Structure of the ATP-Synthase from Chloroplasts and Mitochondria Studied by Electron Microscopy

The structure of the ATP-synthase, F0F1 , from spinach chloroplasts and beef heart mitochondria has been investigated by electron microscopy with negatively stained specimens. The detergent-solubilized ATP-synthase forms string-like structures in which the F0 parts are aggregated. In most cases, the F, parts are arranged at alternating sides along the string. The F0 part has an approximate cylindrical shape with heights of 8.3 and 8.9 nm and diameters of 6.2 and 6.4 nm for the chloroplast and mitochondrial enzyme, respectively. The F, parts are disk-like structures with a diameter of about 11.5 nm and a height of about 8.5 nm. The F, parts are attached to the strings, composed of Fn parts, in most cases, with their smallest dimension parallel to the strings. The stalk connecting F0 and F, has a length of 3.7 nm and 4.3 nm and a diameter of 2.7 nm and 4.3 nm for the chloroplast and mitochondrial enzyme, respectively

Agglomeration mechanism during the preparation of nickel(0) and iron(0) zeolites

Magnetization measurements have been used to study the reduction process of Ni - zeolites and the thermal decomposition of iron pentacarbonyl adsorbed on NaY zeolites . The Ni(0) particle size distribution in H2»reduced NiNaA, Ni NaX, Ni NaY and NiNaM is bidisperse. The amount and the volume of particles exceeding the cage dimensions increases in the sequence Μ,Υ,Χ,Α zeolites. Particle fusion is found to be the rate determining step. With decomposition of Fe(C0)5/NaY adducts, up to 97 wt.% of the iron particles produced are smaller than 1.3 nm. Fluidized sample bed, inert gas atmosphere and fast heating up to 440 Κ are essential to reach mononodal dispersion

Infertility problems and mental health symptoms in a community-based sample: depressive symptoms among infertile men, but not women

Most researchers agree that men’s and women’s experiences of infertility are fundamentally different, and impacts upon the nature of psychological distress encountered. However, design flaws, including non-random samples unrepresentative of the general population, compromise many existing studies. Data derived from a random general community sample provides prevalence of current infertility, and permits examination of longitudinal associations between mental health symptoms and infertility among 1,978 participants aged 28-32 years. In the previous 12-months, infertility was experienced by 2.1% and 5.4% partnered men and women. Infertility independently predicted depressive symptomatology in men, and anxiety symptoms among women. Gender differences were sustained, even controlling for prior depression and anxiety. Health professionals are encouraged to proactively enquire about affective symptoms experienced by both women and men with infertility problems

Postcolonial Theory And The United States: Race, Ethnicity, And Literature

At the beginning of the twenty-first century, we may be in a transnational moment, increasingly aware of the ways in which local and national narratives, in literature and elsewhere, cannot be conceived apart from a radically new sense of shared human histories and global interdependence. To think transnationally about literature, history, and culture requires a study of the evolution of hybrid identities within nation-states and diasporic identities across national boundaries. Studies addressing issues of race, ethnicity, and empire in U.S. culture have provided some of the most innova-tive and controversial contributions to recent scholarship. Postcolonial Theory and the United States: Race, Ethnicity, and Literature represents a new chapter in the emerging dialogues about the importance of borders on a global scale. This book collects nineteen essays written in the 1990s in this emergent field by both well established and up-and-coming scholars. Almost all the essays have been either especially written for this volume or revised for inclusion here

Lesson Plan For Teaching Nicholasa Mohr\u27s The English Lesson

A lesson plan for teaching this story to junior high, high school, and/or college and university students including English Language Learning (ELL) students with a variety of learning objectives, backgrounds, and challenge levels. Developed by Adriana Lecuona and Professor Peter Schmidt

Otto Stern (1888-1969): The founding father of experimental atomic physics

We review the work and life of Otto Stern who developed the molecular beam technique and with its aid laid the foundations of experimental atomic physics. Among the key results of his research are: the experimental determination of the Maxwell-Boltzmann distribution of molecular velocities (1920), experimental demonstration of space quantization of angular momentum (1922), diffraction of matter waves comprised of atoms and molecules by crystals (1931) and the determination of the magnetic dipole moments of the proton and deuteron (1933).Comment: 39 pages, 8 figure

Invasion and establishment of White Pine (Pinus strobus L.) in the Saxon Switzerland National Park

Die naturnahen Waldökosysteme mit Pinus sylvestris auf Sandsteinfelsen im Nationalpark Sächsische Schweiz sind durch die Ausbreitung der Weymouth-Kiefer potenziell gefährdet. Wachstum und Etablierung der Verjüngung sind besonders in lichten Beständen vorzugsweise auf oligotrophen Standorten erfolgreich. Die biologischen und ökologischen Eigenschaften der nichteinheimischen Baumart begünstigen ihre Ausbreitung: häufige Fruktifikation, hohes Regenerationspotenzial, weiter Samenflug und rasches Wachstum. Die Weymouth-Kiefer findet im Nationalpark klimatisch und standortökologisch beste Wuchsbedingungen vor. Erste Anzeichen einer erfolgreichen Ausbreitung sind erkennbar. Aufgrund ihres Konkurrenzpotenzials wird die Baumart sich auch in den naturnahen Beständen des Nationalparkes etablieren können. Die Streuakkumulation ist Ursache eines Rückganges der Kraut- und Moosschicht in den Fels-Kiefernwäldern. Effekte der Ausbreitung, die irreversible Folgen für das Ökosystem hervorrufen können, werden unter Bedingungen eines differenzierten Managements im Nationalpark diskutiert (Entwicklungsszenarien).The ecosystem of the natural Scots Pine forests on sandstone outcrops in the National Park Saxon Switzerland is potentially endangered by the spreading of White Pine. The establishment and growth of regeneration are especially successful in open stands, preferably on oligotrophic soils. Biological and ecological qualities of White Pine facilitate its establishment: frequent fructification, high regeneration potential, wide dispersal of seeds and rapid growth. White Pine finds optimal growth conditions with respect to climate and site ecology in the National Park. First indications of local extensions in range are noticeable. With its competition potential, the tree species may also become established in near-natural and semi-natural stands of the National Park. Competition by White Pine and accumulation of its needles on the soil result in a decline in understorey and ground vegetation (herb and moss layers) in the pine forests on rocky ground. The effects of spreading would have irreversible consequences for the ecosystem. Methods of preventing this using different management strategies for a variety of developmental scenarios are discussed