Edge states in rationally terminated honeycomb structures.

Consider the tight binding model of graphene, sharply terminated along an edge l parallel to a direction of translational symmetry of the underlying period lattice. We classify such edges l into those of "zigzag type" and those of "armchair type," generalizing the classical zigzag and armchair edges. We prove that zero-energy/flat-band edge states arise for edges of zigzag type, but never for those of armchair type. We exhibit explicit formulae for flat-band edge states when they exist. We produce strong evidence for the existence of dispersive (nonflat) edge state curves of nonzero energy for most l.

Women with chronic constipation have more bothersome urogenital symptoms.

BACKGROUND: The aim of our study was to characterize urogenital symptoms in women with and without constipation, and by severity of constipation. METHODS: This was a retrospective cohort study conducted at a pelvic floor disorder center in a tertiary healthcare facility from May 2007 through August 2019 and completed an intake questionnaire were included. We collected demographic, physical exam data and quality of life outcomes. The Urinary Distress Inventory (UDI-6) was used to assess urogenital symptoms. Women with constipation completed the Constipation Severity Instrument (CSI). We excluded women with a history of a bowel resection, inflammatory bowel disease, or pelvic organ prolapse symptoms. The cohort was then divided into two groups, constipated and non-constipated, and the prevalence and severity of urogenital-associated symptoms were compared. A secondary analysis was made among constipated subjects stratified by constipation severity based on CSI scores. RESULTS: During the study period, 875 women (59.5%) had chronic constipation. Women with chronic constipation were more likely to experience urogenital symptoms, such as dyspareunia, urinary hesitancy, and a sensation of incomplete bladder emptying (all p < 0.05). Moreover, on univariate analysis, women with high CSI scores (75 percentile or higher) were found to have higher UDI-6 scores, increased bladder splinting, pad use, urinary frequency and dyspareunia while on multivariate analysis higher UDI score, increased bladder splinting, urinary frequency and dyspareunia were significantly associated (p < 0.05). CONCLUSION: We found that the presence and severity of chronic constipation worsened the degree of bother from urogenital symptoms. Given that chronic constipation can modulate urogenital symptoms, our study suggests that pelvic floor specialists should assess the presence and severity of urogenital and bowel symptoms to provide comprehensive care.

The role of citizen science in addressing grand challenges in food and agriculture research.

The power of citizen science to contribute to both science and society is gaining increased recognition, particularly in physics and biology. Although there is a long history of public engagement in agriculture and food science, the term 'citizen science' has rarely been applied to these efforts. Similarly, in the emerging field of citizen science, most new citizen science projects do not focus on food or agriculture. Here, we convened thought leaders from a broad range of fields related to citizen science, agriculture, and food science to highlight key opportunities for bridging these overlapping yet disconnected communities/fields and identify ways to leverage their respective strengths. Specifically, we show that (i) citizen science projects are addressing many grand challenges facing our food systems, as outlined by the United States National Institute of Food and Agriculture, as well as broader Sustainable Development Goals set by the United Nations Development Programme, (ii) there exist emerging opportunities and unique challenges for citizen science in agriculture/food research, and (iii) the greatest opportunities for the development of citizen science projects in agriculture and food science will be gained by using the existing infrastructure and tools of Extension programmes and through the engagement of urban communities. Further, we argue there is no better time to foster greater collaboration between these fields given the trend of shrinking Extension programmes, the increasing need to apply innovative solutions to address rising demands on agricultural systems, and the exponential growth of the field of citizen science.

Neoadjuvant therapy versus upfront surgical strategies in resectable pancreatic cancer: A Markov decision analysis.

BACKGROUND: Neoadjuvant therapy is gaining acceptance as a valid treatment option for borderline resectable pancreatic cancer; however, its value for clearly resectable pancreatic cancer remains controversial. The aim of this study was to use a Markov decision analysis model, in the absence of adequately powered randomized trials, to compare the life expectancy (LE) and quality-adjusted life expectancy (QALE) of neoadjuvant therapy to conventional upfront surgical strategies in resectable pancreatic cancer patients. METHODS: A Markov decision model was created to compare two strategies: attempted pancreatic resection followed by adjuvant chemoradiotherapy and neoadjuvant chemoradiotherapy followed by restaging with, if appropriate, attempted pancreatic resection. Data obtained through a comprehensive systematic search in PUBMED of the literature from 2000 to 2015 were used to estimate the probabilities used in the model. Deterministic and probabilistic sensitivity analyses were performed. RESULTS: Of the 786 potentially eligible studies identified, 22 studies met the inclusion criteria and were used to extract the probabilities used in the model. Base case analyses of the model showed a higher LE (32.2 vs. 26.7 months) and QALE (25.5 vs. 20.8 quality-adjusted life months) for patients in the neoadjuvant therapy arm compared to upfront surgery. Probabilistic sensitivity analyses for LE and QALE revealed that neoadjuvant therapy is favorable in 59% and 60% of the cases respectively. CONCLUSION(S): Although conceptual, these data suggest that neoadjuvant therapy offers substantial benefit in LE and QALE for resectable pancreatic cancer patients. These findings highlight the value of further prospective randomized trials comparing neoadjuvant therapy to conventional upfront surgical strategies.

Optimization of the thrombin generation test components to measure potency of factor VIII concentrates.

INTRODUCTION: The thrombin generation test (TGT) is used both as a global haemostasis assay, and to compare activities of coagulation factor concentrates that have been spiked into patient plasma. However, TGT has not been systematically optimized to evaluate factor VIII (FVIII) product potency. AIMS: To improve the sensitivity of TGT to FVIII and allow a comparative analysis of the thrombin generating capacities of FVIII concentrates against reference preparations with known FVIII activity. METHODS: Concentrations of TGT components (analytical variables) were assessed to maximize the linearity and range of responses to the concentration of FVIII. RESULTS: We optimized the range and sensitivity of the TGT assay with respect to FVIII through the addition of FXIa to the assay. Other parameters that were adjusted, i.e. tissue factor (TF), procoagulant lipids and plasma concentrations, did not improve the ability of the assay to measure both high and very low levels of FVIII. In the optimized TF/FXIa-activated TGT assay, all thrombin generation curve parameters were suitable for FVIII quantification, but thrombin peak height and maximal velocity demonstrated better linearity in the desired FVIII range. We found that the optimized TF/FXIa-activated TGT has a wider range of sensitivity to FVIII than a commercially available TGT. Additionally, we demonstrated that the TF/FXIa-activated assay performs adequately by comparing potency measurements of five commercially available FVIII products using TGT and traditional chromogenic and one-stage clotting assays. CONCLUSIONS: The optimized TGT assay can be used to quantify and compare the thrombin generating capacities of FVIII concentrates.

Impaired diffusion tensor imaging findings in the corpus callosum and cingulum may underlie impaired learning and memory abilities in systemic lupus erythematosus.

BACKGROUND: Memory impairment is prevalent in systemic lupus erythematosus (SLE); however, its pathogenesis is unknown. In a previous functional magnetic resonance imaging (fMRI) study we demonstrated altered brain activity dynamics and less brain deactivation in patients with SLE as compared with healthy controls, when performing a learning and memory task. Our findings localized this impairment to the default mode network (DMN), and particularly to its anterior medial prefrontal cortex node. In addition, altered networking of the hippocampal subsystem of the DMN was seen in patients with SLE when performing this task, as well as atrophy of the left hippocampus. The present study aimed to search for a structural substrate for the altered recruitment pattern observed in fMRI studies using diffusion tensor imaging (DTI). PATIENTS AND METHODS: Using DTI, we characterized brain diffusivity in 10 patients with SLE and nine healthy controls. Two tracts associated with the DMN were reconstructed: the corpus callosum (CC) and the cingulum bundle. The CC was segmented according to the Witelson segmentation scheme and the cingulum was segmented into superior and descending bundles. RESULTS: A significant increase in mean diffusivity (MD) was seen in patients with SLE without neuropsychiatric SLE (NPSLE) as compared with healthy controls in all five segments of the CC (segment 1: p = 0.043; segment 2: p = 0.005; segment 3: p = 0.003; segment 4: p = 0.012; segment 5: p = 0.023) as well as in the descending portion of the left cingulum bundle (p = 0.026). CONCLUSIONS: Increased MD values in the CC and the left cingulum may indicate impaired organization/reduced integrity of these tracts, which may underlie the abnormal pattern of brain activity recruitment of the DMN observed during a verbal learning and memory task. Taking into account the central role of the left hippocampus in verbal memory, the abnormal integrity of the left cingulum may contribute to the reduced performance of patients with SLE on verbal memory tasks.

The effect of preexisting hypertension on early neurologic results of patients with an acute spinal cord injury.

STUDY DESIGN: Retrospective case-control. OBJECTIVES: To characterize changes in American Spinal Injury Association Motor Score (AMS) in patients treated with relative hypertension (HTN) (mean arterial pressure (MAP) > 85 mm Hg for 5 days) with and without preexisting HTN. SETTING: A regional spinal cord injury (SCI) center in Pennsylvania, United States. METHODS: All patients with an acute SCI who were treated with induced HTN (MAP goal above 85) in the intensive care unit (ICU) for at least 5 days were identified. Patients were stratified based on the presence of preexisting HTN, and the change in the AMS between admission and day 5 was determined. Predictors of outcome were identified using correlation analysis and multiple linear regression. RESULTS: Ninety-two patients met inclusion criteria of which 22 had a previous history of HTN. HTN was a predictor of poor early outcome. Patients with HTN had an average decline in their AMS of 7.6, compared with an average decrease of only 0.6 in the AMS of patients without HTN (P=0.04). HTN had no effect (P>0.05) on other in-hospital variables including length of stay, length of stay in the ICU, complications or mortality. Additionally, multiple linear regression analysis demonstrated that diabetes, coronary artery disease and pulmonary disease had no effect on the change in AMS. CONCLUSION: Chronic HTN is an independent risk factor for poor early neurologic recovery in patients treated with relative HTN for an acute SCI. This is independent of age and other comorbidities.

MRI-based radiologic scoring system for extent of brain injury in children with hemiplegia.

BACKGROUND AND PURPOSE: Brain MR imaging is recommended in children with cerebral palsy. Descriptions of MR imaging findings lack uniformity, due to the absence of a validated quantitative approach. We developed a quantitative scoring method for brain injury based on anatomic MR imaging and examined the reliability and validity in correlation to motor function in children with hemiplegia. MATERIALS AND METHODS: Twenty-seven children with hemiplegia underwent MR imaging (T1, T2-weighted sequences, DTI) and motor assessment (Manual Ability Classification System, Gross Motor Functional Classification System, Assisting Hand Assessment, Jebsen Taylor Test of Hand Function, and Children's Hand Experience Questionnaire). A scoring system devised in our center was applied to all scans. Radiologic score covered 4 domains: number of affected lobes, volume and type of white matter injury, extent of gray matter damage, and major white matter tract injury. Inter- and intrarater reliability was evaluated and the relationship between radiologic score and motor assessments determined. RESULTS: Mean total radiologic score was 11.3 ± 4.5 (range 4-18). Good inter- (ρ = 0.909, P < .001) and intrarater (ρ = 0.926, P = < .001) reliability was demonstrated. Radiologic score correlated significantly with manual ability classification systems (ρ = 0.708, P < .001), and with motor assessments (assisting hand assessment [ρ = -0.753, P < .001]; Jebsen Taylor test of hand function [ρ = 0. 766, P < .001]; children's hand experience questionnaire [ρ = -0. 716, P < .001]), as well as with DTI parameters. CONCLUSIONS: We present a novel MR imaging-based scoring system that demonstrated high inter- and intrarater reliability and significant associations with manual ability classification systems and motor evaluations. This score provides a standardized radiologic assessment of brain injury extent in hemiplegic patients with predominantly unilateral injury, allowing comparison between groups, and providing an additional tool for counseling families.

Isolated mild white matter signal changes in preterm infants: a regional approach for comparison of cranial ultrasound and MRI findings.

OBJECTIVE: To compare echogenicity detected using cranial ultrasound (cUS) and diffuse excessive high signal intensity (DEHSI) detected using magnetic resonance imaging (MRI) by identical region-based scoring criteria in preterm infants. To explore the association between these white matter (WM) signal changes with early neurobehavior. STUDY DESIGN: Forty-nine pre-selected premature infants with only echogenicity on a first routine cUS1 underwent MRI and a repeated cUS2 at term equivalent age. Echogenicity and DEHSI were graded in various brain areas and diffusivity values were calculated. Neurobehavior was assessed using the Rapid Neonatal Neurobehavioral Assessment Procedure. RESULT: WM signal changes were significantly higher on cUS1 than cUS2; and higher in MRI than cUS2 in posterior regions. Infants with DEHSI demonstrated reduced tissue integrity. Imaging findings were not correlated with early neurobehavior. CONCLUSION: Echogenicity and DEHSI likely represent the same phenomenon. Reduction of over-interpretation of WM signal changes may help define criteria for the judicious use of imaging in routine follow-up of premature infants.

Controlled clinical comparison of BacT/alert FA plus and FN plus blood culture media with BacT/alert FA and FN blood culture media.

New blood culture media containing antibiotic-binding polymeric beads have been developed for the BacT/Alert (bioMérieux, Inc., Durham, NC) blood culture system. To assess the performance of these new media, we compared the new BacT/Alert aerobic medium (FA Plus) with resins to BacT/Alert FA medium with activated charcoal and the new BacT/Alert anaerobic medium (FN Plus) to BacT/Alert FN medium at 3 tertiary care medical centers. Study bottle pairs were inoculated with a target volume of 6 to 10 ml of blood from adults and incubated in the BacT/Alert 3D blood culture instrument. In the FA Plus versus FA comparison, there were 1,507 study pairs. Among 170 isolates causing true bloodstream infections (BSIs), significantly more Staphylococcus aureus (P<0.001) and total microorganisms (P<0.01) grew in the FA Plus bottle than in the FA bottle. Fewer coagulase-negative staphylococcal (CoNS) contaminants grew in the FA Plus bottle than in the FA bottle (10 versus 22; P=0.05). In addition, growth was detected earlier in the FA Plus bottle than in the FA bottle (P<0.001). In the FN Plus versus FN comparison, there were 2,386 study pairs. Among 201 isolates causing true BSIs, significantly more S. aureus (P<0.001), CoNS (P<0.005), and total microorganisms (P<0.001) grew in the FN Plus bottle than in the FN bottle. Also, significantly more CoNS contaminants grew in the FN Plus bottle than in the FN bottle (P<0.001). Overall, microorganisms were detected earlier in the FN Plus than in the FN bottle (P<0.001). Medical technologists at all 3 study sites preferred the new media for Gram stain interpretation. We conclude that the FA Plus and FN Plus media provide improved and earlier detection of microorganisms compared with the FA and FN media and are preferable for Gram stain interpretation as well.

Update on blood cultures: how to obtain, process, report, and interpret.

The detection and identification of microorganisms circulating in the bloodstream of patients is arguably one of the most important functions of the clinical microbiology laboratory. Effective implementation of this function requires careful consideration of specimen collection and processing, culture techniques, result reporting, and, perhaps most importantly, result interpretation by the physician. The purpose of this review is to provide a synopsis of the current state of the art for each of these areas, with the intention of providing adequate information to enable clinical laboratory personnel and physicians to critically evaluate and, if required, improve their current blood culture practices.

Are rectoceles the cause or the result of obstructed defaecation syndrome? A prospective anorectal physiology study.

AIM: To determine the relationship between obstructed defaecation syndrome (ODS) and rectoceles. METHOD: From December 2007 to November 2011, all female patients with ODS were prospectively evaluated with full interview, clinical examination and anorectal physiology testing. The characteristics of patients with and without rectoceles were compared, and logistic regression was utilized to identify factors predictive of patients having a rectocele beyond the introitus. RESULTS: Of 239 patients with ODS, 90 (mean age: 52.3 ± 1.7 years) had a rectocele. Patients with rectoceles (R+) had a similar prevalence of incomplete emptying compared with patients with no rectocele (R-) (P ≥ 0.21), but only R+ patients reported splinting with defaecation (36.7% vs 0%; P < 0.0001). Anorectal manometry measurements, including mean resting pressure, maximum resting pressure and maximum squeeze pressure, were similar between groups (P ≥ 0.12). There were also no significant differences in rectal compliance (maximum tolerated volume) or rectal sensitivity (volume of first sensation) (P ≥ 0.65). R+ patients had greater difficulty expelling a 60 cm(3) balloon (70.1% R+ patients vs 57.5% R- patients; P = 0.05), but the prevalence of pelvic floor dyssynergia, as quantified by nonrelaxation on electromyography (EMG) testing, was similar to that of R- patients (P = 0.49). Logistic regression suggested that only difficulty with balloon expulsion was associated with higher odds of having a rectocele (OR = 3.00; P = 0.002), whereas mean resting pressure, EMG nonrelaxation and symptoms of incomplete emptying were not (P ≥ 0.12). CONCLUSION: Rectoceles are not associated with an increased severity of ODS-type symptoms, anorectal abnormalities or pelvic floor dyssynergia in patients with ODS. This suggests that rectoceles may be the result, rather than the cause, of ODS.

A deceptive case of cellulitis caused by a Gram-negative pathogen.

Yokenella regensburgei is a member of the family Enterobacteriaceae that has rarely been implicated in clinical disease. We report here a case of septicemia with a skin and soft tissue source caused by Y. regensburgei in an immunocompromised host.

Controlled multicenter evaluation of a bacteriophage-based method for rapid detection of Staphylococcus aureus in positive blood cultures.

Staphylococci are a frequent cause of bloodstream infections (BSIs). Appropriate antibiotic treatment for BSIs may be delayed because conventional laboratory testing methods take 48 to 72 h to identify and characterize isolates from positive blood cultures. We evaluated a novel assay based on bacteriophage amplification that identifies Staphylococcus aureus and differentiates between methicillin-susceptible and methicillin-resistant S. aureus (MSSA and MRSA, respectively) in samples taken directly from signal-positive Bactec blood culture bottles within 24 h of positive signal, with results available within 5 h. The performance of the MicroPhage KeyPath MRSA/MSSA blood culture test was compared to conventional identification and susceptibility testing methods. At four sites, we collectively tested a total of 1,165 specimens, of which 1,116 were included in our analysis. Compared to standard methods, the KeyPath MRSA/MSSA blood culture test demonstrated a sensitivity, specificity, positive predictive value, and negative predictive value of 91.8%, 98.3%, 96.3%, and 96.1%, respectively, for correctly identifying S. aureus. Of those correctly identified as S. aureus (n = 334), 99.1% were correctly categorized as either MSSA or MRSA. Analysis of a subset of the data revealed that the KeyPath MRSA/MSSA blood culture test delivered results a median of 30 h sooner than conventional methods (a median of 46.9 h versus a median of 16.9 h). Although the sensitivity of the test in detecting S. aureus-positive samples is not high, its accuracy in determining methicillin resistance and susceptibility among positives is very high. These characteristics may enable earlier implementation of appropriate antibiotic treatment for many S. aureus BSI patients.

Parent-of-origin in individuals with familial neurofibromatosis type 1 and optic pathway gliomas.

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant cancer syndromes worldwide. Individuals with NF1 have a wide variety of clinical features including a strongly increased risk for pediatric brain tumors. The etiology of pediatric brain tumor development in NF1 is largely unknown. Recent studies have highlighted the contribution of parent-of-origin effects to tumorigenesis in sporadic cancers and cancer predisposition syndromes; however, there is limited data on this effect for cancers arising in NF1. To increase our understanding of brain tumor development in NF1, we conducted a multi-center retrospective chart review of 240 individuals with familial NF1 who were diagnosed with a pediatric brain tumor (optic pathway glioma; OPG) to determine whether a parent-of-origin effect exists overall or by the patient's sex. Overall, 50 % of individuals with familial NF1 and an OPG inherited the NF1 gene from their mother. Similarly, by sex, both males and females were as likely to inherit the NF1 gene from their mother as from their father, with 52 % and 48 % of females and males with OPGs inheriting the NF1 gene from their mother. In conclusion, in contrast to findings from other studies of sporadic cancers and cancer predisposition syndromes, our results indicate no parent-of-origin effect overall or by patient sex for OPGs in NF1.