18 research outputs found
Ptychographic X-ray tomography reveals additive zoning in nanocomposite single crystals
Single crystals containing nanoparticles represent a unique class of nanocomposites whose properties are defined by both their compositions and the structural organization of the dispersed phase in the crystalline host. Yet, there is still a poor understanding of the relationship between the synthesis conditions and the structures of these materials. Here ptychographic X-ray computed tomography is used to visualize the three-dimensional structures of two nanocomposite crystals â single crystals of calcite occluding diblock copolymer worms and vesicles. This provides unique information about the distribution of the copolymer nano-objects within entire, micron-sized crystals with nanometer spatial resolution and reveals how occlusion is governed by factors including the supersaturation and calcium concentration. Both nanocomposite crystals are seen to exhibit zoning effects that are governed by the solution composition and interactions of the additives with specific steps on the crystal surface. Additionally, the size and shape of the occluded vesicles varies according to their location within the crystal, and therefore the solution composition at the time of occlusion. This work contributes to our understanding of the factors that govern nanoparticle occlusion within crystalline materials, where this will ultimately inform the design of next generation nanocomposite materials with specific structure/property relationships
Field-Induced Magnetic Ordering in the Quantum Spin System KCuCl
KCuCl is a three-dimensional coupled spin-dimer system and has a singlet
ground state with an excitation gap K. High-field
magnetization measurements for KCuCl have been performed in static magnetic
fields of up to 30 T and in pulsed magnetic fields of up to 60 T. The entire
magnetization curve including the saturation region was obtained at K.
From the analysis of the magnetization curve, it was found that the exchange
parameters determined from the dispersion relations of the magnetic excitations
should be reduced, which suggests the importance of the renormalization effect
in the magnetic excitations. The field-induced magnetic ordering accompanied by
the cusplike minimum of the magnetization was observed as in the isomorphous
compound TlCuCl. The phase boundary was almost independent of the field
direction, and is represented by the power law. These results are consistent
with the magnon Bose-Einstein condensation picture for field-induced magnetic
ordering.Comment: 9 pages, 7 figures, 9 eps files, revtex styl
Pre-operative radiochemotherapy with raltitrexed for resectable locally-advanced rectal cancer : a phase II study
Background: The aim of the study was to evaluate the response to and toxicity of pre-operative radiochemotherapy containing raltitrexed (Tomudex) for resectable rectal adenocarcinoma. Patients and Methods: From November 2000 to June 2002, 18 consecutive patients staged T3 N0/N+ were treated with pre-operative chemotherapy (3 mg/m 2 of raltitrexed on days 1, 19, 38) and concurrent radiotherapy (RT) (50.4 Gy) in 6 weeks, followed by radical surgery within 8 weeks. Results: The treatment compliance was high. No major acute toxicity was reported. Concerning late toxicity, genitourinary adverse effects were prevalent. A complete response was observed in one patient (6%), partial response in eight (47%), stable disease in seven (41%) and progression in one case. Three-year actuarial disease-free and overall survival rates were 37% and 87.5%, respectively. Conclusion: Raltitrexed did not increase the pathological response rate compared with the rates obtained with use of preoperative RT alone and reported in the literature. Acute morbidity was low and acceptable, while late toxicity was considerable, prevalently concerning sexual dysfunction and urinary complications
IMPACT-Global Hip Fracture Audit: Nosocomial infection, risk prediction and prognostication, minimum reporting standards and global collaborative audit. Lessons from an international multicentre study of 7,090 patients conducted in 14 nations during the COVID-19 pandemic
53. Time-resolved infrared spectroscopic study of the switching dynamics of a surface-stabilized ferroelectric liquid crystal(poster presentation,Soft Matter as Structured Materials)
ăăźè«æăŻćœç«æ
ć ±ćŠç 究æăźé»ććłæžé€šäșæ„ă«ăăé»ććăăăŸăăăæŹç 究ă§ăŻæéćè§Łè”€ć€ćć
æłă«ăăăć°ć é»ć Žæ„”æ§ćè»ąă«äŒŽăSm-CçžćŒ·èȘé»æ§æ¶Čæ¶ćććé
ćéçšăźăćé
滶æéă«ăăă蔀ć€ăăłăćžć
ćșŠćć
è§äŸćæ§ă«ă€ăăŠèȘżăčăăé·ç§»ćæ„”ćăąăŒăĄăłăăźććžç¶æ
ăšăăźćčłćăźæčć(é
ćè§)ăšăźéąäżăæçąșă«ăăăŸăăé
ćè§æéć€ćăăăăĄă€ă«ăăćććźèœćșăŹăă«ă§ăźćé
ććçæćăæ€èšăăăăźăčă€ăăăłă°ăĄă«ăășă ăæăăă«ăă
Electric-Field-Induced Reorientation of a Ferroelectric Liquid Crystal Molecule without a Carboxylate Group near the Stereocenter Studied by Time-Resolved Infrared Spectroscopy Combined with Normalized SampleâSample Two-Dimensional Correlation Spectroscopy
Osteolytic lesions (brown tumors) of primary hyperparathyroidism misdiagnosed as multifocal giant cell tumor of the distal ulna and radius: a case report
Abstract Background Brown tumors represent a rare clinical manifestation reported in approximately 3% of patients with primary hyperparathyroidism and correspond to radiologically osteolytic lesions with well-defined borders in different parts of the skeleton. Case presentation We report the case of a 53-year-old white man who presented to our hospital with osteolytic lesions of his distal ulna and radius, causing pain and swelling of 2-month duration. A subsequent biopsy revealed histological features consistent with giant cell tumor and a complete resection of his distal ulna was followed, along with curettage and cementoplasty of the distal radial metaphysis. Two weeks later, he was re-admitted with diffuse musculoskeletal soreness, anorexia, constipation, nausea, and localized abdominal pain and multiple osteolytic lesions on plain radiographs. A histopathological examination of the ulna and radius specimens showed similar findings and, given the multifocality, brown tumors related to primary or secondary hyperparathyroidism was included in the differential diagnosis. A laboratory examination showed high total serum calcium (14.5 mg/dl) and low serum phosphorus and 25-hydroxyvitamin D levels. Primary hyperparathyroidism was suspected and confirmed by the elevated parathyroid hormone levels of 1453 pg/mL. At radiological work-up, using computed tomography, ultrasonography, and parathyroid subtraction technetium-99m sestamibi scintigraphy, a 4.5âĂâ2.5âĂâ3.2 cm mass emanating from the right lobe of his thyroid gland was detected, displaying extensive uptake in the right lower parathyroid gland. After appropriate medical support including hyperhydration and high doses of diuretics and diphosphonates, his laboratory profile normalized and he underwent total thyroidectomy with removal of the parathyroid glands. Our patient is now recovering 12 months after surgery, with normal values of serum parathyroid hormone and calcium levels. The lytic bone lesions have almost disappeared and no other additional orthopedic intervention was necessary. Conclusions The present case report emphasizes the need of inclusion of brown tumors in the differential diagnosis of multifocal osteolytic bone lesions, in order to avoid harmful surgical interventions. Laboratory testing of serum phosphate, calcium levels, and parathyroid hormone levels should always be included in the routine survey of patients with multifocal osteolytic lesions