What drives contract design in strategic alliances? Taking stock and how to proceed

We collect and assess prior empirical evidence on contract design in alliances that has been published since Parkhe’s (1993) seminal study on inter-firm contracts. We elaborate on the effects of transaction-related factors, experience gained from prior relationships, and deliberate learning efforts on contracts. Our paper offers three contributions. First, we systematically review the existing literature on alliance contracts and summarize our findings. Second, while prior research has traditionally focused on contractual complexity, we place the content of contracts center stage and identify three contractual functions. While existing studies on contractual functions predominantly refer to safeguarding as a response to appropriation concerns, we also consider coordination and contingency adaptability as outcomes of adaptation concerns. Third, we disentangle the differential influences of previous experiences on distinct contractual functions and show that experience gained from prior relationships has different effects on safeguarding and contingency adaptability than on coordination. Overall, we add to the systematization of the current debate on alliance contract design and trace promising avenues for future research on the impact of transaction- and experience-related factors on the complexity and content of alliance contracts

Cytosolic re-localization and optimization of valine synthesis and catabolism enables increased isobutanol production with the yeast Saccharomyces cerevisiae

Background: The branched chain alcohol isobutanol exhibits superior physicochemical properties as an alternative biofuel. The yeast Saccharomyces cerevisiae naturally produces low amounts of isobutanol as a by-product during fermentations, resulting from the catabolism of valine. As S. cerevisiae is widely used in industrial applications and can easily be modified by genetic engineering, this microorganism is a promising host for the fermentative production of higher amounts of isobutanol. Results: Isobutanol production could be improved by re-locating the valine biosynthesis enzymes Ilv2, Ilv5 and Ilv3 from the mitochondrial matrix into the cytosol. To prevent the import of the three enzymes into yeast mitochondria, N-terminally shortened Ilv2, Ilv5 and Ilv3 versions were constructed lacking their mitochondrial targeting sequences. SDS-PAGE and immunofluorescence analyses confirmed expression and re-localization of the truncated enzymes. Growth tests or enzyme assays confirmed enzymatic activities. Isobutanol production was only increased in the absence of valine and the simultaneous blockage of the mitochondrial valine synthesis pathway. Isobutanol production could be even more enhanced after adapting the codon usage of the truncated valine biosynthesis genes to the codon usage of highly expressed glycolytic genes. Finally, a suitable ketoisovalerate decarboxylase, Aro10, and alcohol dehydrogenase, Adh2, were selected and overexpressed. The highest isobutanol titer was 0.63 g/L at a yield of nearly 15 mg per g glucose. Conclusion: A cytosolic isobutanol production pathway was successfully established in yeast by re-localization and optimization of mitochondrial valine synthesis enzymes together with overexpression of Aro10 decarboxylase and Adh2 alcohol dehydrogenase. Driving forces were generated by blocking competition with the mitochondrial valine pathway and by omitting valine from the fermentation medium. Additional deletion of pyruvate decarboxylase genes and engineering of co-factor imbalances should lead to even higher isobutanol production

What drives contract design in alliances? Taking stock and how to proceed

We collect and assess prior empirical evidence on contract design in alliances that has been published since Parkhe’s (1993) seminal study on inter-firm contracts. We elaborate on the effects of transaction-related factors, experience gained from prior relationships, and deliberate learning efforts on contracts. Our paper offers three contributions. First, we systematically review the existing literature on alliance contracts and summarize our findings. Second, while prior research has traditionally focused on contractual complexity,we place the content of contracts center stage and identify three contractual functions. While existing studies on contractual functions predominantly refer to safeguarding as a response to appropriation concerns, we also consider coordination and contingency adaptability as outcomes of adaptation concerns. Third, we disentangle the differential influences of previous experiences on distinct contractual functions and show that experience gained from prior relationships has different effects on safeguarding and contingency adaptability than on coordination. Overall, we add to the systematization of the current debate on alliance contract design and trace promising avenues for future research on the impact of transaction- and experience-related factors on the complexity and content of alliance contracts

Air Leakage Detection in Building Façades by Combining Lock-In Thermography with Blower Excitation

Air leakage in building envelopes is responsible for a large portion of the building’s heating and cooling requirements. Therefore, fast and reliable detection of leaks is crucial for improving energy efficiency. This paper presents a new approach to determining air leakages in a building’s envelope from the outside, combining lock-in thermography and thermal excitation by a blower door system. The blower creates a periodic overpressure within the building, inducing periodic temperature variations of the surfaces near the leaks on the outside surface, the façade. With the temperature variations excited at a known frequency, Fourier transforms of the time-series of the thermal images at the excitation frequency result in amplitude and phase images highlighting the areas affected by leaks. Periodic excitation and detection by an IR camera is known as lock-in thermography and is widely used to characterize semiconductor devices and in non-destructive testing. Excitation is usually achieved by optical, electrical, or mechanical energy input. For this work, measurements of outside façades have been performed with three excitation cycles of a period of 40 seconds at a 75 Pa pressure difference, leading to a total measurement time of only 2 minutes. Measurements have been performed with air temperature differences of 5 to 7 K at highly variable conditions of irradiance, wind, and cloud cover. The measurements show higher detection quality and less impact from changing ambient conditions than the state-of the-art differential infrared thermography measurements. With the method highlighting the variations in the amplitude image only at the excitation frequency, variations caused by environmental effects are filtered out. A temperature difference as low as a few Kelvin is therefore sufficient, and large façades can be examined from the outside. This amplitude image is already clearer than an image created with differential thermography. A further reduction of unwanted artefacts in the image is demonstrated using phase-weighing of the amplitude by scalar product

Detection of Air Leakage in Building Envelopes using Microphone Arrays

Unintended airflow through building envelopes leads to an increased demand in heating and cooling energy. The most common way to measure air leakage of buildings is the blower door test, which quantifies the overall leakage rate of one room or a building. To reduce air leakage and associated energy loss in new and existing buildings, it is necessary to identify leak locations and prioritize sealing of more substantial leaks. However, detection and quantification of individual leaks with smoke tracers or infrared thermography are challenging, time-consuming, and depend on the operator’s experience. Acoustic methods have been identified to have the potential to localize and quantify individual leaks without the need for pressure or temperature differences. In this work, the acoustic beamforming method is proposed using a microphone array to detect leak locations and visualize them (acoustic camera). The objective of this investigation is to identify the potential of this technique for application to building envelopes. A pair of omnidirectional speakers is placed as a sound generator inside a room, and the microphone ring array with 48 microphones outside. As an experimental setup, cable ties are wedged in a window frame to simulate a damaged window gasket and to create reproducible leaks of different sizes at the same place. Overlay of an optical picture with the acoustic image obtained from beamforming enables the visualization of leaks of sound through the building envelope. All experiments were conducted using white noise with an analyzed frequency range of 1-25 kHz. The sound sources are evaluated at multiple third-octave bands within this frequency range, enabling a distinction between these leaks at different frequencies

Second Generation Linear Focus Sun Simulator to Test Optical Performance of Parabolic Trough Receivers - OptiRec

This paper presents results from a characterization of DLR’s second generation sun simulator test facility (OptiRec) for determining the optical performance of parabolic trough receivers. The configuration of the test bench is an elliptical mirror trough with flat end mirrors. Solar simulator lamps are situated in one focal line, the receiver in the other focal line. Water at ambient temperature flows through the receiver and allows for a calorimetric measurement of the absorbed power. Compared to the first generation test bench (ElliRec) the mirror material is changed from aluminum to glass, the ellipse size is changed and the handling is improved. Based on 34 measurements of the absorbed power the repeatability for OptiRec measurements is measured to 0.13% (1σ), compared to 0.2% in the ElliRec. Seven receivers from different manufacturers are measured in both test benches yielding agreeing relative optical efficiency with <1.1% deviation. Particular differences are larger than the repeatability, which are attributed to differences in spectra and incidence angles between both test benches

Determination of loads and boundary conditions causing deformations of concentrating solar mirrors using non-derivative optimization methods and finite element analysis

Mirror shape optimization is a major part of improving the performance of concentrating solar power (CSP) collectors. Loads and boundary conditions of different origin and with varying influence on shape deviation need to be understood and quantified, e.g., in order to give specifications for the design of new collector generations. Finite element analysis (FEA) has proven to be a suitable method for evaluating mirror shape. An optimization process is presented that utilizes finite element models (FEM) of mirrors and a subsequent evaluation of the slope deviation to approximate a reference, e.g., a measured mirror shape, and determine the load values causing the mirror panel to deform. In this paper, the suggested approach is proven to be feasible: Two optimization algorithms are implemented: BOBYQA and CMA-ES. A simulated reference created in ANSYS Workbench and a reference from a deflectometry measurement are investigated. The determined geometrical parameters are compared to the reference values. For BOBYQA an absolute minimum and maximum deviation of 0.02 % and 0.3 %, and for CMA-ES of 0.0001 % and 0.004 % relative to the reference values is found. With the measured mirror shape as reference, the optimization algorithm was again capable of reproducing the mirror shape in FEA. However, the geometrical load parameters found were only partially in agreement with the measured values. Yet, it is concluded that the proposed method for reproducing mirror shape works

Digitalisierte Arbeit und private Lebensführung

Diewald M, Kunze E, Andernach B. Digitalisierte Arbeit und private Lebensführung. In: Maier GW, Engels G, Steffen E, eds. Handbuch Gestaltung digitaler und vernetzter Arbeitswelten. Springer Reference Psychologie. Berlin: Springer; 2019

Efficient production of multi-modified pigs for xenotransplantation by ‘combineering’, gene stacking and gene editing

Xenotransplantation from pigs could alleviate the shortage of human tissues and organs for transplantation. Means have been identified to overcome hyperacute rejection and acute vascular rejection mechanisms mounted by the recipient. The challenge is to combine multiple genetic modifications to enable normal animal breeding and meet the demand for transplants. We used two methods to colocate xenoprotective transgenes at one locus, sequential targeted transgene placement - ‘gene stacking’, and cointegration of multiple engineered large vectors - ‘combineering’, to generate pigs carrying modifications considered necessary to inhibit short to mid-term xenograft rejection. Pigs were generated by serial nuclear transfer and analysed at intermediate stages. Human complement inhibitors CD46, CD55 and CD59 were abundantly expressed in all tissues examined, human HO1 and human A20 were widely expressed. ZFN or CRISPR/Cas9 mediated homozygous GGTA1 and CMAH knockout abolished α-Gal and Neu5Gc epitopes. Cells from multi-transgenic piglets showed complete protection against human complement-mediated lysis, even before GGTA1 knockout. Blockade of endothelial activation reduced TNFα-induced E-selectin expression, IFNγ-induced MHC class-II upregulation and TNFα/cycloheximide caspase induction. Microbial analysis found no PERV-C, PCMV or 13 other infectious agents. These animals are a major advance towards clinical porcine xenotransplantation and demonstrate that livestock engineering has come of age

Zebrafish Tric-b is required for skeletal development and bone cells differentiation

IntroductionTrimeric intracellular potassium channels TRIC-A and -B are endoplasmic reticulum (ER) integral membrane proteins, involved in the regulation of calcium release mediated by ryanodine (RyRs) and inositol 1,4,5-trisphosphate (IP3Rs) receptors, respectively. While TRIC-A is mainly expressed in excitable cells, TRIC-B is ubiquitously distributed at moderate level. TRIC-B deficiency causes a dysregulation of calcium flux from the ER, which impacts on multiple collagen specific chaperones and modifying enzymatic activity, leading to a rare form of osteogenesis imperfecta (OI Type XIV). The relevance of TRIC-B on cell homeostasis and the molecular mechanism behind the disease are still unknown.ResultsIn this study, we exploited zebrafish to elucidate the role of TRIC-B in skeletal tissue. We demonstrated, for the first time, that tmem38a and tmem38b genes encoding Tric-a and -b, respectively are expressed at early developmental stages in zebrafish, but only the latter has a maternal expression. Two zebrafish mutants for tmem38b were generated by CRISPR/Cas9, one carrying an out of frame mutation introducing a premature stop codon (tmem38b-/-) and one with an in frame deletion that removes the highly conserved KEV domain (tmem38bΔ120-7/Δ120-7). In both models collagen type I is under-modified and partially intracellularly retained in the endoplasmic reticulum, as described in individuals affected by OI type XIV. Tmem38b-/- showed a mild skeletal phenotype at the late larval and juvenile stages of development whereas tmem38bΔ120-7/Δ120-7 bone outcome was limited to a reduced vertebral length at 21 dpf. A caudal fin regeneration study pointed towards impaired activity of osteoblasts and osteoclasts associated with mineralization impairment.DiscussionOur data support the requirement of Tric-b during early development and for bone cell differentiation