1,634 research outputs found
The impact of alkyl chain purity on lipid based nucleic acid delivery systems â is the utilization of lipid components with technical grade justified?
The physicochemical properties and transfection efficacies of two samples of a cationic lipid have been investigated and compared in 2D (monolayers at the air/liquid interface) and 3D (aqueous bulk dispersions) model systems using different techniques. The samples differ only in their chain composition due to the purity of the oleylamine (chain precursor). Lipid 8 (using the oleylamine of technical grade for cost-efficient synthesis) shows lateral phase separation in the Langmuir layers. However, the amount of attached DNA, determined by IRRAS, is for both samples the same. In 3D systems, lipid 8âp forms cubic phases, which disappear after addition of DNA. At physiological temperatures, both lipids (alone and in mixture with cholesterol) assemble to lamellar aggregates and exhibit comparable DNA delivery efficiency. This study demonstrates that non-lamellar structures are not compulsory for high transfection rates. The results legitimate the utilization of oleyl chains of technical grade in the synthesis of cationic transfection lipid
Thermal conductance of thin film YIG determined using Bayesian statistics
Thin film YIG (YFeO) is a prototypical material for
experiments on thermally generated pure spin currents and the spin Seebeck
effect. The 3-omega method is an established technique to measure the
cross-plane thermal conductance of thin films, but can not be used in YIG/GGG
(GaGdO) systems in its standard form. We use two-dimensional
modeling of heat transport and introduce a technique based on Bayesian
statistics to evaluate measurement data taken from the 3-omega method. Our
analysis method allows us to study materials systems that have not been
accessible with the conventionally used 3-omega analysis. Temperature dependent
thermal conductance data of thin film YIG are of major importance for
experiments in the field of spin-caloritronics. Here we show data between room
temperature and 10 K for films covering a wide thickness range as well as the
magnetic field effect on the thermal conductance between 10 K and 50 K
Spectroscopic Behaviour of Copper(II) Complexes Containing 2-Hydroxyphenones
Theoretical investigations by density functional theory (DFT) and time-dependent DFT
(TD-DFT) methods shed light on how the type of ligand or attached groups influence the electronic
structure, absorption spectrum, electron excitation, and intramolecular and interfacial electron
transfer of the Cu(II) complexes under study. The findings provide new insight into the designing
and screening of high-performance dyes for dye-sensitized solar cells (DSSCs)
Reduction Data Obtained from Cyclic Voltammetry of Benzophenones and Copper-2-Hydroxyphenone Complexes
This article provides detailed redox data on nine differently substituted benzophenones and
ten square planar copper(II) complexes containing 2-hydroxyphenones obtained by cyclic voltammetry
(CV) experiments. The information provided is related to the published full research articles âAn electrochemical and computational chemistry study of substituted benzophenonesâ (Electrochim. Acta 2021,
373, 137894) and âElectrochemical behaviour of copper(II) complexes containing 2-hydroxyphenonesâ
(Electrochim. Acta 2022, 424, 140629), where the CVs and electrochemical data at mainly one scan rate,
namely at 0.100 Vsâ1
, are reported. CVs and the related peak current and voltage values, not reported in
the related research article, are provided in this article for nine differently substituted benzophenones and
ten differently substituted copper-2-hydroxyphenone complexes at various scan rates over more than
two orders of magnitude. The redox data presented are the first reported complete set of electrochemical
data of nine 2-hydroxyphenones and ten copper(II) complexes containing 2-hydroxyphenone ligands
Determination of the spin-flip time in ferromagnetic SrRuO3 from time-resolved Kerr measurements
We report time-resolved Kerr effect measurements of magnetization dynamics in
ferromagnetic SrRuO3. We observe that the demagnetization time slows
substantially at temperatures within 15K of the Curie temperature, which is ~
150K. We analyze the data with a phenomenological model that relates the
demagnetization time to the spin flip time. In agreement with our observations
the model yields a demagnetization time that is inversely proportional to T-Tc.
We also make a direct comparison of the spin flip rate and the Gilbert damping
coefficient showing that their ratio very close to kBTc, indicating a common
origin for these phenomena
The impact of prenatal counselling on mothers of surviving children with hypoplastic left heart syndrome: A qualitative interview study
Objective: To explore the role of antenatal counselling in how parents make treatment decisions following an antenatal diagnosis of Hypoplastic Left Heart Syndrome (HLHS). / Background: Antenatal counselling is a critical part of patient management following a diagnosis of fetal congenital heart disease; however, there is a very limited evidence base examining how parents actually experience antenatal counselling and make decisions in this context./ Methods: Semiâstructured interviews were conducted with women who had received an antenatal diagnosis of HLHS. Interviews were digitally recorded, anonymised and transcribed verbatim. A thematic content analysis was performed using a constant comparative approach. / Results: Eight mothers of surviving children with HLHS were interviewed. Eight key themes emerged including new perspectives on how women receive antenatal counselling and how it affects their decision making. Three themes in particular are new to the literature: (a) Mothers of children with HLHS reported feelings of intense guilt that arose in the antenatal period around potentially causing the condition in their child. (b) For this group of women, recollections of perceived pessimism during antenatal counselling had a lasting impact. (c) Despite support from partners or extended family, women nevertheless experienced a strong sense that antenatal decision making was largely a âmaternalâ responsibility. / Conclusions: When recounting their experiences of antenatal counselling, mothers of surviving children with HLHS offer new perspectives that can guide fetal cardiologists in how best to support their individual patients. Further research is needed to comprehensively understand the experience of prospective parents counselled for severe forms of fetal congenital heart disease
Stealthy Deception Attacks Against SCADA Systems
SCADA protocols for Industrial Control Systems (ICS) are vulnerable to
network attacks such as session hijacking. Hence, research focuses on network
anomaly detection based on meta--data (message sizes, timing, command
sequence), or on the state values of the physical process. In this work we
present a class of semantic network-based attacks against SCADA systems that
are undetectable by the above mentioned anomaly detection. After hijacking the
communication channels between the Human Machine Interface (HMI) and
Programmable Logic Controllers (PLCs), our attacks cause the HMI to present a
fake view of the industrial process, deceiving the human operator into taking
manual actions. Our most advanced attack also manipulates the messages
generated by the operator's actions, reversing their semantic meaning while
causing the HMI to present a view that is consistent with the attempted human
actions. The attacks are totaly stealthy because the message sizes and timing,
the command sequences, and the data values of the ICS's state all remain
legitimate.
We implemented and tested several attack scenarios in the test lab of our
local electric company, against a real HMI and real PLCs, separated by a
commercial-grade firewall. We developed a real-time security assessment tool,
that can simultaneously manipulate the communication to multiple PLCs and cause
the HMI to display a coherent system--wide fake view. Our tool is configured
with message-manipulating rules written in an ICS Attack Markup Language (IAML)
we designed, which may be of independent interest. Our semantic attacks all
successfully fooled the operator and brought the system to states of blackout
and possible equipment damage
Parents' responses to prognostic disclosure at diagnosis of a child with a highârisk brain tumor: Analysis of clinicianâparent interactions and implications for clinical practice
Background: Previous studies have found that parents of children with cancer desire more prognostic information than is often given even when prognosis is poor. We explored in audioârecorded consultations the kinds of information they seek. /
Methods: Ethnographic study including observation and audio recording of consultations at diagnosis. Consultations were transcribed and analyzed using an interactionist perspective including tools drawn from conversation and discourse analysis. /
Results: Enrolled 21 parents and 12 clinicians in 13 cases of children diagnosed with a highârisk brain tumor (HRBT) over 20 months at a tertiary pediatric oncology center. Clinicians presented prognostic information in all cases. Through their questions, parents revealed what further information they desired. Clinicians made clear that no one could be absolutely certain what the future held for an individual child. Explicit communication about prognosis did not satisfy parentsâ desire for information about their own child. Parents tried to personalize prognostic information and to apply it to their own situation. Parents moved beyond prognostic information presented and drew conclusions, which could change over time. Parents who were present in the same consultations could form different views of their child's prognosis. /
Conclusion: Population level prognostic information left parents uncertain about their child's future. The need parents revealed was not for more such information but rather how to use the information given and how to apply it to their child in the face of such uncertainty. Further research is needed on how best to help parents deal with uncertainty and make prognostic information actionable
CacheZoom: How SGX Amplifies The Power of Cache Attacks
In modern computing environments, hardware resources are commonly shared, and
parallel computation is widely used. Parallel tasks can cause privacy and
security problems if proper isolation is not enforced. Intel proposed SGX to
create a trusted execution environment within the processor. SGX relies on the
hardware, and claims runtime protection even if the OS and other software
components are malicious. However, SGX disregards side-channel attacks. We
introduce a powerful cache side-channel attack that provides system adversaries
a high resolution channel. Our attack tool named CacheZoom is able to virtually
track all memory accesses of SGX enclaves with high spatial and temporal
precision. As proof of concept, we demonstrate AES key recovery attacks on
commonly used implementations including those that were believed to be
resistant in previous scenarios. Our results show that SGX cannot protect
critical data sensitive computations, and efficient AES key recovery is
possible in a practical environment. In contrast to previous works which
require hundreds of measurements, this is the first cache side-channel attack
on a real system that can recover AES keys with a minimal number of
measurements. We can successfully recover AES keys from T-Table based
implementations with as few as ten measurements.Comment: Accepted at Conference on Cryptographic Hardware and Embedded Systems
(CHES '17
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