Novel Deposition Method of Crosslinked Polyethylene Thin Film for Low-Refractive-Index Mid-Infrared Optical Coatings

Mid-infrared optics require optical coatings composed of high- and low-refractive-index dielectric layers for the design of optical mirrors, filters, and anti-reflection coatings. However, there are not many technologies for depositing a material with a refractive index of less than 2 and a low loss in the mid-infrared region. Here, we present a unique deposition method of crosslinked polyethylene thin film for mid-IR optical filter design. Polyethylene has a refractive index of 1.52 in the mid-infrared region and a small number of absorption peaks, so it is useful for making optical filters in the mid-infrared region. Only 1 keV of energy is required to crosslink the entire film by irradiating an electron beam while depositing polyethylene. In addition, crosslinked polyethylene thin film has high mechanical strength, so there is no cracking or peeling when used with germanium. This allows for the use of crosslinked polyethylene as a low refractive index for mid-infrared optical coating.

Negative Tone Metallic Organic Resists with Improved Sensitivity for Plasma Etching: Implications for Silicon Nanostructure Fabrication and Photomask Production

Metal-organic materials such as [NH₂(CH₂-CH=CH₂)₂][Cr₇NiF₈(Pivalate)₁₆] can act as negative tone resists for electron beam lithography (EBL) with high-resolution patterning of sub-40 nanometer pitch while exhibiting ultrahigh dry etch selectivities >100:1 and giving line dose exposures >11,000 pC/cm. It is clear that the resist sensitivity is too low to be used to manufacture the latest nanoscale photomasks that are suitable for extreme ultraviolet lithography. Therefore, the focus of this work here is to improve the sensitivity of this resist while maintaining its resolution and dry etch selectivity. Using our latest Monte Carlo simulation called Excalibur, we predict that the sensitivity would increase by a factor of 1.4 when the nickel atom is substituted by a cadmium atom. EBL studies showed an excellent agreement with the simulation, and plasma etching studies demonstrated that this did not affect the dry etch performance of the resist which remains very good with a selectively of ca. 99:1 for the etching of silicon at these resolutions with a low sensitivity of 7995 pC/cm.

The brain landscape of the two-hit model of posttraumatic stress disorder

The neurophysiological mechanisms underlying the development of posttraumatic stress disorder (PTSD) are poorly understood. Here we test a proposal that PTSD symptoms reflect fixed, highly correlated neural networks resulting from massive engagement of sensory inputs and the sequential involvement of those projections to limbic areas. Three-tesla functional magnetic resonance imaging (fMRI) data were acquired at rest in 15 veterans diagnosed with PTSD and 21 healthy control veterans from which zero-lag cross correlations between 50 brain areas (N = 1,225 pairs) were computed and analyzed. The brain areas were assigned to tiers based on the neurocircuitry of successively converging sensory pathways proposed by Jones and Powell (Jones EG, Powell TP. Brain 93: 793-820, 1970). The primary analyses assessed normalized proportional differences in cross correlation strength within and across tiers in veterans with PTSD and control veterans. Compared with control veterans, cross correlation strength was higher in veterans with PTSD, within and across tiers of areas involved in processing sensory inputs, and systematically increased from sensory processing areas to limbic areas. The functional relevance of this hypercorrelation was further documented by the finding that the severity of self-reported PTSD symptomatology was positively associated with higher neural correlations.NEW & NOTEWORTHY The neurophysiological mechanisms underlying the development of PTSD are poorly understood. Here we document that massive engagement of sensory modalities during trauma exposure leads to fixed, hypercorrelated frontal, parietal, temporal, and limbic networks, reflecting the successive integration of salient sensory inputs along the framework of Jones and Powell.

Plasma-Etched Pattern Transfer of Sub-10 nm Structures Using a Metal-Organic Resist and Helium Ion Beam Lithography

Field-emission devices are promising candidates to replace silicon fin field-effect transistors as next-generation nanoelectronic components. For these devices to be adopted, nanoscale field emitters with nanoscale gaps between them need to be fabricated, requiring the transfer of, for example, sub-10 nm patterns with a sub-20 nm pitch to substrates like silicon and tungsten. New resist materials must therefore be developed that exhibit the properties of sub-10 nm resolution and high dry etch resistance. A negative tone, metal-organic resist is presented here. It can be patterned to produce sub-10 nm features when exposed to helium ion beam lithography at line doses on the order of tens of picocoulombs per centimeter. The resist was used to create 5 nm wide, continuous, discrete lines spaced on a 16 nm pitch in silicon and 6 nm wide lines on an 18 nm pitch in tungsten, with line edge roughness of 3 nm. After the lithographic exposure, the resist demonstrates high resistance to silicon and tungsten dry etch conditions (SF₆ and C₄F₈ plasma), allowing the pattern to be transferred to the underlying substrates. The resist's etch selectivity for silicon and tungsten was measured to be 6.2:1 and 5.6:1, respectively; this allowed 3 to 4 nm thick resist films to yield structures that were 21 and 19 nm tall, respectively, while both maintained a sub-10 nm width on a sub-20 nm pitch.

Abstract P6-14-02: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Esser MR, Rowe JJ, McCann ML, Nicholas-Alexander M, Helck EP, Lewis SM. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-14-02.

Abstract P6-14-05: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Esser MR, Rowe JJ, McCann ML, Nicholas-Alexander M, Helck EP, Lewis SM. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-14-05.

Extinction to amphetamine-associated context in female rats is dependent upon conditioned orienting

RATIONALE

Females are considered more susceptible to the reinforcing effects of drugs and subsequently at increased risk for drug abuse and relapse after treatment. Estrogen is known to facilitate drug effects in females. However, other factors which contribute to the incidence of drug abuse are important to identify in order to recognize early risk factors and develop effective prevention and treatment schemes. Cue-directed behavior (aka sign tracking) has been implicated as a behavioral phenotype which identifies populations susceptible to drug abuse, partly due to its association with impulsivity and heightened dopamine function.

OBJECTIVES AND METHODS

In this study, we investigate the viability of conditioned orienting (a form of cue-directed behavior) as a potential phenotype which predicts drug proclivity in female rats. In addition, we examine any influence endogenous female hormones across the estrous cycle may have on conditioned orienting and drug proclivity.

RESULTS AND CONCLUSIONS

Utilizing an amphetamine-conditioned place preference task, results suggest that the orienting phenotype is an effective predictor of drug proclivity in females. Rats exhibiting enhanced orienting behavior show more robust preference for an amphetamine-associated context and are more resistant to extinction of this preference than nonorienting counterparts. Furthermore, both conditioned orienting behavior and conditioned place preference are minimally influenced by the estrous cycle.

Coherent Tabletop EUV Ptychography of Nanopatterns

Coherent diffraction imaging (CDI) or lensless X-ray microscopy has become of great interest for high spatial resolution imaging of, e.g., nanostructures and biological specimens. There is no optics required in between an object and a detector, because the object can be fully recovered from its far-field diffraction pattern with an iterative phase retrieval algorithm. Hence, in principle, a sub-wavelength spatial resolution could be achieved in a high-numerical aperture configuration. With the advances of ultrafast laser technology, high photon flux tabletop Extreme Ultraviolet (EUV) sources based on the high-order harmonic generation (HHG) have become available to small-scale laboratories. In this study, we report on a newly established high photon flux and highly monochromatic 30 nm HHG beamline. Furthermore, we applied ptychography, a scanning CDI version, to probe a nearly periodic nanopattern with the tabletop EUV source. A wide-field view of about 15 × 15 μm was probed with a 2.5 μm−diameter illumination beam at 30 nm. From a set of hundreds of far-field diffraction patterns recorded for different adjacent positions of the object, both the object and the illumination beams were successfully reconstructed with the extended ptychographical iterative engine. By investigating the phase retrieval transfer function, a diffraction-limited resolution of reconstruction of about 32 nm is obtained.

Brain Function in Gulf War Illness (GWI) and Associated Mental Health Comorbidities

GWI has affected a substantial number of Gulf War (GW) veterans. The disease involves several organ systems among which the brain is most prominent. Neurological, cognitive and mood-related (NCM) symptoms frequently dominate and are at the root of chronic ill-health and disability in veterans suffering from GWI. In addition, such symptoms frequently co-occur with diagnosable mental health disorders, predominantly posttraumatic stress disorder (PTSD). Here we investigated the possibility that increased GWI severity leads, above a threshold, to a diagnosable mental health disorder (excluding psychosis). For this purpose, we used, in separate analyses, symptom severity scores and resting-state brain functional connectivity patterns, as determined by magnetoencephalography (MEG). Two-hundred-thirty GW-era veterans participated in this study. They completed diagnostic interviews to establish the presence of GWI and assess mental health status. This distinguished 3 groups: healthy controls (N = 41), veterans with GWI and no mental illness (GWI group, N = 91), and veterans with both GWI and mental health disorder (GWI+MH, N = 98). For each veteran, symptom severity scores in the 6 GWI domains (fatigue, pain, NCM, skin, gastrointestinal, respiratory) were available as well as 9 summary measures of the distribution of Synchronous Neural Interactions (SNI) derived from the MEG recordings. We tested the hypothesis that, in the presence of GWI, the appearance of a diagnosable mental health disorder may depend on GWI symptom severity. For that purpose, we performed a logistic regression on the GWI population, where the presence (or absence) of the MH disorder was the dependent variable and the age- and gender-adjusted GWI severity in the 6-symptom domains were the predictors. The outcome was the probability that a participant will have MH disorder or not. Similarly, we tested the hypothesis that the presence of the MH disorder can be predicted by the SNI distribution patterns by performing a second logistic regression as above but with the 9 SNI measures as predictors. We found GWI symptom severity differed significantly across groups (GWI+MH > GWI > Control). SNI distributions of the GWI group also differed significantly from the other groups in a systematic hemispheric pattern, such that the presence of GWI involved predominantly the left hemisphere, and presence of mental health disorders involved, in addition, the right hemisphere. Both logistic regressions yielded highly significant outcomes, demonstrating that both GWI symptom severity and SNI distribution measures can predict the presence of MH disorder in GWI. Remarkably, the prediction probabilities for MH presence derived from the symptom-based and SNI-based logistic regressions were positively and highly statistically significantly correlated. Taken together, both objective (neural) and subjective (symptoms) indices suggest that GWI is distinct from healthy controls and varies in severity in a continuum that leads, at the higher end, to a diagnosable MH disorder. The positive correlation between the GWI symptom-based and brain-based predicted classifications provides a key link between GWI symptom severity and synchronous neural interactions in the context of mental illness.

Reliability and Clinical Impact of the Normalization of the Prothrombin Times in Oral Anticoagulant Control

In 1983, the World Health Organization (WHO) published recommendations for normalization, in oral anticoagulant control, of the prothrombin time (PT). The common denominator is the International Sensitivity Index (ISI) of a thromboplastin, obtained by means of thromboplastin calibration. The common scale is that of the International Normalized Ratio (INR). The INR is the PT ratio Patient PT/normal PT which would have been found normal PT with the WHO primary international reference preparation (IRP) 67/40. The reliability of the INR depends on the extent of calibration precision, patient-specific influences, as well as interlaboratory variation in the PT determination. Under well-controlled conditions the overall coefficient of variation (CV) of the INR is 11-13.5%, if thromboplastins of ISI ≃ 1 are used. For so-called low-sensitivity thromboplastins (ISI ≃ 2-2.5), the overall variation is larger due to a large between-laboratory variation of the measured PT-ratios

The user of thromboplastin will be provided with a chart or graph enabling him to convert the conventional terms used for expressing PTs into INRs. For quality assurance, and to prepare his own calibration chart if necessary, he should check normalization by means of control plasmas to which INRs have been assigned.

There is sufficient clinical evidence to express optimal therapeutic ranges in terms of INR. Manufacturers should revise and adapt their inserts where necessary in order to conform to these requirements.

Mean Platelet Volume and Size Distribution and Their Sensitivity to Agonists in Patients with Coronary Artery Disease and Congestive Heart Failure

Mean platelet volume was related to platelet count in patients with myocardial infarction (n = 55) and patients with congestive heart failure (n = 9). 18 patients with acute myocardial infarction were tested at admission and 4-7 days later, together with 13 patients with chronic stable angina and 10 patients with chest pain which was not related to coronary artery disease. In citrated blood a relative reduced frequency of large platelets (>13 fl) occured in patients with acute myocardial infarction at admission but was not seen during recovery or in patients with chronic stable angina. This suggests consumption of large platelets at time of thrombus formation. No relation was found between plasma catecholamine levels and mean platelet volumes. Effects of serotonine, adrenaline and CGP 28392, a calcium agonist, on platelet volume distributions were determined. Sensitivity of platelets to adrenaline was increased in patients with acute myocardial infarction on admission and reduced 4-7 days later, while in patients with congestive heart failure reactivity to both serotonine and adrenaline were reduced. This indicates a fast down-regulation during the early recovery phase of myocardial infarction and chronically in congestive heart failure.

Elevated temperature increases meiotic crossover frequency via the interfering (Type I) pathway in Arabidopsis thaliana

For most eukaryotes, sexual reproduction is a fundamental process that requires meiosis. In turn, meiosis typically depends on a reciprocal exchange of DNA between each pair of homologous chromosomes, known as a crossover (CO), to ensure proper chromosome segregation. The frequency and distribution of COs are regulated by intrinsic and extrinsic environmental factors, but much more is known about the molecular mechanisms governing the former compared to the latter. Here we show that elevated temperature induces meiotic hyper-recombination in Arabidopsis thaliana and we use genetic analysis with mutants in different recombination pathways to demonstrate that the extra COs are derived from the major Type I interference sensitive pathway. We also show that heat-induced COs are not the result of an increase in DNA double-strand breaks and that the hyper-recombinant phenotype is likely specific to thermal stress rather than a more generalized stress response. Taken together, these findings provide initial mechanistic insight into how environmental cues modulate plant meiotic recombination and may also offer practical applications.

Meiosis is the cell division used by sexually reproducing species to produce sperm and egg cells. During meiosis, programmed Double Strand Breaks (DSBs) occur on each chromosome, which allows DNA to be exchanged between chromosome pairs, resulting in crossovers (COs). COs are necessary to ensure faithful chromosome segregation during meiosis, and thus fertility, but are also an important source of genetic variation. As such, CO formation is tightly regulated. Despite this, CO frequency can be altered by external factors, such as temperature. In Arabidopsis thaliana, COs are formed through two pathways: interference-sensitive (Type I) and interference-insensitive (Type II). An increase in temperature results in an increase in CO frequency. Using a pollen based assay, we show that COs are formed in the Type I pathway, which accounts for approximately 85% of the COs in Arabidopsis. To investigate whether temperature-dependent COs are the result of additional DSBs, we used immunological staining to examine protein foci, which mark the sites of DSBs. We discovered that temperature likely increases CO frequency by shifting alternative repair outcomes, called non-crossovers, to favor additional COs, rather than by increasing DSBs. Lastly, we found that temperature is not a general stress response, as plants subject to salt stress did not exhibit an increase in CO frequency. Our results may prove valuable in aiding plant breeding by enhancing our ability to rapidly introgress suites of elite traits from wild-plants into their crop relatives, a method that is particularly attractive as it does not require genetic modifications.

Protective Effect of Human Leukocyte Antigen (HLA) Allele DRB1*13:02 on Age-Related Brain Gray Matter Volume Reduction in Healthy Women

BACKGROUND

Reduction of brain volume (brain atrophy) during healthy brain aging is well documented and dependent on genetic, lifestyle and environmental factors. Here we investigated the possible dependence of brain gray matter volume reduction in the absence of the Human Leukocyte Antigen (HLA) allele DRB1*13:02 which prevents brain atrophy in Gulf War Illness (James et al., 2017).

METHODS

Seventy-one cognitively healthy women (32-69years old) underwent a structural Magnetic Resonance Imaging (sMRI) scan to measure the volumes of total gray matter, cerebrocortical gray matter, and subcortical gray matter. Participants were assigned to two groups, depending on whether they lacked the DRB1*13:02 allele (No DRB1*13:02 group, N=60) or carried the DRB1*13:02 allele (N=11). We assessed the change of brain gray matter volume with age in each group by performing a linear regression where the brain volume (adjusted for total intracranial volume) was the dependent variable and age was the independent variable.

FINDINGS

In the No DRB1*13:02 group, the volumes of total gray matter, cerebrocortical gray matter, and subcortical gray matter were reduced highly significantly. In contrast, none of these volumes showed a statistically significant reduction with age in the DRB1*13:02 group.

INTERPRETATION

These findings document the protective effect of DRB1*13:02 on age-dependent reduction of brain gray matter in healthy individuals. Since the role of this allele is to connect to matching epitopes of external antigens for the subsequent production of antibodies and elimination of the offending antigen, we hypothesize that its protective effect may be due to the successful elimination of such antigens to which we are exposed during the lifespan, antigens that otherwise would persist causing gradual brain atrophy. In addition, we consider a possible beneficial role of DRB1*13:02 attributed to its binding to cathepsin S, a known harmful substance in brain aging (Wendt et al., 2008). Of course, other factors covarying with the presence of DRB1*13:02 could be involved.

Human Leukocyte Antigen (HLA) and Gulf War Illness (GWI): HLA-DRB1*13:02 Spares Subcortical Atrophy in Gulf War Veterans

Background

Gulf War Illness (GWI) is a multisystem disorder that has affected a substantial number of veterans who served in the 1990–91 Gulf War. The brain is prominently affected, as manifested by the presence of neurological, cognitive and mood symptoms. We reported previously on the protective role of six Human Leukocyte Antigen (HLA) alleles in GWI (Georgopoulos et al., 2016) and their association with regional brain function (James et al., 2016). More recently, we reported on the presence of subcortical brain atrophy in GWI (Christova et al., 2017) and discussed its possible relation to immune mechanisms. Here we focused on one of the six HLA GWI-protective HLA alleles, DRB1*13:02, which has been found to have a protective role in a broad range of autoimmune diseases (Furukawa et al., 2017), and tested its effects on brain volumes.

Methods

Seventy-six Gulf War veterans (55 with GWI and 21 healthy controls) underwent a structural Magnetic Resonance Imaging (sMRI) scan to measure the volumes of 9 subcortical brain regions to assess differences between participants with (N = 11) and without (N = 65) HLA class II allele DRB1*13:02.

Findings

We found that DRB1*13:02 spared subcortical brain atrophy in Gulf War veterans; overall subcortical volume was 6.6% higher in carriers of DRB1*13:02 (P = 0.007). The strongest effect was observed in the volume of cerebellar gray matter which was 9.6% higher (P = 0.007) in carriers of DRB1*13:02 than in non-carriers. By contrast, DRB1*13:01 had no effect.

Interpretation

These findings document the protective effect of DRB1*13:02 on brain atrophy in Gulf War veterans and are in keeping with recent results documenting sharing of brain mechanisms between GWI and other immune-related diseases (Georgopoulos et al., 2017). We hypothesize that the protective role of DRB1*13:02 is due to its successful elimination of external antigens to which Gulf War veterans were exposed, antigens that otherwise would persist causing low-grade inflammation and possibly leading to autoimmunity.

Funding source

U.S. Department of Defense (W81XWH-15-1-0520), Department of Veterans Affairs, American Legion Brain Sciences Chair, and University of Minnesota.

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Subcortical brain atrophy is spared in Gulf War veterans with DRB1*13:02 allele and unaffected by the DRB1*13:01 allele.

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The strongest protective effect of the DRB1*13:02 allele was observed for cerebellar gray matter volume.

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No significant effects were observed at the DRB1*13 gene level, highlighting the importance of 4-digit HLA protein level.

Gulf War Illness (GWI) is a chronic, debilitating disorder that prominently involves the brain and is characterized, in particular, by subcortical brain atrophy. Protective effects of specific Human Leukocyte Antigen (HLA) Class II alleles on GWI have been observed, suggesting immune system involvement in GWI. Here we evaluated protective effects of DRB1*13:02 on subcortical brain volume in Gulf War veterans. The results demonstrate a protective effect of DRB1*13:02 on brain atrophy, with a marked effect on cerebellar gray matter volume. Given the goal of HLA Class II alleles is to eliminate pathogens by producing antibodies against them, the present study provides compelling insights into the likely role of persistent, pathogenic antigens resulting from the absence of DRB1*13:02 in those with GWI.

Gulf War illness (GWI) as a neuroimmune disease

Gulf War illness (GWI) is a chronic disease characterized by the involvement of several organs, including the brain (Christova et al., Exp Brain Res doi: 10.1007/s00221-017-5010-8 , 2017). In a previous study (Georgopoulos et al., J Neural Eng 4:349-355, 2015), we identified six protective alleles from Class II human leukocyte antigen (HLA) genes, and more recently, we investigated the brain correlates of this protection (James et al., EBioMedicine 13:72-79, 2016). Those and other studies (Israeli, Lupus, 21:190-194, 2012) suggested an involvement of the immune system in GWI. In a recent study (Engdahl et al., EBioMedicine doi: 10.1016/j.ebiom.2016.08.030 , 2016), we showed that the brain pattern of synchronous neural interactions (SNI; Georgopoulos et al., J Neural Eng 4:349-355, 2007) in GWI is distinctly different from that in healthy controls. Here we focused on the SNI itself, as a basic measure of neural communication (irrespective of specific connections) and compared it between GWI and seven other diseases that cover a broad spectrum of etiology and pathophysiology. Specifically, we sought to determine which, if any, of those diseases might resemble GWI SNI, overall and within the HLA protective domain, and thus gain further knowledge regarding the nature of GWI brain abnormality. We studied a total of 962 participants from a healthy control population (N = 583) and eight different diseases, including GWI (N = 40), schizophrenia (SZ; N = 21), Alzheimer's disease (AD; N = 66), posttraumatic stress disorder (PTSD; N = 159), major depressive disorder (MDD; N = 10), relapsing-remitting multiple sclerosis (RRMS; N = 43), Sjögren's syndrome (SS; N = 32), and rheumatoid arthritis (RA; N = 8). They all underwent a resting-state magnetoencephalographic (MEG) scan to calculate SNIs. Data were analyzed using analysis of covariance (ANCOVA) with disease as fixed factor, and sex and age as covariates. We found that GWI SNIs differed significantly from control SZ, AD, PTSD and MDD but not from RRMS, SS and RA. In addition, we compared GWI to RRMS, SS and RA with respect to SNIs of MEG sensor pairs that were related to the HLA alleles protective for GWI (James et al., EBioMedicine 13:72-79, 2016). We found that GWI SNIs did not differ significantly from any of these three diseases but they did so from control SZ, AD, PTSD and MDD. These findings indicate that (a) GWI brain synchronicity does not differ significantly from that of known immune-related diseases (RRMS, SS, RA), and (b) that this SNI similarity is present within the HLA-related SNIs. In contrast, GWI SNIs differed significantly from those of the other diseases. We conclude that altered brain communication in GWI likely reflects immune-related processes, as postulated previously (James et al., EBioMedicine 13:72-79, 2016). By extension, these findings also indicate that functional brain abnormalities in RRMS, SS and RA might be, in part, due to lack of protective HLA alleles as documented for GWI (Georgopoulos et al., EBioMedicine 3:79-85, 2015).

Use of Supramolecular Assemblies as Lithographic Resists

A new resist material for electron beam lithography has been created that is based on a supramolecular assembly. Initial studies revealed that with this supramolecular approach, high-resolution structures can be written that show unprecedented selectivity when exposed to etching conditions involving plasmas.

First Results from a Microwave Cavity Axion Search at 24 μeV

We report on the first results from a new microwave cavity search for dark matter axions with masses above 20  μeV. We exclude axion models with two-photon coupling g_{aγγ}≳2×10^{-14}  GeV^{-1} over the range 23.55<m_{a}<24.0  μeV. These results represent two important achievements. First, we have reached cosmologically relevant sensitivity an order of magnitude higher in mass than any existing limits. Second, by incorporating a dilution refrigerator and Josephson parametric amplifier, we have demonstrated total noise approaching the standard quantum limit for the first time in an axion search.

Safety of Computer Interpretation of Normal Triage Electrocardiograms

OBJECTIVES

Frequent interruptions within the emergency department may lead to errors that negatively impact patient care. The immediate review of electrocardiograms (ECGs) obtained from triage patients is one source of interruption. Limiting triage ECGs requiring immediate attending review to those interpreted by the computer as abnormal may be one way to reduce interruption. We hypothesize that triage ECGs interpreted by the computer as "normal ECG" are unlikely to have clinical significance that would affect triage care.

METHODS

All triage ECGs performed at the University of North Carolina were collected between November 14, 2014, and March 3, 2015, according to a standard nursing triage protocol using GE machines running Marquette 12SL software. Triage ECGs with a computer interpretation of "normal ECG" were compared to an attending cardiologist's final interpretation. Triage ECGs for which the cardiologist's interpretation differed from the computer interpretation of normal ECG were presented to two emergency physicians (EPs) blinded to the goals of the study. The physicians were asked to evaluate the ECG for clinical significance. Clinical significance was defined as any change from normal that would alter triage care. Triage ECGs were considered true negatives if either the cardiologist agreed with the normal computer interpretation or if both EPs agreed that the ECG did not show clinical significance.

RESULTS

A total of 855 triage ECGs were collected over 16 weeks. A total of 222 (26%) were interpreted by the computer as normal. The negative predictive value for a triage ECGs interpreted by the computer as "normal" was calculated to be 99% (95% confidence interval = 97% to 99%). Of the ECGs with a computer interpretation of normal ECG, 13 had an interpretation by an attending cardiologist other than normal. Two attending EPs reviewed these triage ECGs. One of the 13 ECGs was found to have clinical significance that would alter triage care by one of the EPs. The stated triage intervention was "bed immediately."

CONCLUSIONS

Our data suggest that triage ECGs identified by the computer as normal are unlikely to have clinical significance that would change triage care. Eliminating physician review of triage ECGs with a computer interpretation of normal may be a safe way to improve patient care by decreasing physician interruptions.

A Magnetoencephalographic (MEG) Study of Gulf War Illness (GWI)

BACKGROUND

Gulf War Illness (GWI) has affected many Gulf War veterans. It involves several organs, most notably the brain. Neurological-cognitive-mood-related symptoms frequently dominate and are at the root of chronic ill-health and disability in GWI. Here we investigated the neural mechanisms underlying brain dysfunction in GWI in the absence of mental health disorders.

METHODS

Eighty-six veterans completed diagnostic interviews to establish the presence of GWI and assess mental health status. Participants diagnosed with GWI met both Center for Disease Control and Kansas criteria. We studied 46 healthy controls and 40 veterans with GWI without mental illness. They all underwent a resting-state magnetoencephalographic (MEG) scan to assess brain communication based on synchronous neural interactions (SNI; Georgopoulos et al., 2007).

FINDINGS

We found substantial differences in SNI between control and GWI groups centered on the cerebellum and frontal cortex. In addition, using the maxima and minima of SNI per sensor as predictors, we successfully classified 94.2% of the 86 participants (95% sensitivity, 93.5% specificity).

INTERPRETATION

These findings document distinct differences in brain function between control and GWI in the absence of mental health comorbidities, differences that are excellent predictors of GWI.

FUNDING

U.S. Department of Veterans Affairs and University of Minnesota.

Postmating transcriptional changes in the female reproductive tract of the European corn borer moth

Mating triggers a cascade of physiological and behavioural responses in females that persist after copulation. In insects, seminal fluid proteins contained within male ejaculates are known to initiate some responses, but our understanding of how females mediate these reactions remains limited. Few studies have examined postmating transcriptional changes within ejaculate-receiving organs within females or how these changes might depend on the identity of the male. Furthermore, whereas males of many insects transfer packaged ejaculates, transcriptional dynamics have mainly been examined in dipterans, in which males transfer a free ejaculate. To identify genes that may be important in mediating female physiological responses in a spermatophore-producing species, we sequenced the transcriptomes of the ejaculate-receiving organs and examined postmating gene expression within and between pheromone strains of the European corn borer (ECB) moth, Ostrinia nubilalis. After within-strain mating, significant differential expression of 978 transcripts occurred in the female bursa or its associated bursal gland, including peptidases, transmembrane transporters, and hormone processing genes; such genes may potentially play a role in postmating male-female interactions. We also identified 14 transcripts from the bursal gland that were differentially expressed after females mated with cross-strain males, representing candidates for previously observed postmating reproductive isolation between ECB strains.

Cortical miscommunication after prenatal exposure to alcohol

We report on the effects of prenatal alcohol exposure on resting-state brain activity as measured by magnetoencephalography (MEG). We studied 37 subjects diagnosed with fetal alcohol spectrum disorder in one of three categories: fetal alcohol syndrome, partial fetal alcohol syndrome, and alcohol-related neurodevelopmental disorder. For each subject, the MEG signal was recorded for 60 s during rest while subjects lay supine. Using time series analysis, we calculated the synchronous neural interactions for all pair-wise combinations of 248 MEG sensors resulting in 30,628 partial correlations for each subject. We found significant differences from control subjects in 6.19 % of the partial zero-lag crosscorrelations (synchronous neural interactions; Georgopoulos et al. in J Neural Eng 4:349-355, 2007), with these differences localized in the right posterior frontal, right parietal, and left parietal/posterior frontal regions. These results show that MEG can detect functional brain differences in the individuals affected by prenatal exposure to alcohol. Furthermore, these differences may serve as a biomarker for future studies linking symptoms and signs to specific brain areas. This may lead to new insights into the neuropathology of fetal alcohol spectrum disorders.

Expression of CD11c and EMR2 on neutrophils: potential diagnostic biomarkers for sepsis and systemic inflammation

There is a need for cellular biomarkers to differentiate patients with sepsis from those with the non-infectious systemic inflammatory response syndrome (SIRS). In this double-blind study we determined whether the expression of known (CD11a/b/c, CD62L) and putative adhesion molecules [CD64, CD97 and epidermal growth factor (EGF)-like molecule containing mucin-like hormone receptor (EMR2)] on blood neutrophils could serve as useful biomarkers of infection and of non-infectious SIRS in critically ill patients. We studied 103 patients with SIRS, 83 of whom had sepsis, and 50 healthy normal subjects, using flow cytometry to characterize neutrophils phenotypically in whole blood samples. Patients with SIRS had an increased prevalence of neutrophils expressing CD11c, CD64 and EMR2 in comparison with healthy subjects (P < 0.001), but normal expression of CD11a, CD11b, CD62L and CD97. An increase in the percentage of neutrophils bearing CD11c was associated with sepsis, EMR2 with SIRS and CD64 with sepsis and SIRS. Neutrophils expressing CD11c had the highest sensitivity (81%) and specificity (80%) for the detection of sepsis, and there was an association between the percentage of neutrophils expressing EMR2 and the extent of organ failure (P < 0.05). Contrary to other reports, we did not observe an abnormal expression of CD11b or CD62L on neutrophils from patients with SIRS, and suggest that this discrepancy is due to differences in cell processing protocols. We propose that blood neutrophils expressing CD11c and EMR2 be considered as potential biomarkers for sepsis and SIRS, respectively.

Diagnosis of posttraumatic stress disorder (PTSD) based on correlations of prewhitened fMRI data: outcomes and areas involved

Successful diagnosis of PTSD has been achieved using neural correlations from prewhitened magnetoencephalographic (MEG) time series (Georgopoulos et al. in J Neural Eng 7:16011, 2010. doi:10.1088/1741-2560/7/1/016011; James et al. 2015). Here, we show that highly successful classification of PTSD and control subjects can be obtained using neural correlations from prewhitened resting-state fMRI data. All but one PTSD (14/15; sensitivity = 93.3 %) and all but one control (20/21; specificity = 95.2 %) subjects were correctly classified using 15 out of 2701 possible correlations between 74 brain areas. In contrast, correlations of the same but non-prewhitened data yielded chance-level classifications. We conclude that, if properly processed, fMRI has the prospect of aiding significantly in PTSD diagnosis. Twenty-five brain areas were most prominently involved in correct subject classification, including areas from all cortical lobes and the left pallidum.

Photonic-band-gap traveling-wave gyrotron amplifier

We report the experimental demonstration of a gyrotron traveling-wave-tube amplifier at 250 GHz that uses a photonic band gap (PBG) interaction circuit. The gyrotron amplifier achieved a peak small signal gain of 38 dB and 45 W output power at 247.7 GHz with an instantaneous -3  dB bandwidth of 0.4 GHz. The amplifier can be tuned for operation from 245-256 GHz. The widest instantaneous -3  dB bandwidth of 4.5 GHz centered at 253.25 GHz was observed with a gain of 24 dB. The PBG circuit provides stability from oscillations by supporting the propagation of transverse electric (TE) modes in a narrow range of frequencies, allowing for the confinement of the operating TE03-like mode while rejecting the excitation of oscillations at nearby frequencies. This experiment achieved the highest frequency of operation for a gyrotron amplifier; at present, there are no other amplifiers in this frequency range that are capable of producing either high gain or high output power. This result represents the highest gain observed above 94 GHz and the highest output power achieved above 140 GHz by any conventional-voltage vacuum electron device based amplifier.

Neural network modulation by trauma as a marker of resilience: differences between veterans with posttraumatic stress disorder and resilient controls

IMPORTANCE

Posttraumatic stress disorder (PTSD) and resilience reflect 2 distinct outcomes after exposure to potentially traumatic events. The neural mechanisms underlying these different outcomes are not well understood.

OBJECTIVE

To examine the effect of trauma on synchronous neural interactions for veterans with PTSD and resilient controls using magnetoencephalography.

DESIGN

Participants underwent diagnostic interviews, a measure of exposure to potentially traumatic events, and magnetoencephalography.

SETTING

U.S. Department of Veterans Affairs medical center.

PARTICIPANTS

Eighty-six veterans with PTSD and 113 resilient control veterans recruited from a large Midwestern Medical Center.

MAIN OUTCOME MEASURES

Multiple regression analyses were performed to examine the effect of lifetime trauma on global and local synchronous neural interactions. In analyses examining the local synchronous neural interactions, the partial regression coefficient indicates the strength and direction of the effect of trauma on the synchronous interactions between the 2 neural signals recorded by a pair of sensors. The partial regression coefficient, or slope, is the primary outcome measure for these analyses.

RESULTS

Global synchronous neural interactions were significantly modulated downward with increasing lifetime trauma scores in resilient control veterans (P = .003) but not in veterans with PTSD (P = .91). This effect, which was primarily characterized by negative slopes (i.e., decorrelations) in small neural networks, was strongest in the right superior temporal gyrus. Significant negative slopes were more common, stronger, and observed between sensors at shorter distances than positive slopes in both hemispheres (P < .001 for all) for controls but not for veterans with PTSD. CONCLUSIONS. Neural modulation involving decorrelation of neural networks in the right superior temporal gyrus and, to a lesser extent, other areas distinguishes resilient veterans from those with PTSD and is postulated to have an important role in healthy response to trauma.

Deep genome-wide measurement of meiotic gene conversion using tetrad analysis in Arabidopsis thaliana

Gene conversion, the non-reciprocal exchange of genetic information, is one of the potential products of meiotic recombination. It can shape genome structure by acting on repetitive DNA elements, influence allele frequencies at the population level, and is known to be implicated in human disease. But gene conversion is hard to detect directly except in organisms, like fungi, that group their gametes following meiosis. We have developed a novel visual assay that enables us to detect gene conversion events directly in the gametes of the flowering plant Arabidopsis thaliana. Using this assay we measured gene conversion events across the genome of more than one million meioses and determined that the genome-wide average frequency is 3.5×10(-4) conversions per locus per meiosis. We also detected significant locus-to-locus variation in conversion frequency but no intra-locus variation. Significantly, we found one locus on the short arm of chromosome 4 that experienced 3-fold to 6-fold more gene conversions than the other loci tested. Finally, we demonstrated that we could modulate conversion frequency by varying experimental conditions.

A compact and realistic cerebral cortical layout derived from prewhitened resting-state fMRI time series: Cherniak's adjacency rule, size law, and metamodule grouping upheld

We used hierarchical tree clustering to derive a functional organizational chart of 52 human cortical areas (26 per hemisphere) from zero-lag correlations calculated between single-voxel, prewhitened, resting-state BOLD fMRI time series in 18 subjects. No special “resting-state networks” were identified. There were four major features in the resulting tree (dendrogram). First, there was a strong clustering of homotopic, left-right hemispheric areas. Second, cortical areas were concatenated in multiple, partially overlapping clusters. Third, the arrangement of the areas revealed a layout that closely resembled the actual layout of the cerebral cortex, namely an orderly progression from anterior to posterior. And fourth, the layout of the cortical areas in the tree conformed to principles of efficient, compact layout of components proposed by Cherniak. Since the tree was derived on the basis of the strength of neural correlations, these results document an orderly relation between functional interactions and layout, i.e., between structure and function.

Determinants of reproductive success across sequential episodes of sexual selection in a firefly

Because females often mate with multiple males, it is critical to expand our view of sexual selection to encompass pre-, peri- and post-copulatory episodes to understand how selection drives trait evolution. In Photinus fireflies, females preferentially respond to males based on their bioluminescent courtship signals, but previous work has shown that male paternity success is negatively correlated with flash attractiveness. Here, we experimentally manipulated both the attractiveness of the courtship signal visible to female Photinus greeni fireflies before mating and male nuptial gift size to determine how these traits might each influence mate acceptance and paternity share. We also measured pericopulatory behaviours to examine their influence on male reproductive success. Firefly males with larger spermatophores experienced dual benefits in terms of both higher mate acceptance and increased paternity share. We found no effect of courtship signal attractiveness or pericopulatory behaviour on male reproductive success. Taken together with previous results, this suggests a possible trade-off for males between producing an attractive courtship signal and investing in nuptial gifts. By integrating multiple episodes of sexual selection, this study extends our understanding of sexual selection in Photinus fireflies and provides insight into the evolution of male traits in other polyandrous species.

The use of the white cell count and haemoglobin in combination as an effective screen to predict the normality of the full blood count

INTRODUCTION

The utility of the full blood count (FBC) is vast with each parameter serving as a tool to aid diagnosis and monitor disease progression. However, the effectiveness of the test is hampered because of increased workload and lack of interpretation. In the effort to redress this issue, the combined use of the white blood cell count (WBC) and haemoglobin in predicting the normality of the FBC is evaluated.

METHOD

FBC data were collated from 2191 patients and classified into two groups depending on whether the WBC and the haemoglobin were within the reference range. Blood films were examined on the abnormal FBC samples in each group and graded on morphology.

RESULTS

The FBC was normal in 89.6% of cases in the presence of a normal WBC and haemoglobin with subtle abnormalities in the remainder; 1+ grading of abnormal morphology in 93%. However, when the WBC and/or haemoglobin was abnormal, the remaining FBC was significantly abnormal (P < 0.05) and the corresponding blood films were grossly abnormal; 2+/3+ grading in 96% of cases.

CONCLUSION

We concluded that in the presence of a normal WBC and haemoglobin, the FBC is normal in almost all cases and measuring these two parameters could be used as an effective screen to predict FBC normality.

Identification of predicted seminal fluid proteins in Tribolium castaneum

In several insect species, seminal fluid proteins (SFPs) have been demonstrated to be key regulators of male and female fitness through their ability to alter female physiology and behaviour. Tribolium castaneum is an economically important pest species and a model system for sexual selection research, but little is known about SFPs in this insect. To create a foundation for the study of T. castaneum SFPs, we used mass spectrometry to identify putative SFPs by comparing proteins detected in the male reproductive glands with those found in the reproductive tracts of virgin and mated females. Fourteen putative SFPs, thirteen with male biased expression, were identified through this approach. We also used reverse transcription PCR (RT-PCR) to examine expression levels across different tissue types. We found strongly male-biased expression in 13 genes, nine of which were expressed only in male accessory gland tissue. This represents the first proteomic-based method of identifying putative SFPs in any coleopteran species, and is the first study in this species to identify putative SFPs that are likely transferred to the female. This work could lead to functional analyses of the role of SFPs in sexual selection, sexual conflict and potential control of a pest species.

True associations between resting fMRI time series based on innovations

We calculated voxel-by-voxel pairwise crosscorrelations between prewhitened resting-state BOLD fMRI time series recorded from 60 cortical areas (30 per hemisphere) in 18 human subjects (nine women and nine men). Altogether, more than a billion-and-a-quarter pairs of BOLD time series were analyzed. For each pair, a crosscorrelogram was computed by calculating 21 crosscorrelations, namely at zero lag ± 10 lags of 2 s duration each. For each crosscorrelogram, in turn, the crosscorrelation with the highest absolute value was found and its sign, value, and lag were retained for further analysis. In addition, the crosscorrelations at zero lag (irrespective of the location of the peak) were also analyzed as a special case. Based on known varying density of anatomical connectivity, we distinguished four general brain groups for which we derived summary statistics of crosscorrelations between voxels within an area (group I), between voxels of paired homotopic areas across the two hemispheres (group II), between voxels of an area and all other voxels in the same (ipsilateral) hemisphere (group III), and voxels of an area and all voxels in the opposite (contralateral) hemisphere (except those in the homotopic area) (group IV). We found the following. (a) Most of the crosscorrelogram peaks occurred at zero lag, followed by ± 1 lag; (b) over all groups, positive crosscorrelations were much more frequent than negative ones; (c) average crosscorrelation was highest for group I, and decreased progressively for groups II-IV; (d) the ratio of positive over negative crosscorrelations was highest for group I and progressively smaller for groups II-IV; (e) the highest proportion of positive crosscorrelations (with respect to all positive ones) was observed at zero lag; and (f) the highest proportion of negative crosscorrelations (with respect to all negative ones) was observed at lag = 2. These findings reveal a systematic pattern of crosscorrelations with respect to their sign, magnitude, lag and brain group, as defined above. Given that these groups were defined along a qualitative gradient of known overall anatomical connectivity, our results suggest that functional interactions between two voxels may simply reflect the density of such anatomical connectivity between the areas to which the voxels belong.

Attitudes toward genetic research review: results from a survey of human genetics researchers

BACKGROUND

Researchers often relate personal experiences of difficulties and challenges with Institutional Review Board (IRB) review of their human genetic research protocols. However, there have been no studies that document the range and frequency of these concerns among researchers conducting human genetic/genomic studies.

METHODS

An online anonymous survey was used to collect information from human genetic researchers regarding views about IRB review of genetic protocols. Logistic regression was used to test specific hypotheses. Results from the national online survey of 351 human genomic researchers are summarized in this report.

RESULTS

Issues involving considerable discussion with IRBs included reconsent of subjects (51%), protection of participants' personal information (39%) and return of results to participants (34%). Over half of the participants had experienced one or more negative consequences of the IRB review process and approximately 25% had experienced one or more positive consequences. Respondents who had served on an IRB were about 80% more likely to report positive consequences of IRB review than their colleagues who had never served on an IRB (p = 0.03). Survey responses were mixed on the need for reconsent before data sharing and risks related to participant reidentification from genomic data.

CONCLUSION

The results from this study provide important perspectives of researchers regarding genetic research review and show lack of consensus on key research ethics issues in genomic research.

ICSH review of the measurement of the erythocyte sedimentation rate

In recognition of the need for a standardization of the measurement of the erythrocyte sedimentation rate (ESR), the International Council for Standardization in Haematology makes the following recommendations: (i) The reference method for measurement of the ESR should be based on the Westergren method, which is a specific test for the ESR, with modifications, (ii) The reference method for measurement of the ESR should use either whole blood anticoagulated with EDTA and later diluted with sodium citrate or saline (4 : 1) or whole blood anticoagulated with sodium citrate (4 : 1) in Westergren pipettes, (iii) The ESR pipettes can be of glass or plastic (with specific characteristics). It must be colourless; a minimum sedimentation scale of 200 mm, a minimum bore of 2.55 mm, which should be constant within 5%. A protocol for the evaluation of alternative methodologies against the reference method is outlined: The new technologies must be tested over a range of ESR values of 2-120 mm. In this comparison, 95% of the differences should be 5 mm or less, with larger differences associated with higher ESR values. A minimum of 40 samples should be tested in 3 different groups of values: 1-20, 21-60 and more than 60 mm. The statistical methods recommended for ESR evaluations are the coefficient of correlation, the Passing-Bablock regression and the Bland-Altman statistical method. This reference method replaces all earlier standardized and reference methods.

Direct and correlated responses to artificial selection on sexual size dimorphism in the flour beetle, Tribolium castaneum

Sexual size dimorphism (SSD) is a conspicuous yet poorly understood pattern across many organisms. Although artificial selection is an important tool for studying the evolution of SSD, previous studies have applied selection to only a single sex or to both sexes in the same direction. In nature, however, SSD likely arises through sex-specific selection on body size. Here, we use Tribolium castaneum flour beetles to investigate the evolution of SSD by subjecting males and females to sexually antagonistic selection on body size (sexes selected in opposite directions). Additionally, we examined correlated responses to body size selection in larval growth rates and development time. After seven generations, SSD remained unchanged in all selected lines; this observed lack of response to short-term selection may be attributed to evolutionary constraints arising from between-sex body size correlations. Developmental traits showed complex correlated responses under different selection treatments. These results suggest that sex-specific larval development patterns may facilitate the evolution of SSD.

Post-traumatic stress disorder: a right temporal lobe syndrome?

In a recent paper (Georgopoulos et al 2010 J. Neural Eng. 7 016011) we reported on the power of the magnetoencephalography (MEG)-based synchronous neural interactions (SNI) test to differentiate post-traumatic stress disorder (PTSD) subjects from healthy control subjects and to classify them with a high degree of accuracy. Here we show that the main differences in cortical communication circuitry between these two groups lie in the miscommunication of temporal and parietal and/or parieto-occipital right hemispheric areas with other brain areas. This lateralized temporal-posterior pattern of miscommunication was very similar but was attenuated in patients with PTSD in remission. These findings are consistent with observations (Penfield 1958 Proc. Natl Acad. Sci. USA 44 51-66, Penfield and Perot 1963 Brain 86 595-696, Gloor 1990 Brain 113 1673-94, Banceaud et al 1994 Brain 117 71-90, Fried 1997 J. Neuropsychiatry Clin. Neurosci. 9 420-8) that electrical stimulation of the temporal cortex in awake human subjects, mostly in the right hemisphere, can elicit the re-enactment and re-living of past experiences. Based on these facts, we attribute our findings to the re-experiencing component of PTSD and hypothesize that it reflects an involuntarily persistent activation of interacting neural networks involved in experiential consolidation.

Fluorodeoxyglucose positron emission tomography of mild cognitive impairment with clinical follow-up at 3 years

BACKGROUND

Alzheimer's disease (AD) is the most common dementing illness. Development of effective treatments directed at AD requires an early diagnosis. Mild cognitive impairment (MCI) often heralds AD. Thus, characterizing MCI is fundamental to the early diagnosis of AD.

METHODS

19 MCI patients referred from a memory loss clinic and 27 healthy subjects, all followed up for 3 years. Metabolism scans (MCI minus controls) were compared voxel-wise after anatomic normalization and were examined both visually and with a computerized classifier.

RESULTS

Agreement between raters as to whether the individual scans were normal or abnormal was high. Agreement between raters of the eventual clinical diagnosis and baseline metabolic pattern was poor. A computerized classifier was unsuccessful at classifying MCI from normal; however, its performance improved when using only prototypic AD-like MCI scans, indicating the classifier worked well when shared patterns existed in the data. Outcomes on follow-up were nine of 19 AD, five of 19 remained MCI, and five of 19 developed dementias other than AD. Both MCI cases of early Lewy body dementia (LBD) showed an AD-like metabolic pattern.

CONCLUSIONS

Visual inspection proved reliable in determining normal from abnormal scans, but it proved unreliable at predicting diagnosis on follow-up. Computerized classification of MCI by using an AD-like metabolic template (such as derived from the averaged MCI images) showed potential to identify patients who will develop AD. However, the metabolic pattern in early LBD did not differ from that in AD.

The synchronous neural interactions test as a functional neuromarker for post-traumatic stress disorder (PTSD): a robust classification method based on the bootstrap

Traumatic experiences can produce post-traumatic stress disorder (PTSD) which is a debilitating condition and for which no biomarker currently exists (Institute of Medicine (US) 2006 Posttraumatic Stress Disorder: Diagnosis and Assessment (Washington, DC: National Academies)). Here we show that the synchronous neural interactions (SNI) test which assesses the functional interactions among neural populations derived from magnetoencephalographic (MEG) recordings (Georgopoulos A P et al 2007 J. Neural Eng. 4 349-55) can successfully differentiate PTSD patients from healthy control subjects. Externally cross-validated, bootstrap-based analyses yielded >90% overall accuracy of classification. In addition, all but one of 18 patients who were not receiving medications for their disease were correctly classified. Altogether, these findings document robust differences in brain function between the PTSD and control groups that can be used for differential diagnosis and which possess the potential for assessing and monitoring disease progression and effects of therapy.

Point-of-care method for total white cell count: an evaluation of the HemoCue WBC device

Point-of-care testing (POCT) is becoming an important adjunct to haematology laboratory practice. An important component of the blood count is the total white cell count (WBC). Previously, this required laborious microscopic cell counting, but it can now be performed by means of automation; however, in many under-resourced countries, costly automated counters are only available in very few central hospitals. Moreover, neither method is practical in most POCT situations. The HemoCue WBC has been developed as a simplified alternative method, consisting of a reagent pre-loaded disposable cuvette together with basic image analysis technology. This report describes an assessment of its utility. The WBC of 500 routine blood samples from the hospital were tested in parallel by the HemoCue WBC and by a reference analyser to assess accuracy and utility of the former. The tests included precision, linearity, type of blood sample and anticoagulant and potential interfering substances in blood specimens. In the tests for accuracy, 192 of the 200 showed percentage difference from the NEQAS reference of <10% whilst the remaining eight samples differed by <12%, thus meeting the requirements of Clinical laboratory improvement amendments (CLIA)-88 regulations. Of the samples tested with potential interfering substances only those with >2% normoblasts or reticulocytosis showed significant differences from the reference measurements. The HemoCue WBC is reliable for WBC counts within the analytical range of 0.4-30.0 x 10(9)/l, except in samples where there are significant numbers of normoblasts or reticulocytes. It is simple to use and provides a valuable advance in the facilities available for POCT in haematology.

Standardization and harmonization of the blood count: the role of International Committee for Standardization in Haematology (ICSH)

Scientific principles of standardization were first applied in haematology in 1963 when the International Committee for Standardization in Haematology was established with a primary objective to improve the measurement of haemoglobin. Subsequently, ICSH has established Expert Panels on a wide range of haematological topics, including especially a Panel on Cytometry. The purpose of haematological standardization is to obtain precision, accuracy, specificity and harmonization of results between different laboratories in all countries and also between different instruments or methods in the same laboratory. To achieve these objectives ICSH sponsors collaborative studies by scientists from academic centres and from industry and uses a consensus procedure for establishing standards on the basis of the scientific data, followed by an educational programme to ensure that the standards are adopted worldwide. ICSH defines material standards and standardized methods. Material standards are classified as primary international standards, certified reference materials, secondary standards and calibrators. These must be distinguished from control preparations which are intended exclusively for quality control. Standardization of methods must also be considered at four levels: definitive, reference, selected and routine. Each has a place in practice but their roles must be clearly defined. ICSH has an established protocol for evaluation of automated blood cell counters. This defines the levels of precision and accuracy of instrument performance. It is also necessary to assess "clinical utility". The main requirement of the practising haematologist is clinical reliability and harmonization of results for comparability. One of the major functions of ICSH is to provide an interface for collaboration between the manufacturers who develop the instruments and the users in order to achieve this goal.

Cerebral cortical mechanisms of copying geometrical shapes: a multidimensional scaling analysis of fMRI patterns of activation

We used multidimensional scaling (MDS) to characterize the integrative neural mechanisms during viewing and subsequently copying nine geometrical shapes. Human subjects initially looked at a central fixation point ("rest" period), then looked at a geometrical shape ("visual" period) which they copied without visual feedback ("copying" period). BOLD signal was recorded from voxels in 28 cortical areas (14 from each hemisphere) using a 4 Tesla magnet. For each voxel, signal ratios of "Visual versus Rest" (VR), and "Copy versus Visual" (CV) were calculated and used to construct two sets of Euclidean distance dissimilarity matrices for the nine shapes, with separate matrices defined for each region of interest (ROI) across subjects. The relations of perceptual and motor aspects of the shapes to MDS dimensions and specific ROIs were assessed using stepwise multiple regressions. The optimal individually scaled (INDSCAL) solutions were 2-dimensional. For the VR condition, MDS dimensions were significantly associated with the presence of crossing in a shape (Dimension 1), and with perimeter, height, cycles, peak segment speed, and horizontal symmetry (Dimension 2). ROIs most prominently associated with these dimensions essentially comprised the medial frontal lobe bilaterally, the inferior frontal gyrus bilaterally, and the left intraparietal sulcus (Dimension 1), and visual areas, including the calcarine sulcus and cuneus bilaterally (Dimension 2). These results document the expected involvement of visual areas and support the hypothesis advanced on the basis of previous findings (Lewis et al. 2003a) that a motor rehearsal of the upcoming shape copying is occurring during this visual presentation period. For the CV condition, practically one motor feature (number of segments drawn) dominated both dimensions, with a secondary engagement of horizontal symmetry in Dimension 1. The right postcentral gyrus, right intraparietal sulcus, right superior parietal lobule and right inferior parietal lobule contributed mostly to Dimension 1; the superior frontal gyrus bilaterally, right middle frontal gyrus, left postcentral gyrus, left inferior parietal lobule contributed mostly to Dimension 2; and the left superior parietal lobule and left intraparietal sulcus contributed to both dimensions approximately equally. CV BOLD activation of ROIs contributing to Dimension 1 (or to both dimensions) was significantly associated with the number of shape segments drawn. Since the direction of movement differs in successively drawn shape segments, the number of segments (minus one) equals the number of changes in the direction of movement. We conclude that this fundamental spatial motor aspect of drawing geometrical shapes is the critical variable, independent of the particular shape drawn, that dominates cortical activation during copying.