4,144 research outputs found
The tidal prism as a dynamic response of a nonlinear harmonic system
As known, the empirical relationship between the equilibrium cross-sectional area of a lagoon inlet and the tidal prism was intuited for the first time by LeConte ["Discussion on the paper, "Notes on the improvement of river and harbor outlets in the United States"by D. A. Watt,"Trans. ASCE 55, 306-308 (1905).] and then formalized by O'Brien ["Estuary tidal prism related to entrance areas,"Civ. Eng. 1(8), 738-739 (1931)]. This relationship requires knowledge of the tidal prism, which can be estimated either using the cubature method or the current data method [Jarrett, Tidal Prism-Inlet Area Relationships (Coastal Engineering Research Center, US Army Corps of Engineers, Fort Belvoir, VA, 1976)], both of which involve the execution of a number of experimental measurements. However, these methods, besides being very expensive, can only provide the prism value in the present condition and do not allow for predictions in the case of significant morphological changes, of both natural and anthropic origin, to the tidal inlet. On the other hand, the hydrodynamic relationship, which links the tidal prism to the product of the tidal range and the basin extension, can only give a coarse estimate of the prism, especially when the value of the tide outside the lagoon is considered. In this work, we propose a simple hydrodynamic relationship based on the dynamic response of a nonlinear harmonic system. This is a relationship that requires the calibration of a single physically based parameter. Through this relationship, knowing the geometric characteristics, the bottom friction of the inlet channel, the surface of the basin, and the tide amplitude in the open sea, it is possible to estimate the tidal prism. The application of this relationship to real cases shows a good agreement with the experimental data
Chronic bacterial prostatitis: efficacy of short-lasting antibiotic therapy with prulifloxacin (Unidrox®) in association with saw palmetto extract, lactobacillus sporogens and arbutin (Lactorepens®)
Bacterial prostatitis (BP) is a common condition accounting responsible for about 5-10% of all prostatitis cases; chronic bacterial prostatitis (CBP) classified as type II, are less common but is a condition that significantly hampers the quality of life, (QoL) because not only is it a physical condition but also a psychological distress. Commonly patients are treated with antibiotics alone, and in particular fluoroquinolones are suggested by the European Urology guidelines. This approach, although recommended, may not be enough. Thus, a multimodal approach to the prolonged antibiotic therapy may be helpful.210 patients affected by chronic bacterial prostatitis were enrolled in the study. All patients were positive to Meares-Stamey test and symptoms duration was > 3 months. The purpose of the study was to evaluate the efficacy of a long lasting therapy with a fluoroquinolone in association with a nutraceutical supplement (prulifloxacin 600 mg for 21 days and an association of Serenoa repens 320 mg, Lactobacillus Sporogens 200 mg, Arbutin 100 mg for 30 days). Patients were randomized in two groups (A and B) receiving respectively antibiotic alone and an association of antibiotic plus supplement.Biological recurrence at 2 months in Group A was observed in 21 patients (27.6%) and in Group B in 6 patients (7.8%). Uropathogens found at the first follow-up were for the majority Gram - (E. coli and Enterobacter spp.). A statistically significant difference was found at the time of the follow-up between Group A and B in the NIH-CPSI questionnaire score, symptoms evidence and serum PSA.Broad band, short-lasting antibiotic therapy in association with a nutritional supplement (serenoa repens, lactobacillus sporogens and arbutin) show better control and recurrence rate on patients affected by chronic bacterial prostatitits in comparison with antibiotic treatment alone.NCT02130713Date of trial Registration: 30/04/2014
Effect of metabolic and antioxidant supplementation on sperm parameters in oligo-astheno-teratozoospermia, with and without varicocele: a double-blind placebo-controlled study
Since sperm require high energy levels to perform their specialised function, it is vital that essential nutrients are available for spermatozoa when they develop, capacitate and acquire motility. However, they are vulnerable to a lack of energy and excess amounts of reactive oxygen species, which can impair sperm function, lead to immotility, acrosomal reaction impairment, DNA fragmentation and cell death. This monocentric, randomised, double-blind, placebo-controlled trial investigated the effect of 6 months of supplementation with l-carnitine, acetyl-l-carnitine and other micronutrients on sperm quality in 104 subjects with oligo- and/or astheno- and/or teratozoospermia with or without varicocele. In 94 patients who completed the study, sperm concentration was significantly increased in supplemented patients compared to the placebo (p =.0186). Total sperm count also increased significantly (p =.0117) in the supplemented group as compared to the placebo group. Both, progressive and total motility were higher in supplemented patients (p =.0088 and p =.0120, respectively). Although pregnancy rate was not an endpoint of the study, of the 12 pregnancies that occurred during the follow-up, 10 were reported in the supplementation group. In general, all these changes were more evident in varicocele patients. In conclusion, supplementation with metabolic and antioxidant compounds could be efficacious when included in strategies to improve fertility
European Guidelines for Obesity Management in Adults with a Very Low-Calorie Ketogenic Diet: A Systematic Review and Meta-Analysis
Background: The very low-calorie ketogenic diet (VLCKD) has been recently proposed as an appealing nutritional strategy for obesity management. The VLCKD is characterized by a low carbohydrate content (<50 g/day), 1-1.5 g of protein/kg of ideal body weight, 15-30 g of fat/day, and a daily intake of about 500-800 calories. Objectives: The aim of the current document is to suggest a common protocol for VLCKD and to summarize the existing literature on its efficacy in weight management and weight-related comorbidities, as well as the possible side effects. Methods: This document has been prepared in adherence with Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Literature searches, study selection, methodology development, and quality appraisal were performed independently by 2 authors and the data were collated by means of a meta-analysis and narrative synthesis. Results: Of the 645 articles retrieved, 15 studies met the inclusion criteria and were reviewed, revealing 4 main findings. First, the VLCKD was shown to result in a significant weight loss in the short, intermediate, and long terms and improvement in body composition parameters as well as glycemic and lipid profiles. Second, when compared with other weight loss interventions of the same duration, the VLCKD showed a major effect on reduction of body weight, fat mass, waist circumference, total cholesterol and triglyceridemia as well as improved insulin resistance. Third, although the VLCKD also resulted in a significant reduction of glycemia, HbA1c, and LDL cholesterol, these changes were similar to those obtained with other weight loss interventions. Finally, the VLCKD can be considered a safe nutritional approach under a health professional's supervision since the most common side effects are usually clinically mild and easily to manage and recovery is often spontaneous. Conclusions: The VLCKD can be recommended as an effective dietary treatment for individuals with obesity after considering potential contra-indications and keeping in mind that any dietary treatment has to be personalized. Prospero Registry: The assessment of the efficacy of VLCKD on body weight, body composition, glycemic and lipid parameters in overweight and obese subjects: a meta-analysis (CRD42020205189)
SPh functionalized bridging-vinyliminium diiron and diruthenium complexes
The SPh functionalized vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(SPh)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [R = Xyl, R′ = Me, 2a; R = Me, R′ = Me, 2b; R = 4-C6H4OMe, R′ = Me, 2c; R = Xyl, R′ = CH2OH, 2d; R = Me, R′ = CH2OH, 2e; Xyl = 2,6-Me2C6H3] are generated in high yields by treatment of the corresponding vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(H)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (1a–e) with NaH in the presence of PhSSPh. Likewise, the diruthenium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(SPh)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (2f) was obtained from the corresponding vinyliminium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(H)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (1f). The synthesis of 2c is accompanied by the formation, in comparable amounts, of the aminocarbyne complex [Fe2{μ-CN(Me)(4-C6H4OMe)}(SPh)(μ-CO)(CO)(Cp)2] (3). The molecular structures of 2d, 2e and 3 have been determined by X-ray diffraction studies
C-N coupling between µ-aminocarbyne and nitrile ligands promoted by tolylacetylide addition to [Fe2CN(Me)(Xyl)}(CO)(CO)(NCCMe3)(Cp)2][SO3CF3]: formation of a novel bridging allene-diaminocarbene ligand
The reaction of the mu-aminocarbyne complex [Fe-2{mu-CN(Me)(Xyl)}(mu-CO)(CO)(NCCMe3)(CP)(2)][SO3CF3] (2) (Xyl = 2,6-Me2C6H3) with tolylacetylide, followed by treatment with HSO3CF3 affords the complex [Fe-2{mu-eta(1):eta(3)C(Tol)double bondCdouble bondC(CMe3)N(H)CN(Me)(Xyl)}(mu-CO)(CO)(Cp-2)][SO3CF3] (3) (Tol = 4-MeC6H4). The X-ray molecular structure of 3 reveals the peculiar character of the bridging ligand, which exhibits both eta(1):eta(2) allene and aminocarbene nature. The formation of 3 proceeds through several intermediate species, which have been detected by IR spectroscopy. Addition of HSO3CF3 at an early stage of the reaction between 2 and LiCdropCTol leads to the formation of the imine complex [Fe-2{mu-CN(Me)Xyl}(mu-CO)(CO){NHC(CdropCTol)CMe3}(Cp)(2)][SO3CF3] (6) indicating that the first step of the reaction consists in the acetylide addition at the coordinated NCCMe3. The molecular structure of 6 has been elucidated by an X-ray diffraction study
Stereochemistry of the insertion of disubstituted alkynes into the metal aminocarbyne bond in diiron complexes
Terminal alkynes (HCdropCR') (R'=COOMe, CH2OH) insert into the metal-carbyne bond of the diiron complexes [Fe-2{mu-CN(Me)(R)} (mu-CO)(CO)(NCMe)(Cp)(2)][SO3CF3] (R=Xyl, 1a; CH2Ph, 1b; Me, 1c; Xyl=2,6-Me2C6H3), affording the corresponding mu-vinyliminium complexes [Fe-2{mu-sigma:eta(3)-C(R')=CHC=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, R'=COOMe, 2; R=CH2Ph, R'=COOMe, 3; R=Me, R'=COOMe, 4; R=Xyl, R'=CH2OH, 5; R=Me, R'=CH2OH, 6). The insertion is regiospecific and C-C bond formation selectively occurs between the carbyne carbon and the CH moiety of the alkyne. Disubstituted alkynes (R'CdropCR') also insert into the metal-carbyne bond leading to the formation of [Fe-2{mu-sigma:eta(3)- C(R')=C(R')C=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R'=Me, R=Xyl, 8; R'=Et, R=Xyl, 9; R'=COOMe, R=Xyl, 10; R'=COOMe, R=CH2Ph, 11; R'= COOMe, R=Me, 12). Complexes 2, 3, 5, 8, 9 and 11, in which the iminium nitrogen is unsymmetrically substituted, give rise to E and/or Z isomers. When iminium substituents are Me and Xyl, the NMR and structural investigations (X-ray structure analysis of 2 and 8) indicate that complexes obtained from terminal alkynes preferentially adopt the E configuration, whereas those derived from internal alkynes are exclusively Z. In complexes 8 and 9, trans and cis isomers have been observed, by NMR spectroscopy, and the structures of trans-8 and cis-8 have been determined by X-ray diffraction studies. Trans to cis isomerization occurs upon heating in THF at reflux temperature. In contrast to the case of HCdropCR', the insertion of 2-hexyne is not regiospecific: both [Fe-2{mu-sigma:eta(3)-C(CH2CH2CH3)=C(Me)C=N(Me)(R)} (mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, 13; R=Me, 15) and [Fe-2{mu-sigma:eta(3)-C(Me)=C(CH2CH2CH3)C=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, 14, R=Me, 16) are obtained and these compounds are present in solution as a mixture of cis and trans isomers, with predominance of the former
Hydride addition at m-vinyliminium ligand obtained from disubstituted alkynes
New μ-vinylalkylidene complexes cis-[Fe2{μ-η1:η3-Cγ(R′)Cβ(R″)CαHN(Me)(R)}(μ-CO)(CO)(Cp)2] (R = Me, R′ = R″ = Me, 3a; R = Me, R′ = R″ = Et, 3b; R = Me, R′ = R″ = Ph, 3c; R = CH2Ph, R′ = R″ = Me, 3d; R = CH2Ph, R′ = R″ = COOMe, 3e; R = CH2 Ph, R′ = SiMe3, R″ = Me, 3f) have been obtained b yreacting the corresponding vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(R″)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (2a–f) with NaBH4. The formation of 3a–f occurs via selective hydride addition at the iminium carbon (Cα) of the precursors 2a–f. By contrast, the vinyliminiumcis-[Fe2{μ-η1:η3-Cγ (R′) = Cβ(R″)Cα = N(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (R′ = R″ = COOMe, 4a; R′ = R″ = Me, 4b; R′ = Prn, R″ = Me, 4c; Prn = CH2CH2CH3, Xyl = 2,6-Me2C6H3) undergo H− addition at the adjacent Cβ, affording the bis-alkylidene complexes cis-[Fe2{μ-η1:η2-C(R′)C(H)(R″)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2], (5a–c). The cis and trans isomers of [Fe2{μ-η1:η3-Cγ(Et)Cβ(Et)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (4d) react differently with NaBH4: the former reacts at Cα yielding cis-[Fe2{μ-η1:η3-Cγ(Et)Cβ(Et)CαHN(Me)(Xyl)}(μ-CO)(CO)(Cp)2], 6a, whereas the hydride attack occurs at Cβ of the latter, leading to the formation of the bis alkylidene trans-[Fe2{μ-η1:η2-C(Et)C(H)(Et)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (5d). The structure of 5d has been determined by an X-ray diffraction study. Other μ-vinylalkylidene complexes cis-[Fe2{μ-η1:η3-Cγ(R′)Cβ(R″)CαHN(Me)(Xyl)}(μ-CO)(CO)(Cp)2], (R′ = R″ = Ph, 6b; R′ = R″ = Me, 6c) have been prepared, and the structure of 6c has been determined by X-ray diffraction. Compound 6b results from treatment of cis-[Fe2{μ-η1:η3-Cγ(Ph)Cβ(Ph)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (4e) with NaBH4, whereas 6c has been obtained by reacting 4b with LiHBEt3. Both cis-4d and trans-4d react with LiHBEt3 affording cis-6a
Practical Recommendations of the Obesity Management Task Force of the European Association for the Study of Obesity for the Post-Bariatric Surgery Medical Management
Bariatric surgery is today the most effective long-term therapy for the management of patients with severe obesity, and its use is recommended by the relevant guidelines of the management of obesity in adults. Bariatric surgery is in general safe and effective, but it can cause new clinical problems and is associated with specific diagnostic, preventive and therapeutic needs. For clinicians, the acquisition of special knowledge and skills is required in order to deliver appropriate and effective care to the post-bariatric patient. In the present recommendations, the basic notions needed to provide first-level adequate medical care to post-bariatric patients are summarised. Basic information about nutrition, management of co-morbidities, pregnancy, psychological issues as well as weight regain prevention and management is derived from current evidences and existing guidelines. A short list of clinical practical recommendations is included for each item. It remains clear that referral to a bariatric multidisciplinary centre, preferably the one performing the original procedure, should be considered in case of more complex clinical situations
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