role for AD therapy; however, it is unclear whether the GPs is asked to do this. This research raises questions about the adequacy of ADs in cancer care and to what extent the GP is able to meet this need.

Objective: Emotional distress (ED) is an under-diagnosed problem in cancer patients and over the last decade a number of national guidelines have recommended an assessment and management model based on appropriate health professional response to a hierarchy of patient need. This study explores the views of cancer professionals regarding their current roles and responsibilities in the detection and management of ED, use of screening tools and access to expert psychological support., Methods: Interviews with 23 professionals were conducted [6 clinical nurse specialists (CNS), 8 oncologists, 4 surgeons and 5 ward sisters] from hospitals in Yorkshire, UK. Data were evaluated using framework analysis., Results: Detection of ED was seen to be the responsibility of the whole cancer team though nurses, particularly CNSs, are heavily depended upon to assess and manage distress. Experience of screening tools was limited and a number of reservations were expressed about routine implementation. A wide range of services are used to support distressed patients but a lack of referral guidance and access to specialist psychological care were reported to be a significant barrier to effective management., Conclusions: Cancer professionals describe working within the fundamental principles of the guidance frameworks; however, access to specialist support do not appear to meet recommendations, leaving the CNS with considerable responsibility for the detection and management of ED. Support for ED may be improved by the introduction of routine screening along with appropriate training and implementation of referral guidelines to assist professionals in accessing specialist psychology services., (Copyright © 2011 John Wiley & Sons, Ltd.)

Physically-based virtual environments (VEs) provide realistic interactions and behaviors for computer-based medical simulations. Limited CPU resources have traditionally forced VEs to be simplified for real-time performance. Multi-core processors greatly increase the computational capacity of computers and are quickly becoming standard. However, developing non-application specific methods to fully utilize all available CPU cores for processing VEs is difficult. The paper describes a pipeline VE architecture designed for multi-core CPU systems. The architecture enables development of VEs that leverage the computational resources of all CPU cores for VE simulation. A VE's workload is dynamically distributed across the available CPU cores. A VE can be developed once and scale efficiently with the number of cores. The described pipeline architecture makes it possible to develop complex physically-based VEs for medical simulations. Initial results for a craniotomy simulator being developed have shown super-linear and near-linear speedups when tested with up to four cores.

A description is given of the methodology based on a single, aircraft-mounted spectroscopic imager to tomographically reconstruct airglow perturbations induced by atmospheric gravity waves. In this configuration, the imager passes under the airglow structure to gather multiple-angle views of the wave structure in a relatively short amount of time. Under the assumption that the airglow structure does not change significantly during the acquisition interval, the data can be tomographically inverted to estimate the 2D (horizontal-vertical) airglow structure. We develop an inversion strategy for this image formation task and illustrate its applicability by inverting time-sequential imaging data taken from different vantage points during the ALOHA-93 campaign to reconstruct atmospheric gravity wave structures.

Purpose: Assistive technology for wayfinding will significantly improve the quality of life for many individuals with cognitive impairments. The user interface of such a system is as crucial as the underlying implementation and localisation technology. We studied the user interface of an indoor navigation system for individuals with cognitive impairments., Method: We built a system using the Wizard-of-Oz technique that let us experiment with many guidance strategies and interface modalities. Through user studies, we evaluated various configurations of the user interface for accuracy of route completion, time to completion, and user preferences. We used a counter-balanced design that included different modalities (images, audio, and text) and different routes., Results: We found that although users were able to use all types of modalities to find their way indoors, they varied significantly in their preferred modalities. We also found that timing of directions requires careful attention, as does providing users with confirmation messages at appropriate times., Conclusions: Our findings suggest that the ability to adapt indoor wayfinding devices for specific users' preferences and needs will be particularly important.

Virtual Reality-based surgical simulators can utilize Collaborative Virtual Environments (C-VEs) to provide team-based training. To support real-time interactions, C-VEs are typically replicated on each user's local computer and a synchronization method helps keep all local copies consistent. This approach does not work well for voxel-based C-VEs since large and frequent volumetric updates make synchronization difficult. This paper describes a method that allows multiple users to interact within a voxel-based C-VE for a craniotomy simulator being developed. Our C-VE method requires smaller update sizes and provides faster synchronization update rates than volumetric-based methods. Additionally, we address network bandwidth/latency issues to simulate networked haptic and bone drilling tool interactions with a voxel-based skull C-VE.

This study describes our experience with using a virtual reality simulator, CricSim, to enhance the training of combat medics to perform a cricothyroidotomy (surgical airway) while in Iraq. Over a six month period, 65 medics used the simulator as part of a Combat Medic Advanced Skills Training class while in Iraq and were asked to evaluate it. Students self-assessed comfort level with the procedure improved dramatically from baseline (p<5.6 x 10(-17)). The CricSim was rated highly on realism but only moderately on ease of use. The use of this simulator in a far forward setting was feasible, enhanced training, and provided necessary end-user feedback for future development of this training platform.

Traumatic head injuries can cause internal bleeding within the brain. The resulting hematoma can elevate intracranial pressure, leading to complications and death if left untreated. A craniotomy may be required when conservative measures are ineffective. To augment conventional surgical training, a Virtual Reality-based intracranial hematoma simulator is being developed. A critical step in performing a craniotomy involves cutting burrholes in the skull. This paper describes volumetric-based haptic and visual algorithms developed to simulate burrhole creation for the simulator. The described algorithms make it possible to simulate several surgical tools typically used for a craniotomy.

Many computer based medical simulators focus on individual skills training. However, medical care is frequently rendered by teams. In addition, the conditions under which care is provided can be a crucial factor in training. For example, mass-casualty events can involve the management and triage of large numbers of victims under austere environments. Learning to care for the injured warfighter during combat requires realistic simulation of battlefield conditions. Current simulation systems do not adequately address team training requirements within lifelike environments. This paper describes our work toward the development of an immersive virtual environment that meets these needs.

Mass-spring systems are often used to model anatomical structures in medical simulation. They can produce plausible deformations in soft tissue, and are computationally efficient. Determining damping values for a stable mass-spring system can be difficult. Previously stable models can become unstable with topology changes, such as during cutting. In this paper, we derive bounds for the damping coefficient in a mass-spring system. Our formulation can be used to evaluate the stability for user specified damping values, or to compute values that are unconditionally stable.

Pulmonary Artery Catheterization (PAC) is a commonly performed procedure. It is used when hemodynamic and other cardiac measures must be accurately monitored in seriously ill patients. A flow-directed, balloon-tipped (Swan-Ganz) catheter is typically inserted into a major vein, passed through the heart, and into the pulmonary artery. This procedure is normally not performed under fluoroscopy. Instead, transducer readings from the catheter tip provide a continuous report of local blood pressure. An experienced practitioner can infer the catheter's location from this information, yet several studies have found that physicians and critical care nurses have a wide variability in competency. A simulator for this procedure can address some of the educational and training issues highlighted. This paper describes our ongoing progress in developing a PAC trainer.