Ultrafast strain propagation and acoustic resonances in nanoscale bilayer systems.

Ultrafast structural probing has greatly enhanced our understanding of the coupling of atomic motion to electronic and phononic degrees-of-freedom in quasi-bulk materials. In bi- and multilayer model systems, additionally, spatially inhomogeneous relaxation channels are accessible, often governed by pronounced interfacial couplings and local excitations in confined geometries. Here, we systematically explore the key dependencies of the low-frequency acoustic phonon spectrum in an elastically mismatched metal/semiconductor bilayer system optically excited by femtosecond laser pulses. We track the spatiotemporal strain wave propagation in the heterostructure employing a discrete numerical linear chain simulation and access acoustic wave reflections and interfacial couplings with a phonon mode description based on a continuum mechanics model. Due to the interplay of elastic properties and mass densities of the two materials, acoustic resonance frequencies of the heterostructure significantly differ from breathing modes in monolayer films. For large acoustic mismatch, the spatial localization of phonon eigenmodes is derived from analytical approximations and can be interpreted as harmonic oscillations in decoupled mechanical resonators.

Allogeneic human umbilical cord-derived mesenchymal stem/stromal cells for chronic obstructive pulmonary disease (COPD): study protocol for a matched case-control, phase I/II trial.

INTRODUCTION: The global prevalence of chronic obstructive pulmonary disease (COPD) is increasing, and it has become a major public health burden worldwide, including in Vietnam. A large body of preclinical and clinical studies supports the safety of mesenchymal stem/stromal cells (MSCs) in the treatment of lung injury, including COPD. The aim of this trial is to investigate the safety and potential therapeutic efficacy of allogeneic administration of umbilical cord-derived MSCs (UC-MSCs) as a supplementary intervention in combination with standard COPD medication treatments in patients with moderate-to-severe COPD based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2019 and Vietnam Ministry of Health's guidelines. METHODS AND ANALYSIS: This matched case-control phase I/II trial is conducted at Vinmec Times City International Hospital, Hanoi, Vietnam between June 2020 and December 2021. In this study, 40 patients will be enrolled and assigned into two age-matched, gender-matched and COPD condition-matched groups, including a UC-MSC group and a control group. Both groups will receive standard COPD medication treatment based on the GOLD 2019 guidelines and the Vietnam Ministry of Health protocol. The UC-MSC group will receive two doses of thawed UC-MSC product with an intervention interval of 3 months. The primary outcome measures will include the incidence of prespecified administration-associated adverse events and serious adverse events. The efficacy will be evaluated based on the absolute changes in the number of admissions, arterial blood gas analysis, lung function and lung fibrosis via CT scan and chest X-ray. The clinical evaluation will be conducted at baseline and 3, 6 and 12 months postintervention. ETHICS AND DISSEMINATION: Ethical approval was secured from the Ethical Committee of Vinmec International Hospital (number:166/2019/QD-VMEC) and Vietnam Ministry of Health (number:2002/QD-BYT). The results will be reported to trial collaborators, publication in peer-reviewed academic journals. TRIAL REGISTRATION NUMBER: NCT04433104.

Persistent Detwinning of Iron-Pnictide EuFe_{2}As_{2} Crystals by Small External Magnetic Fields.

Our comprehensive study on EuFe_{2}As_{2} reveals a dramatic reduction of magnetic detwinning fields compared to other AFe_{2}As_{2} (A=Ba, Sr, Ca) iron pnictides by indirect magnetoelastic coupling of the Eu^{2+} ions. We find that only ∼0.1 T are sufficient for persistent detwinning below the local Eu^{2+} ordering; above T_{Eu}=19 K, higher fields are necessary. Even after the field is switched off, a significant imbalance of twin domains remains constant up to the structural and electronic phase transition (190 K). This persistent detwinning provides the unique possibility to study the low temperature electronic in-plane anisotropy of iron pnictides without applying any symmetry-breaking external force.

The effect of surgically assisted rapid maxillary expansion on sleep architecture: an exploratory risk study in healthy young adults.

Maxillary transverse deficiencies (MTD) cause malocclusions. Rapid maxillary expansion treatment is commonly used treatment for correcting such deficiencies and has been found to be effective in improving respiration and sleep architecture in children with obstructive sleep apnoea (OSA). However, thus far, the effect of surgically assisted rapid maxillary expansion (SARME) treatment on sleep architecture and breathing of normal subjects has not been assessed. We hypothesised that sleep quality will improve after maxillary expansion treatment. The objective of this study is to access the effect of maxillary expansion treatment on sleep structure and respiratory functions in healthy young adults with severe MTD. This is a prospective and exploratory clinical study. Twenty-eight consecutive young adult patients (15 males and 13 females, mean age 20·6 ± 5·8 years) presenting with severe MTD at the orthodontic examination were recruited into the study. All the participants underwent a standardised SARME procedure (mean expansion 6·5 ± 1·8 and 8·2 ± 1·8 mm, intercanine and intermolar distance, respectively) to correct malocclusion caused by MTD. An overnight in-laboratory polysomnography, before and after the treatment, was performed. The mean follow-up time was 9 months. The main outcome parameters were the changes in sleep architecture, including sleep stages, arousals, slow-wave activity (SWA) and respiratory variables. Before surgery, young adult patients with MTD presented no evidence of sleep breathing problems. At baseline sleep recording, 7 of 28 (25%) had apnoea-hypopnoea index (AHI) ≥ 5 events per hour. No negative effect of the SARME was observed in questionnaires or sleep laboratory parameters. In the patients with a higher baseline AHI (AHI ≥ 5 h of sleep), we observed a reduction in AHI after surgical treatment (P = 0·028). SARME did not have a negative effect on any sleep or respiration parameters in healthy young individuals with MTD. It normalised the breathing index in the patients with a mild AHI index.

[Two uncommon extrapulmonary forms of Mycoplasma pneumoniae infection]. / Infections extrapulmonaires àMycoplasma pneumoniae : atteintes neurologique et rénale.

Mycoplasma pneumonia is the second most frequent bacterium in pneumonia and the leading intracellular type. M. pneumoniae pulmonary infection is characterized by a slower onset profile and a lower biological inflammatory picture than pneumococcal infection. Both upper and lower respiratory tracts are often affected and sometimes a Kawasaki-like syndrome can be associated, with conjunctivitis or cheilitis. Extrapulmonary forms of the disease can occur, whether or not it is associated with pulmonary infection. We report two cases: in the first case, a renal form of M. pneumoniae disease developed in a 6-year-old girl, with membranous proliferative glomerulonephritis expressed as a picture of impure nephritic syndrome with decreased serum complement concentration, following an upper respiratory infection. Diagnosis was obtained by means of a kidney biopsy. The second case occurred in an 8-year-old girl who expressed, after a respiratory tract infection, neurological symptoms such as ocular flutter, perception disorder, and ataxia. This onset is typical of post-infectious rhombencephalitis. Biological investigations and imaging were normal. In both cases, M. pneumoniae infection was diagnosed on the basis of immunoglobulin M-positive serology. Direct exploration of the bacterium was negative, due to its fragility and delayed diagnostic hypothesis. Several forms of M. pneumoniae infection are either the direct effect of the bacterium or are secondary to a cross-immunological reaction. As its frequency is increasing, M. pneumoniae infection should be raised as a cause of atypical, less well-known extrapulmonary forms of the disease.

Natural history of small duct primary sclerosing cholangitis: a case series with review of the literature.

BACKGROUND AND AIMS: Information about the natural history of small duct primary sclerosing cholangitis (SDPSC) remains scant despite literature suggesting that it constitutes 6-16% of all cases of primary sclerosing cholangitis (PSC). We combined clinical data on SDPSC cases from two tertiary care institutions with liver transplantation programs with the aim of studying the natural history of SDPSC. METHODS: Medical records of 25 individuals with SDPSC were reviewed. Diagnosis of SDPSC was based on liver biopsy findings consistent with PSC, a normal cholangiogram, and elimination of known causes of secondary sclerosing cholangitis. Demographic information, symptoms, past medical history, laboratory values, and histologic data were evaluated. Our primary outcome measure was liver transplantation or death. Secondary outcome measures included evidence of end-stage liver disease, development of cholangiocarcinoma, and/or the development of classic PSC on a repeat cholangiogram. RESULTS: Data on 25 individuals (13 males, 12 females; mean age 40 ± 15 years) diagnosed with SDPSC were analyzed. Upon presentation, 11 patients had symptoms including abdominal pain, fatigue, and pruritus. Inflammatory bowel disease was present in 14 patients (56%) at diagnosis. On initial liver biopsy, 60% had early-stage disease (I or II) and none had cirrhosis. On follow-up (1-168 months, median 17 months), malignancy or progression to classic large duct PSC was not noted. Two (8%) patients had evidence of varices and one of the two also developed ascites; one of these patients underwent liver transplantation and the other one died due to sepsis. CONCLUSIONS: SDPSC, a mild disease at presentation typically runs a benign course and likely is not an early stage of classic PSC. Further studies with a control group of classic PSC and longer follow-up are needed to study the natural history of SDPSC.

[Acral circumscribed hypokeratosis of plantar and dorsum of the finger localization: two cases]. / Hypokératose acrale circonscrite : forme plantaire et forme du dos du doigt (deux cas).

INTRODUCTION: Palmar or plantar circumscribed hypokeratosis is a remarkable clinicopathologic entity described in 2002. It consists in a well demarcated decrease in thickness of the stratum corneum, that can be clinically mistaken for Bowen's disease or porokeratosis. We present a classical plantar localisation and a more original case on the dorsum of the finger, together with a microscopic and immunohistochemical study. CASE REPORTS: Case 1. A 65-year-old man was seen 15 years after a first consultation for a well demarcated 1.5cm erythematous lesion localised on the border of his left foot. The biopsy, then misinterepreted as keratosis sulcata, was reviewed. It showed a sudden and well demarcated decrease in thickness of the stratum corneum, overlying a slightly acanthotic epidermis, associated with dilated capillaries in the papillary dermis. HPV immunostaining was negative. Case 2. A 75-year-old woman had a well demarcaated erythematous lesion of the dorsum of her right index finger, lasting for months without significant evolution. A first biopsy showed pale and haloed keratinocytes that could be interpreted as koilocytes. She was therefore treated by cryotherapy, 5-fluro-uracile and imiquimod, that proved unsuccessful. A second biopsy showed a sudden and major decrease in thickness of the stratum corneum, overlying an area containing a few pale keratinocytes with perinuclear halo. HPV immunostaing was negative and Ki67 positive cells were slightly decreased in number when compared to lateral normal skin. DISCUSSION: Our first case is typical of plantar hypokeratosis characterised by its long evolution, typical semiology and well demarcated anomaly of the stratum corneum. Our second case is original as it shows that the disease can also affect the dorsum of the fingers. Acral circumscribed hypokeratosis is therefore a better name for this condition. We did not find any arguments in favor of a viral cause or an increased proliferation of keratinocytes. As often described in other cases, the lesion can remain unchanged for decades, which confirm its benign evolution. Topical treatments are generally ineffective. The pathogenesis of this localised hypokeratosis remains mysterious.

[Virology: the contribution of molecular biology in the microbiologic diagnosis of pediatric respiratory diseases]. / Virologie : l'apport de la biologie moléculaire dans le diagnostic microbiologique en pneumopédiatrie.

The conventionnal tools used for virological diagnosis include direct antigen detection by immunofluorescence (IFA) or an immunoenzymatic test (EIA), and viral isolation technique (VIT). In most cases, IFA and EIA have a slightly lower sensitivity than VIT but are also able to detect some VIT-negative samples. Results of several teams using RT-PCR technologies show that the molecular methods detect more positive cases than the conventional tools. Work is under way to expand the number of viruses detected by multiplex RT-PCR and to determine wether newly discovered viruses, such as human metapneumovirus, contribute to burden of paediatric lower respiratory infections. In conclusion, according to requirements of speed, low cost of the methods, and to achieve the highest rate of detection of respiratory viruses, the combined use of IFA and multiplex RT-PCR is today likely to be the best way to improve diagnosis of respiratory illnesses in children.

[Childhood infections: friends or foes?]. / Infections précoces dans l'enfance: amies ou ennemies?

Asthma prevalence has increased significantly; this increase appears to be relatively recent. The observed increases in this prevalence cannot be genetic in origin; on the other hand lifestyles have changed in many ways for environment or feeding. The hygiene hypothesis must be distinguished in terms whether one is addressing asthma or atopy. Although there are associations between asthma and atopy, they are not interchangeable. The pathogenic links between childhood infections and asthma require an undisputed definition of asthma. But many wheezing syndromes have been recognized in the pediatric age group, some overlap exists between these various phenotypes. The age at first severe infection seems to be crucial in determining the outcome of reinfection and suggests that the environment of the neonatal lung is a major determinant of disease and allergic patterns in later life.

[Encoding of diagnosis by medical documentation assistant or ward physician. Influence on the mapping of Diagnostic Related Group (DRG) performance]. / Diagnosenverschlüsselung durch Medizinische Dokumentationsassistentin oder Stationsarzt. Einfluss auf die Abbildung der DRG-Leistung.

BACKGROUND AND OBJECTIVE: Starting in 2004 the patient budget in Germany will be calculated according to the Diagnosis Related Group (DRG) system, by which system the monetary reward of a unit will be directly related to the quality of documentation e. g. diagnosis and procedures. The aim of this study was to compare the quality of documentation by a medical documentation assistant (MDA) with the usual practice of documentation by the ward physician (WP). Additionally, the effect of introducing a completely changed organizational process was tested. METHODS: In a prospective study on the ward of a gastroenterology unit two different approaches of medical documentation were compared. In a first six-month period diagnosis and procedures were encoded by WP. In the following six months an MDA was introduced and involved in the encoding process. RESULTS: In the first six months 221 patients (mean age 55 +/- 16,2 years, 55,7 % males) were evaluated, whereas in the following six months 305 patients (mean age 53 +/- 15,4 years, 59,9 % males) were included. The introduction of an MDA improved medical documentation and economical reference numbers: with an increase of diagnosis per case to 7,43 (in first six months 5,53), patient complexity and comorbidity level (PCCL) to 2,5 (in first six months 2,13), case-mix index to 1,04 (in first six months 0,98). Additionally the medial hospitalization time decreased from 11,2 to 8,1 days. The average daily reimbursement increased in the MDA group from 423 Euro to 603 Euro. This was calculated on the basis of a basic case factor of 2900 Euro. CONCLUSION: Introduction of an MDA in a gastroenterology ward increases the quality of documentation and results in an improved presentation of DRG-relevant efforts with a better reimbursement of medical costs.

[Acute respiratory tract infections due to a human metapneumovirus in children: descriptive study and comparison with respiratory syncytial virus infections]. / Infections respiratoires aiguës à métapneumovirus humain chez l'enfant: études descriptive et comparative avec le virus respiratoire syncytial.

BACKGROUND: A new paramyxovirus, the human metapneumovirus was recently isolated. We report the first French cases collected between 2000 and 2002. MATERIAL AND METHODS: Samples were obtained from nasopharyngeal aspirates from children hospitalised for acute respiratory tract infection in hospitals of Caen and Flers in Basse-Normandie. Human metapneumovirus was studied by polymerase chain reaction on negative samples for respiratory syncytial virus, influenza A and B virus, parainfluenza (1, 2 and 3) virus, adenovirus, coronavirus and rhinovirus. Comparison between metapneumovirus virus and respiratory syncytial virus infections was done after matching sex, age and infection month. RESULTS: Twenty-six human metapneumovirus infections were identified. A comparative study of a matched group of children infected by respiratory syncytial virus found no significative difference for hospitalisation motive, clinical criteria and treatment. CONCLUSION: The human metapneumovirus is responsible for typical acute bronchiolitis in children.

[Adenoviral respiratory diseases in healthy children: a study of 116 hospital cases]. / Prise en charge des pathologies respiratoires à adénovirus chez l'enfant immunocompétent: À propos d'une étude rétrospective de 116 enfants hospitalisés.

Adenoviruses most commonly cause respiratory illness; however, depending on the infecting serotype, they may also cause various other diseases. Diagnosis may be difficult to achieve.The clinical findings for 116 children hospitalised with adenoviral infection were studied retrospectively. In 71 children, the diagnosis was based on detection of adenovirus antigen in the nasopharyngeal specimens and in 71 children on viral culture. The clinical picture of adenoviral infection was characterised by high-grade (mean 39°1C) and prolonged fever (mean duration 4,3 days). Upper respiratory and lower respiratory symptoms were the most common infections. Twelve had been admitted to the hospital due to febrile convulsions, 6 had meningitis. Laboratory findings varied from normal values to values seen in bacterial infections. Thus it was difficult to distinguish adenoviral disease from a bacterial disease. Fifty-nine children were referred to the hospital due to infection unresponsive to antimicrobial therapy.Symptoms of respiratory infection caused by adenovirus may range from the common cold syndrome to pneumonia, croup and bronchiolitis. Adenoviruses can be responsible for severe consequences, even in previously healthy children. Studies of the molecular mechanisms of viral infections of the airways could provide important insights into the nature of the inflammatory process involved in asthma and chronic obstructive pulmonary disease. Most infections are mild and require no therapy or only symptomatic treatment. There are at present time no recognised antiviral agents that are effective in treating serious adenovirus disease. The rapid detection of adenovirus antigen in nasopharygeal specimens proved to have a great clinical value in the diagnosis.

[Role of viral infections and Chlamydia pneumoniae and Mycoplasma pneumoniae infections in asthma in infants and young children. Epidemiologic study of 118 children]. / Rôle des infections virales et des infections à Chlamydia pneumoniae et à Mycoplasma pneumoniae au cours de l'asthme du nourrisson et du jeune enfant. A propos d'une étude épidémiologique chez 118 enfants.

Wheezing associated with upper respiratory tract infections is common in children. Using conventional techniques (viral culture and immunofluorescence) and molecular techniques (PCR), we studied the prevalence of viral, Chlamydia pneumoniae (CP) and Mycoplasma pneumoniae (MP) infections in 118 children hospitalised for acute asthma exacerbation. A virus was identified by conventional techniques in 40 of the 118 nasal swabs (34%), while PCR allowed identification of virus CP and MP in 80 samples (68%). Combination of both techniques allowed identification of an infectious agent in 91 cases (77%). More than one agent was isolated in 15 cases (23%). Rhinovirus (RV) (45%) were prevalent, followed by respiratory syncytial virus (RSV) (28%) and enterovirus (8.5%). RV and RSV have a similar prevalence (42% and 36% respectively) before two years of age, as compared with 66% and 27% respectively in older children. CP and MP were identified by PCR in only 6 cases. Molecular techniques of identification demonstrated a clear advantage in sensitivity compared with conventional techniques. The high prevalence of RV and RSV infections is remarkable, while CP and MP do not seem particularly involved in children acute asthma exacerbation.

Long-term prognosis of patients treated for erythema migrans in France.

BACKGROUND: The long-term prognosis of patients treated for erythema migrans has only rarely been assessed. OBJECTIVES: To evaluate the clinical characteristics and long-term prognosis of patients treated for erythema migrans in the region of Alsace, France. METHODS: In a prospective study, 56 consecutive patients presenting with erythema migrans at the Strasbourg University Hospital between 1995 and 1999 were examined and a Borrelia burgdorferi enzyme immunoassay was performed. Patients were treated with tetracyclines or amoxycillin. Patients were re-examined 6 weeks later and a telephone interview was performed in summer 2000 to evaluate the long-term outcome. RESULTS: There were 25 women and 31 men of mean age 49 years presenting with single (n = 54) or multiple (n = 2) erythema migrans lesions. At the time of diagnosis, 30% of the patients had systemic signs, myalgias or arthralgias and only 36% of 50 patients were seroreactive against B. burgdorferi. None of the 51 patients evaluated at 6 weeks and none of the 37 patients interviewed after a median delay of 3 years had developed complications attributable to Lyme borreliosis. CONCLUSIONS: The prognosis of patients treated for Lyme borreliosis in this part of France is excellent. Therefore, a complete clinical examination is sufficient as an initial evaluation and long-term follow-up is not necessary.