Resonant photon absorption and hole burning in Cr7Ni antiferromagnetic rings

Presented are magnetization measurements on a crystal of Cr7Ni antiferromagnetic rings. Irradiation with microwaves at frequencies between 1 and 10 GHz leads to observation of very narrow resonant photon absorption lines which are mainly broadened by hyperfin interactions. A two-pulse hole burning technique allowed us to estimate the characteristic energy diffusion time.Comment: 4 pages, 5 figure

Will spin-relaxation times in molecular magnets permit quantum information processing?

Using X-band pulsed electron spin resonance, we report the intrinsic spin-lattice ($T_1$) and phase coherence ($T_2$) relaxation times in molecular nanomagnets for the first time. In Cr$_7M$ heterometallic wheels, with $M$ = Ni and Mn, phase coherence relaxation is dominated by the coupling of the electron spin to protons within the molecule. In deuterated samples $T_2$ reaches 3 $\mu$s at low temperatures, which is several orders of magnitude longer than the duration of spin manipulations, satisfying a prerequisite for the deployment of molecular nanomagnets in quantum information applications.Comment: 4 pages, 3 figures, in press at Physical Review Letter

Assessment of HER2 and Ki67 in adenocarcinomas

Biomarkers in tumor tissue can predict cancer behavior or can be targeted with targeted therapy. Two examples of such biomarkers are HER2 and Ki67. These biomarkers are assessed with stains on tissue of patients in clinical pathology. Timco Koopman is a resident in pathology and works at the pathology department of the UMCG. For his thesis he researched the quantitative assessment of HER2 and Ki67 in malignant tumors of glandular tissue (adenocarcinomas). HER2 is a receptor protein that is best known from breast and stomach cancer. Anti-HER2-therapy for HER2-positive tumors of these organs can increase a patient’s chances of curation and survival. Ki67 is a protein that is present in dividing cells. As such, quantification of Ki67 reflects the growth speed and aggressiveness of tumors. The first part of the thesis is about HER2. Koopman explored the prevalence of HER2-positivity in gastric and esophageal cancer and describes how HER2 should be determined in these tumors. Koopman also describes why assessment of HER2 in other tumors than breast, stomach or esophagus can be more problematic. The second part of the thesis is about digital image analysis. Digitizing in modern pathology is on the rise. Digitized images can be analyzed with specific software. Koopman describes why digital image analysis in clinical pathology will benefit the reliability and reproducibility of the assessment of HER2 and Ki67

Assessment of HER2 and Ki67 in adenocarcinomas

Biomarkers in tumor tissue can predict cancer behavior or can be targeted with targeted therapy. Two examples of such biomarkers are HER2 and Ki67. These biomarkers are assessed with stains on tissue of patients in clinical pathology. Timco Koopman is a resident in pathology and works at the pathology department of the UMCG. For his thesis he researched the quantitative assessment of HER2 and Ki67 in malignant tumors of glandular tissue (adenocarcinomas). HER2 is a receptor protein that is best known from breast and stomach cancer. Anti-HER2-therapy for HER2-positive tumors of these organs can increase a patient’s chances of curation and survival. Ki67 is a protein that is present in dividing cells. As such, quantification of Ki67 reflects the growth speed and aggressiveness of tumors. The first part of the thesis is about HER2. Koopman explored the prevalence of HER2-positivity in gastric and esophageal cancer and describes how HER2 should be determined in these tumors. Koopman also describes why assessment of HER2 in other tumors than breast, stomach or esophagus can be more problematic. The second part of the thesis is about digital image analysis. Digitizing in modern pathology is on the rise. Digitized images can be analyzed with specific software. Koopman describes why digital image analysis in clinical pathology will benefit the reliability and reproducibility of the assessment of HER2 and Ki67

g-engineering in hybrid rotaxanes to create AB and AB2 electron spin systems: EPR spectroscopic studies of weak interactions between dissimilar electron spin qubits

Hybrid [2]rotaxanes and pseudorotaxanes are reported where the magnetic interaction between dissimilar spins is controlled to create AB and AB2 electron spin systems,allowing independent control of weakly interacting S =1=2 centers

Molecular engineering of antiferromagnetic rings for quantum computation

The substitution of one metal ion in a Cr-based molecular ring with dominant antiferromagnetic couplings allows to engineer its level structure and ground-state degeneracy. Here we characterize a Cr7Ni molecular ring by means of low-temperature specific-heat and torque-magnetometry measurements, thus determining the microscopic parameters of the corresponding spin Hamiltonian. The energy spectrum and the suppression of the leakage-inducing S-mixing render the Cr7Ni molecule a suitable candidate for the qubit implementation, as further substantiated by our quantum-gate simulations.Comment: To appear in Physical Review Letter

The Vertical Pressure Distribution on Structures Subjected to Rubble-Forming Ice

A laboratory test program has been performed on ice loading through pressured broken ice. The results have applications to both structures and ships in Arctic regions. The work was performed by measuring the loads on a segmented planar structure for various loading conditions. The variables included ice strength, ice thickness, ice density, ice/structure friction and angle of inclination of the structure. Vertical distributions of loads, point of resultant load application and overturning moments have been examined. A comparison of extrapolated peak pressures show excellent agreement with full-scale measurements on the Gulf Canada's arctic structure Molikpaq.NRC publication: Ye