Multiple conducting carriers generated in LaAlO3/SrTiO3 heterostructures

We have found that there is more than one type of conducting carriers generated in LaAlO3/SrTiO3 heterostructures by comparing the sheet carrier density and mobility from optical transmission spectroscopy with those from dc-transport measurements. When multiple types of carriers exist, optical characterization dominantly reflects the contribution from the high-density carriers whereas dc-transport measurements may exaggerate the contribution of the high-mobility carriers even though they are present at low-density. Since the low-temperature mobilities determined by dc-transport in the LaAlO3/SrTiO3 heterostructures are much higher than those extracted by optical method, we attribute the origin of high-mobility transport to the low-density conducting carriers.Comment: 3 figures, supplemental materia

Two-Dimensional Confinement of 3d1 Electrons in LaTiO3/LaAlO3 Multilayers

We report spectroscopic ellipsometry measurements of the anisotropy of the interband transitions parallel and perpendicular to the planes of (LaTiO3)n(LaAlO3)5 multilayers with n = 1-3. These provide direct information about the electronic structure of the two-dimensional (2D) 3d^1 state of the Ti ions. In combination with LDA+U calculations, we suggest that 2D confinement in the TiO2 slabs lifts the degeneracy of the t_{2g} states leaving only the planar d_xy orbitals occupied. We outline that these multilayers can serve as a model system for the study of the t_{2g} 2D Hubbard model.Comment: 7 pages, 4 figures. Accepted for publication in Phys. Rev. Let

Een echte boerderij met een echte boer : de waarde van agrarische productie bij multifunctionele landbouw

Wat is nu precies de meerwaarde van een ‘echte’ boerderij bij kinderopvang, boerengolf, een camping, educatie-activiteiten of het verlenen van zorg? Hoe belangrijk is het dat het bedrijf een deel van zijn inkomsten haalt uit de productie van melk of aardappelen en hoe beïnvloeden beide takken elkaar? Wat zeggen de afnemers over de combinatie van activiteiten en landbouw en hoe denken andere boeren en betrokken organisaties hierover? Allemaal vragen waarop deze brochure ingaat. De tekst is gebaseerd op interviews met multifunctionele ondernemers, klanten en organisaties die actief zijn in de multifunctionele landbouw

Behandeling een kans voor de zorgboer

Er ontstaan door de vele veranderingen in zorg, welzijn en arbeidsparticipatie nieuwe kansen voor zorgboeren. Behandeling is daarvan een uitdagend voorbeeld. Maar deze kans is er niet voor iedereen. Het vraagt nogal wat van je als mens en ondernemer. Hoe zorg je ervoor dat de nieuwe cliënten ook daadwerkelijk een goede behandeling krijgen? Wat betekent het voor de aandacht voor je huidige cliënten? Ben je in staat om met behandelaars samen te werken? En zo ja, op welke wijze? Deze brochure gaat in op al deze vragen via concrete voorbeelden. Dat gebeurt aan de hand van een aantal pionierende zorgboeren die al met behandeling op hun zorgboerderij aan de slag zijn gegaan

A Prospective, Randomized Trial of Structured Treatment Interruption for Patients with Chronic HIV Type 1 Infection

Background. Structured treatment interruption was evaluated in 74 patients who had been pretreated with antiretrovirals, consisting of 2 nucleoside reverse-transcriptase inhibitors (NRTIs) for 1 year followed by 3 years of highly active antiretroviral therapy containing a protease inhibitor. Methods. Patients with a CD4 cell count of ⩾350 cells/µL and a plasma viral load of <50 copies/mL were randomized to 3 therapy arms: (1) continuous therapy, (2) CD4 cell count—guided theory, and (3) week-on/week-off (WOWO) therapy. The efficacy and safety of structured treatment interruption and antiretroviral use were evaluated in human immunodeficiency type 1 (HIV-1)—infected patients. The study end points were percentage of patients who developed AIDS or who died and a CD4 cell count of ⩾350 cells/µL. Intergroup differences were analyzed using analysis of variance and Kruskal-Wallis tests. Results. Baseline characteristics at the start of the structured treatment interruption were similar. At week 48, no patient had died, and 1 patient in the WOWO group had an AIDS-defining condition. The proportions of patients with a CD4 cell count of ⩾350 cells/µL were 100%, 87%, and 96% in treatment arms 1, 2, and 3, respectively. The percentages of weeks of antiretroviral use were 100%, 41.1%, and 69.8% in arms 1, 2, and 3, respectively. The adverse events were not significantly different among arms (P = .27). Thirty-one percent of patients in the WOWO group experienced virological failure. Conclusion. WOWO therapy maintained a CD4 cell count of ⩾350 cells/µL in almost all patients but was associated with high virological failures rates (possibly resulting from previous dual-NRTI therapy), indicating that this strategy is less useful. Receipt of CD4 cell count—guided therapy resulted in comparable clinical outcomes to continuous therapy and may save antiretroviral-associated costs, but this needs to be confirmed by a larger tria

Zidovudine/Lamivudine for HIV-1 Infection Contributes to Limb Fat Loss

Lipoatrophy is known to be associated with stavudine as part of the treatment for HIV infection, but it is less clear if this serious side effect is also related to other nucleoside reverse transcriptase inhibitors like zidovudine. We aimed to determine whether zidovudine-sparing first-line antiretroviral therapy would lead to less lipoatrophy and other metabolic changes than zidovudine-containing therapy.Fifty antiretroviral therapy-naïve HIV-1 infected men with an indication to start antiretroviral therapy were included in a randomized single blinded clinical trial. Randomisation was between zidovudine-containing therapy (zidovudine/lamivudine+lopinavir/ritonavir) and zidovudine-sparing therapy (nevirapine+lopinavir/ritonavir). Main outcome measures were body composition assessed by computed tomography and dual-energy X-ray absorptiometry scan and lipid profile before and after 3, 12, 24 months of antiretroviral therapy. In the zidovudine/lamivudine+lopinavir/ritonavir group, from 3 months onward limb fat decreased progressively by 684+/-293 grams (estimated mean+/-standard error of the mean)(p = 0.02) up to 24 months whereas abdominal fat increased, but exclusively in the visceral compartment (+21.9+/-8.1 cm(2), p = 0.008)). In contrast, in the nevirapine+lopinavir/ritonavir group, a generalized increase in fat mass was observed. After 24 months no significant differences in high density lipoprotein and total/high density lipoprotein cholesterol ratio were found between both treatment groups, but total and low density lipoprotein cholesterol levels were higher in the nevirapine+lopinavir/ritonavir group (6.1+/-0.2 versus 5.3+/-0.2 and 3.6+/-0.1 versus 2.8+/-0.1 mmol/l respectively, p<0.05). Virologic response and safety were comparable in both groups.Zidovudine/lamivudine+lopinavir/ritonavir, but not nevirapine+lopinavir/ritonavir in antiretroviral therapy-naïve patients, is associated with lipoatrophy and greater relative intraabdominal lipohypertrophy, suggesting that zidovudine/lamivudine contributes to both these features of lipodystrophy. These findings support to no longer consider zidovudine/lamivudine as one of the preferred possible components of first-line antiretroviral therapy where alternative treatments are available.ClinicalTrials.gov NCT 00122226