178 research outputs found
Direction-sensitive graphene flow sensor
Graphene flow sensors hold great prospects for applications, but also
encounter many difficulties, such as unwanted electrochemical phenomena, low
measurable signal and limited dependence on the flow direction. This study
proposes a novel approach allowing for the detection of a flow
direction-dependent electric signal in aqueous solutions of salts, acids and
bases. The key element in the proposed solution is the use of a reference
electrode which allows external gating of the graphene structure. Using
external gating enables to enhance substantially the amplitude of the
flow-generated signal. Simultaneous measurement of the reference electrode
current allows us to recover a flow-direction-sensitive component of the
flow-induced voltage in graphene. The obtained results are discussed in terms
of the Coulomb interaction and other phenomena which can be present at the
interface of graphene with the aqueous solution.Comment: 7 pages, 6 figure
Nitrogen hydrides in interstellar gas: Herschel/HIFI observations towards G10.6-0.4 (W31C)
The HIFI instrument on board the Herschel Space Observatory has been used to
observe interstellar nitrogen hydrides along the sight-line towards G10.6-0.4
in order to improve our understanding of the interstellar chemistry of
nitrogen. We report observations of absorption in NH N=1-0, J=2-1 and ortho-NH2
1_1,1-0_0,0. We also observed ortho-NH3 1_0-0_0, and 2_0-1_0, para-NH3 2_1-1_1,
and searched unsuccessfully for NH+. All detections show emission and
absorption associated directly with the hot-core source itself as well as
absorption by foreground material over a wide range of velocities. All spectra
show similar, non-saturated, absorption features, which we attribute to diffuse
molecular gas. Total column densities over the velocity range 11-54 km/s are
estimated. The similar profiles suggest fairly uniform abundances relative to
hydrogen, approximately 6*10^-9, 3*10^-9, and 3*10^-9 for NH, NH2, and NH3,
respectively. These abundances are discussed with reference to models of
gas-phase and surface chemistry.Comment: 5 pages, 3 figures, 2 online pages with 2 figures. Accepted for
publication in A&A July 6 (Herschel/HIFI special issue
Detection of hydrogen fluoride absorption in diffuse molecular clouds with Herschel/HIFI: a ubiquitous tracer of molecular gas
We discuss the detection of absorption by interstellar hydrogen fluoride (HF)
along the sight line to the submillimeter continuum sources W49N and W51. We
have used Herschel's HIFI instrument in dual beam switch mode to observe the
1232.4762 GHz J = 1 - 0 HF transition in the upper sideband of the band 5a
receiver. We detected foreground absorption by HF toward both sources over a
wide range of velocities. Optically thin absorption components were detected on
both sight lines, allowing us to measure - as opposed to obtain a lower limit
on - the column density of HF for the first time. As in previous observations
of HF toward the source G10.6-0.4, the derived HF column density is typically
comparable to that of water vapor, even though the elemental abundance of
oxygen is greater than that of fluorine by four orders of magnitude. We used
the rather uncertain N(CH)-N(H2) relationship derived previously toward diffuse
molecular clouds to infer the molecular hydrogen column density in the clouds
exhibiting HF absorption. Within the uncertainties, we find that the abundance
of HF with respect to H2 is consistent with the theoretical prediction that HF
is the main reservoir of gas-phase fluorine for these clouds. Thus, hydrogen
fluoride has the potential to become an excellent tracer of molecular hydrogen,
and provides a sensitive probe of clouds of small H2 column density. Indeed,
the observations of hydrogen fluoride reported here reveal the presence of a
low column density diffuse molecular cloud along the W51 sight line, at an LSR
velocity of ~ 24kms-1, that had not been identified in molecular absorption
line studies prior to the launch of Herschel.Comment: 4 pages, 3 figures, A&A Letter special issue, accepted on 07/13/201
Excitation and Abundance of C3 in star forming cores:Herschel/HIFI observations of the sight-lines to W31C and W49N
We present spectrally resolved observations of triatomic carbon (C3) in
several ro-vibrational transitions between the vibrational ground state and the
low-energy nu2 bending mode at frequencies between 1654-1897 GHz along the
sight-lines to the submillimeter continuum sources W31C and W49N, using
Herschel's HIFI instrument. We detect C3 in absorption arising from the warm
envelope surrounding the hot core, as indicated by the velocity peak position
and shape of the line profile. The sensitivity does not allow to detect C3
absorption due to diffuse foreground clouds. From the column densities of the
rotational levels in the vibrational ground state probed by the absorption we
derive a rotation temperature (T_rot) of ~50--70 K, which is a good measure of
the kinetic temperature of the absorbing gas, as radiative transitions within
the vibrational ground state are forbidden. It is also in good agreement with
the dust temperatures for W31C and W49N. Applying the partition function
correction based on the derived T_rot, we get column densities N(C3)
~7-9x10^{14} cm^{-2} and abundance x(C3)~10^{-8} with respect to H2. For W31C,
using a radiative transfer model including far-infrared pumping by the dust
continuum and a temperature gradient within the source along the line of sight
we find that a model with x(C3)=10^{-8}, T_kin=30-50 K, N(C3)=1.5 10^{15}
cm^{-2} fits the observations reasonably well and provides parameters in very
good agreement with the simple excitation analysis.Comment: Accepted for publication in Astronomy and Astrophysics (HIFI first
results issue
The chemistry of C3 & Carbon Chain Molecules in DR21(OH)
(Abridged) We have observed velocity resolved spectra of four ro-vibrational
far-infrared transitions of C3 between the vibrational ground state and the
low-energy nu2 bending mode at frequencies between 1654--1897 GHz using HIFI on
board Herschel, in DR21(OH), a high mass star forming region. Several
transitions of CCH and c-C3H2 have also been observed with HIFI and the IRAM
30m telescope. A gas and grain warm-up model was used to identify the primary
C3 forming reactions in DR21(OH). We have detected C3 in absorption in four
far-infrared transitions, P(4), P(10), Q(2) and Q(4). The continuum sources MM1
and MM2 in DR21(OH) though spatially unresolved, are sufficiently separated in
velocity to be identified in the C3 spectra. All C3 transitions are detected
from the embedded source MM2 and the surrounding envelope, whereas only Q(4) &
P(4) are detected toward the hot core MM1. The abundance of C3 in the envelope
and MM2 is \sim6x10^{-10} and \sim3x10^{-9} respectively. For CCH and c-C3H2 we
only detect emission from the envelope and MM1. The observed CCH, C3, and
c-C3H2 abundances are most consistent with a chemical model with
n(H2)\sim5x10^{6} cm^-3 post-warm-up dust temperature, T_max =30 K and a time
of \sim0.7-3 Myr. Post warm-up gas phase chemistry of CH4 released from the
grain at t\sim 0.2 Myr and lasting for 1 Myr can explain the observed C3
abundance in the envelope of DR21(OH) and no mechanism involving
photodestruction of PAH molecules is required. The chemistry in the envelope is
similar to the warm carbon chain chemistry (WCCC) found in lukewarm corinos.
The observed lower C3 abundance in MM1 as compared to MM2 and the envelope
could be indicative of destruction of C3 in the more evolved MM1. The timescale
for the chemistry derived for the envelope is consistent with the dynamical
timescale of 2 Myr derived for DR21(OH) in other studies.Comment: 11 Pages, 6 figures, accepted for publication in A&
How Well Do Couples Care When They Are Expecting Their First Child? Family and Dyadic Predictors of Parental Sensitivity in Expectant Couples
Belsky's Process Model points to family-of-origin (especially experiences of mistreatment in childhood) as well as personality and marital relations as determinants of parenting quality, including parental sensitive responsiveness. Parental sensitivity might be intuitively developed during pregnancy and affects perinatal mental health. However, there is a lack of studies investigating effects of family-of-origin and relationship perceptions on expectant couples' parental sensitive responsiveness. The aim of the presented study was to test mediation and moderation effects of perceived partner's empathic concern and retrospectively assessed abuse experienced in childhood on sensitive parental responsiveness operationalized as caretaking behaviors and emotional reactions to a crying life-like doll. One hundred eleven expectant couples (N = 222; age: Mwomen = 28.4 years, SD = 3.03; age: Mmen = 29.2 years, SD = 3.31; relationship duration: Myears = 6.8, SD = 3.43; gestational week: M = 31.3, SD = 4.58) assessed the extent to which they experienced physical and emotional abuse from their parents in childhood and rated their current partner's empathic concern. In the experimental procedure, couples reacted to a crying life-like doll and were assessed by trained psychologists using the modified Ainsworth Sensitivity Scale to measure couples' sensitive responsiveness. The results confirmed a significant mediational effect of perceived women's (and not men's) empathic concern for the relationship between the reported experience of abuse in family-
The impact of first wave of the SARS-CoV-2 2019 pandemic in Poland on characteristics and outcomes of patients hospitalized due to stable coronary artery disease
Background: An investigation of baseline characteristics, treatment, and outcomes in patients with stable coronary disease after the first wave of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic may provide valuable data and is beneficial for public health strategy in upcoming years. Methods: A multi-institutional registry, including 10 cardiology departments, was searched for patients admitted from June 2020 to October 2020. The baseline characteristics (age, gender, symptoms, comorbidities), treatment (non-invasive, invasive, surgical), and hospitalization outcome (mortality, myocardial infarction, stroke, composite endpoint — major adverse cardiac and cerebrovascular events [MACCE]) were evaluated. The comparison was made to parameters presented by patients from the same timeframe in 2019 (June–October). Multivariable analysis was performed. Results: Number of hospitalized stable patients following lockdown was lower (2498 vs. 1903; p < 0.0001). They were younger (68.0 vs. 69.0; p < 0.019), more likely to present with hypertension (88.5% vs. 77.5%; p < 0.0001), diabetes (35.7% vs. 31.5%; p = 0.003), hyperlipidemia (67.9% vs. 55.4%; p < 0.0001), obesity (35.8% vs. 31.3%; p = 0.002), and more pronounced symptoms (Canadian Cardiovascular Society [CCS] III and CCS class IV angina: 30.4% vs. 26.5%; p = 0.005). They underwent percutaneous treatment more often (35.0% vs. 25.9%; p < 0.0001) and were less likely to be referred for surgery (3.7% vs. 4.9%; p = 0.0001). There were no significant differences in hospitalization outcome. New York Heart Association (NYHA) class IV for heart failure was a risk factor for both mortality and MACCE in multivariate analysis. Conclusions: The SARS-CoV-2 2019 pandemic affected the characteristics and hospitalization course of stable angina patients hospitalized following the first wave. The hospitalization outcome was similar in the analyzed time intervals. The higher prevalence of comorbidities raises concern regarding upcoming years
Long-term outcomes of the Coordinated Care Program in Patients after Myocardial Infarction (KOS-MI)
Background: The Coordinated Care in Myocardial Infarction Program (KOS-MI) was introduced to improve prognosis for patients after myocardial infarction (MI). The program includes complete revascularization followed by unrestricted access to rehabilitation, electrotherapy and cardiac care.
Aim: The aim of this study was to assess major adverse cardiac and cerebrovascular events (MACCE) of patients enrolled in the KOS-MI at 3-year follow-up.
Methods: This is a retrospective, multicenter registry of patients treated for MI. Study group (KOS-MI) of 963 patients was compared to the control group (standard of care) of 1009 patients. At 3-year follow-up MACCE including death, MI, stroke and repeated revascularization were reported. Additionally, hospitalization due to heart failure (HF) was analyzed. Propensity score matching (PSM) was utilized for group baseline characteristics adjustment.
Results: Patients in the KOS-MI group were younger (65 vs. 68; P < 0.001), mostly men (70% vs. 62.9%; P < 0.001), admitted with ST-elevation myocardial infarction (STEMI) (44.6% vs. 36.2%; P < 0.001). Patients in the control group had more comorbidities and were admitted more often with non ST-elevation myocardial infarction (63.8% vs. 55.4%; P < 0.001) and acute HF (5.1% vs. 2.7%; P = 0.007). Following PSM 530 well matched pairs were selected. At three years (92.3% follow-up completeness), the relative risk reduction was: 25% in MACCE (P = 0.008), 38% in mortality (P = 0.008), 29% in repeated revascularization(P = 0.04) and 28% (P = 0.0496) in hospitalization for HF in the KOS-MI group.
Conclusions: The combination of contemporary invasive techniques, complete revascularization, cardiac rehabilitation and ambulatory care included in the KOS-MI Program improves long-term prognosis of patients after MI up to 3-year follow-up
Long-term bio-functional performance of a novel, self-positioning balloon expandable transcatheter biological aortic valve system in the ovine aortic banding model
Background: The aim of the study was to evaluate bio-functionality of a novel, proprietary balloon-expandable biological transcatheter aortic valve implantation (TAVI) system (InFlow, CardValve Consortium, Poland) in an ovine model of aortic banding.
Methods: Surgical ascending aorta banding was created in 21 sheep. Two weeks later, 18 biological valves were implanted within the model using 15–16 F InFlow TAVI systems and carotid cut-down approach. Follow-up transthoracic echocardiography was performed at 30, 90, and 180-day. At designated time, animals were euthanized and valves harvested for analysis.
Results: All sheep survived the banding procedure. There were 4 (22%) procedure related deaths within a 7-day period. During the observation an additional 2 sheep died. In one, the valve dislocated after the procedure — the animal was excluded. Two animals completed 30-day follow up, five 90-day follow-up and four terminal follow-up of 180 days. Valves examined via transesophageal echocardiography showed proper hemodynamic parameters without evidence of structural valve deterioration. The maximum and average flow gradients at 180 days were 31.4 (23.3–37.7) and 17.5 (13.1–20.2) mmHg, respectively. There was one case of moderate insufficiency and no case of perivalvular leaks. By histopathology, there were no inflammation, thrombosis, nor calcifications in any tested valves at long-term follow-up. Neointimal coverage of stent struts increased with time from basal part in “early” groups to nearly 3/4 of stent length in the 180-day group. The pannus tissue showed maturation that increased with time with no stenotic “collar” visible in orthotopically implanted valves.
Conclusions: The study showed good hemodynamic performance, durability and biocompatibility of the novel biological THV
Safety and feasibility of minimally invasive coronary artery bypass surgery early after drug eluting stent implantation due to acute coronary syndrome
Background: The evidence of performing minimally invasive coronary artery surgery early after drug eluting stent (DES) implantation due to acute coronary syndrome (ACS) is limited.
Aim: The aim of the study is to determine the safety and feasibility of this approach.
Methods: This registry includes 115 (78% male) patients from 2013‒2018, who underwent non-LAD percutaneous coronary intervention (PCI) due to ACS with contemporary DES implantation (39% diagnosed with myocardial infarction at baseline), followed by endoscopic atraumatic coronary artery bypass (EACAB) surgery within 180 days, after temporary P2Y12 inhibitor discontinuation. Primary composite endpoint of MACCE (Major Adverse Cardiac and Cerebrovascular Events), defined as death, myocardial infarction (MI), cerebrovascular incident and repeat revascularization was evaluated in long- term follow-up. The follow-up was collected via telephone survey and with National Registry for Cardiac Surgery Procedures.
Results: Median (interquartile range [IQR]) time interval separating both procedures was 100.0 (62.0‒136.0) days. Median (IQR) follow-up duration was 1338.5 (753.0‒2093.0) days and was completed from all patients with regard to mortality. Eight patients (7%) died; 2 (1.7%) had a stroke; 6 (5.2%) suffered from MI and 12 (10.4%) required repeat revascularization. Overall, the incidence of MACCE was 20 (17.4%).
Conclusions: EACAB is a safe and feasible method of LAD revascularization in patients who received DES for ACS within 180 days prior to surgery, despite early dual antiplatelet therapy discontinuation. The adverse event rate is low and acceptable
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