An out-of-core high-resolution FFT algorithm for determining large-scale imperfections of surface potentials in crystals

We present a simple out-of-core algorithm for computing the Fast-Fourier Transform (FFT) needed to determine the two-dimensional potential of surface crystals with large-scale features, like faults, at ultra-high resolution, with around 10⁹ grid points. This algorithm represents a proof of concept that a simple and easy-to-code, out-of-core algorithm can be easily implemented and used to solve large-scale problems on low-cost hardware. The main novelties of our algorithm are: (1) elapsed and I/O times decrease with the number of single records (lines) being read; (2) only basic reading and writing routines is necessary for making the out-of-core access. Our method can be easily extended to 3D and be applied to many grand-challenge problems in science and engineering, such as fluid dynamics.     

Incidence and prevention of deep venous thrombosis occurring late after general surgery: randomised controlled study of prolonged thromboprophylaxis

OBJECTIVE: To study the incidence of late deep venous thrombosis (DVT), and to evaluate a regimen of prolonged thromboprophylaxis after general surgery. DESIGN: Randomised, controlled, open trial, with blinded evaluation. SETTING: University hospital, Denmark. SUBJECTS: 176 consecutive patients undergoing major elective abdominal or non-cardiac thoracic operations, of whom 118 were eligible for evaluation. INTERVENTIONS: Thromboprophylaxis with a low-molecular-weight heparin, tinzaparin, given for four weeks (n = 58), compared with one week (control group, n = 60). MAIN OUTCOME MEASURES: Presence of DVT established by bilateral venography four weeks after the operation. RESULTS: The incidence of late DVT in the control group was 6/60 (10%, 95% confidence interval (CI) 4% to 21%). In the prophylaxis group it was 3/58 (5.2%, 95% CI 1% to 14%) (p = 0.49). CONCLUSION: Prolonged thromboprophylaxis had no significant effect on the incidence of DVT occurring late after general surgery.     

Agents that inhibit Rho, Rac, and Cdc42 do not block formation of actin pedestals in HeLa cells infected with enteropathogenic Escherichia coli

Enteropathogenic Escherichia coli (EPEC) induces formation of actin pedestals in infected host cells. Agents that inhibit the activity of Rho, Rac, and Cdc42, including Clostridium difficile toxin B (ToxB), compactin, and dominant negative Rho, Rac, and Cdc42, did not inhibit formation of actin pedestals. In contrast, treatment of HeLa cells with ToxB inhibited EPEC invasion. Thus, Rho, Rac, and Cdc42 are not required for assembly of actin pedestals; however, they may be involved in EPEC uptake by HeLa cells.     

The ex vivo expansion of feline marrow cells leads to increased numbers of BFU-E and CFU-GM but a loss of reconstituting ability

The role of putrescine in synaptic neurotransmission and plasticity was studied using transgenic mice overexpressing ornithine decarboxylase (ODC), a polyamine-synthesizing enzyme. Transgenic mice were produced using the standard microinjection technique leading to elevated levels of putrescine in the periphery and in the brain. The experiments investigated whether or not ODC mice with elevated levels of putrescine show alterations in synaptic transmission and induction of long-term potentiation in the CA1 field of the hippocampus in vitro. Our results indicated that (1) putrescine levels in brain slices of the transgenic mice were more than ten times higher than those in fresh slices of control mice, although the absolute levels of putrescine and spermine decreased (by 15 and 40%, respectively) after 3-6 h incubation in vitro, while the levels of spermidine slightly increased (by 10%), (2) the excitatory synaptic response waveforms were wider (an increased half-width), and paired-pulse facilitation was somewhat reduced in ODC mice as compared to controls, and (3) potentiation of excitatory synaptic responses (measured 30-45 min after theta burst stimulation) did not differ between ODC and control mice. These results indicate that synaptic transmission is affected, but synaptic plasticity in the field CA1 assessed in vitro is not changed by elevated levels of intracellular putrescine.     

Alcohol consumption and mortality. II. Studies of male populations

AIMS: This is the second of a set of three papers evaluating drinking status and mortality risk. Analysis of eight general population surveys of men evaluated all-cause mortality rates by drinking pattern. DESIGN AND PARTICIPANTS: Raw data from three studies of youth and five studies of adults were evaluated. Logistic regression models controlled for confounding characteristics. Meta-analysis combined study results. MEASUREMENTS: Drinking pattern was alternatively defined by quantity, frequency and volume of drinking. Final models included drinking pattern (as well as abstinence in the youth models and long-term abstainers and former drinkers in adult models), age and other confounding variables. Models also evaluated interactions of age and, respectively, long-term abstinence and former drinking. FINDINGS: No evidence was found for the hypothesis that abstinence is associated with greater mortality risk than light drinking. In the youth samples, abstainers had a lower risk of dying than those drinking less than 15 times per month. One study of the adult samples showed a significant age by former drinker interaction; this did not alter the lack of association of former drinking with mortality risk or the homogeneity of results across studies for this finding. The most consistent finding was the association of heavy drinking with mortality among youth. Among adults, drinking 43 or more drinks per month and drinking 21 or more times per month were associated with increased mortality risk. Quantity per occasion was not significantly associated with mortality risk among adults. CONCLUSIONS: That frequent drinking was related to mortality risk, whereas heavier quantity was unrelated, is inconsistent with the belief that daily consumption of a few glasses of wine has salutary effects. Empirically, however, this pattern tends to be unusual. Findings were homogeneous across studies lending generalizability to results.     

Fractional allelic loss in gastric carcinoma correlates with growth patterns

To gain an insight into the genetic events underlying morphological phenotypes, we analysed 58 gastric carcinoma tissues for the genome-wide allelotype study using microsatellite markers. Based on a binomial distribution, loss of heterozygosity (LOH) that was significantly more frequent than expected (P<0.05) thus interpreted as nonrandom LOH selected during tumorigenesis. The overall extent of chromosomes undergoing LOH i.e. fractional allelic loss (FAL, the ratio of LOH-positive markers to the total number of informative markers) was measured in each tumor patient. Nonrandom LOH was found on 17p (48.0%), 18q (38.4%), 13q (38.1%) and 9p (36.4%). Overall, there were no significant phenotypes correlated with allelic loss on specific chromosome regions. Based on a bimodal distribution of FAL values with two peaks bordered by a mean of 0.233, tumors were classified into LOH-related (>0.233) and LOH-unrelated (<0.233) types. Among 24 patients with LOH-related tumors, increase in the infiltrative type of growth pattern was found to correspond with a significant trend of increasing FAL values. This study shows that the growth pattern of gastric carcinoma is correlated with FAL, suggesting that a malignant phenotype is influenced by LOH event.     

Procedural results and late clinical outcomes after placement of three or more stents in single coronary lesions

BACKGROUND: Previous reports have suggested higher procedural and long-term complications among patients treated with multiple stents for diffuse lesions and/or long dissections. METHODS AND RESULTS: To evaluate procedural success, major complications, and clinical outcomes (> or = 1 year) in a consecutive series of patients treated with multiple (> or = 3) contiguous stents in single lesions, we evaluated in-hospital and long-term (1-year) clinical outcomes in 117 consecutive patients treated with > or = 3 coronary stents compared with a concurrent series of patients treated with 1 or 2 stents (n=1673) between January 1, 1994, and December 31, 1995. Multiple stents were implanted more often in larger vessels, in the right coronary artery or saphenous vein grafts, and for unfavorable lesion characteristics, including long (>20 mm), calcified, ulcerated, thrombotic, and/or flow-obstructing lesions. Overall procedural success was obtained in 97.4% of patients and was similar whether 1 or 2 versus > or = 3 stents were used. Non-Q-wave MI (CK-MB > or = 5 times normal) was more frequent after > or = 3 stents (22.8% versus 13.4%, P=.005). Target lesion revascularization (TLR) was 14.6% for 1 or 2 stents and 13.3% for > or = 3 stents (P=.70). There was no difference in death (2.2% versus 0.9%, P=.34) or Q-wave MI (1.4% versus 0.9%, P=.64) between the two groups (1 or 2 stents versus > or = 3 stents, respectively), and overall cardiac event-free survival was similar during follow-up (P=.70). CONCLUSIONS: Patients treated with multiple (> or = 3) contiguous stents compared with 1 or 2 stents have (1) similar in-hospital procedural success and major complications despite having more unfavorable lesion characteristics, (2) a higher rate of procedural non-Q-wave MI, and (3) similar TLR and overall major cardiac event rates during 1 year of follow-up.