A fish perspective: detecting flow features while moving using an artificial lateral line in steady and unsteady flow.

For underwater vehicles to successfully detect and navigate turbulent flows, sensing the fluid interactions that occur is required. Fish possess a unique sensory organ called the lateral line. Sensory units called neuromasts are distributed over their body, and provide fish with flow-related information. In this study, a three-dimensional fish-shaped head, instrumented with pressure sensors, was used to investigate the pressure signals for relevant hydrodynamic stimuli to an artificial lateral line system. Unsteady wakes were sensed with the objective to detect the edges of the hydrodynamic trail and then explore and characterize the periodicity of the vorticity. The investigated wakes (Kármán vortex streets) were formed behind a range of cylinder diameter sizes (2.5, 4.5 and 10 cm) and flow velocities (9.9, 19.6 and 26.1 cm s(-1)). Results highlight that moving in the flow is advantageous to characterize the flow environment when compared with static analysis. The pressure difference from foremost to side sensors in the frontal plane provides us a useful measure of transition from steady to unsteady flow. The vortex shedding frequency (VSF) and its magnitude can be used to differentiate the source size and flow speed. Moreover, the distribution of the sensing array vertically as well as the laterally allows the Kármán vortex paired vortices to be detected in the pressure signal as twice the VSF.

Crystal structure studies of human dental apatite as a function of age.

Studies of the average crystal structure properties of human dental apatite as a function of age in the range of 5-87 years are reported. The crystallinity of the dental hydroxyapatite decreases with the age. The a-lattice constant that is associated with the carbonate content in carbonate apatite decreases with age in a systematic way, whereas the c-lattice constant does not change significantly. Thermogravimetric measurements demonstrate an increase of the carbonate content with the age. FTIR spectroscopy reveals both B and A-type carbonate substitutions with the B-type greater than the A-type substitution by a factor up to ~5. An increase of the carbonate content as a function of age can be deduced from the ratio of the nu(2)CO(3) to the nu(1)PO(4) IR modes.

Observation of 54Ni: cross-conjugate symmetry in f7/2 mirror energy differences.

Gamma decays from excited states up to Jpi=6+ in the N=Z-2 nucleus 54Ni have been identified for the first time. Level energies are compared with those of the isobars 54Co and 54Fe and of the cross-conjugate nuclei of mass A=42. The good but puzzling f7/ cross-conjugate symmetry in mirror and triplet energy differences is analyzed. Shell model calculations reproduce the new data but the necessary nuclear charge-dependent phenomenology is not fully explained by modern nucleon-nucleon potentials.

Prevalence and risk factors of Helicobacter pylori-negative peptic ulcer: a multicenter study.

Peptic ulcer disease (PUD) has been described in the absence of Helicobacter pylori (Hp) infection, suggesting that different factors are involved in its etiopathogenesis. We investigated prevalence and characteristics of Hp-negative (Hp-) PUD in an area of Northern Italy and calculated the rate of Hp-positive (Hp+) patients with PUD in whom Hp might be coincidental and not causal. Four hundred nine consecutive patients with endoscopically diagnosed PUD were enrolled in seven hospitals. Hp infection was assessed by rapid urease test and histologic examination. The attributable risk percentages in different age groups were calculated by appropriate formulas. Of 409 patients, 31 (7.6%) were Hp- (gastric, 8.3%; duodenal, 7.6%). Age, nonsteroidal antiinflammatory drug (NSAID) consumption, and complication rates were significantly higher in Hp-than Hp+ patients with duodenal ulcers (DUs). Of the Hp-patients with DU, 58% did not use NSAIDs. In patients with Hp+ DU, the attributable risk percentage for Hp infection in patients aged <40 years, 40-60 years, or >60 years was 98%, 88%, and 66%, respectively. The prevalence of Hp- PUD was about 8%, mainly unrelated to any known etiologic factor. In about one-third of Hp+ patients with PUD aged over 60 years, Hp infection might be coincidental and not causal.

Seven-day triple therapy with ranitidine bismuth citrate or omeprazole and two antibiotics for eradication of Helicobacter pylori in duodenal ulcer: a multicentre, randomized, single-blind study.

AIM: To investigate the efficacy of a 1-week triple therapy with amoxycillin, clarithromycin, and omeprazole or ranitidine bismuth citrate (RBC) in curing Helicobacter pylori infection and healing duodenal ulcers. METHODS: One hundred and ninety-two consecutive out-patients with duodenal ulcer, in whom H. pylori infection was confirmed by histology and a urease biopsy test, were randomly assigned to a 1-week treatment with either 400 mg b.d. ranitidine bismuth citrate (RAC group) or 20 mg omeprazole b.d. (OAC group) in combination with 1 g amoxycillin b.d. and 500 mg clarithromycin b.d. RESULTS: Eradication of H. pylori was successful in 77% (per protocol) and 61% (intention-to-treat) of the patients in the RAC group and in 79% (per protocol) and 70% (intention-to-treat) of those in the OAC group. The difference was not significant. Per protocol analysis showed ulcers were healed in 97% of patients in the RAC group and 96% in the OAC group. Adverse effects were seen in four patients in each group: they caused discontinuation of the therapy in one patient of the OAC group. CONCLUSIONS: Eradication rates obtained in this study were lower than those expected on the basis of previously reported studies. The two 1-week treatment regimens were equally effective in healing H. pylori associated duodenal ulcer disease.

Comparison of omeprazole and lansoprazole in short-term triple therapy for Helicobacter pylori infection.

BACKGROUND: Effective anti-Helicobacter pylori therapies with few side-effects are needed. AIM: To study the effectiveness of short-term triple therapy with amoxycillin, clarithromycin and either omeprazole or lansoprazole for eradication and healing of peptic ulcers. METHODS: Patients with gastric or duodenal ulcers received amoxycillin (1 g b.d.), clarithromycin (500 mg b.d.) and lansoprazole (30 mg b.d.) (LAC) or omeprazole (20 mg b.d.) (OAC) for 7 days. Endoscopic examinations were performed before treatment and at least 4 weeks after completion of therapy. H. pylori status was confirmed by rapid urease test and histological examination (Giemsa stain) from gastric biopsies taken from both the antrum and the body. RESULTS: A total of 356 patients were randomized in this single-blind study. On a per protocol basis, H. pylori was eradicated in 134 of 170 patients (79%) in the lansoprazole group and in 105 of 146 (72%) in the omeprazole group (P = 0.189); and in intention-to-treat analysis 72% and 62%, respectively (P = 0.043). Healing of the ulcers was obtained in 166 of 186 (98%), and in 139 of 146 patients (95%), respectively (P = 0.357). Side-effects occurred in two patients in the LAC group and in six in the OAC group B (four stopped therapy). CONCLUSIONS: This study has shown that the two regimens are highly effective in healing duodenal ulcers and are well tolerated. Neither treatment achieves the ideal cure rate for H. pylori. Lansoprazole does not appear to have a significant advantage over omeprazole either in ulcer healing or in H. pylori eradication.

Randomized study comparing omeprazole plus amoxycillin versus omeprazole plus clarithromycin for eradication of Helicobacter pylori.

BACKGROUND: Dual therapy with omeprazole plus amoxycillin or with omeprazole plus clarithromycin has been proposed for eradication of Helicobacter pylori. The main problem is the great variability in the rate of eradication. METHODS: A group of 287 consecutive patients with active peptic ulcers and H. pylori infections were admitted to a prospective, randomized, multicentre study, to be given omeprazole 20 mg b.d. plus either amoxycillin 1 g b.d. or clarithromycin 500 mg t.d.s. for 2 weeks. Cure was defined as the absence of H. pylori infection, 4-6 weeks after completing anti-microbial therapy, assessed by urease activity and histology of antral and body gastric biopsies. RESULTS: The bacteria were eradicated in 68/143 patients (48%) treated with amoxycillin and omeprazole and 70/144 patients (49%) treated with clarithromycin and omeprazole (intention-to-treat analysis). The ulcers were healed in 118/127 patients (93%) treated with amoxycillin and in 115/123 (94%) of those treated with clarithromycin. Undesirable effects were rare with both treatments. CONCLUSIONS: Combined treatment with omeprazole plus either amoxycillin or clarithromycin produced a high percentage of short-term healing of ulcers and was well tolerated, but is not useful as first-line anti-Helicobacter pylori treatment.

Combined ranitidine and pirenzepine in the treatment of duodenal ulcer: a multicentre double-blind study using endoscopy.

The efficacy of a combination of ranitidine and pirenzepine in the short-term treatment of duodenal ulcer was evaluated in a double-blind trial. In a multicentre study, 352 patients with active duodenal ulcers were randomly allocated to be treated with 300 mg/day ranitidine plus placebo (group I), 300 mg/day ranitidine plus 50 mg/day pirenzepine (group II), or 300 mg/day ranitidine plus 100 mg/day pirenzepine (group III) for 4 weeks. The respective healing rates assessed using endoscopic examination after 2 and 4 weeks' treatment were 40% and 70% in group 1, 44% and 82% in group II, and 37% and 77% in group III. The differences between the treatment groups were not significant, although 300 mg/day ranitidine plus 50 mg/day pirenzepine tended to be superior to the other treatments. Analgesic activity was the same in the three groups with 33%, 34% and 33% reductions, respectively, in the numbers of patients experiencing pain after 2 weeks. Side-effects (mainly dry mouth and blurred vision) were significantly more frequent in group III patients.

Combined hereditary deficiency of factors VII and VIII: a distinct coagulation disorder due to the 'lack' of an autosomal gene controlling factor VII and VIII activation?

A patient with a combined hereditary deficiency of factors VII and VIII is presented together with a family study. The main bleeding manifestations were easy bruising and bleeding after tooth extractions. No hemarthrosis was ever observed. The main laboratory features consisted in a mild prolongation of prothrombin time and of partial thromboplastin time. TG test was abnormal and was corrected by the addition of adsorbed normal plasma. Specific assays revealed a moderate defect of factors VII and VIII. All other clotting factors were within normal limits. The factor VII antigen in the propositus was normal or nearly normal. The factor-VIII-associated antigen was also normal. Five additional family members presented the same coagulation pattern and were variably symptomatic. The hereditary transmission pattern seems to be autosomal dominant. The defect appears to be due to a structural abnormality of a gene controlling factors VII and VIII activation.