Attosecond physics at the nanoscale

Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds (1 attosecond  =  1 as  =  10^-18 s), which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is  ∼152 as. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this report on progress we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metallic and dielectric nanostructures. In particular we elucidate how the spatially inhomogeneous laser induced fields at a nanometer scale modify the laser-driven electron dynamics. Consequently, this has important impact on pivotal processes such as above-threshold ionization and high-order harmonic generation. The deep understanding of the coupled dynamics between these spatially inhomogeneous fields and matter configures a promising way to new avenues of research and applications. Thanks to the maturity that attosecond physics has reached, together with the tremendous advance in material engineering and manipulation techniques, the age of atto-nanophysics has begun, but it is in the initial stage. We present thus some of the open questions, challenges and prospects for experimental confirmation of theoretical predictions, as well as experiments aimed at characterizing the induced fields and the unique electron dynamics initiated by them with high temporal and spatial resolution.

Highly Carboxylated Cellulose Nanofibers via Succinic Anhydride Esterification of Wheat Fibers and Facile Mechanical Disintegration

We report herein the preparation of 4-6 nm wide carboxyl-functionalized cellulose nanofibers (CNF) via the esterification of wheat fibers with cyclic anhydrides (maleic, phtalic, and succinic) followed by an energy-efficient mechanical disintegration process. Remarkable results were achieved via succinic anhydride esterification that enabled CNF isolation by a single pass through the microfluidizer yielding a transparent and thick gel. These CNF carry the highest content of carboxyl groups ever reported for native cellulose nanofibers (3.8 mmol g^-1). Compared to conventional carboxylated cellulose nanofibers prepared via Tempo-mediated oxidation of wheat fibers, the present esterified CNF display a higher molar-mass and a better thermal stability. Moreover, highly carboxylated CNF from succinic anhydride esterification were effectively integrated into paper filters for the removal of lead from aqueous solution and are potentially of interest as carrier of active molecules or as transparent films for packaging, biomedical or electronic applications.

[Expert recommendations: Hepatitis C and transplantation]

With the approval of new direct acting antiviral agents (DAA), therapeutic options for patients with chronic hepatitis C virus (HCV) infection are now generally available before and after liver transplantation (LT). Interferon-free DAA regimens are highly effective therapies and provide a good safety profile. However, the body of clinical evidence in this patient population is limited and the best treatment strategies for patients on the waiting list with (de)compensated cirrhosis and after LT are not well defined. The following recommendations for antiviral therapy in the context of LT are based on the currently available literature and clinical experience of experts in the field, and have been discussed in an expert meeting. The aim of this article is to guide clinicians in the decision making when treating patients before and after LT with DAAs.

Design of a hierarchically structured hybrid material via in situ assembly of a silica aerogel into a wood cellular structure

We present a route for incorporation of silica aerogel into wood cellular structure. Modification results in an improved dimensional stability and reduced water retention of the material, with lower thermal conductivity and total heat of combustion.

Rhinovirus inhibits IL-17A and the downstream immune responses in allergic asthma

The proinflammatory cytokine interleukin-17A (IL-17A) is known to mediate antimicrobial activity, but its role during rhinovirus (RV) infections and in asthma needs further investigation. Therefore, we addressed the role of IL-17A during allergic asthma and antiviral immune response in human and murine immunocompetent cells. In this study we found that asthmatic children with a RV infection in their upper airways have upregulated mRNA levels of the antiviral cytokine interferon type I (IFN)-β and the transcription factor T-box 21 (TBX21) and reduced levels of IL-17A protein in their peripheral blood mononuclear cells (PBMCs). We also found that IL-17A inhibited RV1b replication in infected human lung epithelial cells A549. Furthermore, by using gene array analysis we discovered that targeted deletion of Il17a in murine lung CD4(+) T cells impaired Oas1g mRNA downstream of Ifnβ, independently from RV infection. Additionally, in PBMCs of children with a RV infection in their nasalpharyngeal fluid OAS1 gene expression was found downregulated. Finally RV1b inhibited IL-17A production in lung CD4(+) T cells in a setting of experimental asthma. These results indicate that the RV1b inhibits IL-17A in T helper type 17 cells and IL-17A clears RV1b infection in epithelial cells. In both cases IL-17A contributes to fend off RV1b infection by inducing genes downstream of interferon type I pathway.

Humic acid adsorption onto cationic cellulose nanofibers for bioinspired removal of copper(II) and a positively charged dye

Waste pulp residues are herein exploited for the synthesis of a sorbent for humic acid (HA), which is a major water pollutant. Cellulose pulp was etherified with a quaternary ammonium salt in water thereby introducing positive charges onto the surface of the pulp fibers, and subsequently mechanically disintegrated into high surface area cellulose nanofibers (CNF). CNF with three different charge contents were produced and their adsorption capacity towards HA was investigated with UV-spectrophotometry, quartz crystal microbalance with dissipation, and ζ-potential measurements. Substantial coverage of the CNF surface with HA in a wide pH range led to a reversal of the positive ζ-potentials of CNF suspensions. The HA adsorption capacity and the kinetics of HA uptake were found to be promoted by both acidic pH conditions and the surface charge content of CNF. It is suggested that HA adsorption onto CNF depends on electrostatic interactions between the two components, as well as on the conformation of HA. At pH ∼ 6, up to 310 mg g(-1) of HA were adsorbed by the functionalized CNF, a substantially higher capacity than that of previously reported HA sorbents in the literature. It is further shown that CNF-HA complexes could be freeze-dried into "soil-mimicking" porous foams having good capacity to capture Cu(II) ions and positive dyes from contaminated water. Thus, the most abundant natural polymer, i.e., cellulose could effectively bind the most abundant natural organic matter for environmental remediation purpose.

New onset of diabetes after transplantation is associated with improved patient survival after liver transplantation due to confounding factor

BACKGROUND

The influence of NODAT on survival of liver transplant recipients has not been clarified. Therefore, we evaluated the effect of NODAT on survival in LT recipients.

METHODS

Data from 352 LT patients were totally analyzed. 97 patients with pretransplant diabetes mellitus were excluded, and 255 patients without diabetes mellitus at time of transplantation were included.

RESULTS

NODAT was diagnosed in 41 patients (16.1%). There was no difference in frequency of NODAT according to the etiology of liver cirrhosis. NODAT was associated with a higher body weight (p=0.004) and BMI (p=0.002) 5years after LT, but not with weight gain (p=0.201) or increase in BMI (p=0.335) 5years after LT. HbA1c 5years after LT was significantly higher in patients with NODAT (p=0.001), but mean HbA1c still remained lower than 6.5% (6.4(±1.2) %). Patients with NODAT showed better survival rates (log rank: p=0.002) compared to LT recipients without diabetes. According to all existing knowledge of diabetes mellitus (DM) better survival cannot be a direct effect of this disease. Our results are rather influenced by an not known confounding factor (possibly recovery from cachexia) associated with better survival and NODAT, while complications of NODAT will not appear during the relatively short postoperative time and observation period (mean follow up 6.08 (±2.67) years).

CONCLUSION

NODAT is frequently diagnosed in LT recipients and is associated with an improved 5year survival after LT due to a not exactly known confounding factor.

Carrier-wave Rabi-flopping signatures in high-order harmonic generation for alkali atoms

We present a theoretical investigation of carrier-wave Rabi flopping in real atoms by employing numerical simulations of high-order harmonic generation (HHG) in alkali species. Given the short HHG cutoff, related to the low saturation intensity, we concentrate on the features of the third harmonic of sodium (Na) and potassium (K) atoms. For pulse areas of 2π and Na atoms, a characteristic unique peak appears, which, after analyzing the ground state population, we correlate with the conventional Rabi flopping. On the other hand, for larger pulse areas, carrier-wave Rabi flopping occurs, and is associated with a more complex structure in the third harmonic. These characteristics observed in K atoms indicate the breakdown of the area theorem, as was already demonstrated under similar circumstances in narrow band gap semiconductors.

ASTRAL: genome-scale coalescent-based species tree estimation

MOTIVATION

Species trees provide insight into basic biology, including the mechanisms of evolution and how it modifies biomolecular function and structure, biodiversity and co-evolution between genes and species. Yet, gene trees often differ from species trees, creating challenges to species tree estimation. One of the most frequent causes for conflicting topologies between gene trees and species trees is incomplete lineage sorting (ILS), which is modelled by the multi-species coalescent. While many methods have been developed to estimate species trees from multiple genes, some which have statistical guarantees under the multi-species coalescent model, existing methods are too computationally intensive for use with genome-scale analyses or have been shown to have poor accuracy under some realistic conditions.

RESULTS

We present ASTRAL, a fast method for estimating species trees from multiple genes. ASTRAL is statistically consistent, can run on datasets with thousands of genes and has outstanding accuracy-improving on MP-EST and the population tree from BUCKy, two statistically consistent leading coalescent-based methods. ASTRAL is often more accurate than concatenation using maximum likelihood, except when ILS levels are low or there are too few gene trees.

AVAILABILITY AND IMPLEMENTATION

ASTRAL is available in open source form at https://github.com/smirarab/ASTRAL/. Datasets studied in this article are available at http://www.cs.utexas.edu/users/phylo/datasets/astral.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

[Etiology and complications of liver cirrhosis: data from a German centre]

BACKGROUND

Liver cirrhosis develops as a terminal complication of chronic liver disease. The clinical course is determined by the underlying etiology and the accompanying risk factors, which are influenced by the geographic and cultural background.

METHODS

A total of 236 patients (159 men, 77 women, median age 57 [22-81] years) were included for retrospective analysis between July 2012 and February 2014 using standardized questionnaires during an outpatient visit at a hepatology clinic.

RESULTS

The most common etiologies of liver cirrhosis were related to alcohol consumption (52 %), chronic hepatitis C (28 %) or hepatitis B (14 %) infection and NASH (nonalcoholic steatohepatitis, 6 %). At the time of presentation 55 % patients had compensated cirrhosis corresponding to Child-Turcotte-Pugh (CTP) stage A, while 45 % were in a decompensated stage (30 % CTP B and 15 % CTP C). Subgroups were analyzed for the incidence of complications and the emergence of infections. Most frequently esophageal varices (60 %) and ascites (49 %) were observed, followed by pleural effusion (14 %), hepatic encephalopathy (25 %) or hepatorenal syndrome (18 %). 16 % of patients exhibited infection based on clinical criteria. An infective agent was isolated in 38 % of all cases with infection and of those 50 % were gram positive bacteria. In multivariate analysis only the presence of ascites was an independent risk factor for infection.

CONCLUSION

Despite improved medical therapies for viral hepatitis, these were the most frequent causes of liver cirrhosis, closely followed by alcoholic cirrhosis. The observed complications included bacterial infection and complication related to portal hypertension.

Tacrolimus effects and side effects after liver transplantation: is there a difference between immediate and extended release?

BACKGROUND

Immunosuppressive therapy after orthotopic liver transplantation (OLT) requires a high degree of patient compliance to guarantee safety and avoid side effects. In 2007, prolonged-release tacrolimus was launched in Europe to improve compliance. In this prospective observational crossover single-center trial, we analyzed effects and side effects of prolonged-release tacrolimus in OLT patients.

METHODS

LT patients at our center were included if they were older than l8 years of age, had had the procedure at least 6 months prior, and were outpatients currently on twice-daily tacrolimus. Patients were observed for 6 months before switching to once-daily tacrolimus. Patient history, clinical examination, and laboratory examinations were recorded on inclusion as well as after 3, 6, 9, 12, and 18 months.

RESULTS

The rates of rejection, hypertension, hypercholesterolemia, and diabetes mellitus were compared during twice-daily and once-daily tacrolimus. Similarly, laboratory parameters were identical during both periods with the exception of glycated hemoglobin, which was significantly elevated under once-daily tacrolimus (P = .00l).

CONCLUSION

Converting patients to extended-release tacrolimus with was safe in terms of rejection, hypertension, and hypercholesterolemia as well as renal and liver functions. Further investigations concerning pharmacokinetics and glucose metabolism will be needed to evaluate prolonged-release tacrolimus.

[Potentially inappropriate medication in elderly primary care patients : A retrospective, longitudinal analysis]

BACKGROUND

Elderly people are often burdened by several diseases. This accounts for a higher medication intake and increases the risk of adverse drug events. To minimize this risk, several lists (Beers, PRISCUS) have been published of drugs that elderly patients should not take. We present a longitudinal analysis of the use of potentially inappropriate medication (PIM) over a period 4.5 years in a cohort of patients aged 75 years or more.

METHODS

Data were collected from the prospective, multicenter, observational study "German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe)," initially enrolling 3,327 patients. We investigated the prevalence of PIM by checking medications during visits to patients' homes. Furthermore, we analyzed the use of individual PIM agents over time.

RESULTS

At baseline, we found a PIM prevalence of 29 % according to the PRISCUS list, which decreased to 25.0 % 4.5 years later (χ(2): 7.87, p = 0.004). The Beers list yielded a prevalence of 21 % at baseline, decreasing after 4.5 years to 17.1 % (χ(2): 10.77, p = 0.000). A time-dependent multilevel model confirmed these results. Older age, depression, and the use of numerous prescribed agents are independent risk factors for using a PRISCUS-PIM.

CONCLUSION

Our results seem to support a trend toward a more rational drug therapy because fewer patients were prescribed PIM. Thus, for the individual patient, the risk of adverse effects and side effects is reduced as are the costs of these effects.

Preoperative left ventricular hypertrophy is associated with reduced patient survival after liver transplantation

Left ventricular hypertrophy (LVH) has been described in the context of cirrhotic cardiomyopathy. The influence of LVH on survival of liver transplant (LT) recipients has not been clarified. Therefore, we evaluated the effect of LVH on survival in LT recipients. In total, data from 352 LT patients were analyzed. LVH was diagnosed by echocardiographic measurement of left ventricular wall thickness before LT. Patients were followed up for a mean of 4.2 yr. LVH was diagnosed in 135 (38.4%) patients. Patients with LVH had significantly more frequently male gender (p = 0.046), diastolic dysfunction (p < 0.001), and hepatocellular carcinoma (HCC; p = 0.004). Furthermore, LVH patients were older (p < 0.001) and had a higher body mass index (BMI; p = 0.001). There was no difference in frequency of arterial hypertension, pre-transplant diabetes mellitus, or etiology of liver cirrhosis. Patients without LVH had a better survival (log rank: p = 0.05) compared with LVH patients. In a multivariate Cox regression LVH (p = 0.031), end-stage renal disease (ESRD; p = 0.003) and lack of arterial hypertension (p = 0.004) but not MELD score (p = 0.885) were associated with poorer survival.

CONCLUSION

LVH is frequently diagnosed in patients on the waiting list and influences survival after LT.

Diabetic liver injury from streptozotocin is regulated through the caspase-8 homolog cFLIP involving activation of JNK2 and intrahepatic immunocompetent cells

The endemic occurrence of obesity and the associated risk factors that constitute the metabolic syndrome have been predicted to lead to a dramatic increase in chronic liver disease. Non-alcoholic steatohepatitis (NASH) has become the most frequent liver disease in countries with a high prevalence of obesity. In addition, hepatic steatosis and insulin resistance have been implicated in disease progression of other liver diseases, including chronic viral hepatitis and hepatocellular carcinoma. The molecular mechanisms underlying the link between insulin signaling and hepatocellular injury are only partly understood. We have explored the role of the antiapoptotic caspase-8 homolog cellular FLICE-inhibitory protein (cFLIP) on liver cell survival in a diabetic model with hypoinsulinemic diabetes in order to delineate the role of insulin signaling on hepatocellular survival. cFLIP regulates cellular injury from apoptosis signaling pathways, and loss of cFLIP was previously shown to promote injury from activated TNF and CD95/Apo-1 receptors. In mice lacking cFLIP in hepatocytes (flip^−/−), loss of insulin following streptozotocin treatment resulted in caspase- and c-Jun N-terminal kinase (JNK)-dependent liver injury after 21 days. Substitution of insulin, inhibition of JNK using the SP600125 compound in vivo or genetic deletion of the mitogen-activated protein kinase (MAPK)9 (JNK2) in all tissues abolished the injurious effect. Strikingly, the difference in injury between wild-type and cFLIP-deficient mice occurred only in vivo and was accompanied by liver-infiltrating inflammatory cells with a trend toward increased amounts of NK1.1-positive cells and secretion of proinflammatory cytokines. Transfer of bone marrow from rag-1-deficient mice that are depleted from B and T lymphocytes prevented liver injury in flip^−/− mice. These findings support a direct role of insulin on cellular survival by alternating the activation of injurious MAPK, caspases and the recruitment of inflammatory cells to the liver. Thus, increasing resistance to insulin signaling pathways in hepatocytes appears to be an important factor in the initiation and progression of chronic liver disease.

Intraoperative chemiluminometric assay for simplified localization of parathyroid adenomas during surgery for primary hyperparathyroidism

Hyperparathyroidism is no longer considered an uncommon endocrinopathy. Between 1994 and 2002, 138 patients underwent neck exploration for primary hyperparathyroidism at the Department for Surgery in the University Hospital of Dresden. Common reasons for operation failure are usually hyperplasia or remnant parathyroid tissue, inadequate parathyroidectomy at initial operation or the occurrence of abnormal hyperfunctioning supernumerary glands. To reduce the operation time, as well as the failure rate that accompanies the incomplete excision of hypersecreting parathyroid tissue, we perform an intraoperative monitoring of parathyroid hormone with an immunochemiluminometric assay (Nichols Advantagetrade mark Intact PTH). With modification of this assay, it was possible to perform the assay in the operating theatre and to attain the hormone values within 10 min. In all cases of successful operation with excision of the adenomatous parathyroid gland the PTH values declined to under 20 percent of the initial intraoperative PTH values. Our results declare the intraoperative parathyroid hormone monitoring as a cost-effective method to control the effect of surgical treatment.

[Congenital disorders of the lungs and airways--survey of cases at the Paediatric Hospital Erlangen in the period 2000 to 2011]

BACKGROUND

Congenital malformations of the lungs are rare, but might limit the quality of life of the patient. With the increased possibilities of diagnostic and therapeutic procedures during the last decades, these diseases can be recognised and successfully treated earlier than before. The aim of this article is to give an overview about the congenital malformations of the lungs in children who have been treated at the Kinderklinik Erlangen during the years 2000 and 2011. Clinical symptoms of the disease and associated malformations, diagnostic and therapeutic procedures were discussed.

METHODS

The analysis was done retrospectively (January 1st 2000-April 15th 2011) on the basis of the patients records. Patients who had been treated only at the outpatient clinic were not considered. All patients' data were listed according to the ICD code.

RESULTS

121 children were treated because of a congenital malformation of the lungs in the years between 2000 and 2011 in Erlangen. 68.6 % (n = 83) were males and 31.45 % (n = 38) were females. Nearly all of the malformations of the lungs were associated with other abnormalities. Most of the children also suffered from at least one cardiac defect. 28 of the 121 children had more than one malformation of the lungs. The diagnostic and therapeutic interventions correlated with the published recommendations.

CONCLUSIONS

The analysis of the patients' data used in this study indicate the importance of the early diagnosis and treatment. The cooperation of different medical disciplines is mandatory for a good outcome of those children.