Atomic Step Flow on a Nanofacet

Crystal growth often proceeds by atomic step flow. When the surface area available for growth is limited, the nucleation and progression of the steps can be affected. This issue is particularly relevant to the formation of nanocrystals. We examine the case of Au-catalyzed GaAs nanowires, which we grow in a transmission electron microscope. Our in situ observations show that atomic layers nucleate at the periphery of the interface between the nanowire and the catalyst droplet. From this starting location, the atomic step flows within a restricted area of hexagonal shape. At specific partial coverages, the monolayer configuration changes abruptly. A simple model based on the geometry of the system and its edge energies explains these observations. In particular, we observe an inversion of the step curvature which reveals that the effective energy per unit length of monolayer edge is much lower at the interface periphery than inside the catalyst droplet.

Misdiagnosis trends in patients with hereditary angioedema from the real-world clinical setting

BACKGROUND

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) causes swelling in the skin and upper airways and pain in the abdomen because of mucosal swelling. C1-INH-HAE is frequently misdiagnosed, leading to delays in diagnosis, inadequate treatment, and unnecessary procedures.

OBJECTIVE

To evaluate the history of misdiagnosis in patients participating in the Icatibant Outcome Survey (IOS).

METHODS

The IOS is an observational study in which safety and effectiveness of icatibant have been evaluated since 2009. As part of the IOS, patients record any misdiagnoses received before being diagnosed as having C1-INH-HAE.

RESULTS

In January 2016, a total of 418 of 633 IOS patients with C1-INH-HAE type I or II had provided misdiagnosis data. Of these, 185 of 418 (44.3%) received 1 or more prior misdiagnoses. The most common misdiagnoses were allergic angioedema (103 of 185) and appendicitis (50 of 185). A variety of other misdiagnoses were reported, including a substantial number of gastrointestinal disorders (excluding appendicitis). Misdiagnosis rates were similar between males (41.1%) and females (46.5%) and between C1-INH-HAE type I (43.7%) and type II (51.6%). Patients with family members diagnosed as having C1-INH-HAE were significantly less likely to be misdiagnosed than patients without a family history (140 of 366 [41.7%] vs 38 of 58 [65.5%], respectively; P = .001). Patients with a prior misdiagnosis had longer median delay to C1-INH-HAE diagnosis (13.3 years) than patients without (1.7 years; P < .001).

CONCLUSION

From this large database, approximately 50% of patients with C1-INH-HAE type I or II have previously had their conditions misdiagnosed, most commonly as allergic angioedema or appendicitis. Misdiagnosis results in marked delays in receiving the correct diagnosis, during which time patients cannot access effective, lifesaving treatment.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01034969.

Hereditary angioedema with normal C1 inhibitor and factor XII mutation: a series of 57 patients from the French National Center of Reference for Angioedema

Hereditary angioedema (HAE) is a rare disease associated with either a quantitative or qualitative deficiency in C1-inhibitor (C1-INH) or normal C1-INH. HAE with normal C1-INH is associated in 20% of cases with mutations in the gene for factor XII (FXII) or FXII-HAE. A recent review described 41 families, including 14 German and 15 Spanish families. We have constructed a register of French patients and their characteristics. A national survey was launched through the French National Center of Reference for Angioedema (CREAK) to study the clinical, biological and therapeutic characteristics of patients with HAE linked to a mutation of FXII gene. Fifty-seven patients were identified from 24 different families. In most cases they were young women (mean age at diagnosis: 31 years, mean age at first symptom: 21 years, female/male ratio: 76%). Twenty-one per cent of the patients experienced angioedema attacks only during pregnancy or when on oestrogen contraception. Sixty-three per cent had attacks at all times, but they were more severe during these same periods. Male carriers of the mutation were more frequently asymptomatic than females (P = 0·003). C1-INH concentrate and icatibant were both effective for treating attacks. The prophylactic use of tranexamic acid led to a 64% decrease in the number of attacks. This is one of the largest series reported of HAE patients with FXII mutation. The therapeutic management appeared to be identical to that of HAE with C1-INH deficiency.

[Acquired von Willebrand syndrome: from diagnosis to treatment]

Acquired von Willebrand syndrome is a rare bleeding disorder, which has been related in various diseases including lymphoproliferative disorders or autoimmune diseases. Its diagnosis is an important step before treatment of patients and particularly in case of bleeding. We report four cases from Caen Hemophilia Treatment Center, diagnosed and treated from 1999 to 2008. Mucocutaneous bleeds in every case were the same as in hereditary von Willebrand disease. All patients had no personal or family history of bleeding. Phenotype was identified as type 2 von Willebrand disease with a loss of high molecular weight multimers. Anti-von Willebrand factor inhibitor screening was positive for three patients. The etiological diagnosis was one chronic lymphocytic leukaemia, two monoclonal gammapathies of undetermined significance (MGUS) and one undetermined case. The management of patients need two stages: first infusions of factor von Willebrand/factor VIII concentrates to stop bleeds, then treatment of the underlying disease such as chemotherapy, corticotherapy and treatment with high doses of polyvalents immunoglobulins. In every case, treatment was effective and improved patient's quality of life.

[Cardiac surgery without transfusion in 2005]

PURPOSE

Between January 1991 and October 2003, 200 Jehovah Witnesses adult patients underwent elective cardiac surgery. To asses the impact on continuing progress of blood saving protocols and the increasing operative risk of patients proposed to surgery, we have re-assessed our results in this specific population.

METHODOLOGY

Files of the first 100 patients operated upon between 1991 and 1998 were reviewed, and compared to the following 100 ones treated between 1998 to today. All patients were scored using the Euroscore model.

RESULTS

In the latest series, patients are older (68 vs 51) and 13% underwent an iterative procedure, although there was none in the first series. Three deaths occurred after one month at the beginning of our experience, only one in the latest series. Operative risk factors had distinctly deteriorated, with more redux, and ejection fraction lower than 35%. Major progress to maintain morbi-mortality stability were multifactorial: preoperative erythropoietin in order to reach an haemoglobin minimal value of 14 g/dL, Cornell University protocol, mini-ECC, warm blood cardioplegia, ultra-early extubation.

CONCLUSION

Cardiac surgery without transfusion can be realised with an equivalent risk to that of classical surgery, despite an operative risk aggravation, due to the association of recent conservative techniques.

Prevalences of rheumatoid arthritis in Roman Catholic nuns and the general female population in Brittany, France: a pilot study

OBJECTIVE

To evaluate the influence of lifestyle factors on the prevalence of rheumatoid arthritis (RA) by comparing Roman Catholic nuns and the general female population.

METHOD

RA prevalence in the general population was evaluated using a standardized telephone survey in 1857 homes taken at random. Individuals who reported an inflammatory joint disease were contacted by a rheumatologist of our unit, missing data were collected from the general practitioner or rheumatologist with the patient's permission, and if necessary a physical examination was done by a rheumatologist. The 9 largest Roman Catholic nun communities in Brittany were screened using the same standardized questionnaire administered face-to-face; nuns who reported an inflammatory joint disease were interviewed and examined by rheumatologists. In both populations, RA was diagnosed when (1) the rheumatologist of our unit who interviewed the patient considered the RA classification criteria positive and (2) the rheumatologist who examined the patient gave a diagnosis of RA independently from RA classification criteria.

RESULTS

Data were available for 1706 adult females in the general population and 721 nuns. Of the 20 nuns who reported RA or polyarthritis, 11 received a diagnosis of RA (prevalence 1.52%). The prevalences adjustedfor the French population after 40 years were 1.66% (95% confidence interval, 0.84-2.44) and 1.33 (0.27-2.40) among the nuns and the general female population, respectively.

CONCLUSION

Although our nun population was too small for definite conclusions, we found no evidence of a difference in RA prevalence among nuns and the general female population in Brittany.

The European space suit, a design for productivity and crew safety

In order to fulfill the two major mission objectives, i.e. support planned and unplanned external servicing of the COLUMBUS FFL and support the HERMES vehicle for safety critical operations and emergencies, the European Space Suit System baseline configuration incorporates a number of design features, which shall enhance the productivity and the crew safety of EVA astronauts. The work in EVA is today--and will be for several years--a manual work. Consequently, to improve productivity, the first challenge is to design a suit enclosure which minimizes movement restrictions and crew fatigue. It is covered by the "ergonomic" aspect of the suit design. Furthermore, it is also necessary to help the EVA crewmember in his work, by giving him the right information at the right time. Many solutions exist in this field of Man-Machine Interface, from a very simple system, based on cuff check lists, up to advanced systems, including Head-Up Displays. The design concept for improved productivity encompasses following features: easy donning/doffing thru rear entry, suit ergonomy optimisation, display of operational information in alpha-numerical and graphical form, and voice processing for operations and safety critical information. Concerning crew safety the major design features are: a lower R-factor for emergency EVA operations thru increased suit pressure, zero prebreath conditions for normal operations, visual and voice processing of all safety critical functions, and an autonomous life support system to permit unrestricted operations around HERMES and the CFFL. The paper analyses crew safety and productivity criteria and describes how these features are being built into the design of the European Space Suit System.