CF Units Research Articles

Modeling and Decoupling the GPU Power Consumption for Cross-Domain DVFS

Dynamic voltage and frequency scaling (DVFS) is a popular technique to improve the energy-efficiency of high-performance computing systems. It allows placing the devices into lower performance states when the computational demands are lower, opening the possibility for significant power/energy savings. This work presents a GPU power consumption model, used to predict the GPU power consumption of any application at different frequency levels. To obtain this model, an estimation algorithm is proposed, relying on careful benchmarking of the GPU architecture. The model can estimate the contribution of twelve different GPU components (FP32-ADD/MUL/FMA, FP64-ADD/MUL/FMA, INT, SF, CF units, shared memory, L2-cache, and DRAM) to the GPU power consumption. Different model use cases are evaluated (fixed-frequency, DVFS, and scaling-factors), which can obtain both the total or the per-component GPU power consumption. A technique to export models to a distinct GPU from the one it was estimated on is also proposed. These approaches were extensively validated on five different GPUs from the three most recent microarchitectures with a set of 42 standard benchmarks, achieving very accurate predictions. In particular, the scaling-factor power model achieves an average prediction error of 3.5 percent (Titan Xp), 4.6 percent (GTX Titan X), 3.1 percent (GTX 980) and 2.4 percent (Tesla K40c).

Base Catalyzed Thiol–Ene Click Chemistry toward Inner CHCF Bonds for Controlled Functionalization of Poly(vinylidene fluoride)

AbstractA facile and controlled base catalyzed thiol–ene click chemistry toward electron‐deficient CHCF double bonds in poly(vinylidene fluoride) PVDF (P(VDF‐DB)) is reported in present contribution for the first time. The addition reaction is carefully conducted under varied conditions including at the elevated temperature, in the different solvents, and with the altered catalysts and thiols. The addition reaction is well confirmed to follow the base catalyzed route and exhibits close dependence onto the reaction conditions. Besides the addition reaction, the other two side reactions catalyzed by alkylamines, including the further main chain degradation of P(VDF‐DB) substrates together with the nucleophilic substitution of thiols to CHCF units, can be completely avoided by choosing a catalyst with a proper pKa value. With respect to the universality and well controlled feature of the reaction, the low cost and readily prepared P(VDF‐DB) substrate and the mild reaction conditions, this strategy may offer a robust tool for attaching various functional groups into PVDF side chain.

Editorial introductions

Editorial introductions

222 Prevalence of overweight & obesity in the Scottish paediatric CF population

Objectives Children with CF should have a BMI ≥50 th percentile [1]. Scotland has a rate of 28.8% childhood overweight/obesity [2]. We compared rates of overweight/obesity in the Scottish paediatric CF population. Methods A questionnaire was sent to 10 Scottish paediatric CF Units. 8 responded providing data on 293 children with CF. BMI was plotted on the UK 1990 BMI chart. Results 12% (34) of the Scottish paediatric CF population were overweight or obese; 8% above the 91 st centile and 4% above the 98 th centile. The majority (65%) were between 5 and 11 years old, 15% were Pseudomonas aeruginosa . Glucose tolerance, as assessed by OGTT, was normal in 50% of those old enough for OGTT. 6 children (17%) had impaired glucose tolerance. 10 children were too young for OGTT. Conclusion Prevalence of overweight/obesity in the Scottish paediatric CF population is lower compared to the general Scottish paediatric population. Long term health consequences of being overweight/obese with CF are unknown. However, it is likely to be an increasing issue as treatments and life expectancy improve. Primary school age children may be at greatest risk of becoming overweight/obese. Genotype may not be an indication of future fatness/thinness, as a large proportion of this group were homozygote for DF508.

259 Improving inpatient cystic fibrosis related diabetes (CFRD) care: The patients’ perspective

Objectives In CFRD, tight glycaemic control is important, particularly when patients are undergoing IV antibiotic therapy. To facilitate this, we have developed a dedicated weekly ward round led by a CFRD Advanced Nurse Practitioner (ANP) and CF dietitian, providing treatment advice tailored to patients' blood glucose levels and dietary intake. We wished to assess our patients' views of this new service. Methods Using a structured questionnaire, we surveyed 30 patients with CFRD (14 male) in the first 6 months since the service started. Results Twenty eight patients(97%) rated the new service as or in helping them understand and manage their CFRD, and 26 (90%) felt able to ask questions freely. Five patients (16%) felt that changes to treatment could have been explained more clearly, but the remainder were satisfied. Other comments included excellent chance to understand how blood sugars are affected when taking other medication and also dietary advice on eliminating excess sugar from my diet, staff approachable & supportive, hugely beneficial to see CF nurse/dietitian/diabetic nurse all together as matters can be discussed in more detail, and staff approachable & supportive. Suggested improvements included allocating time slots in advance so patients could prepare blood sugar charts to help with changes. Conclusion Our new and innovative MDT approach to the inpatient management of CFRD is well liked by patients, essential when patient involvement is necessary to ensure satisfactory glycaemic control and good outcomes. We recommend this service to other adult CF units, where CFRD is an increasingly common complication of this complex disease.

G93 Aminoglycoside use and ototoxicity monitoring in UK CF units

BackgroundCystic fibrosis (CF) patients are at high risk of aminoglycoside ototoxicity, causing hearing loss, tinnitus or balance problems which can have significant social and psychological implications. The incidence of aminoglycoside...

236 Acceptability of continuous glucose monitoring (CGM) in cystic fibrosis

Objective: Real-time monitoring of glucose by CGM is a validated tool in the management of diabetes, but its use in CF-related diabetes (CFRD) is new and the attitudes of CF patients towards it are unknown. To assess this further, we surveyed our adult CF patients who had undergone CGM as part of the management of their CFRD. Method: Thirty patients (20 female) completed a 5-point Likert questionnaire. Results: Most (83%) found the device easy to use and the instructions clear, and 77% indicated that CGM did not affect their daily routine, but in the remainder it interfered with sleep (50%), washing activities (42%), and choice of clothing (38%). Side-effects were reported by only 27%: of these, 57% noted pain and 43% a skin reaction − 1 patient found these unacceptable. The majority stated they did not modify their diet (86%) or exercise regimen (90%) during the test. Two thirds also performed blood glucose monitoring during the duration of CGM as instructed, with 68% reporting a good correlation with the CGM results. Following this test, 73% reported a better understanding of blood glucose levels, 47% of insulin management and 77% of the relationship between dietary intake and blood glucose levels. Subsequently, 33% have modified their diet, and 90% would undergo CGM in future if required. Conclusions: Although intrusive, CGM is perceived by patients as a useful and acceptable tool for the monitoring of their CFRD, with a low side-effect profile. We encourage other CF units to consider its use for the management of this increasingly common adult CF complication.

Observation of a Novel PFOS-Precursor, the Perfluorooctane Sulfonamido Ethanol-Based Phosphate (SAmPAP) Diester, in Marine Sediments

The environmental occurrence of perfluorooctane sulfonate (PFOS) can arise from its direct use as well as from transformation of precursors ((N-alkyl substituted) perfluorooctane sulfonamides; FOSAMs). Perfluorooctane sulfonamidoethanol-based phosphate (SAmPAP) esters are among numerous potential PFOS-precursors which have not been previously detected in the environment and for which little is known about their stability. Based on their high production volume during the 1970s-2002 and widespread use in food contact paper and packaging, SAmPAP esters may be potentially significant sources of PFOS. Here we report for the first time on the environmental occurrence of SAmPAP diester in marine sediments from an urbanized marine harbor in Vancouver, Canada. SAmPAP diester concentrations in sediment (40-200 pg/g dry weight) were similar to those of PFOS (71-180 pg/g). A significant (p < 0.05) correlation was observed between SAmPAP diester and N-ethyl perfluorooctane sulfonamido acetate (an anticipated degradation product of SAmPAP diester). ∑PFOS-precursor (FOSAM) concentrations in sediment (120-1100 pg/g) were 1.6-24 times greater than those of PFOS in sediment. Although SAmPAP diester was not detected in water, PFOS was observed at concentrations up to 710 pg/L. Among the per- and polyfluoroalkyl substances monitored in the present work, mean log-transformed sediment/water distribution coefficients ranged from 2.3 to 4.3 and increased with number of CF(2) units and N-alkyl substitution (in the case of FOSAMs). Overall, these results highlight the importance of FOSAMs as potentially significant sources of PFOS, in particular for urban marine environments.

A survey of weekend physiotherapy provision in UK adult CF units

A survey of weekend physiotherapy provision in UK adult CF units

Bloodstream infections in cystic fibrosis – ten years experience at the Leeds Paediatric and Adult CF Units

Bloodstream infections in cystic fibrosis – ten years experience at the Leeds Paediatric and Adult CF Units

194 A review of outpatient segregation policies across specialist CF units in the UK

194 A review of outpatient segregation policies across specialist CF units in the UK

Delay analysis in the auditory brainstem of the rat: comparison with click latency

Many cells in the auditory brainstem ‘phase lock’ to tone stimuli. From the changing phase relationship between the stimulus and the neural response in phase-locking cells, the delay between them can be estimated. This delay, however, is consistently greater than the latency measured in response to click stimuli, an important discrepancy. In this paper the different measures of delay, namely phase delay, group delay and signal-front delay are re-examined. An improved method for computing the average group delay is presented, which accounts for the cyclical nature of the phase data. Data were collected from units in successive processing sites of auditory pathway: the auditory nerve, the cochlear nucleus, the trapezoid body and the medial nucleus of the trapezoid body. Low-characteristic frequency (CF) units gave multimodal post-stimulus-time histograms in response to clicks, and showed stepwise decreases in latency with increasing intensity, with the appearance of earlier peaks in the response, rather than shifts in the timing of the peaks. The separation of peaks corresponded to the inverse of the unit’s CF. High-CF units also showed a decline in click latency with intensity, but to a lesser degree than low CF units. We present an analysis which explains the difference between click latency and delay, and which in contrast to previous accounts is experimentally testable. We demonstrate that this new framework accounts for the discrepancy between the two measures of delay, and in addition accounts for the observed stepwise shifts in click latency for low-CF units.

Crystal and molecular structures of trifluoroacrylonitrile, F2C=CF-CN, and trifluorovinyl isocyanide, F2C=CF-NC, by low-temperature X-ray crystallography and ab initio calculations.

The structures of trifluoroacrylonitrile, F2C=CF-CN, monoclinic, P2(1/n) (no. 14), a = 8.595(4), b = 8.748(1), c = 5.421(1) A, beta = 102.83(2) degrees, Z = 4, and its thermally unstable isomer trifluorovinyl isocyanide, F2C=CF-NC, monoclinic, P2(1/n), a = 8.501(2), b = 8.828(2), c = 5.599(2) A, beta = 101.11(2) degrees, Z = 4 were determined by X-ray crystal structure analysis at 113 and 128 K, respectively, from single crystals grown by partial melting and gradient cooling in small glass capillaries. Selected experimental bond lengths of F2C=CF-CN/F2C=CF-NC are as follows: C=C 1.326(1)/1.304(2), C...N 1.158(1)/1.167(2) A. The C-F bond lengths of the CF2 group are significantly shorter than those of the CF(NC) and CF(CN) units, respectively. The vibrational frequencies and molecular geometries of this cyanide/isocyanide pair were also calculated by ab initio methods for comparison with the experimental results, which were found to be in general agreement.

Solid state crystalline and liquid crystalline structure of semifluorinated 1-bromoalkane compounds

A series of semifluorinated 1-bromoalkane (SFBA) mesogens have been synthesized and characterized to better understand their solid state crystalline and liquid crystalline structures. In the solid state, the local conformation of the fluorocarbon segments becomes disordered once the fluorocarbon chain reaches a length above eight CF units. This is evident from the pronounced decrease of molar melting enthalpy. An increasing amount of helix and helix reverse conformations and increasingly disordered packing can also be observed with each addition of a fluorocarbon segment. X-ray diffraction peaks in the small angle region can be indexed by a tilted, two dimensional layered (herring bone) structure. The crystal structure is similar to a type of plastic crystal in which the amphiphilic character is clear, because the two segments of fluorocarbon and hydrocarbon are almost immiscible. Heating of F(CF2)12(CH2)10Br leads to a transition from plastic crystal to smectic B, as revealed by time-resolved XRD and FTIR analysis. At this solid-to-liquid transition temperature, conformational analysis confirmed an onset of the CH2 gauche conformation within the hexagonal lattice, most likely due to changes occurring in the hydrocarbon segment, and a sudden increase of helix defects along the fluorocarbon segment. The disordered helix rigid-rod structure of the fluorocarbon segment and its poor compatibility with the hydrocarbon segment play an important role in the crystalline solid and liquid crystalline structures.

The Coordination Chemistry of Fluorocarbons: Difluoro-m-cyclophane-Based Fluorocryptands and Their Group I and II Metal Ion Complexes.

The reactions of 1,3-bis(bromomethyl)-2-fluorobenzene with the bis(trifluoroacetamides) of 1,3-bis(aminomethyl)-2-fluorobenzene and 1,3-bis(aminomethyl)benzene yield the respective 1+1-condensed [3.3]-m-cyclophanes, respectively termed F(2)-phane (yield 39%) and HF-phane (yield 48%) without trifluoroacetamide groups. The reactions of F(2)-phane with 1,8-diiodo-3,6-dioxaoctane and 1,11-diiodo-3,6,9-trioxaundecane result in the respective 1+1-addition products 1,10-diaza-25,26-difluoro-4,7-dioxatetracyclo[8.7.7.1(12,16).1(19,23)]hexaeicosa-12,14,16(25),19,21,23(26)-hexene (= F(2)-[2.1.1]-cryptand) (yield 5%) and 1,13-diaza-28,29-difluoro-4,7,10-trioxatetracyclo[11.7.7.1(15,19).1(22,26)]nonaeicosa-15,17,19(28),22,24,26(29)-hexene (= F(2)-[3.1.1]-cryptand) (yield 39%). Analogous reactions of the HF-phane give the related macrocycles HF-[2.1.1]-cryptand (yield 68%) and HF-[3.1.1]-cryptand (yield 76%). The coordination of alkali and alkaline earth metal ions by these fluorophane cryptands results in significant shifts of the (19)F NMR resonances: F(2)-[2.1.1]-cryptand, delta -100.70 ppm; its Li(+) complex, delta -129.23 ppm. The (1)J(CF) coupling constant for such complexes is correlated with the degree of interaction between CF units and metal ions, and the most pronounced decrease (262 Hz to 232 Hz) is found for the lithium complex of the F(2)-[2.1.1]-cryptand. Competition experiments show the difluoro F(2)-[3.1.1]-cryptand to form significantly stronger complexes with Na(+) than the monofluoro HF-[3.1.1]-cryptand. In the crystal structure of F(2)-[2.1.1]-cryptand.NaCF(3)SO(3), the sodium ion displays an unusual F(2)O(4)N coordination sphere with extremely short sodium-fluorine distances: CF.Na(+) = 229.8(3), 235.7(4) pm; O-Na(+) = 228.5(4), 242.0(4), 243.8(4), 247.6(4) pm; N-Na(+) = 285.1(7) pm. In the closely related crystal structure of HF-[3.1.1]-cryptand.NaClO(4), the metal has an FO(5)N coordination sphere: CF.Na(+) = 236.0(4) pm; O-Na(+) = 234.8(6), 239.3(6), 240.3(12), 240.6(6), 285.7(17) pm; N-Na(+) = 272.3(6) pm. In the crystal structure of F(2)-[3.1.1]-cryptand.HCF(3)SO(3), the proton is in a pseudotetrahedral environment: N-H = 84 pm; O.HN = (216 pm; CF.HN = 224, 236 pm. This, however, is not considered indicative of significant CF.HN hydrogen bonding.

Coordination Chemistry with CF Units as σ Donors: Ag+Complexes of Partially Fluorinated Crown Ethers with Direct Metal–Fluorine Interactions

AbstractThe partially fluorinated cryptandsFN2O4andBenzoFN2O4, which are relatives of the [2.2.1]cryptand, were synthesized in good yields from 1,3‐bis(bromomethyl)‐2‐fluorobenzene and diaza‐18‐crown‐6 or benzodiaza‐18‐crown‐6, respectively. These macrobicyclic ligands form very stable complexes with Ag(I) salts, and it was shown that close fluorinesilver interactions occur in solution as well as in the solid state. Numerous experimental evidence for this is available: NMR competition experiments show that Ag+complexes ofFN2O4are significantly more stable than those ofHN2O4(the two ligands are identical except that one fluorine atom is replaced by one hydrogen atom inHN2O4); the1JCFcoupling constants of Ag+·FN2O4and Ag+·BenzoFN2O4are reduced by 10 Hz compared to those of the respective free ligandsFN2O4(1JCF=253 Hz) andBenzoFN2O4. (1JCF=252 Hz). The X‐ray crystal structure of Ag+·FN2O4revelas short Ag+–F distances [271.4(3) pm]; coupling of the107,109Ag+and19F nuclei is observed in the19F‐NMR spectra (J=24 Hz for Ag+·FN2O4,J=25 Hz for Ag+·BenzoFN2O4). The1H‐NMR spectrum of Ag+·FN2O4is very complex and exhibits sixteen unique proton resonances, whose evaluation yielded coupling constants and NOEs, which show that the structure in solution is compatible with the results obtained by the X‐ray crystal structure determination.

Thin polymer films prepared by radio frequency plasma sputtering of polytetrafluoroethylene and polyetherimide targets

Plasma polymerization is a common technique used for the deposition of thin polymer films. Radio frequency (rf) sputtering may also be employed for plasma polymerization with the principal difference being the introduction of fragmented polymer species (for the latter) rather than gaseous monomer species into the plasma. The thrust of this work is to study the integrity of thin films prepared by rf plasma sputtering of two substantially different polymer systems. Polytetrafluoroethylene (PTFE) has a simple linear chain molecular structure and is noted for its lubrication and nonwetting properties. Conversely, polyetherimide (PEI) possesses a complex ring molecular structure and is known for its dielectric strength and high temperature stability. The techniques utilized to characterize the films were x-ray photoelectron spectroscopy (XPS), DRIFT, UV–Visible, x-ray diffraction, and scanning electron microscopy (SEM). Periodic controlled ion sputter treatment during XPS analysis of both virgin and sputtered deposited films was also found to be a method of inducing simulations of some of the effects of sputter-deposited growth. Thin films prepared from targets of both polymers were found to be amorphous. DRIFT observations showed a dismantling of the PEI molecule with a total elimination of C=O and C—O groups, and fracturing of the imide group. The retention of some benzene groups, with a partial aromatic to aliphatic transition was also observed. These results were supported by XPS findings. Conversely, PTFE films were found to contain CH, CF, CF2, and CF3 structural units like those found in plasma polymerized PTFE films. After nominal sputter treatment, the CH, CF2, and CF3 species were significantly removed while the CF content appeared to increase, indicative of damage from ion beam exposure. For PEI films, further rearrangement of the C(1s), O(1s), and N(1s) peak structures occurs from ion beam exposure resulting in the formation of C and N variants. While PTFE films are similar to their parent material, observations of rf sputtered PEI indicate a very different type of film formation.

Wettability and surface chemistry of irradiated PTFE

AbstractLow energy electron irradiation of PTFE induced fluorine depletion and introduction of oxygen on the surface. The effect on surface chemistry was shown to be dependent mostly on the amount of electrons reaching the sample, rather than on their energy.Changes in surface energy resulted in different wetting behaviors. The measurement of advancing water contact angles and the analysis of XPS C‐1s peak shapes showed that the least wettable portion of irradiated surfaces is made in most cases of CF2CF  units. When the treatment caused a nearly complete fluorine depletion, only isolated CF2 or CF groups are present. Receding angle values decreased linearly depending on the amount of oxygen introduced on the sample during the treatment, suggesting the formation of strongly oxidized polymer islets. The invariance of contact angles with aging time indicated very low macromolecular mobility, probably related to extensive surface crosslinking.

Neural response to very low-frequency sound in the avian cochlear nucleus.

Recordings were made in the chick cochlear nucleus from neurons that are sensitive to very low frequency sound. The tuning, discharge rate response and phase-locking properties of these units are described in detail. The principal conclusions are: 1. Low frequency (LF) units respond to sound frequencies between 10-800 Hz. Best thresholds average 60 dB SPL, and are occasionally as low as 40 dB SPL. While behavioral thresholds in this frequency range are not available for the domestic chick, these values are in good agreement with the pigeon behavioral audiogram (Kreithen and Quine 1979). 2. About 60% of the unit population displays tuning curves resembling low-pass filter functions with corner frequencies between 50-250 Hz. The remaining units have broad band-pass tuning curves. Best frequencies range from 50-300 Hz. 3. Spontaneous discharge rate was analyzed quantitatively for LF units recorded from nucleus angularis. The distribution of spontaneous rates for LF units is similar to that seen from higher CF units (300-5000 Hz) found in the same nucleus. However, the spontaneous firing of LF units is considerably more regular than that of their higher CF counterparts. 4. Low frequency units with low spontaneous rates (SR's less than 40 spikes/s) show large driven rate increases and usually saturate by discharging once or twice per stimulus cycle. Higher SR units often show no driven rate increases. 5. All LF units show strong phase-locking at all excitatory stimulus frequencies. Vector strengths as high as 0.98 have been observed at moderate sound levels. 6. The preferred phase of discharge (relative to the sound stimulus) increases with stimulus frequency in a nearly linear manner. This is consistent with the LF units being stimulated by a traveling wave. The slope of these phase-frequency relationships provides an estimate of traveling wave delay. These delays average 7.2 ms, longer than those seen for higher CF auditory brainstem units. These observations suggest that the peripheral site of low frequency sensitivity is the very distal region of the basilar papilla, an area whose morphology differs significantly from the rest of the chick basilar papilla. 7. LF units are described whose response to sound is inhibitory at frequencies above 50 Hz.

C 1s excitation studies of diamond (111). I. Surface core levels.

By comparing the C 1s photoemission intensities from a clean diamond (111) surface to those obtained from a fluorine-covered surface, we conclude that a single (111) layer of atoms participates in the diamond 2\ifmmode\times\else\texttimes\fi{}1 surface reconstruction. The data interpretation presented does not rely on assuming an electron mean free path, but, in fact provides an independent measurement of its value. For clean diamond (111) a surface core-level peak is observed at 0.80\ifmmode\pm\else\textpm\fi{}0.05 eV lower binding energy than the bulk-C 1s peak at 285.0 eV below ${E}_{F}$. After fluorine exposure a single chemically shifted carbon peak is observed at 1.85\ifmmode\pm\else\textpm\fi{}0.05 eV higher binding energy than the bulk peak, indicating the presence of CF units at the surface.