Polarised neutron scattering from dynamic polarised nuclei 1972-2022.

With the inauguration of the small-angle instrument D11 of the Institute Laue-Langevin (ILL) in September 1972 neutron scattering revolutionized methods of contrast variation. Very soon D11 was oversubscribed by proposals relying on isotopic substitution of hydrogen isotopes. At the same time in Oxford first experiments of polarised neutron diffraction from dynamic polarised protons in lanthanum magnesium nitrate crystals demonstrated the great utility of this approach. In the early eighties a new type of polarised target material led to a boom of contrast variation by nuclear polarisation. The new samples of frozen solutions of macromolecules lent themselves to small-angle scattering. Often in collaboration with research centres of High Energy Physics various groups in Europe and Japan started experiments of polarized neutron scattering from dynamic polarised protons. Techniques of NMR and EPR considerably enlarged the spectrum of nuclear contrast variation. This is shown with time-resolved polarised neutron scattering from dynamic polarized proton spins of a free radical and of tyrosyl doped catalase using D22 at the ILL.

What motivates men to offer sperm donation via the internet?

To investigate why men offer sperm donation via the internet, a questionnaire was disseminated via 39 Dutch-language websites thought to be visited by potential sperm donors. Nine internet donors completed the survey, men who typically knew the women they were donating to. Their responses were compared with those of a control group of 35 general sperm bank donors who were recruited using flyers in Dutch sperm banks, and who were typically unaware of the identity of the eventual recipients. The findings shed light on the motives and attitudes of internet donors. Both groups of donors indicated that their primary motivation for donating was altruism (>80% of all respondents). However, internet donors had a more pronounced desire to procreate than sperm bank donors (6 out of 9, i.e. 66 vs. 22%, respectively) and more often felt that they had good genes they wished to pass on (5 out of 9, i.e. 55 vs. 31%, respectively). The main reason internet donors gave for donating via the internet was that they wanted to know the prospective parents and be kept up to date on the progress of the offspring conceived from their donations. This distinguishes them significantly from sperm bank donors. A further finding was that they were not prompted to avoid the formal donation circuit for which, by law in the Netherlands, pregnancies resulting from donations have to be registered in a central database. This study is subject to several, in some cases inevitable, limitations, but it provides an interesting starting point that future studies can seek to confirm and extend.

Survival after neoadjuvant chemotherapy with or without bevacizumab or everolimus for HER2-negative primary breast cancer (GBG 44-GeparQuinto)†.

BACKGROUND: The GeparQuinto study showed that adding bevacizumab to 24 weeks of anthracycline-taxane-based neoadjuvant chemotherapy increases pathological complete response (pCR) rates overall and specifically in patients with triple-negative breast cancer (TNBC). No difference in pCR rate was observed for adding everolimus to paclitaxel in nonearly responding patients. Here, we present disease-free (DFS) and overall survival (OS) analyses. PATIENTS AND METHODS: Patients (n = 1948) with HER2-negative tumors of a median tumor size of 4 cm were randomly assigned to neoadjuvant treatment with epirubicin/cyclophosphamide followed by docetaxel (EC-T) with or without eight infusions of bevacizumab every 3 weeks before surgery. Patients without clinical response to EC ± Bevacizumab were randomized to 12 weekly cycles paclitaxel with or without everolimus 5 mg/day. To detect a hazard ratio (HR) of 0.75 (α = 0.05, ß = 0.8) 379 events had to be observed in the bevacizumab arms. RESULTS: With a median follow-up of 3.8 years, 3-year DFS was 80.8% and 3-year OS was 89.7%. Outcome was not different for patients receiving bevacizumab (HR 1.03; P = 0.784 for DFS and HR 0.974; P = 0.842 for OS) compared with patients receiving chemotherapy alone. Patients with TNBC similarly showed no improvement in DFS (HR = 0.99; P = 0.941) and OS (HR = 1.02; P = 0.891) when treated with bevacizumab. No other predefined subgroup (HR+/HER2-; locally advanced (cT4 or cN3) or not; cT1-3 or cT4; pCR or not) showed a significant benefit. No difference in DFS (HR 0.997; P = 0.987) and OS (HR 1.11; P = 0.658) was observed for nonearly responding patients receiving paclitaxel with or without everolimus overall as well as in subgroups. CONCLUSIONS: Long-term results, in opposite to the results of pCR, do not support the neoadjuvant use of bevacizumab in addition to an anthracycline-taxane-based chemotherapy or everolimus in addition to paclitaxel for nonearly responding patients. CLINICAL TRIAL NUMBER: NCT 00567554, www.clinicaltrials.gov.

Photophysical, amplified spontaneous emission and charge transport properties of oligofluorene derivatives in thin films.

We investigate the photophysical and amplified spontaneous emission properties of a series of monodisperse solution-processable oligofluorenes functionalized with hexyl chains at the C9 position of each fluorene unit. Thin films of these oligofluorenes are then used in organic field-effect transistors and their charge transport properties are examined. We have particularly focused our attention on the influence of oligofluorene length on the absorption and steady-state fluorescence spectra, on the HOMO/LUMO energy levels, on the photoluminescence lifetime and quantum yield as well as on the amplified spontaneous emission properties and the charge carrier mobilities. Differential scanning calorimetry and X-ray diffraction measurements demonstrate that, among all oligofluorene derivatives used in this study, only the structure and morphology of the pentafluorene film is significantly modified by a thermal treatment above the glass transition temperature, resulting in a 9 nm blue-shift of the fluorescence spectrum without significant changes in the photoluminescence quantum yield and in the amplified spontaneous emission threshold. In parallel, hole field-effect mobility is significantly increased from 8.6 × 10(-7) to 3.8 × 10(-5) cm(2) V(-1) s(-1) upon thermal treatment, due to an increase of crystallinity. This study provides useful insights into the morphological control of oligofluorene thin films and how it affects their photophysical and charge transport properties. Moreover, we provide evidence that, because of the low threshold, the tunability of the amplified spontaneous emission and the photostability of the films, these oligofluorenes are promising candidates for organic solid-state laser applications.

Puckering stick-slip friction induced by a sliding nanoscale contact.

An atomic force microscope reveals that the sliding of a nanotip on a graphite surface occurs through a nanoscale stick-slip mechanism. The angle between the sliding direction and a stiff crystallographic axis determines the periodicity of the slip events defining domains of various friction properties. The experimental data are interpreted using the reaction rate theory, with the energy barrier driven by a local deformation of the surface and a thermally activated relaxation.

Damping in yttrium iron garnet nanoscale films capped by platinum.

Strong damping enhancement in nm-thick yttrium iron garnet (YIG) films due to Pt capping layers was observed. This damping is substantially larger than the expected damping due to conventional spin pumping, is accompanied by a shift in the ferromagnetic resonance field, and can be suppressed by the use of a Cu spacer in between the YIG and Pt films. The data indicate that such damping may originate from the ferromagnetic ordering in Pt atomic layers near the YIG/Pt interface and the dynamic exchange coupling between the ordered Pt spins and the spins in the YIG film.

A prospective multicenter phase II study of oral and i.v. vinorelbine plus trastuzumab as first-line therapy in HER2-overexpressing metastatic breast cancer.

BACKGROUND: To evaluate the efficacy and safety of oral and i.v. vinorelbine plus trastuzumab as first-line regimen in a patient-convenient application for human epidermal growth factor receptor 2 (HER2)-overexpressing patients with metastatic breast cancer. PATIENTS AND METHODS: Forty-two women were enrolled in a multicenter study. The patients received i.v. vinorelbine at a dose of 25 mg/m(2) on day 1 followed by oral vinorelbine at a dose of 60 mg/m(2) on days 8 and 15 in a 3-week cycle. Standard dose trastuzumab was given at 3-week intervals. RESULTS: Complete response was observed in 7 patients (18.9%) and partial response in 19 patients (51.4%), for an overall response rate of 70.3% [95% confidence interval (CI) 53.0-84.1]. The disease control rate reached 91.9% (95% CI 78.1-98.3). The median time to progression was 9.3 months, while median overall survival reached 35.6 months. Hematological and non-hematological toxic effects were acceptable with grade 3-4 leukopenia of 14% and neutropenia of 38%; cardiac toxicity did not reach the level of clinical relevance. CONCLUSION: The combination of i.v. and oral vinorelbine plus trastuzumab demonstrates high activity and good tolerability in first-line treatment of HER2-overexpressing metastatic breast cancer. In addition, it offers convenience for the patients with only one i.v. treatment every 3 weeks.

Engineering negative differential conductance with the Cu(111) surface state.

Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate electron tunneling from a C60-terminated tip into a Cu(111) surface. Tunneling between a C60 orbital and the Shockley surface states of copper is shown to produce negative differential conductance (NDC) contrary to conventional expectations. NDC can be tuned through barrier thickness or C60 orientation up to complete extinction. The orientation dependence of NDC is a result of a symmetry matching between the molecular tip and the surface states.

Spin pumping at the magnetic insulator (YIG)/normal metal (Au) interfaces.

Spin injection across the ferrimagnetic insulator (YIG)/normal metal (Au) interface was studied by ferromagnetic resonance. The spin mixing conductance was determined by comparing the Gilbert damping in bare YIG films with those covered by a Au/Fe/Au structure. The Fe layer in Au/Fe/Au acted as a spin sink as displayed by an increased Gilbert damping parameter α compared to that in the bare YIG. In particular, for the 9.0 nm YIG/2.0 nm Au/4.3 nm Fe/6.1 nm Au structure, the YIG and Fe films were coupled by an interlayer exchange coupling, and the exchange coupled YIG exhibited an increased Gilbert damping compared to the bare YIG. This relationship between static and dynamic coupling provides direct evidence for spin pumping. The transfer of spin momentum across the YIG interface is surprisingly efficient with the spin mixing conductance g(↑↓) ≃ 1.2 × 10(14) cm(-2).

Dispersion and localization of electronic states at a ferrocene/Cu(111) interface.

Low-temperature scanning tunneling microscopy and spectroscopy combined with first-principles simulations reveal a nondissociative physisorption of ferrocene molecules on a Cu(111) surface, giving rise to ordered molecular layers. At the interface, a 2D-like electronic band is found, which shows an identical dispersion as the Cu(111) Shockley surface-state band. Subsequent deposition of Cu atoms forms charged organometallic compounds that localize interface-state electrons.

Modified pyridine-triazole and 2,2'-bipyrimidine ligands generating robust titanium complexes constructed around a TiO4N2 core.

The synthesis and characterisation of novel chelate nitrogen ligands with phasmidic tails (pyridine-triazole ligand 1b; 2,2'-bipyrimidine ligands 2b and 3b) as well as their titanium(IV) coordination complexes are reported. The analogous ligands 1a, 2a and 3a with methoxy substituents instead of the tails were also synthesized, together with titanium complexes that could be crystallographically characterised. A good agreement is noticed between analytical data of the complexes in solution (NMR) and in the solid state (X-ray diffraction). The complexes are overall robust on phases like alumina or silica, so that they could be characterised by TLC and sometimes chromatographied. Supramolecular architectures were generated from an equimolar solution of titanium(IV) isopropoxide, ligand 1a and a polyphenol ligand 5-H4, leading to a double-stranded helicate characterised by MS, NMR and crystallography, which was then converted into a trinuclear complex as shown by MS and NMR DOSY data. The liquid-crystalline behaviour of the ligands 1b, 2b and 3b incorporating the long alkyl tails and that of the complexes derived from these ligands have been investigated.

[Process and outcome quality of the German Paediatric Surveillance Unit (ESPED)]. / Evaluation der Prozess- und Ergebnisqualität der Erhebungseinheit für seltene pädiatrische Erkrankungen in Deutschland (ESPED).

UNLABELLED: The German paediatric surveillance unit (ESPED) was founded in 1992 with the objective to generate incidence data and to describe symptoms, diagnostic procedures, therapy and prevention for rare paediatric diseases requiring in hospital treatment. Every month the ESPED office sends a mailing card to the heads of all paediatric departments asking for the incident diagnosis of up to 12 conditions. In 2007 about 96% of the cards are returned. Each condition is represented by a principal investigator. Up till now surveillance of 52 conditions has been performed. Reports on the mailing card prompt immediate mailing of the full questionnaire. For 43 conditions the return rates were in the range of 70-100% and for 7 conditions <70% (unknown 2). The highest return rates were achieved if the principal investigator was supported by staff comprising at least two persons or if the mailing of the questionnaire was handled by the ESPED office. The scientific impact of the ESPED System was assessed by the impact factors of the journals, in which the respective ESPED studies were published. By August 31 (st) 2008 the investigators of 38 studies reported up to 7 publications per conditions surveyed. A total of 104 publications was reported: 27 of these appeared in journals without an impact factor. Among the 77 other publications 10 appeared in journals with an impact factor >10. CONCLUSION: Surveillance in ESPED has contributed significantly to high quality research on rare conditions in children.

Energetics of honeybee swarm thermoregulation.

Honeybee swarms regulate their core temperature at a high set point (near 36 degrees C) and the mantle at a low set point (near 15 degrees C). The temperature gradient from core to mantle permits considerable energy economy, and it is abolished only shortly before swarm takeoff.

Keeping a cool head: honeybee thermoregulation.

At high ambient temperatures, honeybees regulate head teriperature by evaporative cooling of regurgitated honeycrop contents. Thoracic temperature is secondarily stabilized as heat flows from thorax to head by means of passive conduction and physiological facilitation resulting from accelerated blood flow. The mechanism permits flight at the extraordinarily high ambient temperature of 46 degrees C without overheating the head and thorax despite prodigious amounts of heat produced as a by-product of flight metabolism. In contrast, at low ambient temperatures, thoracic rather than head temperature is regulated; no liquid is regurgitated, and the head is heated passively by conduction both in flight and while stationary.

Thermoregulation in endothermic insects.

On the basis of body weight, most flying insects have higher rates of metabolism, and hence heat production, than other animals. However, rapid rates of cooling because of small body size in most cases precludes appreciable endothermy. The body temperature of small flies in flight is probably close to ambient temperature, and that of flying butterflies and locusts is 5 degrees to 10 degrees C above ambient temperature. Many moths and bumblebees are insulated with scales and hair, and their metabolism during flight can cause the temperature of the flight muscles to increase 20 degrees to 30 degrees C above ambient temperature. Curiously, those insects which (because of size, insulation) retain the most heat in the thorax during flight, also require the highest muscle temperature in order to maintain sufficient power output to continue flight. The minimum muscle temperature for flight varies widely between different species, while the maximum temperature varies over the relatively narrow range of 40 degrees to 45 degrees C. As a consequence, those insects that necessarily generate high muscle temperatures during flight must maintain their thoracic temperature within a relatively narrow range during flight. Active heat loss from the thorax to the abdomen prevents overheating of the flight motor and allows some large moths to be active over a wide range of ambient temperatures. Bumblebees similarly transfer heat from the flight musculature into the abdomen while incubating their brood by abdominal contact. Many of the larger insects would remain grounded if they did not actively increase the temperature of their flight muscles prior to flight. Male tettigoniid grasshoppers elevate their thoracic temperature prior to singing. In addition, some of the social Hymenoptera activate the "flight" muscles specifically to produce heat not only prior to flight but also during nest temperature regulation. During this "shivering" the "flight" muscles are often activated in patterns different from those during flight. The muscles contract primarily against each other rather than on the wings. However, the rate of heat production during shivering and flight is primarily a function of the action potential frequency rather than of the patterns of activation. Thermoregulation is a key factor in the energetics of foraging of some of the flower-visiting insects. The higher their muscle temperature the more flowers they can visit per unit time. When food supplies are ample, bees may invest relatively large amounts of energy for thermoregulation. While shivering to maintain high body temperatures during the short intervals they are perched on flowers (as well as while in the nest), bumblebees often expend energy at rates similar to the rates of energy expenditure in flight. Unlike vertebrates, which usually regulate their body temperature at specific set points, the body temperature of insects is labile. It often appears to be maintained near the lower temperature at which the muscles are able to perform the function at hand. The insects' thermal adaptations may not differ as much from those of vertebrates as previously supposed when size, anatomy, and energy requirements are taken into account.

Nervous control of the heart during thoracic temperature regulation in a sphinx moth.

Heating the thorax of the sphinx moth, Manduca sexta, evoked pulsations of the heart in the abdomen. These pulsations were of relatively high rate and amplitude, and traveled from the abdomen into the thorax. While heat was continuously applied exclusively to the thorax, thoracic temperature often stabilized and abdominal temperature increased sharply. Thoracic heating of moths with transected nerve cord, however, did not evoke these responses. It is inferred that the heart in the abdomen responds to overheating of the thorax through neural influence.

Thoracic Temperature Stabilization byn Blood Circulation in a Free-Flying Moth.

The sphinx moth, Manduca sexta, maintains its thoracic temperature within a degree of 42 degrees C while in free flight over a range of air temperatures from about 17 degrees to 32 degrees C. Tying off the dorsal vessel abolishes temperature control. Moths with tied off vessels overheat and then stop flying at air temperatures of about 23 degrees C. However, flight at this temperature is possible when the thoracic scales are removed. The mechanism of temperature control involves transfer of the heat produced in the thorax to the blood pumped from the dorsal vessel, and the subsequent dissipation of this heat when the blood returns to the relatively cool abdomen.

Temperature Regulation in the Bumblebee Bombus vagans: A Field Study.

Bombus vagans forages for nectar at 5 degrees C in shade and at 31 degrees C in sunshine. The production of heat while the bumblebee is on flowers, at ambient temperatures below 24 degrees C, helps to maintain a thoracic temperature that is near the minimum for flight between flowers. However, at ambient temperatures above 24 degrees C the thoracic temperature is no longer regulated at 32 degrees to 33 degrees C and rises.

Flight of Winter Moths Near 0{degrees}C.

Some noctuid winter moths fly at near 0 degrees C by maintaining an elevated(30 degrees to 35 degrees C) thoracic muscle temperature. Geometrid winter moths sustain themselves in free flight at subzero muscle temperatures. However, the temperature characteristics of citrate synthase and pyruvate kinase from both of these different kinds of moths and from a sphinx moth that flies with a muscles temperature of 40 degrees C are nearly identical. Furthermore, mass-specific rates of energy expenditure of both kinds of winter moths are also similar at given thoracic temperature (near 0 degrees C). The geometrids that are able to fly with a thoracic temperature near 0 degrees C do so largely because of unusually low wing-loading, which permits a low energetic cost of flight.