Kinetics of the hydrolysis of polysaccharide galacturonic acid and neutral sugars chains from flaxseed mucilage

Different hydrolysis procedures of flaxseed polysaccharides (chemical and enzymatic) were carried out with H2SO4, HCl and TFA at different acid concentrations (0.2, 1 and 2 M) and temperatures (80 and 100°C). Enzymatic and combined chemical and enzymatic hydrolyses of polysaccharide from flaxseed mucilage were also studied. Acid hydrolysis conditions (2 M H2SO4, 4 h, 100°C) are required to quantify total monosaccharide content of flaxseed mucilage. The enzymatic pathway (Pectinex™ Ultra SP) limits sugar destruction during hydrolysis, but it is also insufficient for complete depolymerization. The combination of the two treatments, i.e. moderate chemical hydrolysis (0.2 M H2SO4, 80°C, 48 h) combined with enzymatic hydrolysis is not more effective compared to chemical hydrolysis in drastic conditions (2 M H2SO4 at 100°C). The strong interaction between the neutral and acid fractions of flaxseed mucilage may hinder total release of sugar residues. Physical treatment prior to the hydrolysis could be necessary to achieve complete depolymerisation of flaxseed mucilage

Wage led aggregate demand in the United Kingdom

The wage led aggregate demand hypothesis is examined for the United Kingdom over the period 1971 - 2007. Existing studies disagree on the aggregate demand regime for the UK, and this appears to be due to differing empirical approaches. Studies relying on equation-by-equation estimation procedures tend to find support for wage led aggregate demand in the UK, while the single study using systems estimation finds no support for the hypothesis. In order to resolve this incongruity, we test the wage led aggregate demand hypothesis in the UK using VAR models estimated on quarterly data. We use a liberal partial identification strategy based on movements in real earnings rather than in the labour share. The results provide support for the wage led aggregate demand hypothesis during the period of study

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Biogeochemical Stoichiometry of Antarctic Dry Valley Ecosystems

Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10–10⁶ years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates

Laparoscopic cholecystectomy for melanoma metastatic to the gallbladder: is it an adequate surgical procedure? Report of a case and review of the literature

<p>Abstract</p> <p>Background</p> <p>Only 2% to 4% of patients with melanoma will be diagnosed with gastrointestinal metastasis during the course of their disease. The most common sites of gastrointestinal metastases from melanoma include the small bowel (35%–67%), colon (9%–15%) and stomach (5%–7%), with a median survival of 6–10 months after surgery, and 18% survival at five years. Metastatic melanoma to the gallbladder is extremely rare and it is associated with a very poor prognosis.</p> <p>Case presentation</p> <p>We report a case of a 54-year old man presented to observation with diagnosis of 6.1 mm thick, Clark's level IV, ulcerated melanoma of the trunk, developing in the course of the disease metastatic involvement of the gallbladder as first site of recurrence, treated by laparoscopic cholecystectomy. To date only few cases of patients with metastatic melanoma of the gallbladder treated by this surgical procedure have been reported in literature.</p> <p>Conclusion</p> <p>Gallbladder metastasis represents a rare event as a first site of recurrence. It must be considered a possible expression of systemic disease also despite radiological absence of other metastatic lesions. Laparoscopic approach has a possible therapeutic role, but open surgery has also a concomitant diagnostic purpose because gives the possibility of manual exploration of abdominal cavity, useful particularly to reveal bowel metastatic lesions, not easily identifiable by preoperative imaging examinations.</p

The Rise and Fall of Export-Led Growth

This paper traces the rise of export-led growth as a development paradigm and argues that it is exhausted owing to changed conditions in emerging market (EM) and developed economies. The global economy needs a recalibration that facilitates a new paradigm of domestic demand-led growth. Globalization has so diversified global economic activity that no country or region can act as the lone locomotive of global growth. Political reasoning suggests that EM countries are not likely to abandon export-led growth, nor will the international community implement the international arrangements needed for successful domestic demand-led growth. Consequently, the global economy likely faces asymmetric stagnation

A Queueing Theoretic Approach to Decoupling Inventory

This paper investigates the performance of different hybrid push-pull systems with a decoupling inventory at the semi-finished products and reordering thresholds. Raw materials are ‘pushed’ into the semi-finished product inventory and customers ‘pull’ products by placing orders. Furthermore, production of semi-finished products starts when the inventory goes below a certain level, referred to as the threshold value and stops when the inventory attains stock capacity. As performance of the decoupling stock is critical to the overall cost and performance of manufacturing systems, this paper introduces a Markovian model for hybrid push-pull systems. In particular, we focus on a queueing model with two buffers, thereby accounting for both the decoupling stock as well as for possible backlog of orders. By means of numerical examples, we assess the impact of different reordering policies, irregular order arrivals, the set-up time distribution and the order processing time distribution on the performance of hybrid push-pull systems

Wage‐led versus profit‐led demand: a comprehensive empirical analysis

This study investigates various economic factors’ impact in determining the relationship between functional income distribution and aggregate demand from both a theoretical and an empirical viewpoint. We base our analysis on a demand‐driven growth model for an open economy that allows for either profit‐led or wage‐led regimes. Our results strongly indicate that a higher level of trade openness is associated with a lower probability of being wage‐led. We find evidence that lower wage inequality makes an economy more wage‐led and that countries with a greater private credit‐to‐gross domestic product (GDP) ratio are more likely to be profit‐led