Cell Force-Driven Basement Membrane Disruption Fuels EGF- and Stiffness-Induced Invasive Cell Dissemination from Benign Breast Gland Acini

Local basement membrane (BM) disruption marks the initial step of breast cancer invasion. The activation mechanisms of force-driven BM-weakening remain elusive. We studied the mechanical response of MCF10A-derived human breast cell acini with BMs of tuneable maturation to physical and soluble tumour-like extracellular matrix (ECM) cues. Traction force microscopy (TFM) and elastic resonator interference stress microscopy (ERISM) were used to quantify pro-invasive BM stress and protrusive forces. Substrate stiffening and mechanically impaired BM scaffolds induced the invasive transition of benign acini synergistically. Robust BM scaffolds attenuated this invasive response. Additional oncogenic EGFR activation compromised the BMs’ barrier function, fuelling invasion speed and incidence. Mechanistically, EGFR-PI3-Kinase downstream signalling modulated both MMP- and force-driven BM-weakening processes. We show that breast acini form non-proteolytic and BM-piercing filopodia for continuous matrix mechanosensation, which significantly push and pull on the BM and ECM under pro-invasive conditions. Invasion-triggered acini further shear and compress their BM by contractility-based stresses that were significantly increased (3.7-fold) compared to non-invasive conditions. Overall, the highest amplitudes of protrusive and contractile forces accompanied the highest invasiveness. This work provides a mechanistic concept for tumour ECM-induced mechanically misbalanced breast glands fuelling force-driven BM disruption. Finally, this could facilitate early cell dissemination from pre-invasive lesions to metastasize eventually.     

Hydrogen production from swine manure biogas via steam reforming of methane (SRM) and water gas shift (WGS): A ecological,technical, and economic analysis

Inadequate management of swine manure can lead to contamination of watercourses, groundwater, soil, and air, representing a risk to the sustainability and expansion of pig farming as an economic activity. The aim of this study was to evaluate the potential of this waste for the production of hydrogen from swine manure biogas through steam reforming and water gas shift processes. In this study, calculations of ecological, exergetic and economic efficiencies were carried out. The ecological efficiency, pollution indicator and energy efficiency of the process were, respectively, 93.73%, 19.15 and 79.06%, showing the viability from an ecological standpoint. This is an 8-year plant payback with a hydrogen production cost of $0.14/kWh, in a production scenario of 8760 h/year, showing an exergetic efficiency of 76%. The results from these analyses demonstrates that this type of hydrogen production is an attractive economic route. The results from these analyses have shown that this hydrogen production technology has great economic potential and presents high exegetic yield.     

Decreased sensitivity in the membranous urethra after orthotopic ileal bladder substitute

PURPOSE: The effect of cystoprostatectomy with orthotopic substitution on membranous urethral sensation and subsequent urinary continence is unknown. We determined the sensory threshold for electrical stimulation of the membranous urethra and correlated it with continence, nerve sparing surgical technique and potency. MATERIALS AND METHODS: The sensory threshold was measured in a control group of 35 men before radical prostatectomy or cystoprostatectomy and in 47 men after cystoprostatectomy and ileal bladder substitution. RESULTS: The sensory threshold of the membranous urethra was 9+/-2 in the control group compared to 27+/-11 mA. in the postoperative group (p<0.001). Patients with daytime continence had a threshold of 24+/-9 compared to 39+/-10 mA. in incontinent patients (p<0.001). We were unable to show any correlation between the sensory threshold in patients with (25+/-10 mA.) and without (31+/-11 mA.) attempted nerve sparing surgery (p = 0.1) nor between potent (25+/-12 mA.) and impotent (27+/-11 mA.) patients (p = 0.4). CONCLUSIONS: Sensitivity in the membranous urethra decreased in patients after cystoprostatectomy and ileal bladder substitution. Urethral sensitivity in the sphincter area was better in continent than incontinent patients. Since we were unable to find any correlation between the sensory threshold and nerve sparing surgery or potency, it may be assumed that at least part of the sensory fibers to the membranous urethra pass through the pudendal nerve and/or the intrapelvic extrapudendal nerve fibers.     

Two approaches for an adaptive multimedia transfer service for mobile environments

Mobile environments are characterized by varying locations and network access points of end users, by varying levels of network QoS and often also by limited connectivity and reliability. These aspects have to be considered specifically for distributed multimedia applications, typically involving large amounts of data and specific QoS requirements. This article presents concepts and experiences concerning adaptive services for asynchronous multimedia transmission in mobile environments. We describe two different approaches to solve the problems of adaptation to variable network QoS using generic mechanisms. The first approach takes advantage of a mobile queuing service and is based on our former work on a support platform for mobile computing (see Schill and Kümmel. Mobile Computing Special Issue of Distributed Systems Engineering Journal 1995; 128–41; Schill et al. Proceedings of IMC 96 Workshop on Information Visualization and Mobile Computing. Zentrum für graphische Datenverarbeitung, February 1996). The second approach uses the mobile agent paradigm in the context of an application partitioning model to gain flexibility and maintainability (see Schill et al. In: Papaioannou, Minar, editors, Proceedings. Mobile Agents in the Context of Competition and Cooperation (MAC3), a workshop at Autonomous Agents '99, 1999. p. 34–41.). Both approaches exploit software-based conversion to adapt multimedia data according to bandwidth availability. Decoupling of communication peers with automatic notifications about communication actions helps to address disconnection problems.     

In Vitro Fermentation Behavior of Isomalto/Malto‐Polysaccharides Using Human Fecal Inoculum Indicates Prebiotic Potential

1 Scope

This study characterize intestinal fermentation of isomalto/malto‐polysaccharides (IMMPs), by monitoring degradation of IMMPs, production of short chain fatty acids (SCFAs), lactic acid, and succinic acid as well as enzyme activity and microbiota composition.

2 Methods and results

IMMP‐94 (94% α‐(1→6) glycosidic linkages), IMMP‐96, IMMP‐27, and IMMP‐dig27 (IMMP‐27 after removal of digestible starch segments) are fermented batchwise in vitro using human fecal inoculum. Fermentation digesta samples are taken for analysis in time up till 48 h. The fermentation of α‐(1→6) glycosidic linkages in IMMP‐94, IMMP‐96, and IMMP‐dig27 starts after 12 h and finishes within 48 h. IMMP‐27 fermentation starts directly after inoculation utilizing α‐(1→4) linked glucosyl residues; however, the utilization of α‐(1→6) linked glucoses is delayed and start only after the depletion of α‐(1→4) linked glucose moieties. SCFAs are produced in high amounts with acetic acid and succinic acid being the major products next to propionic acid and butyric acid. The polysaccharide fraction is degraded into isomalto‐oligosaccharides (IMOs) mainly by extracellular enzymes. The smaller IMOs are further degraded by cell‐associated enzymes. Overall microbial diversity and the relative abundance of Bifidobacterium and Lactobacillus, significantly increase during the fermentation of IMMPs.

3 Conclusion

IMMP containing segments of α‐(1→6) linked glucose units are slowly fermentable fibers with prebiotic potential.     

(−)‐Sparteine‐Mediated Directed ortho‐Metalation of N‐Cumyl‐N‐ethylferrocenecarboxamide. Versatile Routes to Functionalized Planar Chiral Ferrocenecarboxamides,Amines, Esters and Phosphines

N‐Cumyl‐N‐ethylferrocenecarboxamide 5 provides planar chiral carboxamides 6 in high yield and % ee via (−)‐sparteine‐mediated directed ortho‐metalation. Mild decumylation affords secondary amides 7 , which serve as intermediates for a convenient and general route to the venerable Ugi planar chiral ferrocenylamines 13 and as versatile precursors for the preparation of novel chiral ferrocenes 15 and 20 . The chiral TMS‐ferrocenyl derivative 7c is used to prepare the enantiomeric (S)‐ 7f , circumventing the lack of availability of (+)‐sparteine.     

Degradation of zinc oxide thin films in aqueous environment: Part I – Bare Films

As their optical, electrical, and electrochemical properties can be modified, zinc oxide thin films are employed as optically transparent conductors in the production of many different microdevices. Although microdevices are generally encapsulated for protection from aggressive environment, the zinc oxide thin films can still degrade with a resultant decrease in device performance. The investigation of the mechanism of degradation for these films is, therefore, of significant interest in prolonging the lifetime of many electronic devices. In this paper, the behaviour of bare zinc oxide thin films produced by magnetron‐sputtering (MS‐ZnO) and exposed to aqueous aerated 3.5% NaCl at 25°C was investigated. Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS) and DC measurements were employed to study the degradation mechanisms of two sputtered‐ZnO films having different microstructures. The experimental tests were primarily focused on defining the relationship between microstructure and the degradation rate of the ZnO thin films. Due to the development of moisture induced microfractures in the ZnO films, a two stage mechanism was suggested. Two different equivalent electrical circuits are, thus, proposed to interpret the EIS data at different stages in the degradation. The parameters of the equivalent network were related to degradation development, the change of degradation mechanism and the extent of microfracture in the film.     

Interface Molecular Engineering for Laminated Monolithic Perovskite/Silicon Tandem Solar Cells with 80.4% Fill Factor

A multipurpose interconnection layer based on poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS), and d ‐sorbitol for monolithic perovskite/silicon tandem solar cells is introduced. The interconnection of independently processed silicon and perovskite subcells is a simple add‐on lamination step, alleviating common fabrication complexities of tandem devices. It is demonstrated experimentally and theoretically that PEDOT:PSS is an ideal building block for manipulating the mechanical and electrical functionality of the charge recombination layer by controlling the microstructure on the nano‐ and mesoscale. It is elucidated that the optimal functionality of the recombination layer relies on a gradient in the d ‐sorbitol dopant distribution that modulates the orientation of PEDOT across the PEDOT:PSS film. Using this modified PEDOT:PSS composite, a monolithic two‐terminal perovskite/silicon tandem solar cell with a steady‐state efficiency of 21.0%, a fill factor of 80.4%, and negligible open circuit voltage losses compared to single‐junction devices is shown. The versatility of this approach is further validated by presenting a laminated two‐terminal monolithic perovskite/organic tandem solar cell with 11.7% power conversion efficiency. It is envisioned that this lamination concept can be applied for the pairing of multiple photovoltaic and other thin film technologies, creating a universal platform that facilitates mass production of tandem devices with high efficiency.