To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Aerosol generation during temporal bone surgery caries the risk of viral transmission. Steps to mitigate this problem are of particular importance during the coronavirus disease 2019 pandemic.
To quantify the effect of barrier draping on particulate material dispersion during temporal bone surgery.
The study involved a cadaveric model in a simulated operating theatre environment. Particle density and particle count for particles sized 1–10 μ were measured in a simulated operating theatre environment while drilling on a cadaveric temporal bone. The effect of barrier draping to decrease dispersion was recorded and analysed.
Barrier draping decreased counts of particles smaller than 5 μ by a factor of 80 in the operating theatre environment. Both particle density and particle count showed a statistically significant reduction with barrier draping (p = 0.027).
Simple barrier drapes were effective in decreasing particle density and particle count in the operating theatre model and can prevent infection in operating theatre personnel.
This study examined the reasons for e-cigarette (EC) use, changes in self-efficacy and association between EC use and cessation of tobacco among Canadian young adult smokers over a 6-month period.
A secondary analysis was conducted using data from a randomised controlled trial (RCT) of young adult Canadian smokers. EC exposure was defined as persistent, transient and non-use of ECs at baseline and follow-up. The association between EC exposure and cessation was examined using logistic regression and adjusting for co-variates.
At 6-month follow-up, persistent EC use was associated with a lower cessation rate (13%) than transient (23%) or non-use (29%). After adjusting for covariates, non-use and transient use were associated with higher odds of cessation than persistent use (AOR = 3.23, 95% CI = 1.41–7.40, P < 0.01; AOR = 2.40, 95% CI = 1.01–5.58, P < 0.05). At 6-month follow-up, persistent users (68%) had high self-efficacy as compared to transient (15%) or non-use (12%). Top reasons for EC use included use as a quit aid (67%), perceived use as less harmful (52%) and taste (32%).
Among young adult Canadian smokers enrolled in a RCT of a cessation intervention, persistent and transient use of ECs was associated with a lower smoking cessation rate at 6 months.
Dust vortices with a void at the centre are reported in this paper. The role of the spatial variation of the plasma potential in the rotation of dust particles is studied in a parallel plate glow discharge plasma. Probe measurements reveal the existence of a local potential minimum in the region of formation of the dust vortex. The minimum in the potential well attracts positively charged ions, while it repels the negatively charged dust particles. Dust rotation is caused by the interplay of the two oppositely directed ion drag and Coulomb forces. The balance between these two forces is found to play a major role in the radial confinement of the dust particles above the cathode surface. Evolution of the dust vortex is studied by increasing the discharge current from 15 to 20 mA. The local minimum of the potential profile is found to coincide with the location of the dust vortex for both values of discharge currents. Additionally, it is found that the size of the dust vortex as well as the void at the centre increases with the discharge current.
In this paper we study the number of customers in infinite-server queues with a self-exciting (Hawkes) arrival process. Initially we assume that service requirements are exponentially distributed and that the Hawkes arrival process is of a Markovian nature. We obtain a system of differential equations that characterizes the joint distribution of the arrival intensity and the number of customers. Moreover, we provide a recursive procedure that explicitly identifies (transient and stationary) moments. Subsequently, we allow for non-Markovian Hawkes arrival processes and nonexponential service times. By viewing the Hawkes process as a branching process, we find that the probability generating function of the number of customers in the system can be expressed in terms of the solution of a fixed-point equation. We also include various asymptotic results: we derive the tail of the distribution of the number of customers for the case that the intensity jumps of the Hawkes process are heavy tailed, and we consider a heavy-traffic regime. We conclude by discussing how our results can be used computationally and by verifying the numerical results via simulations.
We have studied, the relationship between monthly variations of average counting rates of cosmic ray intensity (CRI) at Moscow super neutron monitoring station with mid cut-off rigidities (~2.42 GV), and the solar radio flux at 10.7cm (F10.7) and sunspot number (SSN) during the solar cycles 22 − 24. The F10.7cm (2800 MHz) and SSN is an excellent indicator of solar activity for the study period. We have investigated the patterns of long-term and mid-term periodicities of SSN and F10.7, using Fast Fourier Transform (FFT) technique. We have observed the time-lag between ascending phase of CRI with F10.7cm and SSN during solar cycles 22 − 24.
A comparative analysis of radiated power in relativistic magnetron is done using particle-in-cell simulations performed on Magic3d code developed by ATK Mission Systems. The Resonator with dielectric side-walls (DSW) is compared with no-side wall (NSW) configuration having same input parameters and resonator dimensions. Observations and comments have been made on the output power, obtained both axially and radially, taking into consideration π as well as 2π modes of operation for both configurations. The DSW assist in π-mode operation at 3.3 GHz and delivers radial peak power output of ~2.5 GW, which is more than ~1.5 GW, the radial peak power for the NSW case. The NSW case operates in dominant 2π mode (radially) at 5.68 GHz with axial power radiated at dominant π-mode frequency. The electron kinetic energies and their distribution in the cavity are discussed together with the dynamic behavior of particles, which result in spokes formation.
Glucose-6-phosphate dehydrogenase (G6PD), a regulatory enzyme of the pentose phosphate pathway from Brugia malayi, was cloned, expressed and biochemically characterized. The Km values for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (NADP) were 0·25 and 0·014 mm respectively. The rBmG6PD exhibited an optimum pH of 8·5 and temperature, 40 °C. Adenosine 5′ [γ-thio] triphosphate (ATP-γ-S), adenosine 5′ [β,γ-imido] triphosphate (ATP-β,γ-NH), adenosine 5′ [β-thio] diphosphate (ADP-β-S), Na+, K+, Li+ and Cu++ ions were found to be strong inhibitors of rBmG6PD. The rBmG6PD, a tetramer with subunit molecular weight of 75 kDa contains 0·02 mol of SH group per mol of monomer. Blocking the SH group with SH-inhibitors, led to activation of rBmG6PD activity by N-ethylmaleimide. CD analysis indicated that rBmG6PD is composed of 37% α-helices and 26% β-sheets. The unfolding equilibrium of rBmG6PD with GdmCl/urea showed the triphasic unfolding pattern along with the highly stable intermediate obtained by GdmCl.
The combined motion of the human thumb, index and middle fingers while rotating a small object across the extended, intermediate and flexed planes with respect to the fingers was analyzed. Auto reflective markers were attached on the fingers to track their motion across three postures and planes via a 3D motion capture system. Central, right and left rotation postures were considered in each plane for investigation and the rotation experiments were performed with 30 healthy subjects. The obtained data were used to compute the finger joint angles. Based on the three criteria of (i) manipulability measure, (ii) major axis direction angle of the manipulability ellipsoid and (iii) ratio of the minor over major axis lengths, the collective behavior of the fingers was studied. It has been found after analysis that the thumb and middle finger were active, while the index finger operated passively when manipulating small objects in cooperative rotational motion across the three planes. Activeness refers to the independence of a digit in controlling the motion of an object whereas passiveness denotes its dependence on other digits. An active finger governs the motion of an object whereas a passive finger simply supports it. The results of this investigation are of great importance in planning treatment for rehabilitation and for designing controllers for robotic therapists, finger exoskeletons and prostheses.
Pigeonpea is an important legume crop of the semi-arid tropics. In India, pigeonpea is mostly grown in areas prone to waterlogging, resulting in major production losses. It is imperative to identify genotypes that show tolerance at critical crop growth stages to prevent these losses. A selection of 272 diverse pigeonpea accessions was evaluated for seed submergence tolerance for different durations (0, 120, 144, 168 and 192 h) under in vitro conditions in the laboratory. All genotypes exhibited high (0·79–0·98) survival rates for up to 120 h of submergence. After 192 h of submergence, the hybrids as a group exhibited significantly higher survival rates (0·79) than the germplasm (0·71), elite breeding lines (0·68) and commercial varieties (0·58). Ninety-six genotypes representing the phenotypic variation observed during laboratory screening were further evaluated for waterlogging tolerance at the early seedling stage using pots, and survival rates were recorded for 8 days after completion of the stress treatment. Forty-nine of these 96 genotypes, representing the phenotypic variation for waterlogging tolerance, were chosen in order to evaluate their performance under natural field conditions. The following cultivated varieties and hybrids were identified as tolerant after three levels of testing (in vitro, in pots and in the field): ICPH 2431, ICPH 2740, ICPH 2671, ICPH 4187, MAL 9, LRG 30, Maruti, ICPL 20128, ICPL 332, ICPL 20237, ICPL 20238, Asha and MAL 15. These materials can be used as sources of waterlogging tolerance in breeding programmes.
The aim of this study was to evaluate the CD4+/CD8+ ratio in peripheral blood of dogs with localized and generalized demodicosis. Sixteen dogs were examined, 8 with localized and 8 with generalized demodicosis, while 8 healthy dogs were used as controls. Peripheral blood was obtained and CD4+ and CD8+ T cells were determined by flow cytometry. Significantly higher numbers of CD8+ T cells and lower numbers of CD4+ T cells were found in dogs with generalized demodicosis compared to dogs with localized demodicosis and healthy controls. Significantly higher numbers of CD8+ T cells and lower numbers of CD4+ T cells were also found in dogs with localized demodicosis compared to healthy controls. The CD4+/CD8+ ratio was also found to be significantly lower in dogs with generalized demodicosis in comparison with dogs with localized demodicosis and healthy controls. It is concluded that significant alteration in the CD4+/CD8+ ratio may be implicated in the pathogenesis of generalized canine demodicosis.
A total of 637 strains of Salmonella bareilly received from different parts of India between 1959 and 1985 were phage typed using five locally isolated wild phages. The overall typability was 94·5% and 11 different phagc types could be defined. Phago types 10 and 1 were the most prevalent and the geographical and source distribution is described.
The electrostatic lower-hybrid wave is shown to decay parametrically into a whistler wave and a resonant ion cyclotron mode or an ion cyclotron quasi-mode or a reactive quasi-mode. The convective threshold powers for these decay instabilities are found to be much larger than presently available pump powers. These decay instabilities, however, are expected to play an important role in the saturation of the parametrically excited short-wavelength lower-hybrid waves having frequency close to ωlh.
This work is aimed at understanding the nature of the interactions between
metal interconnects and nanoporous dielectrics in integrated circuits.
Electrical testing of MIS capacitors is used to assess Cu diffusion and
charge injection in the dielectric in the presence of an electric field. We
have found that surface modification of nanoporous silica reveals the
importance of chemically bound or adsorbed water species in the dielectric
and how they trigger metal diffusion. We propose that a combination of
moisture-related species in the dielectric and interfacial oxygen oxidize
Cu. The copper oxide acts as a source for Cu ions available for diffusion. A
quantitative analysis of Cu drift in nanoporous dielectrics that shows the
importance of surface chemistry is presented and the mechanism of metal
diffusion and charge injection in nanoporous dielectrics is discussed.
Polymerization occurring during fluorocarbon plasma treatment as a potential
method for pore sealing was investigated. CHF3 was used as a
reactant gas to expedite the rate of polymerization due to the presence of
hydrogen and the low C/F ratio. The reactor pressure was varied from 30mTorr
to 90mTorr to change the number of neutrals that act as the polymerizing
species. The films were exposed to the plasma for times of 1min, 3min, and 5
min to observe the penetration depth of neutrals and the thickness of
modified layer as a function of time. Dielectric constants were measured
before and after plasma treatment. The film morphology was investigated by
scanning electron microscopy before and after plasma treatment and a
featureless surface morphology was observed at 90mTorr on a 56% porosity
film. After plasma treatment, the average pore neck size decreases which may
help reduce metal precursor penetration during metallization.
Two particularly important reliability issues facing the integration of low-
κ dielectric films are the fracture energy of the barrier-dielectric
interface and the barrier layer integrity during processing. We have noticed
that the compressive stresses in the barrier layers on low- κ dielectrics
lead to spontaneous delamination and formation of telephone-cord like
morphologies. These morphologies allow the measurement of fracture energy
and are advantageous over artificially contrived features to yield realistic
debonding parameters. The fracture energy of common barrier films, TaN and
Ta, was determined using this method for varying porosity nanoporous silica
and MSQ. Detailed characterization of the telephone cord morphology using a
combination of Optical Microscopy, SEM and Profilometry was done. The
fracture energy for Ta on different low-κ dielectrics was evaluated using a
1-D model for straight buckles. The kinetic coefficient of buckling was also
Using self-consistent field theory, we attempt to elucidate the links between microscopically determined properties, such as the bridging fraction of chains, and mechanical properties of multiblock copolymer materials. We determine morphological aspects such as period and interfacial width and calculate the bridging fractions, and compare with experimental data.
The World Health Organization has determined that obsessive-compulsive disorder (OCD) is the 10th leading medical cause of disability across the globe. Unfortunately, a substantial proportion of patients with OCD fail to respond to medication trials. In the pivotal double-blind, placebo-controlled trials that established the efficacy of clomipramine and the selective serotonin reuptake inhibitors (SSRIs), 40% to 60% of patients were nonresponders to a given drug. Moreover, patients who do not respond to their first medication trial may be less likely than treatment-naive patients to respond to subsequent trials. For example, only 33% of patients participating in double-blind trials who had failed trials of one or more serotonin reuptake inhibitors (SRIs) benefited from a subsequent trial of sertra-line, compared with 53% of those who were treatment naive (Rasmussen, Baer, Eisen, and Shera, unpublished data, 15th Annual Meeting, American Psychiatric Association, May 17-22, 1997).
At the Fourth International Obsessive-Compulsive Disorder Conference, held in February 2000 in St. Thomas, US Virgin Islands, an afternoon panel was devoted to considering issues and strategies related to treatment-refractory OCD. The panel presentations were divided into three groups: time to response and outcome after long-term followup; pharmacologic strategies for nonresponders; and new data concerning nonpharmacologic interventions.
Motivated by recent experiments on filled polymer thin films, we study the effect of the presence of filler particles on phase separating mixtures. Using a generalized Cahn-Hillard-cook model, we show that the preferential wetting of one phase on the filler surface generates transient composition waves in the phase separating blends. The interference of the composition waves from different particles can stabilize the transient patterns, leading to desirable control of the morphology.
Abstract We compare for multiblock copolymers the results of mean field calculations with those from Monte Carlo simulations based on the bond uctuation method and experimental results from scattering data. The application of Leibler's  theory for copolymers and the results of Monte Carlo simulations indicate that the microphase separation transition occurs at larger xN as the number of blocks is increased beyond two (i.e., beyond diblock), and that the characteristic length scale of the emerging morphology decreases as the number of blocks increases. The latter is in qualitative agreement with published experimental results  for model multiblock poly(styrene-isoprene) systems and recent results  for a segmented poly(ester-urethane).