Chronic obstructive pulmonary disease in patients with end‐stage kidney disease on hemodialysis

The objectives of this study were to assess the prevalence of chronic obstructive pulmonary disease (COPD) in hemodialysis patients with spirometry and to examine the effects of fluid removal by hemodialysis on lung volumes. Patients ≥18 years at two Danish hemodialysis centers were included. Forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC ratio were measured with spirometry before and after hemodialysis. The diagnosis of COPD was based on both the GOLD criteria and the lower limit of normal criteria. There were 372 patients in treatment at the two centers, 255 patients (69%) completed spirometry before dialysis and 242 of these (65%) repeated the test after. In the initial test, 117 subjects (46%) had airflow limitation indicative of COPD with GOLD criteria and 103 subjects (40.4%) with lower limit of normal criteria; COPD was previously diagnosed in 24 patients (9%). Mean FVC and FEV₁ decreased mildly after dialysis (FVC: 2.84 to 2.79 L, P < 0.01. FEV₁: 1.97 to 1.93 L, P < 0.01) Hemodialysis did not affect the FEV₁/FVC ratio or number of subjects with airflow limitation indicative of COPD (113 vs. 120, P = 0.324; n = 242). COPD is a frequent and underdiagnosed comorbidity in patients on chronic hemodialysis. Spirometry should be considered in all patients on dialysis in order to address dyspnea adequately. Hemodialysis induced a small fall in mean FEV₁ and FVC, which was more pronounced in patients with little or no fluid removal, but the FEV₁/FVC ratio and the number of subjects with airflow limitation indicative of COPD were not affected by dialysis.     

Cryptanalysis of an iterated halving-based hash function: CRUSH

Iterated Halving has been suggested as a replacement to the Merkle?Damga?rd (MD) construction in 2004 anticipating the attacks on the MDx family of hash functions. The CRUSH hash function provides a specific instantiation of the block cipher for Iterated Halving. The authors identify structural problems with the scheme and show that they can trivially identify collisions and second preimages on many equal-length messages of length ten blocks or more. The cost is ten decryptions of the block cipher, this being less than the generation of a single digest. In addition, these attacks can be used to differentiate CRUSH from a random oracle in O(1). The authors show that the complexity of finding a preimage in the unpadded CRUSH with the length encoding is negligible and extend this attack on CRUSH with the length encoding in cost O(2/sup 32/). This attack is a multi-preimage attack, since the attacker can produce a large number of messages for a given message digest for the cost of O(2/sup 32/). Hence, this attack can be used as a multi-collision and a multisecond- preimage as well. They show that if the attacker knows the last 64-bits of the message digest in advance, he can do the time-consuming part of the attack off-line. The authors show that even if Iterated Halving is repaired, the construction has practical issues that means it is not suitable for general deployment.     

Analysis of the diffusive mass transport in the anode side porous backing layer of a direct methanol fuel cell

In this work we present an analysis of the mass transport in the anode side porous backing layer of a direct methanol fuel cell (DMFC). The effective transport coefficient of different backing layers at various compressions was measured and compared to two different literature models and a single particle random walk simulation which accounts for details of the geometrical fibre microstructure. Based on the measured values of the effective transport coefficient limiting current densities for diffusive transport were calculated taking into account geometric boundary conditions and anisotropic and inhomogeneous backing layer properties. Comparison with the measured values for the limiting current in fuel cell operation shows qualitative agreement. A systematic underestimation indicates that also other transport processes contribute significantly to the mass transfer at the used experimental setup.     

Changes in Molecular Characteristics of Cereal Carbohydrates after Processing and Digestion

Different extraction, purification and digestion methods were used to investigate the molecular properties of carbohydrates in arabinoxylan and β-glucan concentrates, dietary fiber (DF) rich breads and ileum content of bread fed pigs. The breads studied were: a low DF wheat bread (WF), whole meal rye bread (GR), rye bread with kernels (RK), wheat bread supplemented with wheat arabinoxylan concentrate (AX) and wheat bread supplemented with oat β-glucan concentrate (BG). The weight average molecular weight (M_w) of extractable carbohydrates in β-glucan concentrate decreased eight-fold after inclusion in the BG bread when exposed to in vitro digestion, while the M_w of purified extractable carbohydrates in AX bread was reduced two-fold, and remained almost unaffected until reaching the terminal ileum of pigs. Similarly, the M_w of purified extractable carbohydrates in GR and RK bread was not significantly changed in the ileum. The AX bread resulted in the highest concentration of dissolved arabinoxylan in the ileum among all the breads that caused a substantial increased in ileal AX viscosity. Nevertheless, for none of the breads, the M_w of extractable carbohydrates was related neither to the bread extract nor ileal viscosity.     

Desmin and troponin T are degraded faster in type IIb muscle fibers than in type I fibers during postmortem aging of porcine muscle

A novel approach was applied in this study to directly evaluate the effect of muscle fiber type on postmortem protein degradation. Porcine muscle fibers were isolated from longissimus muscle at day 1, 3, and 6 postmortem. Fibers were sorted by immunochemical myosin heavy chain isoform typing. Western blot analysis of fibers pooled separately into type I or IIb showed that the relative amounts of 39- and 50-kDa desmin degradation fragments at day 6, and 28- to 31-kDa fragments of troponin T fast type isoform (fTnT) at day 1 and 6 postmortem were higher in type IIb than in type I fibers. At day 6 troponin T slow type isoform (sTnT) was less degraded than fTnT in type I fibers. These results indicated greater rate and extent of proteolysis in type IIb than in type I fibers and higher susceptibility of fTnT to proteolysis than that of sTnT isoform.     

The Effective Factors on the Structure of Butter and Other Milk Fat‐Based Products

Butter and other milk fat‐based products are valuable products for the dairy industry due to their unique taste, their textural characteristics, and nutritional value. However, an increased consumer demand for low‐fat‐based products increases the need for an increased essential understanding of the effective factors governing the structure of milk fat‐based products. Today, 2 manufacturing techniques are available: the churning method and the emulsification method. The first is typically used for production of butter with a globular structure, which has become increasingly popular to obtain low‐fat‐based products, typically without presence of milk fat globules. The microstructure of milk fat‐based products is strongly related to their structural rheology, hence applications. Structural behavior is not determined by one single parameter, but by the interactions between many. This complexity is reviewed here. Parameters such as thermal treatment of cream prior to butter making, water content, and chemical composition influence not only crystal polymorphism, but also the number and sizes of fat crystals. The number of crystal–crystal interactions formed within the products is related to product hardness. During storage, however, postcrystallization increases the solid fat content and strengthens the fat crystal network. The fat crystal network is strengthened by the formation of more and stronger crystal–crystal interactions due to mechanically interlinking of fat crystals, which occurs during crystal growth. Postcrystallization is directly linked to chemical composition. The initially observed microstructural difference causing different rheological behavior will disappear during storage due to postcrystallization and formation of more crystal–crystal interactions.