678 research outputs found
Measurement of adsorption of a single component from the liquid phase : modelling investigation and sensitivity analysis
In this work, we consider an alternative approach for the measurement of adsorption from the liquid phase. Consider a mixture consisting of a non-adsorbed component (B) and an adsorbed component (A) present at some low concentration. Initially, a feed of component B only flows through a column packed with an adsorbent. Then, the feed is switched to the mixture of A and B. As soon as the mixture enters the column, there will be a reduction in the outlet flow rate as component A leaves the liquid phase and passes into the adsorbed phase. There are three stages to this work. The first is to develop overall and component balances to show how the amount adsorbed of component A can be determined from the variation in the column outlet flow rate. The second is to determine the actual variation in the column outlet flow rate for both plug flow and axial-dispersed plug flow. The final stage is to consider the suitability of a gravity-fed system to deliver the feed to the column. An analysis of the results shows that the experimental arrangement should be able to accurately monitor adsorption from the liquid phase where the mass fraction of the solute is of the order of 1%: the limiting experimental factor is how constant the volumetric flow rate of the liquid feed can be maintained
Dynamic Provable Data Possession Protocols with Public Verifiability and Data Privacy
Cloud storage services have become accessible and used by everyone.
Nevertheless, stored data are dependable on the behavior of the cloud servers,
and losses and damages often occur. One solution is to regularly audit the
cloud servers in order to check the integrity of the stored data. The Dynamic
Provable Data Possession scheme with Public Verifiability and Data Privacy
presented in ACISP'15 is a straightforward design of such solution. However,
this scheme is threatened by several attacks. In this paper, we carefully
recall the definition of this scheme as well as explain how its security is
dramatically menaced. Moreover, we proposed two new constructions for Dynamic
Provable Data Possession scheme with Public Verifiability and Data Privacy
based on the scheme presented in ACISP'15, one using Index Hash Tables and one
based on Merkle Hash Trees. We show that the two schemes are secure and
privacy-preserving in the random oracle model.Comment: ISPEC 201
Keyword-Based Delegable Proofs of Storage
Cloud users (clients) with limited storage capacity at their end can
outsource bulk data to the cloud storage server. A client can later access her
data by downloading the required data files. However, a large fraction of the
data files the client outsources to the server is often archival in nature that
the client uses for backup purposes and accesses less frequently. An untrusted
server can thus delete some of these archival data files in order to save some
space (and allocate the same to other clients) without being detected by the
client (data owner). Proofs of storage enable the client to audit her data
files uploaded to the server in order to ensure the integrity of those files.
In this work, we introduce one type of (selective) proofs of storage that we
call keyword-based delegable proofs of storage, where the client wants to audit
all her data files containing a specific keyword (e.g., "important"). Moreover,
it satisfies the notion of public verifiability where the client can delegate
the auditing task to a third-party auditor who audits the set of files
corresponding to the keyword on behalf of the client. We formally define the
security of a keyword-based delegable proof-of-storage protocol. We construct
such a protocol based on an existing proof-of-storage scheme and analyze the
security of our protocol. We argue that the techniques we use can be applied
atop any existing publicly verifiable proof-of-storage scheme for static data.
Finally, we discuss the efficiency of our construction.Comment: A preliminary version of this work has been published in
International Conference on Information Security Practice and Experience
(ISPEC 2018
Unusual compulsive motor activity during treatment with clothiapine in a mentally retarded adolescent
Atypical antipsychotic agents, specifically those with a high hyposerotonergic activity such as clozapine and clothiapine, have been
associated with de novo obsessive–compulsive symptoms. We report the case of a 16-year-old adolescent male with severe mental
impairment and disruptive behaviour who developed a compulsive head and body turning disorder on clothiapine. Such a symptom had to be
distinguished from epileptic partial seizures; it promptly disappeared with the drug discontinuation
Allergen immunotherapy for respiratory allergy: to what extent can the risk of systemic reactions be reduced?
Introduction: Allergen immunotherapy is an effective treatment for respiratory allergy, but the administration to patients of extracts of the causative allergen may elicit systemic reactions, which include, particularly with subcutaneous immunotherapy (SCIT), anaphylaxis. In the past, the occurrence (tough rare) of fatal reactions has represented a serious problem that has limited the prescription of SCIT. Areas covered: The authors analyzed in this review the safety data of SCIT, especially concerning the years following the identification of uncontrolled asthma at the moment of allergen injection as the major risk of life-threatening reactions and fatalities. The safety of SLIT, which is far better than SCIT, was analyzed and its specific risk factors for systemic reactions were highlighted. Expert opinion: Presently, the safety profile of SCIT and SLIT is satisfactory, provided the treatment is administered by physicians experienced in this treatment, who are aware of the known risk factors for severe reactions and who implement all measures to avoid them. For SLIT, which is self-administered by the patient, receiving the first dose under medical control is recommended
Quantitative analysis of videokymography in normal and pathological vocal folds: a preliminari study.
Videokymography (VKG) captures high-speed
images of the vocal folds independently of the periodicity
of the acoustic signal. The aim of this study was to preliminarily
assess a software package that can objectively
measure specific parameters of vocal fold vibration. From
August 2009 until December 2010, we prospectively
evaluated 40 subjects (Group A, 18 normal subjects;
Group B, 14 patients with benign lesions of the middle
third of the vocal fold, such as polyps and cysts; Group C, 8
patients treated by endoscopic excision of vocal fold
benign lesions) by videoendoscopy, videolaryngostroboscopy,
and VKG. A VKG camera was coupled to a 70
telescope and video was recorded during phonation. Images
were objectively analyzed by a post-processing software
tool (VKG-Analyser) with a user-friendly interface
developed by our group. Different parameters were considered,
including the ratio between the amplitude of the
vibration of one vocal fold with respect to the contralateral
(Ramp), the ratio between the period of one vocal fold
vibration and the opposite one (Rper), and the ratio between
the duration of the open and closed phase within a glottal
cycle (Roc). Mean values for Ramp, Rper, and Roc in Group A
were 1.05, 1.04, and 1.35, respectively; in Group B were
1.63, 0.92, and 0.97, respectively; and in Group C were
1.13, 0.91, and 1.85, respectively. Quantitative analysis of
videokymograms by the herein presented tool, named VKG-Analyser, is useful for objective evaluation of the
vibratory pattern in normal and pathologic vocal folds.
Important future developments of this tool for the study of
both physiologic and pathologic patterns of vocal fold
vibration can be expected
Practical observations on the performance of bare silica in hydrophilic interaction compared with C18 reversed-phase liquid chromatography
The kinetic performance of a bare silica and C18 phase prepared from the same sub-2. μm and 3.5. μm base materials were compared in the HILIC and RP mode using both charged and neutral solutes. The HILIC column was characterised using the neutral solute 5-hydroxymethyluridine, the weak base cytosine, and the strong base nortriptyline, the latter having sufficient retention also in the RP mode to allow comparison of performance. Naphthalene was also used as a simple neutral substance to evaluate the RP column alone. The retention factors of all substances were adjusted to give similar values (k'. ~. 5.5) at their respective optimum linear velocities. Reduced van Deemter b-coefficients (determined by curve fitting and by the peak parking method, using a novel procedure involving switching to a dummy column) were significantly lower in HILIC for all substances compared with those found under RP conditions. Against expectation, c-coefficients were always lower in RP when compared with HILIC using sub-2. μm particles. While measurement of these coefficients is complicated by retention shifts caused by the influence of high pressure and by frictional heating effects, broadly similar results were obtained on larger particle (3.5. μm) phases. The mechanism of the separations was further investigated by examining the effect of buffer concentration on retention. It was concluded that HILIC can sometimes show somewhat inferior performance to RP for fast analysis at high mobile phase velocity, but clearly shows advantages when high column efficiencies, using longer columns at low flow velocity, are employed. The latter result is attributable to the lower viscosity of the mobile phase in HILIC and the reduced pressure requirement as well as the lower b-coefficients. © 2014 David V. McCalley
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