Constructing cropland ecological stability assessment method based on disturbance-resistance-response processes and classifying cropland ecological types

The cropland ecosystem stability (CES) has received increasing attention, especially in ecologically fragile areas, because of its impact on cropland quality, agricultural production and its ability to resist external disturbances. In this study, we first introduced the concepts of resilience and resistance, proposed the ecosystem disturbance-resistance-response process, and established a framework for evaluating the spatial and temporal dynamics of the CES based on RS data, and innovatively combined the RS assessment results of CES with soil field samples data to further classify cropland ecological types (CET) in a key agricultural areas of the Qinghai-Tibetan Plateau, which can effectively identify those croplands in need of priority ecological protection. Results indicate that the combined interactions of disturbance, resistance and response systems affect CES, forming a complex process with significant fluctuations and spatial variations. We also conclude that the disturbance system is positively influenced by topography and precipitation, while slope negatively affects resistance system. Hydrothermal conditions positively influence resistance system, while the response system is influenced by environmental factors at a lower intensity in six periods. It was interesting to note that soil α-biodiversity indicators are significantly and positively correlated with CES at the end of the study period. Therefore, based on the CES assessment results, we further combined the soil α-biodiversity indicators to classify the type of spatial pattern of CET and found that the eastern and northern areas have better quality, which implied an increase in the CES and a higher level of soil biodiversity, which was ideal for cropland expansion. On the contrary, we concluded that the ecosystem maintenance of the Huangshui headwaters and the northern mountainous areas needs to be strengthened in order to reverse the ecological fragility here and safeguard the cropland productive capacity.

Lightweight Potential of Anisotropic Plate Lattice Metamaterials

Additive manufacturing enables the production of lattice structures, which have been proven to be a superior class of lightweight mechanical metamaterials whose specific stiffness can reach the theoretical limit of the upper Hashin-Shtrikman bound for isotropic cellular materials. To achieve isotropy, complex structures are required, which can be challenging in powder bed additive manufacturing, especially with regard to subsequent powder removal. The present study focuses on the Finite Element Method simulation of 2.5D anisotropic plate lattice metamaterials and the investigation of their lightweight potential. The intentional use of anisotropic structures allows the production of a cell architecture that is easily manufacturable via Laser Powder Bed Fusion (LPBF) while also enabling straightforward optimization for specific load cases. The work demonstrates that the considered anisotropic plate lattices exhibit high weight-specific stiffnesses, superior to those of honeycomb structures, and, simultaneously, a good de-powdering capability. A significant increase in stiffness and the associated surpassing of the upper Hashin-Shtrikman bound due to anisotropy is achievable by optimizing wall thicknesses depending on specific load cases. A stability analysis reveals that, in all lattice structures, plastic deformation is initiated before linear buckling occurs. An analysis of stress concentrations indicates that the introduction of radii at the plate intersections reduces stress peaks and simultaneously increases the weight-specific stiffnesses and thus the lightweight potential. Exemplary samples illustrate the feasibility of manufacturing the analyzed metamaterials within the LPBF process.

Increasing protein identifications in bottom-up proteomics of T. castaneum - Exploiting synergies of protein biochemistry and bioinformatics

Depending on the respective research question, LC-MS/MS based bottom-up proteomics poses challenges from the initial biological sample all the way to data evaluation. The focus of this study was to investigate the influence of sample preparation techniques and data analysis parameters on protein identification in Tribolium castaneum by applying free software proteomics platform Max Quant. Multidimensional protein extraction strategies in combination with electrophoretic or chromatographic off-line protein pre-fractionation were applied to enhance the spectrum of isolated proteins from T. castaneum and reduce the effect of co-elution and ion suppression effects during nano-LC-MS/MS measurements of peptides. For comprehensive data analysis, MaxQuant was used for protein identification and R for data evaluation. A wide range of parameters were evaluated to gain reproducible, reliable, and significant protein identifications. A simple phosphate buffer, pH 8, containing protease and phosphatase inhibitor cocktail and application of gentle extraction conditions were used as a first extraction step for T.castaneum proteins. Furthermore, a two-dimensional extraction procedure in combination with electrophoretic pre-fractionation of extracted proteins and subsequent in-gel digest resulted in almost 100% increase of identified proteins when compared to chromatographic fractionation as well as one-pot-analysis. The additionally identified proteins could be assigned to new molecular functions or cell compartments, emphasizing the positive effect of extended sample preparation in bottom-up proteomics. Besides the number of peptides during post-processing, MaxQuant's Match between Runs exhibited a crucial effect on the number of identified proteins. A maximum relative standard deviation of 2% must be considered for the data analysis. Our work with Tribolium castaneum larvae demonstrates that sometimes - depending on matrix and research question - more complex and time-consuming sample preparation can be advantageous for isolation and identification of additional proteins in bottom-up proteomics.

Active and passive microrheology with large tracers in hard colloids

The dynamics of a tracer particle in a bath of quasi-hard colloidal spheres is studied by Langevin dynamics simulations and mode coupling theory (MCT); the tracer radius is varied from equal to up to seven times larger than the bath particles radius. In the simulations, two cases are considered: freely diffusing tracer (passive microrheology) and tracer pulled with a constant force (active microrheology). Both cases are connected by linear response theory for all tracer sizes. It links both the stationary and transient regimes of the pulled tracer (for low forces) with the equilibrium correlation functions; the velocity of the pulled tracer and its displacement are obtained from the velocity auto-correlation function and the mean squared displacement, respectively. The MCT calculations give insight into the physical mechanisms: At short times, the tracer rattles in its cage of neighbours, with the frequency increasing linearly with the tracer radius asymptotically. The long-time tracer diffusion coefficient from passive microrheology, which agrees with the inverse friction coefficient from the active case, arises from the transport of transverse momentum around the tracer. It can be described with the Brinkman equation for the transverse flow field obtained in extension of MCT, but cannot be recovered from the MCT kernel coupling to densities only. The dynamics of the bath particles is also studied; for the unforced tracer the dynamics is unaffected. When the tracer is pulled, the velocity field in the bath follows the prediction of the Brinkman model, but different from the case of a Newtonian fluid.

Deepfake smiles matter less-the psychological and neural impact of presumed AI-generated faces

High-quality AI-generated portraits ("deepfakes") are becoming increasingly prevalent. Understanding the responses they evoke in perceivers is crucial in assessing their societal implications. Here we investigate the impact of the belief that depicted persons are real or deepfakes on psychological and neural measures of human face perception. Using EEG, we tracked participants' (N = 30) brain responses to real faces showing positive, neutral, and negative expressions, after being informed that they are either real or fake. Smiling faces marked as fake appeared less positive, as reflected in expression ratings, and induced slower evaluations. Whereas presumed real smiles elicited canonical emotion effects with differences relative to neutral faces in the P1 and N170 components (markers of early visual perception) and in the EPN component (indicative of reflexive emotional processing), presumed deepfake smiles showed none of these effects. Additionally, only smiles presumed as fake showed enhanced LPP activity compared to neutral faces, suggesting more effortful evaluation. Negative expressions induced typical emotion effects, whether considered real or fake. Our findings demonstrate a dampening effect on perceptual, emotional, and evaluative processing of presumed deepfake smiles, but not angry expressions, adding new specificity to the debate on the societal impact of AI-generated content.

Shorter Is Better: The α-(l)-Threofuranosyl Nucleic Acid Modification Improves Stability, Potency, Safety, and Ago2 Binding and Mitigates Off-Target Effects of Small Interfering RNAs

Chemical modifications are necessary to ensure the metabolic stability and efficacy of oligonucleotide-based therapeutics. Here, we describe analyses of the α-(l)-threofuranosyl nucleic acid (TNA) modification, which has a shorter 3'-2' internucleotide linkage than the natural DNA and RNA, in the context of small interfering RNAs (siRNAs). The TNA modification enhanced nuclease resistance more than 2'-O-methyl or 2'-fluoro ribose modifications. TNA-containing siRNAs were prepared as triantennary N-acetylgalactosamine conjugates and were tested in cultured cells and mice. With the exceptions of position 2 of the antisense strand and position 11 of the sense strand, the TNA modification did not inhibit the activity of the RNA interference machinery. In a rat toxicology study, TNA placed at position 7 of the antisense strand of the siRNA mitigated off-target effects, likely due to the decrease in the thermodynamic binding affinity relative to the 2'-O-methyl residue. Analysis of the crystal structure of an RNA octamer with a single TNA on each strand showed that the tetrose sugar adopts a C4'-exo pucker. Computational models of siRNA antisense strands containing TNA bound to Argonaute 2 suggest that TNA is well accommodated in the region kinked by the enzyme. The combined data indicate that the TNA nucleotides are promising modifications expected to increase the potency, duration of action, and safety of siRNAs.

[Effect of low-dose PDT on perfusion of the choriocapillaris in cCSCR : An OCT-angiography-based study]

BACKGROUND

In patients with chronic central serous chorioretinopathy (cCSCR) it is assumed that low-dose photodynamic therapy (PDT) induces short-term hypoperfusion of the choriocapillaris, which leads to long-term choroidal vascular remodeling and subsequent reduction of vascular hyperpermeability and leakage; however, it remains unclear whether the hypoperfusion completely returns to normal. The main aim of the retrospective study was to analyze the choroidal flow signal after treatment with low-dose PDT by optical coherence tomography-angiography (OCT‑A).

PATIENTS AND METHODS

In this study 16 eyes with a total of 19 treated areas were included. Aside from visual acuity and metamorphopsia checks, all patients underwent enhanced depth imaging-OCT (EDI-OCT) and OCT‑A in the areas treated with low-dose PDT. In the present study, the flow signal in the choriocapillaris and choroidal thickness were measured retrospectively both in the PDT-treated area and in a non-treated reference area located in close proximity with similar eccentricity to the center of the fovea.

RESULTS

The study found a mean reduction of 33% (p < 0.001) of the choroidal flow signal in the treated area compared to the reference area and an average decrease in choroidal thickness of 71 µm (p = 0.001). In the long term 7 out of 10 patients suffered from metamorphopsia despite the low-dose PDT; however, visual acuity was improved in almost half of the patients by the treatment.

CONCLUSION

Using OCT‑A it could be shown that at the choriocapillaris level, hypoperfusion persists in spite of low-dose PDT. Thus, the choroidal vascular remodeling is not able to completely compensate for the hypoperfusion induced by thrombosis.

Lorentz resonance in the homogenization of plasmonic crystals

We explain the Lorentz resonances in plasmonic crystals that consist of two-dimensional nano-dielectric inclusions as the interaction between resonant material properties and geometric resonances of electrostatic nature. One example of such plasmonic crystals are graphene nanosheets that are periodically arranged within a non-magnetic bulk dielectric. We identify local geometric resonances on the length scale of the small-scale period. From a materials perspective, the graphene surface exhibits a dispersive surface conductance captured by the Drude model. Together these phenomena conspire to generate Lorentz resonances at frequencies controlled by the surface geometry and the surface conductance. The Lorentz resonances found in the frequency response of the effective dielectric tensor of the bulk metamaterial are shown to be given by an explicit formula, in which material properties and geometric resonances are decoupled. This formula is rigorous and obtained directly from corrector fields describing local electrostatic fields inside the heterogeneous structure. Our analytical findings can serve as an efficient computational tool to describe the general frequency dependence of periodic optical devices. As a concrete example, we investigate two prototypical geometries composed of nanotubes and nanoribbons.

The Nonclinical Disposition and PK/PD Properties of GalNAc-conjugated siRNA Are Highly Predictable and Build Confidence in Translation to Man

Conjugation of oligonucleotide therapeutics, including small interfering ribonucleic acids (siRNAs) or antisense oligonucleotides (ASOs) to N-acetylgalactosamine (GalNAc) ligands has become the primary strategy for hepatocyte-targeted delivery, and with the recent approvals of GIVLAARI® (givosiran) for the treatment of acute hepatic porphyria, OXLUMO^TM (lumasiran) for the treatment of primary hyperoxaluria, and Leqvio® (inclisiran) for the treatment of hypercholesterolemia, the technology has been well-validated clinically. While much knowledge has been gained over decades of development there is a paucity of published literature on the DMPK properties of GalNAc-siRNA. With this in mind the goals of this mini-review are to provide an aggregate analysis of these nonclinical ADME data to build confidence on the translation of these properties to human. Upon subcutaneous administration, GalNAc-conjugated siRNAs are quickly distributed to the liver, resulting in plasma pharmacokinetic (PK) properties that reflect rapid elimination through ASGPR-mediated uptake from circulation into hepatocytes. These studies confirm that liver PK, including half-life and, most importantly, siRNA levels in RNA-induced silencing complex (RISC) in hepatocytes are better predictors of pharmacodynamics (PD) than plasma PK. Several in vitro and in vivo nonclinical studies were conducted to characterize the absorption, distribution, metabolism and excretion (ADME) properties of GalNAc-conjugated siRNAs. These studies demonstrate that the PK/PD and ADME properties of GalNAc-conjugated siRNAs are highly conserved across species, largely predictable, and can be accurately scaled to human, allowing us to identify efficacious and safe clinical dosing regimens in the absence of human liver PK profiles. Significance Statement Several nonclinical ADME studies have been conducted in order to provide a comprehensive overview of the disposition and elimination of GalNAc-conjugated siRNAs and the PK/PD translation between species. These studies demonstrate that the ADME properties of GalNAc-conjugated siRNAs are well correlated and predictable across species building confidence in the ability to extrapolate to human.

Digging into the roots: understanding direct and indirect drivers of ecosystem service trade-offs in coastal grasslands via plant functional traits

Recent empirical and theoretical approaches have called for an understanding of the processes underpinning ecosystem service provision. Environmental gradients have shown effects on key plant functional traits that subsequently explain ecosystem properties of several systems. However, little is known concerning how associations between plant functional traits, including both below- and aboveground plant components, predict ecosystem properties and independently measured final ecosystem services. Here, we modeled (1) the responses of the leaf and plant economics spectrum, Plant size axis, and root growth to environmental gradients and (2) how associations between plant functional traits explain trade-offs and synergies between multiple ecosystem properties and final services. Forty-four plots were studied in a coastal marsh landscape of the German North Sea Coast. We used a partial least square structural equation model approach to test the hypothesized model. We found (1) a negative covariation between plant traits pertaining to a size axis and traits explaining both plant growth (roots and stems) and the leaf economics spectrum; (2) this trade-off responded significantly to the land use gradient and nutrient availability, which were both strongly driven by the groundwater gradient; (3) this trade-off explained an initial major trade-off between carbon stocks, at one extreme of the axis, and both the habitat value to conserve endangered plants and forage production for meat and dairy products at the other extreme. However, a secondary trade-off between nature conservation value and forage production, explained by a trade-off between leaf economics spectrum and plant growth in response to the land use intensity gradient, was also found.

[MEK inhibitor-associated retinopathy under binimetinib treatment for cutaneous malignant melanoma]

Die Behandlungsmöglichkeiten für Patienten mit metastasierendem Melanom (MM) wurden in den letzten Jahren mit der Zulassung von neuen Medikamenten dramatisch erweitert. Die MEK(mitogen-aktivierte Proteinkinase-Kinasen)- und BRAF(Serin/Threonin-Kinase B-Raf kodierendes Gen)-Hemmer-Kombinationstherapie gehört aktuell zum Versorgungsstandard für das Stadium IIIC/IV des BRAF-mutierten Melanoms. MEKAR (MEK-Inhibitor-assoziierte Retinopathie) werden bei Patienten mit metastasierendem Melanom beobachtet, die mit einer solchen Kombinationstherapie behandelt werden bzw. wurden. Wir berichten über den Fall eines 72-jährigen Patienten, der eine solche Pathologie unter der Therapie mit Binimetinib in Kombination mit Nivolumab erlitt. Diese Kasuistik verdeutlicht die Wichtigkeit einer interdisziplinären Zusammenarbeit bei der Behandlung von MM-Patienten.

Nutrients, bioactive compounds, and minerals in the juices of 16 varieties of apple (Malus domestica) harvested in Austria: A four-year study investigating putative correlations with weather conditions during ripening

This study was conducted to examine putative correlations between weather parameters during April-September and the amounts of nutrients, minerals and bioactive compounds in the juices of 16 apple varieties from four harvest years in Lower Austria. For most sugar-parameters, negative correlations were found with the total precipitation (r between -0.42 and -0.64). Conversely, positive correlations were observed with the mean air temperature (r between 0.32 and 0.66), the global radiation (r between 0.32 and 0.61) and the number of tropical days (r between 0.39 and 0.51). The sum of 14 polyphenols (HPLC quantitation) was positively correlated with the mean air temperature and global radiation (r_s 0.44 and 0.42). Negative correlations were observed between the global radiation and potassium, magnesium and calcium contents (correlation coefficients -0.49, -0.68 and -0.69). We conclude that increased temperatures and global radiation can be correlated with enhanced sugar synthesis and polyphenol formation.

A European multicentre evaluation of detection and typing methods for human enteroviruses and parechoviruses using RNA transcripts

Polymerase chain reaction (PCR) detection has become the gold standard for diagnosis and typing of enterovirus (EV) and human parechovirus (HPeV) infections. Its effectiveness depends critically on using the appropriate sample types and high assay sensitivity as viral loads in cerebrospinal fluid samples from meningitis and sepsis clinical presentation can be extremely low. This study evaluated the sensitivity and specificity of currently used commercial and in-house diagnostic and typing assays. Accurately quantified RNA transcript controls were distributed to 27 diagnostic and 12 reference laboratories in 17 European countries for blinded testing. Transcripts represented the four human EV species (EV-A71, echovirus 30, coxsackie A virus 21, and EV-D68), HPeV3, and specificity controls. Reported results from 48 in-house and 15 commercial assays showed 98% detection frequencies of high copy (1000 RNA copies/5 µL) transcripts. In-house assays showed significantly greater detection frequencies of the low copy (10 copies/5 µL) EV and HPeV transcripts (81% and 86%, respectively) compared with commercial assays (56%, 50%; P = 7 × 10-5 ). EV-specific PCRs showed low cross-reactivity with human rhinovirus C (3 of 42 tests) and infrequent positivity in the negative control (2 of 63 tests). Most or all high copy EV and HPeV controls were successfully typed (88%, 100%) by reference laboratories, but showed reduced effectiveness for low copy controls (41%, 67%). Stabilized RNA transcripts provide an effective, logistically simple and inexpensive reagent for evaluation of diagnostic assay performance. The study provides reassurance of the performance of the many in-house assay formats used across Europe. However, it identified often substantially reduced sensitivities of commercial assays often used as point-of-care tests.

Homogenization of plasmonic crystals: seeking the epsilon-near-zero effect

By using an asymptotic analysis and numerical simulations, we derive and investigate a system of homogenized Maxwell's equations for conducting material sheets that are periodically arranged and embedded in a heterogeneous and anisotropic dielectric host. This structure is motivated by the need to design plasmonic crystals that enable the propagation of electromagnetic waves with no phase delay (epsilon-near-zero effect). Our microscopic model incorporates the surface conductivity of the two-dimensional (2D) material of each sheet and a corresponding line charge density through a line conductivity along possible edges of the sheets. Our analysis generalizes averaging principles inherent in previous Bloch-wave approaches. We investigate physical implications of our findings. In particular, we emphasize the role of the vector-valued corrector field, which expresses microscopic modes of surface waves on the 2D material. We demonstrate how our homogenization procedure may set the foundation for computational investigations of: effective optical responses of reasonably general geometries, and complicated design problems in the plasmonics of 2D materials.

Influenza B virus infections in Western Saxony, Germany in three consecutive seasons between 2015 and 2018: Analysis of molecular and clinical features

BACKGROUND

The impact of annual influenza epidemics and prevailing strains varies worldwide and regional. The majority of vaccines used contained two influenza A strains and only one influenza B strain (trivalent vaccine).

AIM

The aim of the study was to compare laboratory confirmed influenza B cases during three consecutive years with respect to vaccination history, clinical symptoms and molecular virology.

METHODS

Partial HA gene sequences were analyzed for lineage determination and complete HA sequence in cases with reported vaccination and in fatal cases. Clinical data were retrieved from patient charts.

FINDINGS

During the 2015/16 season, 75 influenza B cases were retrieved; 11 in 2016/17, and 274 in 2017/18. The frequency of Yamagata-lineage strains increased from 7.6% to 100%. No difference was detected in the relative frequency of co-morbidities in season 2017/18. 37.7% of the adult patients and 4.5% of pediatric patients were vaccinated against influenza.

INTERPRETATION

Phylogenetically, Yamagata strains clustered similarly in 2017/2018 when compared to the previous two influenza seasons. While the relative frequency of influenza B cases differed, the clinical symptoms remained similar.

CONCLUSION

World Health Organization recommendations for the use of tetravalent vaccines that contain two influenza B strains (Yamagata and Victoria) in addition to the two influenza A strains (H1N1 and H3N2) should be implemented in national vaccination guidelines.

FUNDING

This research was partially supported by the Association of Sponsors and Friends of Leipzig University.

[Vitrectomy and iOCT-assisted inverted ILM flap technique in patients with full thickness macular holes]

BACKGROUND

In large full thickness macular holes (FTMH) the closure rate after vitrectomy and conventional internal limiting membrane (ILM) peeling is less than 90%. The aim of this study was to examine the visual acuity and anatomical success rate with high-resolution optical coherence tomography (OCT) after transconjunctival sutureless 23-gauge pars plana vitrectomy as well as intraoperative OCT (iOCT) and Brilliant Peel (BP)-assisted ILM peeling using the inverted ILM flap technique in patients with large FTMHs.

METHOD

In this retrospective study 25 eyes of 25 consecutive patients with large FTMH were treated by 23-G vitrectomy with BP and iOCT-assisted ILM peeling using the inverted ILM flap technique followed by gas tamponade. In all patients best corrected visual acuity (BCVA) and the maximum diameter, base and height of the FTMH as well as intraretinal alterations were measured preoperatively using high-resolution spectral domain OCT (SD-OCT, Spectralis, Heidelberg Engineering, Germany). The BCVA was measured after 1, 3, and 6 months. Additionally, the closure rate and the microstructural integrity of the outer retinal layers, e.g. external limiting membrane (ELM), ellipsoid zone und photoreceptor outer segment (OS) were registered in the SD-OCT and correlated with the results of BCVA after macular hole surgery.

RESULTS

In all surgical procedures with the inverted ILM flap technique the application of iOCT enabled a good visualization and a controlled positioning of the ILM flaps. At baseline mean BCVA was 0.2 (0.7 logMAR) and improved significantly after 1, 3 und 6 months to 0.4 (0.4 logMAR), 0.5 (0.3 logMAR) and 0.63 (0.2 logMAR), respectively. The closure rate of the FTMHs was 100%. Microstructural integrity of the outer retinal layers was evaluated semiquantitatively and showed good correlation with BCVA.

CONCLUSION

Vitrectomy with BP and iOCT-assisted ILM peeling using the inverted ILM flap technique in patients with large FTMH is a very controlled and safe microsurgical strategy and shows good functional and anatomical results. The morphology of the FTMH, the ILM flap and the position of the inverted ILM flap under air was well visualized by IOCT. The microstructural integrity of the outer retinal layers is displayed in detail on SD-OCT and represents an important predictive parameter for BCVA after macular hole surgery.

[Macular changes in optic disc pits-Optic disc pit maculopathy (ODP-M) : Pathophysiology and possibilities of surgical treatment]

An optic disc pit is a rare congenital abnormality of the optic nerve, which in most cases presents as a unilateral finding. Clinically, a greyish oval excavation is seen, most commonly on the temporal side of the optic nerve disc. The optic disc pit alone normally does not lead to substantial symptoms or functional limitations; however, when a maculopathy with intraretinal and/or subretinal fluid and additional other morphological changes in the macula occur, this leads to a decrease in visual acuity. With spectral domain optical coherence tomography (SDOCT) it is possible to identify the various forms of expression, which show different natural courses. Especially the presence of subretinal fluid and defects in the outer retinal layers have a poor prognosis and have the highest risk for further deterioration. Spontaneous resolution can occur but is rare. Observation is recommended in the first step. In cases of progression or pronounced deterioration, surgical intervention is indicated. Many different techniques have been proposed but there is no gold standard at the moment. Most of the surgical approaches comprise pars plana vitrectomy with peeling of the internal limiting membrane (ILM) and gas endotamponade. Newer methods, such as the ILM flap technique also show good results. Generally, it is important to know that postoperative healing and resorption of the fluid often take a long time period of up to 1 year or even longer.

[Morphology of the vitreoretinal interface in fellow eyes of patients with full thickness macular holes]

PURPOSE

We performed a retrospective, observational clinical study to evaluate the vitreoretinal interface (VRI) in fellow eyes of patients with full thickness macular holes (FTMH) based on spectral domain optical coherence tomography (SD-OCT) examinations.

METHODS

The VRI in fellow eyes of 38 patients with idiopathic FTMH, 6 of which had concomitant vitreomacular traction (VMT) and the VRI of 32 patients with FTMH with complete resolution of VMT were examined by SD-OCT for the presence of vitreomacular adhesion (VMA), VMT and the formation of FTMH, lamellar macular holes (LMH), macular pseudoholes (MPH) or epiretinal membranes (ERM). Patients underwent complete ophthalmic evaluation, including SD-OCT at baseline and follow-up visits. To classify the morphology of the VRI, we used the international vitreomacular traction study classification system by Duker et al. (Ophthalmology 2013), evaluating the baseline SD-OCT data for significant classification parameters, including size of VMA, macular thickness and volume and structural changes of retinal layers.

RESULTS

Of the 38 eyes with FTMH, 2 (5.3%) fellow eyes also showed evidence of FTMH, 5 (13.2%) had isolated VMT while 5 (13.2%) showed formation of ERM, of which 2 demonstrated MPH. In 5 patients (13.2%) showing evidence of VMA and 17 patients (44.7%) with an unremarkable VRI, 22 fellow eyes (57.9%) showed no pathological morphology. Altogether, 16 fellow eyes (42.1%) of patients with FTMH showed pathological changes of the vitreoretinal interface.

CONCLUSION

This high-resolution SD-OCT-based retrospective study showed that fellow eyes of patients with VMT or FTMH were at increased risk of demonstrating pathological changes in the morphology of the VRI.

[Silver coating on tumour prostheses]

BACKGROUND

Modular endoprostheses, so-called "tumour or megaprostheses" are mainly used for limb salvage surgery after resection of malignant soft tissue or a bone tumour. Sometimes, this type of prosthesis is also used for revision surgeries after failed primary joint arthroplasty. Despite continuously improving techniques and quality management systems, periprosthetic infection is one of the most serious complications.

AIM OF THE STUDY

Review of the literature in the PubMed data base with the main focus on silver coatings in joint arthroplasty and their effect on infection rate, outcome and patients' safety.

RESULTS

The current literature shows that there is a beneficial role of silver coatings in megaprostheses in terms of revision rates for septic complications, especially following tumour resection with bad soft tissue coverage or in (multimorbid) high-risk patients, compared to uncoated implants.

DISCUSSION

Based on the results of previous publications examining blood or serum silver concentrations or silver levels in urine, silver coatings do not appear to have side effects, except for local argyria. Continuous monitoring of silver levels in blood or serum is still recommended, and additional long-term studies will be necessary to verify the effectiveness and safety of silver coatings.

Axonal myelin decrease in the splenium in major depressive disorder

The corpus callosum has become a key area of interest for researchers in severe mental illness. Disruptions in fractional anisotropy in the callosum have been reported in schizophrenia and major depressive disorder. No change has been reported in oligodendrocyte density and overall size of the callosum in either illness, suggesting that gross morphology is unchanged, but subtler organisational disruption may exist within this structure. Using high-resolution oil immersion microscopy, we examined the cross-sectional area of the nerve fibre and the axonal myelin sheath; and using standard high-resolution light microscopy, we measured the density of myelinated axons. These measurements were made in the splenium of the corpus callosum. Measures were taken in the sagittal plane in the callosal splenium to contrast with the previous similar examination of the callosal genu. Cases of major depressive disorder had significantly decreased mean myelin cross-sectional area (p = 0.014) per axon in the splenium than in controls or schizophrenia groups. There was no significant change in the density of myelinated axons. The results suggest a clear decrease of myelin in the axons of the callosal splenium in MDD, although this type of neuropathological study is unable to clarify whether this is caused by changes during life or has a developmental origin. In contrast with increased myelin in the callosal genu, this result suggests a longitudinal change in callosal myelination in major depressive disorder not present in normal or schizophrenic brains.

Native Language Promotes Access to Visual Consciousness

Can our native language influence what we consciously perceive? Although evidence that language modulates visual discrimination has been accumulating, little is known about the relation between language structure and consciousness. We employed electroencephalography and the attentional-blink paradigm, in which targets are often unnoticed. Native Greek speakers ( N = 28), who distinguish categorically between light and dark shades of blue, showed boosted perception for this contrast compared with a verbally unmarked green contrast. Electrophysiological signatures of early visual processing predicted this behavioral advantage. German speakers ( N = 29), who have only one category for light and dark shades of blue, showed no differences in perception between blue and green targets. The behavioral consequence of categorical perception was replicated with Russian speakers ( N = 46), reproducing this novel finding. We conclude that linguistic enhancement of color contrasts provides targets with a head start in accessing visual consciousness. Our native language is thus one of the forces that determine what we consciously perceive.

Novel model coupling approach for resilience analysis of coastal plant communities

Resilience is a major research focus covering a wide range of topics from biodiversity conservation to ecosystem (service) management. Model simulations can assess the resilience of, for example, plant species, measured as the return time to conditions prior to a disturbance. This requires process-based models (PBM) that implement relevant processes such as regeneration and reproduction and thus successfully reproduce transient dynamics after disturbances. Such models are often complex and thus limited to either short-term or small-scale applications, whereas many research questions require species predictions across larger spatial and temporal scales. We suggest a framework to couple a PBM and a statistical species distribution model (SDM), which transfers the results of a resilience analysis by the PBM to SDM predictions. The resulting hybrid model combines the advantages of both approaches: the convenient applicability of SDMs and the relevant process detail of PBMs in abrupt environmental change situations. First, we simulate dynamic responses of species communities to a disturbance event with a PBM. We aggregate the response behavior in two resilience metrics: return time and amplitude of the response peak. These metrics are then used to complement long-term SDM projections with dynamic short-term responses to disturbance. To illustrate our framework, we investigate the effect of abrupt short-term groundwater level and salinity changes on coastal vegetation at the German Baltic Sea. We found two example species to be largely resilient, and, consequently, modifications of SDM predictions consisted mostly of smoothing out peaks in the occurrence probability that were not confirmed by the PBM. Discrepancies between SDM- and PBM-predicted species responses were caused by community dynamics simulated in the PBM and absent from the SDM. Although demonstrated with boosted regression trees (SDM) and an existing individual-based model, IBC-grass (PBM), our flexible framework can easily be applied to other PBM and SDM types, as well as other definitions of short-term disturbances or long-term trends of environmental change. Thus, our framework allows accounting for biological feedbacks in the response to short- and long-term environmental changes as a major advancement in predictive vegetation modeling.

Approach to the Core Structure of 15-epi-Exiguolide

The synthesis of seco acid 41 of the macrolactone part of 15-epi-exiguolide, containing a bis-pyran subunit and a trans double bond, is described. Key features of the synthetic strategy include a Feringa–Minnaard asymmetric organocuprate addition to unsaturated ester 17 to set the stereocenter at C15. The derived acid 8 (C9–C16 fragment) was ideally suited for combination with aldehyde 9 (C17–C21 fragment) via an aldol strategy leading to β-lactone 25 which upon thermal decarboxylation provided alkene 26. Chain extension led to propargylic alcohol 7. Treatment of 7 with a LAu+ catalyst promoted a Meyer–Schuster rearrangement to enone 30 that led to cis-tetrahydropyran 31 via intramolecular oxa-Michael reaction. The second pyran ring was prepared from alkoxy ketone 5 by reductive cyclization. The further steps toward macrolactone 43 were hampered by the epimeric mixture at C5.

Group-Level EEG-Processing Pipeline for Flexible Single Trial-Based Analyses Including Linear Mixed Models

Here we present an application of an EEG processing pipeline customizing EEGLAB and FieldTrip functions, specifically optimized to flexibly analyze EEG data based on single trial information. The key component of our approach is to create a comprehensive 3-D EEG data structure including all trials and all participants maintaining the original order of recording. This allows straightforward access to subsets of the data based on any information available in a behavioral data structure matched with the EEG data (experimental conditions, but also performance indicators, such accuracy or RTs of single trials). In the present study we exploit this structure to compute linear mixed models (LMMs, using lmer in R) including random intercepts and slopes for items. This information can easily be read out from the matched behavioral data, whereas it might not be accessible in traditional ERP approaches without substantial effort. We further provide easily adaptable scripts for performing cluster-based permutation tests (as implemented in FieldTrip), as a more robust alternative to traditional omnibus ANOVAs. Our approach is particularly advantageous for data with parametric within-subject covariates (e.g., performance) and/or multiple complex stimuli (such as words, faces or objects) that vary in features affecting cognitive processes and ERPs (such as word frequency, salience or familiarity), which are sometimes hard to control experimentally or might themselves constitute variables of interest. The present dataset was recorded from 40 participants who performed a visual search task on previously unfamiliar objects, presented either visually intact or blurred. MATLAB as well as R scripts are provided that can be adapted to different datasets.

Cryptogamic stem covers may contribute to nitrous oxide consumption by mature beech trees

Naturally produced by microbial processes in soil, nitrous oxide (N₂O) is an important greenhouse gas contributing to climate change. Accordingly, there is a need to accurately quantify the capability of forest ecosystems to exchange N₂O with the atmosphere. While N₂O emissions from soils have been well studied, trees have so far been overlooked in N₂O inventories. Here, we show that stems of mature beech trees (Fagus sylvatica) may act as a substantial sink of N₂O from the atmosphere under conditions of soils consuming N₂O. Consistent consumption of N₂O by all stems investigated (ranging between −2.4 and −3.8 µg m⁻² h⁻¹) is a novel finding in contrast to current studies presenting trees as N₂O emitters. To understand these fluxes, N₂O exchange of photoautotrophic organisms associated with beech bark (lichens, mosses and algae) was quantified under laboratory conditions. All these organisms were net N₂O sinks at full rehydration and temperature of 25 °C. The consumption rates were comparable to stem consumption rates measured under field conditions. Cryptogamic stem covers could be a relevant sink of N₂O in European beech forests.

4'-C-Methoxy-2'-deoxy-2'-fluoro Modified Ribonucleotides Improve Metabolic Stability and Elicit Efficient RNAi-Mediated Gene Silencing

We designed novel 4'-modified 2'-deoxy-2'-fluorouridine (2'-F U) analogues with the aim to improve nuclease resistance and potency of therapeutic siRNAs by introducing 4'-C-methoxy (4'-OMe) as the alpha (C4'α) or beta (C4'β) epimers. The C4'α epimer was synthesized by a stereoselective route in six steps; however, both α and β epimers could be obtained by a nonstereoselective approach starting from 2'-F U. ¹H NMR analysis and computational investigation of the α-epimer revealed that the 4'-OMe imparts a conformational bias toward the North-East sugar pucker, due to intramolecular hydrogen bonding and hyperconjugation effects. The α-epimer generally conceded similar thermal stability as unmodified nucleotides, whereas the β-epimer led to significant destabilization. Both 4'-OMe epimers conferred increased nuclease resistance, which can be explained by the close proximity between 4'-OMe substituent and the vicinal 5'- and 3'-phosphate group, as seen in the X-ray crystal structure of modified RNA. siRNAs containing several C4'α-epimer monomers in the sense or antisense strands triggered RNAi-mediated gene silencing with efficiencies comparable to that of 2'-F U.

[Intraoperative optical coherence tomography in retinal detachment]

BACKGROUND

Using intraoperative optical coherence tomography (iOCT) can be advantageous during macular surgery and lamellar keratoplasty. It is yet unknown if there is a distinct benefit in its application in retinal detachment surgery.

OBJECTIVE

What can be shown using iOCT during retinal detachment surgery? Can therapeutically relevant decisions be made and do they have a prognostic implication on postoperative results?

METHODS

Based on already published (11 patients/eyes) and our own new data (23 patients/eyes),findings by iOCT during retinal detachment surgery are presented.

RESULTS

Outer retinal corrugations are a frequent feature in iOCT in retinal detachment. These corrugations persist during the application of heavy liquids. Even when the retina seems clinically reattached under the use of perfluoroctane, there is significant subfoveal fluid. Using perfluordecaline, there seems to be less subfoveal fluid. In patients with retinal detachment and macula off situation, subclinical full thickness macular holes seem to be more common than assumed. It is unclear if their incidence is influenced by the use of heavy liquids. They appear to have a negative predictive value regarding postoperative visual acuity.

CONCLUSION

Even if there are no obvious benefits in using iOCT in retinal detachment surgery, this new technique offers deeper insights into the microarchitecture of the detached retina. Further investigations in more patients will show if the use of the iOCT will result in a better prognosis for our patients.

A targeted drug delivery platform for assisting retinal surgeons for treating Age-related Macular Degeneration (AMD)

In this paper we present our latest robotic setup, which has been modified for sub-retinal interventions. The setup consists of: 1) sub-retinal micro cannula with automatic pump; 2) Micromanipulator; 3) patient fixation mechanism and 4) clinically compatible workstation. The primary objective of this work is to allow ophthalmologists to improve administration of substances such as drugs, stem-cells and gene cargos to their desired targets in the sub-retinal microstructures. Such a delivery method will enable effective treatment of Age-related Macular Degeneration (AMD). AMD is the leading cause of blindness in developed countries and as yet there is no efficient treatment. To validate the precision of the system a successful targeted delivery scenario with the proposed setup and using an intra-operative OCT integrated microscope in a clinical environment is presented in this paper.

Haptic interface for robot-assisted ophthalmic surgery

Vitreo-retinal surgery is challenging, as delicate structures have to be manipulated. Eliminating tremor caused by human motions when doing micromanipulation can therefore improve the outcome of such an intervention. An eye surgery robot has been built to overcome this problem. The contribution of this paper is the design of a telemanipulation setup for the robotic system. A telemanipulation setup using a haptic device featuring force feedback as a user interface for controlling a hybrid parallel-serial micromanipulator is designed and developed. The position error control scheme is chosen and different control modes are provided. The output forces of the haptic device are analyzed. The system allows the surgeon to perform precise and comfortable micromanipulation. Nevertheless a way to provide more meaningful force feedback still has to be found.

[Optical coherence tomography in eyes with senile retinoschisis : SD-OCT versus ultrasound examinations and assessment of the vitreoretinal interface]

BACKGROUND

In addition to ocular ultrasonography (US), spectral domain optical coherence tomography (SD-OCT) is available in order to diagnose senile retinoschisis (sRS). SD-OCT also allows for classification of posterior vitreous detachment (PVD) in healthy eyes.

OBJECTIVES

Reevaluation of the value and additional benefit of both imaging procedures. SD-OCT-based evaluation of PVD stages in sRS patients.

MATERIALS AND METHODS

Diagnostic results of 33 eyes in 26 patients with clinical suspicion of sRS were retrospectively analysed. All patients received a SD-OCT and a 10 MHz US examination of the region of interest (RoI). In 32 eyes the PVD stage was classified by SD-OCT using the description by Uchino et al. The vitreous position in peripheral SD-OCT scans with sRS was reviewed.

RESULTS

SD-OCT confirmed sRS in 29 eyes. US examination identified sRS in 26 eyes. In 11 eyes, the examination results of the two methods differed. In 7 eyes sRS was identified by SD-OCT but not by US examination. US examination confirmed sRS in 4 eyes for which SD-OCT scans were not useful. Most cases of sRS were detected in temporal located retinal lesions. There was no significant difference between the results of both imaging procedures regarding the RoI (p = 0.64). SD-OCT provided additional information in 27 eyes. Four eyes did not present PVD. Early and intermediate stages of PVD were detected in 9 eyes, while 19 eyes showed complete PVD. In most cases, the vitreous could not be identified in the SD-OCT scans of the periphery.

CONCLUSIONS

In clinical practice, neither SD-OCT nor US ensure an explicit finding of sRS in each eye with sRS. However, both methods positively complement one another and together they improve image-based diagnosis. All stages of PVD may be found in eyes with sRS. The contribution of the vitreous to the pathogenesis of sRS remains uncertain.

[Maculopathy with optic nerve pits : Morphological criteria in SD-OCT]

PURPOSE

Optic pit is a congenital anomaly with malformation similar to coloboma of the optic disc. The cause of optic pit maculopathy is controversial. We used high resolution OCT to investigate changes in the vitreoretinal and vitreopapillary transition within optic pit eyes.

METHODS

The vitreoretinal and vitreo-papillary transition of 12 eyes was accurately analyzed using SD-OCT. We registered the following criteria: liquefaction of prepapillary vitreous, papillary vitreous traction, discontinuity within the hyaloid cortex and communication spaces between pit and retinal edema.

RESULTS

Communication gaps between pit and retinal edema were identified in 8 eyes. 4 eyes had a papillary vitreous traction. 4 showed a discontinuity in the hyaloid cortex. 2 of the 12 patients showed no maculopathy in SD-OCT. Those patients had an adjacent papillary vitreous without prepapillary liquefaction. However all eyes showed vitreous liquefaction at some stage premacullary or prepapillary.

CONCLUSION

Yet the cause of optic pit maculopathy is not clearly understood. High resolution OCT imaging provides a very detailed assessment of the vitreoretinal transition prepapillary and premacullary, however with limited penetration depth and analyzation of deeper lying structures. Our observations suggest that prepapillary liquefaction and pressure gradients within cerebrospinal and intraokular pressure could be key factors.