BACKGROUND: The objective was to assess whether expectant management of sonographically benign ovarian cysts may be an option for selected asymptomatic premenopausal women. METHODS: This is a ...prospective observational longitudinal study. Between January 1997 and December 2002, 323 asymptomatic premenopausal women (mean age: 40.6 years; range: 19–50 years) diagnosed as having a sonographically benign ovarian cyst measuring <6 cm were offered conservative management with periodic follow-up at 6–12 month intervals. In all cases, a first check was performed 3 months after diagnosis to confirm the ‘persistent’ nature of the cyst. A total of 120 women agreed to participate in this study and constitute the basis of the data presented. RESULTS: Mean diameter at diagnosis for the most frequent lesions were as follows: endometrioma 3.3 cm (SD 1.5); simple cyst 4.1 cm (SD 1.6); dermoid cyst 3.2 cm (SD 1.4); haemorrhagic cyst 3.5 cm (SD 1.2); hydrosalpinx 2.9 cm (SD 1.0). With a median follow-up of 42 months (range: 18–94 months), most lesions remained unchanged, both in size and sonographic appearance. Ten cysts (8.3%) disappeared during follow-up, all of them after more than 2 years of follow-up. No patient has developed signs or symptoms suggesting ovarian cancer. CONCLUSION: Most sonographically benign ovarian cysts remain unchanged during long-term follow-up. Our data would support conservative management in these cases.
The enantioselectivity of the base-promoted cyclization of
N-alkyl-
N-chloroacetyl amino acid derivatives to β-lactams is dependent on the substituents on the starting material. While
t
Bu esters are ...preferred over Me esters, and
N-Bzl-,
N-Pmb,
N-Nph and
N-Mom groups gave similar e.e. values, only amino acid derivatives with branched side-chains at the γ-position were able to show a good memory of chirality.
Graphic
Thio derivatives of hydroxytyrosol containing thiol, thioacetate and disulfide functionalities were synthesized from natural hydroxytyrosol (3,4-DHPEA) via 3,4-dihydroxyphenethyl halides. These ...compounds, containing the combination of catechol moiety and divalent sulfur functions, were tested for the pro-apoptotic and anti-proliferative activities on both parental HL60 and multi-drug resistant HL60R cells. It was found that all synthesized compounds were more effective than 3,4-DHPEA in inducing apoptosis on HL60R cells, and that the hydroxytyrosol disulfide was the most active pro-apoptotic and anti-proliferative compound on both HL60 and HL60R cells. Different from 3,4-DHPEA, all thio derivatives of hydroxytyrosol induced apoptosis by a mechanism not involving the release of H2O2 in the culture medium. The data on HL60R cells suggest that these compounds could be able to reverse the resistance toward the most common drugs in cancer therapy.
Objective: The aim of this study was to investigate whether concurrent bandwidth feedback improves learning of the lane-keeping task in a driving simulator.
Background: Previous research suggests ...that bandwidth feedback improves learning and that off-target feedback is superior to on-target feedback. This study aimed to extend these findings for the lane-keeping task.
Method: Participants without a driver’s license drove five 8-min lane-keeping sessions in a driver training simulator: three practice sessions, an immediate retention session, and a delayed retention session 1 day later. There were four experimental groups (n = 15 per group): (a) on-target, receiving seat vibrations when the center of the car was within 0.5 m of the lane center; (b) off-target, receiving seat vibrations when the center of the car was more than 0.5 m away from the lane center; (c) control, receiving no vibrations; and (d) realistic, receiving seat vibrations depending on engine speed. During retention, all groups were provided with the realistic vibrations.
Results: During practice, on-target and off-target groups had better lane-keeping performance than the nonaugmented groups, but this difference diminished in the retention phase. Furthermore, during late practice and retention, the off-target group outperformed the on-target group. The off-target group had a higher rate of steering reversal and higher steering entropy than the nonaugmented groups, whereas no clear group differences were found regarding mean speed, mental workload, or self-reported measures.
Conclusion: Off-target feedback is superior to on-target feedback for learning the lane-keeping task.
Application: This research provides knowledge to researchers and designers of training systems about the value of feedback in simulator-based training of vehicular control.
► We model a real furnace, fuelled with orujo, used to dry olive pomace. ► We apply a radial basic functions–auto-regression with exogenous variables (ARXs–RBFs) method. ► Root-mean-square error and ...r2 are used to validate the ARX–RBF model.
Drying operations are common in food industries. One of the main components in a drying system is the furnace. The furnace operation involves heat–mass transfer and combustion, thus it demands a complex mathematic representation. Since autoregressive methods are simple, and help to simulate rapidly a system, we model a drying furnace of olive pomace via an auto-regression with exogenous variables (ARXs) method. A neural network of radial basic functions (RBFs) defines the ARX experimental relation between the amounts of dry pomace (moisture content of 15%) used like fuel and the temperature of outlet gases. A real industrial furnace is studied to validate the proposed model, which can help to control the drying process.
The use of antihypertensive medication and hypertension control has significantly increased during recent decades in some developed countries, but the impact of improved drug treatment on blood ...pressure (BP) control in the population is unknown.
Data were taken from 2 surveys representative of the population aged ≥ 60 years in Spain conducted with the same methodology in 2000 to 2001 and in 2008 to 2010. BP was measured 6×. The first BP reading was discarded, and the average of the remaining 3 to 5 BP readings was taken for analysis. Hypertension prevalence was 68.7% in 2000 to 2001 and 66.0% in 2008 to 2010. Between both time periods there was an improvement in hypertension awareness (63.6%-67.7%), drug treatment among those aware (84.5%-87.5%), and BP control among treated hypertensives (30.3%-42.9%). Overall, BP control among all hypertensives increased from 16.3% to 25.4%. After adjustment for age, sex, education, hypertension duration, smoking, alcohol consumption, body mass index, sedentary behavior, diabetes mellitus, cardiovascular disease, and visits to the physician through logistic regression, ≈ 7% of the improvement in BP control among all hypertensives was explained by higher hypertension awareness, and 36.2% was explained by a higher treatment rate. Among the treated hypertensives, 22.6% of the progress in BP control was because of the increase in the number of BP medications used in each patient.
BP control among the older hypertensive population in Spain has improved from 2000 to 2001 to 2008 to 2010 because of a higher treatment rate and more intense antihypertensive drug treatment.
Chiral spirocyclic 2,6-dioxopiperazines were synthesized from amino acid derived α-quaternary α-amino nitriles via H2SO4-promoted cyano hydration, followed by base-mediated cyclization and ...N-alkylation. This methodology, requiring the previous preparation of the amino nitrile by a modified Strecker reaction, was applied to Phe, Trp, Pro, Asp, Glu, and Ser derivatives. In the case of the Trp-derived amino nitrile the major product of the treatment with H2SO4 was not the expected carboxamide, but a new tetracyclic indoline derivative containing the novel heterocyclic system hexahydropyrrolo1‘,2‘,3‘:1,9a,9imidazo1,2-aindole, as a result of a domino tautomerization. The treatment of this indoline derivative with refluxing 1 N HCl led to a Trp-derived 2,6-dioxopiperazine. The 2,6-dioxopiperazine ring opened under the reaction conditions of methyl ester saponification, giving N-(carboxyalkyl)amino acid derivatives. Therefore, the synthesis of 2,6-dioxopiperazines containing free carboxylic acids from the respective methyl esters required transesterification to benzyl esters, followed by hydrogenolysis.
Senecio inaequidens, a south African species that has recently invaded parts of Europe, especially human disturbed habitats, was examined under laboratory and glasshouse conditions to assess the ...germination of achenes, soil seed banks, growth of seedlings and its breeding system. These observations allowed identification of ecological characteristics that may contribute to the invasiveness of the species. Achenes derived from three populations of S. inaequidens were germinated over a wide temperature range (from 14/6 °C day/night temperatures to a constant temperature of 30 °C). They exhibited a rapid achene germination especially when temperatures reached 20 °C. Germination of seeds from soil samples also exhibited a prolonged germination over time suggesting therefore different types of dormancy. Growth response was studied along a nitrogen gradient from 0.33 to 16.0 mmol l^sup -1^ and data were interpreted using growth analysis. Seedlings of S. inaequidens exhibited a slow growth in low nutrient availability and a rapid growth rate when exposed to high nutrient availability, which contributed to producing a large leaf area and biomass. Four types of pollination were studied in S. inaequidens. Hand-pollinations showed that S. inaequidens was mostly self-incompatible. Self-pollinated capitula only showed 7.6% viable achenes, significantly lower than insect-pollinated and cross-pollinated capitula. Some individuals were more self-fertile than others ensuring the production of some offspring in a situation of colonisation. Natural pollination occurred with generalist insects. Most of these results confirm the invasive ability of S. inaequidens.PUBLICATION ABSTRACT
Reverse turns, a common motif in proteins and peptides, have attracted attention due to their relevance in a wide variety of biological processes. In an attempt to artificially imitate and stabilize ...these turns in short peptides, we have developed versatile synthetic methodologies for the preparation of 2-alkyl-2-carboxyazetidines and incorporated them into the i + 1 position of model tetrapeptides, where they have shown a tendency to induce γ-turns. However, to ascertain the general utility of these restricted amino acids as γ-type reverse turn inducers, it was then required to study the conformational preferences when located at other positions. To this end, model tetrapeptides R-CO-Ala-Xaa-NHMe, containing differently substituted azetidine moieties (Xaa = Aze, 2-MeAze, 2-BnAze) at the i + 2 position, were synthesized and subjected to a thorough conformational analysis. The theoretical and experimental results obtained, including the X-ray diffraction structure of a dipeptide derivative containing this skeleton, provide evidence that the 2-alkyl-2-carboxyazetidine scaffold is able to efficiently induce γ-turns when incorporated into these short peptides, irrespective of their localization in the peptide chain.
Enantiopure β-amino acids represent interesting scaffolds for peptidomimetics, foldamers and bioactive compounds. However, the synthesis of highly substituted analogues is still a major challenge. ...Herein, we describe the spontaneous rearrangement of 4-carboxy-2-oxoazepane α,α-amino acids to lead to 2'-oxopiperidine-containing β(2,3,3) -amino acids, upon basic or acid hydrolysis of the 2-oxoazepane α,α-amino acid ester. Under acidic conditions, a totally stereoselective synthetic route has been developed. The reordering process involved the spontaneous breakdown of an amide bond, which typically requires strong conditions, and the formation of a new bond leading to the six-membered heterocycle. A quantum mechanical study was carried out to obtain insight into the remarkable ease of this rearrangement, which occurs at room temperature, either in solution or upon storage of the 4-carboxylic acid substituted 2-oxoazepane derivatives. This theoretical study suggests that the rearrangement process occurs through a concerted mechanism, in which the energy of the transition states can be lowered by the participation of a catalytic water molecule. Interestingly, it also suggested a role for the carboxylic acid at position 4 of the 2-oxoazepane ring, which facilitates this rearrangement, participating directly in the intramolecular catalysis.
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