A Solvable Model for Polymorphic Dynamics of Biofilaments

We investigate an analytically tractable toy model for thermally induced polymorphic dynamics of cooperatively rearranging biofilaments - like microtubules. The proposed 4 -block model, which can be seen as a coarse-grained approximation of the full polymorphic tube model, permits a complete analytical treatment of all thermodynamic properties including correlation functions and angular fourier mode distributions. Due to its mathematical tractability the model straightforwardly leads to some physical insights in recently discussed phenomena like the "length dependent persistence length". We show that a polymorphic filament can disguise itself as a classical worm like chain on small and on large scales and yet display distinct anomalous tell-tale features indicating an inner switching dynamics on intermediate length scales

The Controversial History of Hormone Replacement Therapy

The history of hormone replacement therapy (HRT) started in the 1960s, with very high popularity in the 1990s. The first clinical trials on HRT and chronic postmenopausal conditions were started in the USA in the late 1990s. After the announcement of the first results of the Women's Health Initiative (WHI) in 2002, which showed that HRT had more detrimental than beneficial effects, HRT use dropped. The negative results of the study received wide publicity, creating panic among some users and new guidance for doctors on prescribing HRT. The clear message from the media was that HRT had more risks than benefits for all women. In the following years, a reanalysis of the WHI trial was performed, and new studies showed that the use of HRT in younger women or in early postmenopausal women had a beneficial effect on the cardiovascular system, reducing coronary disease and all-cause mortality. Notwithstanding this, the public opinion on HRT has not changed yet, leading to important negative consequences for women's health and quality of life

Sine-Gordon solitons, auxiliary fields, and singular limit of a double pendulums chain

We consider the continuum version of an elastic chain supporting topological and non-topological degrees of freedom; this generalizes a model for the dynamics of DNA recently proposed and investigated by ourselves. In a certain limit, the non-topological degrees of freedom are frozen, and the model reduces to the sine-Gordon equations and thus supports well-known topological soliton solutions. We consider a (singular) perturbative expansion around this limit and study in particular how the non-topological field assume the role of an auxiliary field. This provides a more general framework for the slaving of this degree of freedom on the topological one, already observed elsewhere in the context of the mentioned DNA model; in this framework one expects such phenomenon to arise in a quite large class of field-theoretical models.Comment: 18 pages, 2 figure

Ospemifene in the management of vulvar and vaginal atrophy: Focus on the assessment of patient acceptability and ease of use

Endocrinological changes that occur with menopause lead to a chronic and progressive condition named vulvar and vaginal atrophy (VVA). This disease is characterized by symptoms such as dryness, dyspareunia, itching, burning, and dysuria. According to recent epidemiological studies, VVA has a high prevalence and can also occur in younger women prior to the menopause, negatively affecting quality of life, sexual function, intimacy and relationship with the partner. Accordingly, therapy should be effective, initiated early and continued for as long as possible. Up to recent years, available therapeutic options have included over-the-counter lubricants and moisturizers, vaginal oestrogens and systemic hormones. These products are not indicated for all women. Hormones are mostly contraindicated in women with a history of hormone-sensitive cancer and are frequently not accepted even by women without contraindications. Local therapies are frequently considered uncomfortable, difficult to apply, and messy. Indeed, these treatments have a high spontaneous discontinuation rate, mostly due to dissatisfaction, safety concern, side effects and difficulty in vaginal placement. Recently, ospemifene, a new non-hormonal systemic remedy, was approved by FDA (Food and Drug Administration) and EMA (European Medicines Agency) for the treatment of the two most bothersome symptoms of VVA: dryness and dyspareunia. Because ospemifene is a selective estrogen receptor modulator (SERM), it can be administered also in women with a history of breast cancer, and this makes it more acceptable by any woman. In addition, its route of administration minimizes those bothersome side effects intrinsic to the vaginal route of administration. Available data indicate that women using ospemifene have higher adherence to treatment, higher persistence and lower discontinuation rate. Satisfaction is higher than with other local therapies and overall health care cost is lower

Scaffolds for controlled release of cartilage growth factors

In recent years, cell-based therapies using adult stem cells have attracted considerable interest in regenerative medicine. A tissue-engineered construct for cartilage repair should provide a support for the cell and allow sustained in situ delivery of bioactive factors capable of inducing cell differentiation into chondrocytes. Pharmacologically active microcarriers (PAMs), made of biodegradable and biocompatible poly (d,l-lactide-co-glycolide acid) (PLGA), are a unique system which combines these properties in an adaptable and simple microdevice. This device relies on nanoprecipitation of proteins encapsulated in polymeric microspheres with a solid in oil in water emulsion-solvent evaporation process, and their subsequent coating with extracellular matrix protein molecules. Here, we describe their preparation process, and some of their characterization methods for an application in cartilage tissue engineering

The Conjugated-Circuit Model: Application to Benzenoid Hydrocarbon Radicals

We have applied the conjugated-circuit model to benzenoid hydrocarbon radicals and predicted their aromatic stabilities. Our predictions are supported by alternative theoretical schemes such as the structure-resonance approach and by available experimental data. This work points to a considerable potential of the conjugated-circuit model for qualitative and quantitative discussion of thermodynamic stabilities of polycyclic conjugated radicals

The Conjugated-Circuit Model: Application to Benzenoid Hydrocarbon Radicals

We have applied the conjugated-circuit model to benzenoid hydrocarbon radicals and predicted their aromatic stabilities. Our predictions are supported by alternative theoretical schemes such as the structure-resonance approach and by available experimental data. This work points to a considerable potential of the conjugated-circuit model for qualitative and quantitative discussion of thermodynamic stabilities of polycyclic conjugated radicals

Helices at Interfaces

Helically coiled filaments are a frequent motif in nature. In situations commonly encountered in experiments coiled helices are squeezed flat onto two dimensional surfaces. Under such 2-D confinement helices form "squeelices" - peculiar squeezed conformations often resembling looped waves, spirals or circles. Using theory and Monte-Carlo simulations we illuminate here the mechanics and the unusual statistical mechanics of confined helices and show that their fluctuations can be understood in terms of moving and interacting discrete particle-like entities - the "twist-kinks". We show that confined filaments can thermally switch between discrete topological twist quantized states, with some of the states exhibiting dramatically enhanced circularization probability while others displaying surprising hyperflexibility

Analysis of salinity tolerance of Vitis vinifera 'Thompson Seedless' transformed with AtNHX1

Several transgenic plant species expressing AtNHX1, coding for a vacuolar Na+/H+ antiporter from Arabidopsis thaliana, have shown their ability to cope with salinity. The aim of this study was to analyze the response of Vitis vinifera cv. 'Thompson Seedless' transformed with AtNHX1 to salt stress, using soil substrate or hydroponic media, and to compare the response with untransformed 'Thompson Seedless' and allegedly tolerant 'Criolla' cultivars: 'Pedro Giménez' and 'Criolla Chica'. 'Thompson Seedless' embryogenic calli were transformed with Agrobacterium tumefaciens carrying AtNHX1 under the control of CaMV 35S promoter. Transgenic and untransformed plants were grown in a greenhouse under hydroponics or in pots with soil, and were subjected to increasing concentrations of sodium chloride (NaCl) up to 150 mM for a period of 7 weeks. Growth and toxicity symptoms were less affected in transgenics as compared to the untransformed grapevines, and transgenic lines had higher shoot length, leaf area and dry weights at the end of the experiment. Root concentrations of Na in transgenics were similar or lower than that observed in untransformed genotypes. Growth impairment and toxicity symptoms were observed in all genotypes under both conditions, but effects were more severe in plants growing with hydroponic culture. Potassium content and shoot to root dry weight ratio decreased with NaCl in hydroponics but not in pots. 'Criolla' cultivars grew less than the other genotypes, although 'Pedro Giménez' always exhibited highest shoot/root ratios