Crackling versus continuumlike dynamics in brittle failure

We study how the loading rate, specimen geometry, and microstructural texture select the dynamics of a crack moving through an heterogeneous elastic material in the quasistatic approximation. We find a transition, fully controlled by two dimensionless variables, between dynamics ruled by continuum fracture mechanics and crackling dynamics. Selection of the latter by the loading, microstructure, and specimen parameters is formulated in terms of scaling laws on the power spectrum of crack velocity. This analysis defines the experimental conditions required to observe crackling in fracture. Beyond failure problems, the results extend to a variety of situations described by models of the same universality class, e.g., the dynamics in wetting or of domain walls in amorphous ferromagnets.

Fabrication of CdZnTe Strip Detectors for Large Area Arrays

A CdZnTe strip detector large area array (∼ 60 cm2 with 36 detectors) with capabilities for high resolution imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. The detector array also has applications in nuclear medical imaging. Two dimensional orthogonal strip detectors with 100 μm pitch have been fabricated and tested. Details for the array design, fabrication and evaluation of the detectors will be presented.

Performance of Prototype Segmented CdZnTe Arrays

The Burst and All Sky Imaging Survey (BASIS) is a proposed mission to provide ∼3 arc second locations of approximately 90 Gamma-Ray Bursts (GRBs) per year. The BASIS coded aperture imaging system requires a segmented detector plane able to detect the interaction position of (10 - 150 keV) photons to less than 100 μm. To develop prototype detector arrays with such fine position resolution we have fabricated many 15 mm × 15 mm × 2 mm 100 μm pitch CdZnTe strip detectors. We have assembled these fine pitch CdZnTe strip detectors into prototype 2 × 2 and 6 × 6 element arrays read out by ASIC electronics. The assembly and electronics readout of the 6 × 6 flight prototype array will be discussed, and preliminary data illustrating the uniformity and efficiency of the array will be presented.

Liver resection after downstaging hepatocellular carcinoma with sorafenib

Background. Sorafenib is a molecular-targeted therapy used in palliative treatment of advanced hepatocellular carcinoma in Child A patients. Aims. To address the question of sorafenib as neoadjuvant treatment. Methods. We describe the cases of 2 patients who had surgery after sorafenib. Results. The patients had a large hepatocellular carcinoma in the right liver with venous neoplastic thrombi (1 in the right portal branch, 1 in the right hepatic vein). After 9 months of sorafenib, reassessment showed that tumours had decreased in size with a necrotic component. A right hepatectomy with thrombectomy was performed, and histopathology showed 35% to 60% necrosis. One patient had a recurrence after 6 months and had another liver resection; they are both recurrence-free since then. Conclusion. Sorafenib can downstage hepatocellular carcinoma and thus could represent a bridge to surgery. It may be possible to select patients in good general condition with partial regression of the tumour with sorafenib for a treatment in a curative intent.

Ruptured liver cell adenoma in man: great fortune in misfortune

Liver cell adenoma is mostly known as a tumour affecting women with long-term use of contraceptive hormones. Its incidence in men is very low, and particularly few cases of acute complications are related in the literature. We report the case of a 44-year-old man presenting with a life-threatening rupture of a hepatic tumour, successfully treated in emergency with primary endovascular embolization, followed by hepatectomy, once stabilized. The pathological findings were fortunately consistent with the diagnosis of liver-cell adenoma. To our knowledge, it is the first case reported in a man treated by a combined interventional radiological and surgical approach.

[Abdominal cystic tumor revealing lymphangioleiomyomatosis]

We report the case of a 39 year-old woman with many years of intermittent abdominal pain who was found to have cystic masses evocative of cystic lymphangioma involving the posterior mediastinal and retroperitoneum. Worsening abdominal pain led to a recommendation for laparoscopic unroofing and decompression of the cysts. During the postoperative period, hemorrhagic shock required reintervention with excision of the tumoral mass. Pathologic examination revealed lymphangioleiomyomatosis (LAM). On the 15th postoperative day, the patient developed a chylopneumothorax which required prolonged chest tube drainage. The presence of multiple polycystic lesions in the pulmonary parenchyma supported the diagnosis of diffuse LAM with primary extrapulmonary presentation. This diagnosis should be considered preoperatively since it modifies the treatment: a complete excision of the cystic lesions seems to be necessary in order to prevent bleeding and lymphatic extravasation.

A short γ-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225

Gamma-ray bursts (GRBs) come in two classes: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z approximately 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars. In contrast, no short GRB had been accurately (< 10'') and rapidly (minutes) located. Here we report the detection of the X-ray afterglow from--and the localization of--the short burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.

A giant γ-ray flare from the magnetar SGR 1806–20

Two classes of rotating neutron stars-soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars-are magnetars, whose X-ray emission is powered by a very strong magnetic field (B approximately 10(15) G). SGRs occasionally become 'active', producing many short X-ray bursts. Extremely rarely, an SGR emits a giant flare with a total energy about a thousand times higher than in a typical burst. Here we report that SGR 1806-20 emitted a giant flare on 27 December 2004. The total (isotropic) flare energy is 2 x 10(46) erg, which is about a hundred times higher than the other two previously observed giant flares. The energy release probably occurred during a catastrophic reconfiguration of the neutron star's magnetic field. If the event had occurred at a larger distance, but within 40 megaparsecs, it would have resembled a short, hard gamma-ray burst, suggesting that flares from extragalactic SGRs may form a subclass of such bursts.

Sentinel Node Biopsy in Head and Neck Cancer: Preliminary Results of a Multicenter Trial

BACKGROUND

The aim was to determine the reliability and reproducibility of sentinel node biopsy (SNB) as a staging tool in head and neck squamous cell carcinoma (HNSCC) for T1/2 clinically N0 patients by means of a standardized technique.

METHODS

Between June 1998 and June 2002, 227 SNB procedures have been performed in HNSCC cases at six centers. One hundred thirty-four T1/2 tumors of the oral cavity/oropharynx in clinically N0 patients were investigated with preoperative lymphoscintigraphy (LSG), intraoperative use of blue dye/gamma probe, and pathological evaluation with step serial sectioning and immunohistochemistry, with a follow-up of at least 12 months. In 79 cases SNB alone was used to stage the neck carcinoma, and in 55 cases SNB was used in combination with an elective neck dissection (END).

RESULTS

In 125/134 cases (93%) a sentinel node was identified. Of 59 positive nodes, 57 were identified with the intraoperative gamma probe and 44 with blue dye. Upstaging of disease occurred in 42/125 cases (34%): with hematoxylin-eosin in 32/125 (26%) and with additional pathological staging in 10/93 (11%). The sensitivity of the technique with a mean follow-up of 24 months was 42/45 (93%). The identification of SNB for floor of mouth (FOM) tumors was 37/43 (86%), compared with 88/91 (97%) for other tumors. The sensitivity for FOM tumors was 12/15 (80%), compared with 30/30 (100%) for other tumor groups.

CONCLUSION

SNB can be successfully applied to early T1/2 tumors of the oral cavity/oropharynx in a standardized fashion by centers worldwide. For the majority of these tumors the SNB technique can be used alone as a staging tool.

Microchemical transformation of bioactive glass particles of narrow size range, a 0-24 months study

Previous studies demonstrated the capacity of bioactive glass particles of narrow size range (300-355 microm, Biogran) to stimulate bone tissue formation without contact with pre-existing bone tissue. Chemical interactions between the bioactive glass and the surrounding tissue fluids caused the glass transformation. This study quantifies the time-dependent transformation process. Particles were implanted in the jaws of beagle dogs and resected after 1, 2, 3, 6, 12 and 24 months. Microchemical analysis was performed using a scanning electron microscope equipped with an energy dispersive X-ray analysis system. After one month, Na-ions were leached out and the particles transformed into two layers. In the center, a Si-rich gel was found on the outer surface, a Ca- and P-rich shell. After two months, the concentration levels of the outer Ca- and P-rich shell remained. In the center the Si-concentration decreased and the Ca and P concentration increased. After three months, Si disappeared completely from the center of the particle, while the Ca and P concentration increased. At one and two years, the Ca and P concentrations in the transformed particles equalled those of bone tissue, turning the transformed particle into a chemical equivalent of the bone mineral phase.

Identification of the atomic structure of the fivefold surface of an icosahedral Al-Pd-Mn quasicrystal: helium diffraction and scanning tunneling microscopy studies

High resolution He diffraction and scanning tunneling microscopy images of the fivefold surface of a single-grain i-AlPdMn quasicrystal are obtained showing an almost perfect quasicrystal order. Observed configurations can be identified within the framework of polyhedral models. The terrace terminations are found to be Al-rich planes and successions of step heights agree with distances between dense Al planes in the model. This shows the ability of recent 6D polyhedral models to describe real quasicrystalline atomic configurations.

Temporomandibular arthroscopy: a retrospective clinical study (1995-1999) of 61 cases

OBJECTIVES

A study was made of the internal derangements of the temporomandibular joint (TMJ) in order to: (a) determine the coincidence between the preoperative clinical diagnosis and imaging findings and the intraoperative arthroscopic observations, (b) establish the efficacy of arthroscopic treatment, and (c) evaluate the complications of the procedure.

DESIGN

A descriptive and retrospective clinical study (1995-1999) of 61 TMJ arthroscopies was design.

RESULTS

Coincidence was recorded between the clinical diagnosis and arthroscopic findings in 66.6% of cases, and the imaging diagnostic observations (magnetic resonance imaging) in 71.6%. The surgical outcome in terms of movement range was considered excellent (aperture > 40 mm) in 19 patients (42.2%), good (30-40 mm) in 19 (42.2%), and poor (< 30 mm) in 7 patients (15.6%). Postoperative pain assessment was in turn excellent (absence of pain) in 27 patients (60%), good (significant pain remission) in 9 (20%) and poor (persistent or increased pain) in 9 patients (20%). There were 7 complications and all healed without sequelae.

CONCLUSIONS

The global results indicate an excellent or good movement range in 84.2%, with either no postoperative pain or only minimum pain in 81.4% of cases. Consequently, if arthroscopy is used for a precise indication in an adequate patient, it can improve the quality of life of individuals with TMJ pathology in situations where conservative procedures have failed.

Knee joint arthroplasty in a patient with haemophilia A and high inhibitor titre using recombinant factor VIIa (NovoSeven): a new case report and review of the literature

Elective orthopaedic surgery is regularly withheld from patients with haemophilia and high inhibitor titre despite the presence of severe arthropathy and urgent medical need. A knee joint arthroplasty was performed in a patient with severe haemophilia A and a high inhibitor titre using recombinant factor VIIa (rFVIIa) as the sole coagulation factor. There was no abnormal bleeding during surgery although an increased blood loss through surgical drains did occur during the first 6 h postoperatively. Rehabilitation was started on day 1 and continued for 3 months. Walking commenced on day 4. After 1 year of follow-up, the clinical outcome of surgery was considered excellent with no pain, knee mobility at 0-5-90 degrees, and an International Knee Society score of 95/100. No rFVIIa-associated side-effects or thrombotic complications were reported. In conclusion, knee joint arthroplasty is now an option for haemophilia patients with a high inhibitor titre. An international review of all available data on elective orthopaedic surgery in inhibitor patients is required so that the optimal treatment regime can be defined and the short- and long-term risk-benefit ratio of surgery compared to that of noninhibitor patients.