Selective Laser Melting of Porous Structures

Within the Center of Smart Interfaces “Understanding and Designing Fluid Boundaries”, a German Excellence Initiative, the Institute of Production Management, Technology and Machine Tools examines the manufacturing of porous structures by using selective laser melting (SLM). In this paper two different strategies are presented in order to obtain porosity: One strategy is to manufacture geometrically defined lattice structures. SLM allows here complex geometries that cannot be manufactured by conventional technologies to be built. The second approach is to manufacture geometrically undefined porosity by a specific modification of exposure parameters. The SLM generated porous structures are investigated with respect to the heat and mass transfer. The research focus is to increase the efficiency of spraycooling effects and the manipulation of the Leidenfrost point.Mechanical Engineerin

Are serial CA 19-9 kinetics helpful in predicting survival in patients with advanced or metastatic pancreatic cancer treated with gemcitabine and cisplatin?

Background: Serial kinetics of serum CA 19-9 levels have been reported to reflect response and survival in patients with pancreatic cancer undergoing surgery, radiotherapy, and chemotherapy. We prospectively studied serial kinetics of serum CA 19-9 levels of patients with locally advanced or metastatic disease treated with gemcitabine and cisplatin. Patients and Methods: Enrolled in the study were 87 patients (female/male = 26/61; stage III/IV disease = 24/63). Patients received gemcitabine 1,000 mg/m(2) on days 1, 8, and 15 plus cisplatin 50 mg/m(2) on days 1 and 15, every 4 weeks. Serum samples were collected at the onset of chemotherapy and before the start of a new treatment cycle (day 28). Results: 77 of 87 patients (88.5%) with initially elevated CA 19-9 levels were included for evaluation. According to imaging criteria, 4 (5.2%) achieved a complete remission and 11 (14.3%) achieved partial remission, yielding an overall response rate of 19.5%. 43 (55.8%) patients were CA 19-9 responders, defined by greater than or equal to50% decrease in CA 19-9 serum levels within 2 months after treatment initiation. Except for one, all patients who had responded by imaging criteria (n = 14) fulfilled the criterion of a CA 19-9 responder. Despite being characterized as non-responders by CT-imaging criteria (stable/progressive disease), 29 patients were classified as CA 19-9 responders (positive predictive value 32.5%). Independent of the response evaluation by CT, CA 19-9 responders survived significantly longer than CA 19-9 non-responders (295 d; 95% CI: 285-445 vs. 174 d; 95% CI: 134-198; p = 0.022). Conclusion: CA 19-9 kinetics in serum serve as an early and reliable indicator of response and help to predict survival in patients with advanced pancreatic cancer receiving effective treatment with gemcitabine and cisplatin

Driven Rydberg atoms reveal quartic level repulsion

The dynamics of Rydberg states of a hydrogen atom subject simultaneously to uniform static electric field and two microwave fields with commensurate frequencies is considered in the range of small fields amplitudes. In the certain range of the parameters of the system the classical secular motion of the electronic ellipse reveals chaotic behavior. Quantum mechanically, when the fine structure of the atom is taken into account, the energy level statistics obey predictions appropriate for the symplectic Gaussian random matrix ensemble.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let

Postural instability in an immersive Virtual Reality adapts with repetition and includes directional and gender specific effects

The ability to handle sensory conflicts and use the most appropriate sensory information is vital for successful recovery of human postural control after injury. The objective was to determine if virtual reality (VR) could provide a vehicle for sensory training, and determine the temporal and spatial nature of such adaptive changes. Twenty healthy subjects participated in the study (10 females). The subjects watched a 90-second VR simulation of railroad (rollercoaster) motion in mountainous terrain during five repeated simulations, while standing on a force platform that recorded their stability. The immediate response to watching the VR movie was an increased level of postural instability. Repeatedly watching the same VR movie significantly reduced both the anteroposterior (62%, p < 0.001) and lateral (47%, p = 0.001) energy used. However, females adapted more slowly to the VR stimuli as reflected by higher use of total (p = 0.007), low frequency (p = 0.027) and high frequency (p = 0.026) energy. Healthy subjects can significantly adapt to a multidirectional, provocative, visual environment after 4–5 repeated sessions of VR. Consequently, VR technology might be an effective tool for rehabilitation involving visual desensitisation. However, some females may require more training sessions to achieve effects with VR

Wavefunction statistics in open chaotic billiards

We study the statistical properties of wavefunctions in a chaotic billiard that is opened up to the outside world. Upon increasing the openings, the billiard wavefunctions cross over from real to complex. Each wavefunction is characterized by a phase rigidity, which is itself a fluctuating quantity. We calculate the probability distribution of the phase rigidity and discuss how phase rigidity fluctuations cause long-range correlations of intensity and current density. We also find that phase rigidities for wavefunctions with different incoming wave boundary conditions are statistically correlated.Comment: 4 pages, RevTeX; 1 figur

False claims about false memory research

Pezdek and Lam [Pezdek, K. & Lam, S. (2007). What research paradigms have cognitive psychologists used to study “False memory,” and what are the implications of these choices? Consciousness and Cognition] claim that the majority of research into false memories has been misguided. Specifically, they charge that false memory scientists have been (1) misusing the term “false memory,” (2) relying on the wrong methodologies to study false memories, and (3) misapplying false memory research to real world situations. We review each of these claims and highlight the problems with them. We conclude that several types of false memory research have advanced our knowledge of autobiographical and recovered memories, and that future research will continue to make significant contributions to how we understand memory and memory errors

Sources and Structures of Mitotic Crossovers That Arise When BLM Helicase Is Absent in Drosophila

The Bloom syndrome helicase, BLM, has numerous functions that prevent mitotic crossovers. We used unique features of Drosophila melanogaster to investigate origins and properties of mitotic crossovers that occur when BLM is absent. Induction of lesions that block replication forks increased crossover frequencies, consistent with functions for BLM in responding to fork blockage. In contrast, treatment with hydroxyurea, which stalls forks, did not elevate crossovers, even though mutants lacking BLM are sensitive to killing by this agent. To learn about sources of spontaneous recombination, we mapped mitotic crossovers in mutants lacking BLM. In the male germline, irradiation-induced crossovers were distributed randomly across the euchromatin, but spontaneous crossovers were nonrandom. We suggest that regions of the genome with a high frequency of mitotic crossovers may be analogous to common fragile sites in the human genome. Interestingly, in the male germline there is a paucity of crossovers in the interval that spans the pericentric heterochromatin, but in the female germline this interval is more prone to crossing over. Finally, our system allowed us to recover pairs of reciprocal crossover chromosomes. Sequencing of these revealed the existence of gene conversion tracts and did not provide any evidence for mutations associated with crossovers. These findings provide important new insights into sources and structures of mitotic crossovers and functions of BLM helicase

Human bipedal instability in tree canopy environments is reduced by “light touch” fingertip support

Whether tree canopy habitats played a sustained role in the ecology of ancestral bipedal hominins is unresolved. Some argue that arboreal bipedalism was prohibitively risky for hominins whose increasingly modern anatomy prevented them from gripping branches with their feet. Balancing on two legs is indeed challenging for humans under optimal conditions let alone in forest canopy, which is physically and visually highly dynamic. Here we quantify the impact of forest canopy characteristics on postural stability in humans. Viewing a movie of swaying branches while standing on a branch-like bouncy springboard destabilised the participants as much as wearing a blindfold. However “light touch”, a sensorimotor feedback strategy based on light fingertip support, significantly enhanced their balance and lowered their thigh muscle activity by up to 30%. This demonstrates how a light touch strategy could have been central to our ancestor’s ability to avoid falls and reduce the mechanical and metabolic cost of arboreal feeding and movement. Our results may also indicate that some adaptations in the hand that facilitated continued access to forest canopy may have complemented, rather than opposed, adaptations that facilitated precise manipulation and tool use

Principles and processes behind promoting awareness of rights for quality maternal care services: a synthesis of stakeholder experiences and implementation factors

BACKGROUND: Promoting awareness of rights is a value-based process that entails a different way of thinking and acting, which is at times misunderstood or deemed as aspirational. METHODS: Guided by the SURE framework, we undertook a secondary analysis of 26 documents identified by an earlier systematic review on promoting awareness of rights to increase use of maternity care services. We thematically analysed stakeholder experiences and implementation factors across the diverse initiatives to derive common elements to guide future efforts. RESULTS: Interventions that promote awareness of rights for maternal health varied in nature, methodological orientation, depth and quality. Materials included booklets, posters, pamphlets/ briefs and service standards/charters. Target populations included women, family members, communities, community structures, community-based and non governmental organizations, health providers and administrators, as well as elected representatives. While one initiative only focused on raising awareness, most were embedded within larger efforts to improve the accountability and responsiveness of service delivery through community monitoring and advocacy, with a few aiming to change policies and contest elections. Underlying these action oriented forms of promoting awareness of rights, was a critical consciousness and attitudinal change gained through iterative capacity-building for all stakeholders; materials and processes that supported group discussion and interaction; the formation or strengthening of community groups; situational analysis to ensure adaptation to local context; facilitation to ensure common ground and language across stakeholders; and strategic networking and alliance building across health system levels. While many positive experiences are discussed, few challenges or barriers to implementation are documented. The limited documentation and poor quality of information found indicate that while various examples of promoting awareness of rights for maternal health exists, research partnerships to systematically evaluate their processes, learning and effects are lacking. CONCLUSION: Rather than being aspirational, several examples of promoting awareness of women’s rights for quality maternity care services exist. More than mainly disseminate information, they aim to change stakeholder mindsets and relationships across health system levels. Due to their transformatory intent they require sustained investment, with strategic planning, concrete operationalization and political adeptness to manage dynamic stakeholder expectations and reactions overtime. More investment is also required in research partnerships that support such initiatives and better elucidate their context specific variations.ScopusIS