Preventing Atomicity Violations with Contracts

Software developers are expected to protect concurrent accesses to shared regions of memory with some mutual exclusion primitive that ensures atomicity properties to a sequence of program statements. This approach prevents data races but may fail to provide all necessary correctness properties.The composition of correlated atomic operations without further synchronization may cause atomicity violations. Atomic violations may be avoided by grouping the correlated atomic regions in a single larger atomic scope. Concurrent programs are particularly prone to atomicity violations when they use services provided by third party packages or modules, since the programmer may fail to identify which services are correlated. In this paper we propose to use contracts for concurrency, where the developer of a module writes a set of contract terms that specify which methods are correlated and must be executed in the same atomic scope. These contracts are then used to verify the correctness of the main program with respect to the usage of the module(s). If a contract is well defined and complete, and the main program respects it, then the program is safe from atomicity violations with respect to that module. We also propose a static analysis based methodology to verify contracts for concurrency that we applied to some real-world software packages. The bug we found in Tomcat 6.0 was immediately acknowledged and corrected by its development team

Coffee industrial waste as a natural source of bioactive compounds with antibacterial and antifungal activities

Coffee is one of the most popular and consumed beverages in the world, which leads to a high contents of solid residue known as spent coffee grounds (SCG). As is known, coffee beans contain several classes of health related chemicals, including phenolic compounds, melanoidins, diterpenes, xanthines and carotenoids which are associated with therapeutic and pharmaceutical effects, due to antimicrobial, antioxidant, anti-infectious and antitumour activities. Considering that this coffee industrial waste has no commercial value and are currently disposed as a solid waste or employed as fertilizers, we intend to highlight the use of SCG as a raw material with potential interest to the food and pharmaceutical industries. Moreover, this work seems to be valuable to promote the use of SCG as natural and an inexpensive food supplements or pharmaceutical additive. The phytochemical compounds content among the crude aqueous extracts of SCG followed this order: phenolics > flavonoids > carotenoids (mg/ g dry waste), respectively. Caffeine content found in SCG was ~ 0.82 g/100 g dry waste, 70 % lower than coffee roasting beans. Coffee ground extracts showed inhibition to S. aureus and E. coli growth for concentrations of 1.0 mg/ mL and a stronger inhibition was also observed against C. albicans, C. krusei and C. parapsilosis growth using lower concentration (0.5 mg/ mL).info:eu-repo/semantics/publishedVersio

Coffee industrial waste as a natural source of bioactive compounds with antibacterial and antifungal activities

Coffee is one of the most popular and consumed beverages in the world, which leads to a high contents of solid residue known as spent coffee grounds (SCG). As is known, coffee beans contain several classes of health related chemicals, including phenolic compounds, melanoidins, diterpenes, xanthines and carotenoids which are associated with therapeutic and pharmaceutical effects, due to antimicrobial, antioxidant, anti-infectious and antitumour activities. Considering that this coffee industrial waste has no commercial value and are currently disposed as a solid waste or employed as fertilizers, we intend to highlight the use of SCG as a raw material with potential interest to the food and pharmaceutical industries. Moreover, this work seems to be valuable to promote the use of SCG as natural and an inexpensive food supplements or pharmaceutical additive. The phytochemical compounds content among the crude aqueous extracts of SCG followed this order: phenolics > flavonoids > carotenoids (mg/ g dry waste), respectively. Caffeine content found in SCG was ~ 0.82 g/100 g dry waste, 70 % lower than coffee roasting beans. Coffee ground extracts showed inhibition to S. aureus and E. coli growth for concentrations of 1.0 mg/ mL and a stronger inhibition was also observed against C. albicans, C. krusei and C. parapsilosis growth using lower concentration (0.5 mg/ mL).info:eu-repo/semantics/publishedVersio

Comparative studies of ultrasound and membrane emulsification for the production of stable Perfluorocarbon-in-water nanoemulsions

Low-molecular weight perfluorocarbons (PFCs) are usually chemically and biologically inert, clear, colorless liquids, presenting a high affinity for many gases, namely for O2, NO and CO2, which turn them particularly suitable in various biomedical applications involving gas capture, transport and release. In fact, PFC-in-Water emulsions were one of the two major classes of systems proposed as blood substitutes and for O2/NO therapeutics. However there are still some important issues concerning this type of systems which have limited their efficiency, approval and commercial success, namely those related to emulsion stability, hydrodynamic size distribution and reduced shelf-lives. Stability issues can easily lead to PFC diffusion in water, to aggregation and to the consequent hydrodynamic size increase and emulsion degradation [1]. Nanoemulsions (typically within a range of hydrodynamic sizes of 10-100 nm) exhibit various advantages over typical microemulsions [2]. Hence, our aim is to produce monodisperse PFC nanoemulsions presenting larger surface-to-volume ratios, enhanced stabilities and more efficient gas capture/delivery properties. A first approach to achieve these goals is to prepare and to study a mixed surfactant system based on Tween 80 and on a perfluorinated surfactant (perfluorooctyl phosphocholine) at different relative compositions. PFC-in-Water nanoemulsions were produced by using the traditional ultrasound emulsification method (500W). The effects of co-surfactants relative compositions on CMC values, on the kinetics of emulsion formation and on the corresponding stabilities of prepared nanoemulsions were evaluated. Hydrodynamic sizes and Zeta-potentials were also assessed, being able to obtain stable nanoemulsions with hydrodynamic sizes between 150 and 200 nm. In a comparative study, PFC-in-Water nanoemulsions were also produced by membrane emulsification. This low energy-intensive technique has received increasing interest as it allows more flexible operating conditions. Regenerated cellulose membranes such as Nadir UC500 and Millipore Ultracel RC100, polyethersulphone membranes such as Nadir UP150 and Millipore PBHK04310, and a promising polycarbonate Whatman Track-ethched 30 nm Nuclepore membrane, were employed to produce nanoemulsions, and using the same mixed surfactant system and relative compositions. The energy inputs of these two methods were compared and discussed along with their efficiencies in terms of producing nanoemulsions presenting improved stabilities, smaller hydrodynamic sizes and narrower hydrodynamic size distributions. References [1] M.P. Krafft, A. Chittofrati, J.G. Riess, Curr Opin in Colloid Interface Sci., 8 (2003) 251–258 [2] E. Piacentini, E. Drioli, L. Giorno, J. of Membr. Sci., 468 (2014) 410–42

Chemical Modifications on Proteins Using Glutaraldehyde

In this work the effect of crosslinking the enzyme esperase (E.C. 3.4.21.62) and the proteins bovine serum albumin and casein with the bifunctional compound glutaraldehyde on molecular mass increase was studied. Two common techniques for measuring molecular mass of proteins were used: SEC and SDS-PAGE. These techniques revealed that the proteins bovine albumin and casein, when subjected to chemical crosslinking with glutaraldehyde, volume fraction 0.25 %, increased their molecular mass by 20- and 40-fold, respectively. It was also observed that Mr increased proportionally to the increase of glutaraldehyde concentration in the solution, and that the addition of glutaraldehyde should be done slowly, in small amounts, in order to attain bigger protein aggregates. When the proteolytic enzyme esperase was subjected to glutaraldehyde, no increase in its Mr was achieved. Several assumptions can be made to explain these results, the most reasonable being the low amount of free lysine groups available for crosslinking. This study confirms that glutaraldehyde is not an adequate crosslinker for esperase

Natural resources with sweetener power: phytochemistry and antioxidant characterisation of Stevia Rebaudiana (Bert.), sensorial and centesimal analyses of lemon cake recipes with S. Rebaudiana incorporation

Stevia rebaudiana leaf extracts are calorie-free sweeteners of natural origin, derived from the Stevia rebaudiana plant known as a natural sweetener, which contains steviol glycosides and others bioactive compounds recognized by their biological properties. The present study was designed to evaluate the total phenolics (26.0 mg gallic acid/g) and total flavonoids contents (9.7 mg catechin/g) of a hydroalcoholic extract of Stevia rebaudiana dried leaves. A similar hydroalcoholic extract of commercial powder steviol sweetener was also evaluated, showing lower contents of bioactive compounds (11.9 mg/g and 5.1 mg/g, for total phenolics and flavonoids, respectively). The hydroalcoholic extract of dried Stevia rebaudiana leaves also showed high in vitro antioxidant activity, besides a positive correlation between total phenolic compounds and the DPPH and FRAP assays. Moreover, Stevia rebaudiana leaves have sensory and functional properties superior to those of many other high-potency sweeteners and is likely to become a major source of natural sweetener for the growing food market. Thus, four different lemon cakes formulations were studied (a traditional cake control recipe with sugar, two cakes with incorporation of Stevia rebaudiana fresh leaf and a cake with commercial powder steviol), using a sensory analysis covering 100 untrained consumers. Centesimal composition analyses of the four lemon cakes showed significant differences in fat, ashes, proteins and carbohydrates contents (p<0.05). Also, the raised energy value observed for the cake control was superior to the cake with Stevia rebaudiana leaves incorporation (309.8 Kcal/100 g, 268.0 Kcal/100 g,142 respectively). Sensorial analysis results showed that Stevia rebaudiana leaves were accepted and, in the future, they can be a natural option to replace some or all the saccharose in cakes formulations.info:eu-repo/semantics/publishedVersio

Mitogen-activated protein kinase kinase 5 regulates proliferation and biosynthetic processes in procyclic forms of Trypanosoma brucei

The pathogenic protozoan T. brucei alternates into distinct developmental stages in the mammalian and insect hosts. The mitogen-activated protein kinase (MAPK) signaling pathways transduce extracellular stimuli into a range of cellular responses, which ultimately lead to the adaptation to the external environment. Here, we combined a loss of function approach with stable isotope labeling with amino acids in cell culture (SILAC)-based mass spectrometry (MS) to investigate the role of the mitogen-activated protein kinase kinase 5 (MKK5) in T. brucei. The silencing of MKK5 significantly decreased the proliferation of procyclic forms of T. brucei. To shed light on the molecular alterations associated with this phenotype, we measured the total proteome and phosphoproteome of cells silenced for MKK5. In the total proteome, we observed a general decrease in proteins related to ribosome and translation as well as down-regulation of several components of the fatty acids biosynthesis pathway. In addition, we observed alterations in the protein levels and phosphorylation of key metabolic enzymes, which point toward a suppression of the oxidative metabolism. Taken together, our findings show that the silencing of MKK5 alters cell growth, energy metabolism, protein and fatty acids biosynthesis in procyclic T. brucei

Natural resources with sweetener power: phytochemistry and antioxidant characterisation of Stevia Rebaudiana (Bert.), sensorial and centesimal analyses of lemon cake recipes with S. Rebaudiana incorporation.

Stevia rebaudiana leaf extracts are calorie-free sweeteners of natural origin, derived from the Stevia rebaudiana plant known as a natural sweetener, which contains steviol glycosides and others bioactive compounds recognized by their biological properties. The present study was designed to evaluate the total phenolics (26.0 mg gallic acid/g) and total flavonoids contents (9.7 mg catechin/g) of a hydroalcoholic extract of Stevia rebaudiana dried leaves. A similar hydroalcoholic extract of commercial powder steviol sweetener was also evaluated, showing lower contents of bioactive compounds (11.9 mg/g and 5.1 mg/g, for total phenolics and flavonoids, respectively). The hydroalcoholic extract of dried Stevia rebaudiana leaves also showed high in vitro antioxidant activity, besides a positive correlation between total phenolic compounds and the DPPH and FRAP assays. Moreover, Stevia rebaudiana leaves have sensory and functional properties superior to those of many other high-potency sweeteners and is likely to become a major source of natural sweetener for the growing food market. Thus, four different lemon cakes formulations were studied (a traditional cake control recipe with sugar, two cakes with incorporation of Stevia rebaudiana fresh leaf and a cake with commercial powder steviol), using a sensory analysis covering 100 untrained consumers. Centesimal composition analyses of the four lemon cakes showed significant differences in fat, ashes, proteins and carbohydrates contents (p<0.05). Also, the raised energy value observed for the cake control was superior to the cake with Stevia rebaudiana leaves incorporation (309.8 Kcal/100 g, 268.0 Kcal/100 g,142 respectively). Sensorial analysis results showed that Stevia rebaudiana leaves were accepted and, in the future, they can be a natural option to replace some or all the saccharose in cakes formulations.info:eu-repo/semantics/publishedVersio

Semi-synthesis of small molecules of aminocarbazoles: tumor growth inhibition and potential impact on p53

The tumor suppressor p53 is inactivated by mutation in approximately 50% of human cancers. Small molecules that bind and stabilize those mutants may represent effective anticancer drugs. Herein, we report the tumor cell growth inhibitory activity of carbazole alkaloids and amino derivatives, as well as their potential activation of p53. Twelve aminocarbazole alkaloids were semi-synthesized from heptaphylline (1), 7-methoxy heptaphylline (2), and 7-methoxymukonal (3), isolated from Clausena harmandiana, using a reductive amination protocol. Naturally-occurring carbazoles 1–3 and their amino derivatives were evaluated for their potential effect on wild-type and mutant p53 activity using a yeast screening assay and on human tumor cell lines. Naturally-occurring carbazoles 1–3 showed the most potent growth inhibitory effects on wild-type p53-expressing cells, being heptaphylline (1) the most promising in all the investigated cell lines. However, compound 1 also showed growth inhibition against non-tumor cells. Conversely, semi-synthetic aminocarbazole 1d showed an interesting growth inhibitory activity in tumor cells expressing both wild-type and mutant p53, exhibiting low growth inhibition on non-tumor cells. The yeast assay showed a potential reactivation of mutant p53 by heptaphylline derivatives, including compound 1d. The results obtained indicate that carbazole alkaloids may represent a promising starting point to search for new mutp53-reactivating agents with promising applications in cancer therapy.The authors thank to national funds provided by FCT—Foundation for Science and Technology and European Regional Development Fund (ERDF) and COMPETE under the Strategic Funding of CIIMAR UIDB/04423/2020 (Natural Products and Medicinal Chemistry) and LAQV/REQUIMTE (UID/QUI/50006/2020), the project PTDC/SAU-PUB/28736/2017 (reference POCI-01–0145-FEDER028736), PTDC/DTP-FTO/1981/2014-POCI-01-0145-FEDER-016581). We also thank FCT for the fellowship SFRH/BD/128673/2017 (J. Loureiro). Ploenthip Puthongking thanks Thailand Research Fund (DBG6080006), Thailand

Nutritional, rheological, sensory characteristics and environmental impact of a yogurt-like dairy drink for children enriched with lupin flour

Studies have demonstrated that the addition of pulses to foods can make them more nutritious. We hypothesize that lupin flour adds nutritional benefits to yogurts. This study aimed to characterize a lupin-enriched yogurt in nutritional, rheological, and sensorial terms by a trained panel, and assess its environmental impact using the life cycle assessment (LCA) approach. For comparison, natural yogurt and a commercial formula were used as controls. The developed yogurt is “high in protein” (7g/100g), “source of fiber” (1.9g/100g), and “source of omega 3” (53 mg/100g). The lupin yogurt was the stiffest with the highest viscosity than controls according to rheological parameters. There were no significant sensory differences between the lupin-enriched yogurt and the controls, although some undesirable sensory characteristics such as bitterness, granularity, and after-taste were observed. The environmental impact per 100 g serving was similar to natural yogurt and slightly worse regarding commercial yogurt but better when expressed per Nutritional Density Unit (NDU). Using lupin flour to enrich yogurts for children can be an alternative to producing more nutritious products.N/