Electrically controlled topological micro cargo transportation.

We demonstrate electrically controlled linear translation and precision positioning of a colloidal particle in a soft matter device. The basis of transportation is the time dependent electric field reconfiguration and manipulation of a topological line defect between two distinct hybrid aligned nematic liquid crystal domains having opposing tilt orientations. Deliberately tuning an applied voltage relative to a low threshold value (5.7 V at 1 kHz) permits defect trapping of the colloidal particle and allows subsequent control over the particle's velocity and bidirectional linear movement over millimeter distances, without the need for externally imposed flow nor for lateral confining walls.

Adenosine diphosphate platelet dysfunction on thromboelastogram is independently associated with increased morality in traumatic brain injury.

PURPOSE: The purpose of this study is to determine if adenosine diphosphate (ADP) platelet dysfunction on thromboelastogram (TEG) is associated with increased in-hospital mortality in patients with head trauma. The hypothesis is that ADP dysfunction is associated with increased mortality. METHODS: This retrospective review evaluated trauma patients admitted to a level 1 trauma center from February 2011 to October 2013 who received a TEG. Patients were included if the TEG was drawn within the first 24 h of admission and the head abbreviated injury score was greater than or equal to three. Patients were categorized as severe ADP dysfunction if the degree of ADP inhibition on TEG exceeded 60 %. RESULTS: A total of 90 patients were included (no ADP dysfunction n = 37; ADP dysfunction n = 53). Initial Glasgow Coma Scale [GCS (12 ± 4 vs. 11 ± 5; p = 0.26)] and use of pre-injury antiplatelet agents (30 vs. 28 %; p = 0.88) were similar. Patients with ADP dysfunction on TEG had a higher in-hospital mortality rate (8 vs. 32 %; p < 0.01). ADP dysfunction was independently associated with in-hospital mortality upon fixed logistic regression (OR 6.2; 95 % CI 1.2-33) while controlling for age, gender, hypotension, pre-injury antiplatelet agents, GCS and Injury Severity Score. CONCLUSION: ADP dysfunction on TEG is associated with increased mortality in patients with traumatic brain injury.

Dynamic response of a thin sessile drop of conductive liquid to an abruptly applied or removed electric field.

We consider, both theoretically and experimentally, a thin sessile drop of conductive liquid that rests on the lower plate of a parallel-plate capacitor. We derive analytical expressions for both the initial deformation and the relaxation dynamics of the drop as the electric field is either abruptly applied or abruptly removed, as functions of the geometrical, electrical, and material parameters, and investigate the ranges of validity of these expressions by comparison with full numerical simulations. These expressions provide a reasonable description of the experimentally measured dynamic response of a drop of conductive ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate.

Flow-induced delayed Freedericksz transition.

We demonstrate that a compact manometer experiment allows direct observation of a delay to the classical electric-field-induced Freedericksz transition produced by flow in a highly dispersive nematic liquid crystal layer. The Ericksen-Leslie equations are used to show that a flow aligning torque generated in the nematic layer under Poiseuille flow competes with the orthogonal electric-field reorientation torque. This model fully reproduces the experimental results using only self-consistently determined viscosity values, and predicts a more generally applicable expression for the dependence of the delay E(c)∝sqrt[ζ/Δχ(e)] on the shear rate ζ and on the electric susceptibility anisotropy Δχ(e).

Voltage-induced spreading and superspreading of liquids.

The ability to quickly spread a liquid across a surface and form a film is fundamental for a diverse range of technological processes, including printing, painting and spraying. Here we show that liquid dielectrophoresis or electrowetting can produce wetting on normally non-wetting surfaces, without needing modification of the surface topography or chemistry. Additionally, superspreading can be achieved without needing surfactants in the liquid. Here we use a modified Hoffman-de Gennes law to predict three distinct spreading regimes: exponential approach to an equilibrium shape, spreading to complete wetting obeying a Tanner's law-type relationship and superspreading towards a complete wetting film. We demonstrate quantitative experimental agreement with these predictions using dielectrophoresis-induced spreading of stripes of 1,2 propylene glycol. Our findings show how the rate of spreading of a partial wetting system can be controlled using uniform and non-uniform electric fields and how to induce more rapid superspreading using voltage control.

Dielectrowetting driven spreading of droplets.

The wetting of solid surfaces can be modified by altering the surface free energy balance between the solid, liquid, and vapor phases. Here we show that liquid dielectrophoresis induced by nonuniform electric fields can be used to enhance and control the wetting of dielectric liquids. In the limit of thick droplets, we show theoretically that the cosine of the contact angle follows a simple voltage squared relationship analogous to that found for electrowetting on dielectric. Experimental observations confirm this predicted dielectrowetting behavior and show that the induced wetting is reversible. Our findings provide a noncontact electrical actuation process for meniscus and droplet control.

Alcohol exposure and outcomes in trauma patients.

OBJECTIVE: To determine the injury patterns, complications, and mortality after alcohol consumption in trauma patients. METHODS: The Trauma Registry at an American College of Surgeons (ACS) level I center was queried for all patients with a toxicology screen admitted between 1st January 2002 and 31st December 2005. Alcohol-positive (AP) patients were matched to control patients who had a completely negative screen (AN) using age, gender, mechanism, Injury Severity Score (ISS), head Abbreviated Injury Scale (AIS), chest AIS, abdominal AIS, and extremity AIS. Injuries and outcomes were compared between the groups. RESULTS: As many as 5,317 patients had toxicology data, of which 471 (8.9%) had a positive alcohol screen (AP). A total of 386 AP patients were then matched to 386 control (AN) patients. The AP group had a significantly higher mortality than the AN group overall (23 vs. 13%; p < 0.001), and by ISS stratification: ISS < 16 (6 vs. 0.4%; p < 0.001), ISS 16-25 (53 vs. 28%; p = 0.01), and ISS > 25 (90 vs. 67%; p = 0.01). AP patients had a higher incidence of admission systolic blood pressure < 90 (18 vs. 10%; p < 0.001) and Glasgow Coma Scale (GCS) score ≤ 8 (25 vs. 17%; p = 0.002). AN patients had a significantly higher incidence of hemopneumothorax (11 vs. 7%; p = 0.03), while AP patients had a higher incidence of cardiac arrest (8 vs. 3%; p = 0.004). There was no difference in intensive care unit (ICU) and hospital length of stay. CONCLUSION: In a mixed population of trauma patients, an AP screen is associated with an increased incidence of admission hypotension and depressed GCS score. In this case-matched study, alcohol exposure appeared to increase mortality after injury.

Defect trajectories and domain-wall loop dynamics during two-frequency switching in a bistable azimuthal nematic device.

Bistable azimuthal nematic alignment textures have been created in micrometer-scale channels for which one sidewall is smooth and straight and the other possesses a symmetric sawtooth morphology. The optical textures have been observed during dynamic switching between the two stable states in response to dual frequency ac waveform driving of a highly dispersive nematic liquid crystal. The switching processes involves collapsing of filamentlike director reorientation (tilt-wall) loops and the associated motion and annihilation of surface defects along and close to the edge at the sawtooth sidewall. The predictions from both the n-director-based Ericksen-Leslie theory and the Q-tensor theory are in good agreement with the experimental observations.

Theoretical analysis of the magnetic Fréedericksz transition in the presence of flexoelectricity and ionic contamination.

We have derived an approximate analytical expression for the static director distortion of a planar nematic layer subject to a magnetic field H immediately above the critical Fréedericksz transition H=H{c} . The layer contains a voltage-independent density of positively and negatively singly charged ionic species that interact with the flexoelectric and dielectric polarizations which appear when the director is distorted. The analytical solution is shown to correspond closely to a full numerical calculation when H/H{c}=1.01. The analytical approach allows a quantitative insight into how the mobile charge shields the polarization for different values of the elastic constants, the ionic density, the flexoelectric coefficients, and the layer thickness.

Pulsed addressing of a dual-frequency nematic liquid crystal.

A continuum theory of dielectric relaxation within liquid crystal materials is described and used to model the response of dual frequency materials to single pulse voltage waveforms. The equations governing the anisotropic axis (director) angle, electric field, and induced polarizations are solved numerically to investigate pulsed addressing of a model zenithally bistable liquid crystal device. By suitably tailoring the voltage pulse, it is found to be possible to switch between both bistable states. For short pulses the high frequency components of the leading edge of the voltage pulse excites the perpendicular polarization and forces the director to lie parallel to the cell substrates. For longer voltage pulses the constant dc component of the voltage pulse excites the parallel polarization causing the director to lie perpendicular to the substrates. It is also found that reducing rotational viscosity and increasing the achievable dielectric anisotropies (particularly the high frequency value) can significantly reduce the operating voltages of such a device.

Influence of flexoelectricity above the nematic Fréedericksz transition.

Continuum theory is used to demonstrate that the presence of flexoelectricity significantly alters the response to an applied voltage of a homogeneous nematic liquid crystal cell above the ac Fréedericksz threshold voltage. In such a system there is a fitting degeneracy: we obtain very good fits between theory and experimental permittivity data using any value of the sum of flexoelectric coefficients, e(11)+e(33), between 0.0 C/m and 1.5 x 10(-11) C/m. The corresponding values of the nematic bend elastic constant show an inverse parabolic relationship with e(11)+e(33), with K33 being reduced down to 90% of its value when flexoelectricity is neglected.

Dementia with leukoaraiosis: clinical differentiation by temporoparietal hypometabolism on (18)FDG-PET imaging.

Patients with dementia and leukoaraiosis may have either Alzheimer's disease (AD) with cerebrovascular changes or a form of vascular dementia (VaD). The presence or absence of the characteristic AD pattern of bilateral temporoparietal hypometabolism on (18)FDG-PET was used to differentiate 30 patients with progressive dementia and severe leukoaraiosis. Compared to 18 patients with the typical AD pattern (group I), the remaining 12 (group II) had better recognition memory, and greater difficulty with sustained attention and serial reversals. Better recognition memory, confluent periventricular leukoaraiosis, and poorer sustained attention distinguished all group II patients from group I. Dementia patients with severe leukoaraiosis and bilateral temporoparietal hypometabolism may have predominant AD; those who lack this pattern and have confluent leukoaraiosis may have a greater contribution from VaD. Copyrightz1999S.KargerAG,Basel

The role of positron emission tomography in occult primary head and neck cancers.

PURPOSE: To evaluate the utility of positron emission tomography (PET) fluorodeoxyglucose (FDG) imaging in the workup of unknown primary head and neck tumors. METHODS: Fourteen patients with squamous cell carcinoma of cervical lymph node metastasis of unknown primary origin (clinical stage N2-N3) were studied prospectively. The patients underwent conventional workup, including physical examination, computed tomography, and random biopsies of the potentially suspected sites. If no primary site was found, 8 to 13 mCi of FDG was given intravenously, and whole-body scans with standardized uptake values were obtained. The results of FDG-PET imaging were compared with clinical, CT, and histopathologic findings. To eliminate bias, PET scans were reviewed by nuclear medicine physicians who had no previous knowledge of the other findings. RESULTS: PET identified the location of primary tumor in three patients: lung hilum, base of tongue, and pyriform sinus. These lesions were pathologically confirmed. All these primary sites were not visualized on CT or physical examination, except for a pyriform sinus lesion, which was seen on CT, but initial biopsy result was negative. In one patient, the initial PET did not identify a primary tumor, but a nasopharyngeal carcinoma was identified in post-radiation therapy follow-up PET. In the remaining nine patients, a primary lesion was never found. All cervical lymph nodes detected by CT were identified by PET. DISCUSSION: A previously unknown primary tumor can be identified with FDG-PET in about 21% of the patients in our prospective series. PET can be of value in guiding endoscopic biopsies for histologic diagnosis and treatment options.

Primary care for women: the role of the obstetrician-gynecologist.

It is critical to understand that "one size does not fit all" in health care. Each patient is unique and involved in her own destiny. Our goal should be to maximize her health status, to provide health education, and to advocate for her health and well-being. We must implement a spectrum of primary care in the office to further expand the excellent health care that obstetrician-gynecologists have always provided to women.

Involuntary laughter and inappropriate hilarity.

Laughter is a particularly human behavior. Neuropsychiatrists are faced with disorders of laughter, yet the nature of this behavior and its disturbances remains obscure. The authors report an unusual patient with involuntary and unremitting laughter for 20 years and review the literature. The nature of laughter suggests that it has a unique role in human communication, particularly in the social exploration of incongruous information. The disorders of laughter suggest a neuroanatomical circuitry that includes the anterior cingulate gyrus, caudal hypothalamus, temporal-amygdala structures, and a pontomedullary center. Treatment includes the use of antidepressant and antimanic agents for disorders of laughter.

Specificity determinants of proteolytic processing of Aspergillus PacC transcription factor are remote from the processing site, and processing occurs in yeast if pH signalling is bypassed.

The Aspergillus nidulans transcription factor PacC, which mediates pH regulation, is proteolytically processed to a functional form in response to ambient alkaline pH. The full-length PacC form is unstable in the presence of an operational pH signal transduction pathway, due to processing to the relatively stable short functional form. We have characterized and used an extensive collection of pacC mutations, including a novel class of "neutrality-mimicking" pacC mutations having aspects of both acidity- and alkalinity-mimicking phenotypes, to investigate a number of important features of PacC processing. Analysis of mutant proteins lacking the major translation initiation residue or truncated at various distances from the C terminus showed that PacC processing does not remove N-terminal residues, indicated that processing yields slightly heterogeneous products, and delimited the most upstream processing site to residues approximately 252 to 254. Faithful processing of three mutant proteins having deletions of a region including the predicted processing site(s) and of a fourth having 55 frameshifted residues following residue 238 indicated that specificity determinants reside at sequences or structural features located upstream of residue 235. Thus, the PacC protease cuts a peptide bond(s) remote from these determinants, possibly thereby resembling type I endonucleases. Downstream of the cleavage site, residues 407 to 678 are not essential for processing, but truncation at or before residue 333 largely prevents it. Ambient pH apparently regulates the accessibility of PacC to proteolytic processing. Alkalinity-mimicking mutations L259R, L266F, and L340S favor the protease-accessible conformation, whereas a protein with residues 465 to 540 deleted retains a protease-inaccessible conformation, leading to acidity mimicry. Finally, not only does processing constitute a crucial form of modulation for PacC, but there is evidence for its conservation during fungal evolution. Transgenic expression of a truncated PacC protein, which was processed in a pH-independent manner, showed that appropriate processing can occur in Saccharomyces cerevisiae.

Functional electrical stimulation effect on skeletal muscle blood flow measured with H2(15)O positron emission tomography.

OBJECTIVE: To test the hypothesis that the limitation in muscle power development with functional electrical stimulation (FES) results from an insufficient increase in muscle blood flow (MBF) in response to activity. SUBJECTS AND METHODS: Five subjects with neurologically complete spinal cord injury (SCI) were tested to measure the MBF response to FES-induced knee extension. The MBF response to voluntary knee extension was measured in five age-matched, able-bodied controls. MBF was measured with positron emission tomography (PET) using H2(15)O as a tracer. Three scans were performed with muscle at rest (baseline), immediately after 16min of FES-induced or voluntary knee extension (activity), and 20min after the second scan (recovery). RESULTS: In SCI subjects, mean +/-SE MBF (mL/100g/min) values were: baseline = 1.85 +/- .48; post-FES = 31.9 +/- 5.65 (p = .0058 vs baseline); recovery = 6.06 +/- 1.52 (p = .0027 vs baseline). In able-bodied controls, mean +/-SE MBF values were: baseline = 8.52 +/- 3.24, post-voluntary exercise = 12.62 +/- 3.03 (p = .023 vs post-FES in SCI subjects); recovery = 10.7 +/- 6.01. CONCLUSIONS: MBF does not appear to be the limiting factor in muscle power generation with FES. The greater increase in MBF observed with FES in SCI subjects when compared with able-bodied subjects performing a similar task (unloaded knee extension against gravity) may relate to abnormal metabolism in FES-stimulated muscle.

Specific DNA recognition by the Aspergillus nidulans three zinc finger transcription factor PacC.

The three zinc fingers of PacC, the transcription factor mediating pH regulation in Aspergillus nidulans, are necessary and sufficient to recognise specifically the target ipnA2 site. Missing nucleoside footprints confirmed the core target (double-stranded) hexanucleotide 5'-GCCAAG-3'. Any base substitution resulted in substantial or complete loss of binding, excepting A5 (partially replaceable by G). A T preceding the hexanucleotide enhanced binding. Interference footprinting indicates that the four Gs and A4 participate in specific contacts and that five pyrimidines are essential for binding. The size of the target sequence and the amino acid sequence of finger 1 suggested that its probe helix would not participate in base-specific contacts. Using site-directed mutagenesis and analogy to GLI, we propose that finger 1 crucially interacts with finger 2, a pair of conserved Trp residues in the Cys knuckles contacting hydrophobically. Finger 2 would also participate in extensive base contacts with the 5' moiety of the hexanucleotide. The specificity mutation Lys159Gln shows that finger 3 binds the 3' moiety of the hexanucleotide. Replacement of residues in positions +3 (His128Asn) and +2 (Gln155Lys) of the reading helices of fingers 2 and 3, respectively, prevented binding. Our biochemical and molecular data plus modelling using previously determined zinc finger-DNA complexes, predict specific contacts of fingers 2 and 3 to ipnA2. Our data indicate compact organisation of the PacC-ipnA2 complex (with nearly every base involved in specific contacts), illustrate the binding versatility of zinc finger domains and should facilitate analysis of other PacC family members, including Saccharomyces cerevisiae RIM1.

PET scans of abdominal malignancy.

Positron emission tomography (PET) with fluorine-18-2-d-deoxyglucose (FDG) currently is being integrated into clinical oncology because it provides unique functional information that can be applied to the management of cancer. In particular, it is useful for assessing tumor activity and growth, evaluating efficacy of therapy, and detecting tumor recurrence. Studies have demonstrated the value of whole-body PET-FDG imaging when staging and managing abdominal malignancy.