Functional Counterpart Research Articles

Scalar-on-function local linear regression and beyond

Summary It is common to want to regress a scalar response on a random function. This paper presents results that advocate local linear regression based on a projection as a nonparametric approach to this problem. Our asymptotic results demonstrate that functional local linear regression outperforms its functional local constant counterpart. Beyond the estimation of the regression operator itself, local linear regression is also a useful tool for predicting the functional derivative of the regression operator, a promising mathematical object in its own right. The local linear estimator of the functional derivative is shown to be consistent. For both the estimator of the regression functional and the estimator of its derivative, theoretical properties are detailed. On simulated datasets we illustrate good finite-sample properties of the proposed methods. On a real data example of a single-functional index model, we indicate how the functional derivative of the regression operator provides an original, fast and widely applicable estimation method.

Exploring Heterostructured Upconversion Nanoparticles: From Rational Engineering to Diverse Applications.

Upconversion nanoparticles (UCNPs) represent a class of optical nanomaterials that can convert low-energy excitation photons to high-energy fluorescence emissions. On the basis of UCNPs, heterostructured UCNPs, consisting of UCNPs and other functional counterparts (metals, semiconductors, polymers, etc.), present an intriguing system in which the physicochemical properties are largely influenced by the entire assembled particle and also by the morphology, dimension, and composition of each individual component. As multicomponent nanomaterials, heterostructured UCNPs can overcome challenges associated with a single component and exhibit bifunctional or multifunctional properties, which can further expand their applications in bioimaging, biodetection, and phototherapy. In this review, we provide a summary of recent achievements in the field of heterostructured UCNPs in the aspects of construction strategies, synthetic approaches, and types of heterostructured UCNPs. This review also summarizes the trends in biomedical applications of heterostructured UCNPs and discusses the challenges and potential solutions in this field.

Mechanosensory neuron regeneration in adult Drosophila.

Auditory and vestibular mechanosensory hair cells do not regenerate following injury or aging in the adult mammalian inner ear, inducing irreversible hearing loss and balance disorders for millions of people. Research on model systems showing replacement of mechanosensory cells can provide mechanistic insights into developing new regenerative therapies. Here, we developed lineage tracing systems to reveal the generation of mechanosensory neurons in the Johnston's organ (JO) of intact adult Drosophila, which are the functional counterparts to hair cells in vertebrates. New JO neurons develop cilia and target central brain circuitry. Unexpectedly, mitotic recombination clones point to JO neuron self-replication as a likely source of neuronal plasticity. This mechanism is further enhanced upon treatment with experimental and ototoxic compounds. Our findings introduce a new platform to expedite research on mechanisms and compounds mediating mechanosensory cell regeneration, with nascent implications for hearing and balance restoration.

Myocardial perfusion PET imaging to evaluate coronary microvascular dysfunction in men with prostate cancer receiving androgen deprivation therapy.

211 Background: Strategies to inform cardiovascular (CV) risk are needed for prostate cancer patients initiating androgen deprivation therapy (ADT). Reduced myocardial blood flow reserve (MBFR) and coronary microvascular dysfunction (CMD) represent functional counterparts of traditional CV risk factors, including hyperlipidemia, insulin-resistance, and the metabolic syndrome. Myocardial perfusion PET stress imaging quantifies MBFR and detects CMD. However, the potential utility of these measures to indicate adverse CV changes in prostate cancer patients receiving ADT is poorly understood. Methods: In this prospective study (NCT03535987), eligible prostate cancer patients were planned for at least 6 months of ADT and curative-intent radiation therapy. All patients had a Framingham 10-year general CV risk score of at least 10% and no prior ADT exposure. Myocardial perfusion PET stress imaging was performed within 3 weeks of ADT initiation and again following 6 months of ADT exposure. MBFR was calculated as the ratio of MBF during stress / MBF during rest, and CMD was defined per established criteria as reduced MBFR (ratio < 2.0) in patients without coronary artery disease. Study outcomes included the change in MBFR following 6 months of ADT exposure and the incidence of reduced MBFR and CMD. McNemar’s test and Wilcoxon signed rank test were used for comparison of paired data. Results: Fifteen patients completed baseline myocardial perfusion PET imaging, of whom 13 completed follow-up imaging at 6 months. At baseline, the median (IQR) Framingham CV risk score was 30.4% (19.6, 35.5). One patient (7.7%) had reduced MBFR at baseline, and 5 additional patients (46.2%) developed newly reduced MBFR (ratio < 2.0) within 6 months of ADT initiation (p = 0.025). While no patients had CMD at baseline, 3 patients (30%) developed incident CMD (p = 0.083). MBFR declined in 69% of patients [median decline -0.32 (IQR -0.51, -0.22)] over 6 months ADT exposure. Conclusions: Myocardial perfusion PET imaging demonstrated a high incidence of reduced MBFR and CMD within 6 months of ADT initiation. These findings support further investigation of myocardial PET imaging, a widely-available clinical tool, as a potential research and clinical strategy to inform CV risk assessment in prostate cancer patients receiving ADT. Clinical trial information: NCT03535987.

Restoration of type I interferon signaling in intrahepatically primed CD8+ T cells promotes functional differentiation.

Hepatitis B virus–specific (HBV-specific) CD8+ T cells fail to acquire effector functions after priming in the liver, but the molecular basis for the dysfunction is poorly understood. By comparing the gene expression profile of intrahepatically primed, dysfunctional HBV-specific CD8+ T cells with that of systemically primed, functional effector counterparts, we found that the expression of interferon-stimulated genes (ISGs) is selectively suppressed in the dysfunctional CD8+ T cells. The ISG suppression was associated with impaired phosphorylation of STAT1 in response to IFN-α treatment. Importantly, a strong induction of type I interferons (IFN-Is) in the liver facilitated the functional differentiation of intrahepatically primed HBV-specific CD8+ T cells in association with the restoration of ISGs’ expression in the T cells. These results suggest that intrahepatic priming suppresses IFN-I signaling in CD8+ T cells, which may contribute to the dysfunction. The data also suggest a therapeutic value of the robust induction of intrahepatic IFN-Is for the treatment of chronic HBV infection.

The silent variants of pituitary tumors: demographic, radiological and molecular characteristics.

Tumors of the anterior pituitary gland (PTs) are mostly benign tumors with a low prevalence, which has nevertheless increased with advances in brain radiology techniques. Nearly half of PTs are not associated with a clinical endocrine syndrome. These tumors have been indistinctly named non-functioning pituitary adenomas (NFPAs) or silent pituitary tumors (SPTs) and the mechanisms of silencing are not fully known. To study the frequency and characterize the silent variant of PTs in a large local series, and to assess their pituitary adenohypophyseal gene expression. This observational, cross-sectional study was performed in a Pituitary Tumor Center of Excellence and involved 268 PTs. After identifying the different subtypes according to the immunohistochemical (IHC) expression of adenohypophyseal hormones, we studied their gene expression by RT-qPCR. We found that silent tumors were larger and more invasive, but not more proliferative than their functional counterparts. The RT-qPCR complements the IHC typification of PTs, reducing the proportion of null-cell subtype. Finally, some silent PT subtype variants showed lower specific adenohypophyseal hormone gene expression than their functional counterparts, which may contribute to the absence of endocrine manifestations. This paper highlights the importance of identifying the silent variant of the PTs subtypes. As expected, silent tumors were larger and more invasive than their functioning counterparts. However, there was no difference in the proliferation activity between them. Finally, the lower specific gene expression in the silent than in the functioning counterparts of some PTs subtypes gives insights into the silencing mechanisms of PTs.

Pros and cons of the time-dependent hybrid density functional approach for calculating the optical spectra of solids: a case study of CeO2.

The prediction of optical spectra of complex solids remains a great challenge for first-principles calculations due to the huge computational cost of the state-of-the-art many-body perturbation theory based GW-Bethe Salpeter equation (BSE) approach. An alternative method is the time-dependent density-functional theory (TDDFT) based on hybrid exchange-correlation functionals, which involves the essential ingredients of electron-hole interactions in its formalism in contrast to its local/semi-local functional counterparts. In this work, we investigate the optical absorption spectra of ceria (CeO2), a prototypical lanthanide oxide with a 4f0 configuration, utilizing TDDFT based on four well-established hybrid functionals for ground state DFT calculations. All four functionals reproduce well the excitonic features of the experimental optical spectra, in spite of the significant differences in their band structures arising from different hybridization parameters (i.e. the fraction of the Hartree-Fock exchange and the screening parameter). It is demonstrated that the apparently weak dependence of the resulting optical spectra on the employed functionals is quite universal and applies to simple semiconductors such as Si and GaAs and insulator LiF as well. This study highlights the feasibility of TDDFT based on existing hybrids to describe optical spectra of solids, and also, points out the difficulty of obtaining accurate exciton binding energies using these hybrid functionals due to the strong functional dependence of quasi-particle band structures.

Variations on Salem–Zygmund results for random trigonometric polynomials: application to almost sure nodal asymptotics

On a probability space $(\Omega, \mathcal F, \mathbb P)$ we consider two independent sequences $(a_k)_{k \geq 1}$ and $(b_k)_{k \geq 1}$ of i.i.d. random variables that are centered with unit variance and which admit a moment strictly higher than two. We define the associated random trigonometric polynomial \[ f_n(t) :=\frac{1}{\sqrt{n}} \sum_{k=1}^n a_k \cos(kt)+b_k \sin(kt), \quad t \in \mathbb R. \] In their seminal work, for Rademacher coefficients, Salem and Zygmund showed that $\mathbb P$ almost surely: \[ \forall t\in\mathbb R,\quad \frac{1}{2\pi}\int_{0}^{2\pi} \exp\left(i t f_n(x)\right) dx \xrightarrow[n\to\infty]~e^{-\frac{t^2}{2}}. \] In other words, if $X$ denotes an independent random variable uniformly distributed on $[0,2\pi]$, $\mathbb{P}$ almost surely, under the law of $X$, $f_n(X)$ converges in distribution to a standard Gaussian variable. In this paper, we revisit the above result from different perspectives. Namely, i) we establish a possibly sharp convergence rate for some adequate metric via the Stein's method, ii) we prove a functional counterpart of Salem--Zygmund CLT, iii) we extend it to more general distributions for $X$, iv) we also prove that the convergence actually holds in total variation. As an application, in the case where the random coefficients have a symmetric distribution and admit a moment of order $4$, we show that $\mathbb{P}$ almost surely, for any interval $[a,b] \subset [0, 2\pi]$ \[\frac{\mathcal N(f_n,[a,b])}{n} \xrightarrow[n \to +\infty]{} \frac{(b-a)}{\pi \sqrt{3}},\] where $\mathcal N(f_n,[a,b])$ denotes the number of real zeros of $f_n$ in the interval $[a,b]$. To the best of our knowledge, such an almost sure result is new in the framework of random trigonometric polynomials, even in the case of Gaussian coefficients.

Mast Cell Chymase and Kidney Disease.

A sizable part (~2%) of the human genome encodes for proteases. They are involved in many physiological processes, such as development, reproduction and inflammation, but also play a role in pathology. Mast cells (MC) contain a variety of MC specific proteases, the expression of which may differ between various MC subtypes. Amongst these proteases, chymase represents up to 25% of the total proteins in the MC and is released from cytoplasmic granules upon activation. Once secreted, it cleaves the targets in the local tissue environment, but may also act in lymph nodes infiltrated by MC, or systemically, when reaching the circulation during an inflammatory response. MC have been recognized as important components in the development of kidney disease. Based on this observation, MC chymase has gained interest following the discovery that it contributes to the angiotensin-converting enzyme’s independent generation of angiotensin II, an important inflammatory mediator in the development of kidney disease. Hence, progress regarding its role has been made based on studies using inhibitors but also on mice deficient in MC protease 4 (mMCP-4), the functional murine counterpart of human chymase. In this review, we discuss the role and actions of chymase in kidney disease. While initially believed to contribute to pathogenesis, the accumulated data favor a more subtle view, indicating that chymase may also have beneficial actions.

Coordinated control of adiposity and growth by anti-anabolic kinase ERK7.

Energy storage and growth are coordinated in response to nutrient status of animals. How nutrient‐regulated signaling pathways control these processes in vivo remains insufficiently understood. Here, we establish an atypical MAP kinase, ERK7, as an inhibitor of adiposity and growth in Drosophila. ERK7 mutant larvae display elevated triacylglycerol (TAG) stores and accelerated growth rate, while overexpressed ERK7 is sufficient to inhibit lipid storage and growth. ERK7 expression is elevated upon fasting and ERK7 mutant larvae display impaired survival during nutrient deprivation. ERK7 acts in the fat body, the insect counterpart of liver and adipose tissue, where it controls the subcellular localization of chromatin‐binding protein PWP1, a growth‐promoting downstream effector of mTOR. PWP1 maintains the expression of sugarbabe, encoding a lipogenic Gli‐similar family transcription factor. Both PWP1 and Sugarbabe are necessary for the increased growth and adiposity phenotypes of ERK7 loss‐of‐function animals. In conclusion, ERK7 is an anti‐anabolic kinase that inhibits lipid storage and growth while promoting survival on fasting conditions.

Subjective cognitive decline is associated with neurocognition in the SOL‐INCA study

AbstractBackgroundSubjective cognitive decline (SCD) is the experience of cognitive decline not yet apparent through formal neuropsychological testing. SCD is required to meet clinical criteria for mild cognitive impairment (MCI) and is a potential early risk marker of neurocognitive changes. Despite increased risk of cognitive decline in US Hispanics/Latinos, SCD research in this group is lacking. We investigated if SCD is cross‐sectionally associated with objective neurocognitive performance in SOL‐INCA, a large community‐based sample of diverse Hispanics/Latinos.MethodParticipants (N=5,282) were age 50+ and without reported dementia. The Everyday Cognition Short Form (ECog‐12) scale measured SCD. A global score, as well as memory and executive ECog‐12 sub‐scale scores, were calculated by averaging across z‐scores of individual items assessing memory and executive functional abilities (all items were averaged for the global score). Objective neurocognitive function was measured with tests of memory (Spanish English Verbal Learning Test‐Sum and Recall scores) and executive functions (word fluency, Trail Making Test A & B, and Digit Symbol Substitution scores). Memory, executive, and global neurocognitive composite scores were created by averaging across z‐scores for each cognitive domain listed above, and across all tests for the global composite. Regression models interrogated associations of ECog‐12 (global and sub‐scale scores) with their respective objective neurocognitive function counterparts (global cognition, memory, and executive function neurocognitive composite scores), adjusting for age, sex, education, Hispanic/Latino background, depression, anxiety, and cardiovascular risk factors.ResultWomen comprised 53% of the sample and 25% of the sample were age 70+. Global score, memory, and executive sub‐scale ECog‐12 scores were significantly associated with global (B= ‐0.14), memory (B= ‐0.11), and executive function (B= ‐0.11) neurocognitive composite scores respectively (all p‐values <.001), such that higher ECog‐12 scores (more complaints) were related to lower neurocognition for all three neurocognitive composites.ConclusionContrary to previous research in non‐Hispanic Whites, SCD is associated with concurrent objective neurocognitive function among Hispanic/Latino community‐dwelling adults. SCD may have utility as an early risk marker in this population. More research is needed to determine the predictive value of SCD reporting within Hispanics/Latinos as well as the utility of informant’s report in predicting neurocognitive change.

378 Making-Do When Big Data Isn’t Big Enough: Limitations and pathways of possible development in the prediction of Thoroughbred racing performance as a breeding outcome

Abstract A performance genetics model adapted to real-world data of Thoroughbred racing and breeding will be presented. The continuity of ancestry and performance is documented in the annals of pedigree, not as functional counterparts, but as corresponding signs of market value. Pedigree invites chronic misprision of highly diverse genetic resources competing for scarce opportunity in the racing economy, resulting in samples that are often small and of dubious composition. Data is specialized for competing “pedigree analysis” that packages the system of signification to meet market demand for meaning. Given statistical deficits, this data is a necessary inferential asset of the model. The model’s premise is that predictability is optimized if racing performance is defined as the function of an indivisible relation between parents. Statistical data consists of 6-generation ancestries of mares that produced offspring by a subject stallion. Comparison of proportions is used to identify effects resulting from his relation to individual ancestors of the subject mare. Expected performance by the sire’s offspring is defined as the proportion of mares that produced a superior runner by him. Each ancestor of a subject mare also has descendants among the mares that produced offspring by the stallion. For each of those groups, the proportion of mares that produced a superior runner is compared with the stallion’s expected performance using a t-test of statistical significance at the .10 level. Probable effect is further tested by case study involving such variables as racing class, generational distance, sex-linkage, inbreeding, and an ancestor’s pattern of effect across the stallion population. Stallions with the highest prevalence of positive effects are preferred for the subject mare. This model, under the trade name LyonScore®, has been used since 2012 by Werk Thoroughbred Constultants, Inc. as a component of its client services. Table 1: The data, listed in tabular format below, is graphically displayed for actual use on an ancestry tree whose nodes are numbered by relation to a subject mare (“Position”). Each statistical data item in the table is derived from the stud record of a stallion named Distorted Humor and corresponds with an ancestor of a mare named Positively Royal. Each ancestor of this mare is also an ancestor of a group of mares that produced offspring of Distorted Humor and were at least three years of age as of 2019. A proportion of each of those groups of mares produced at least one superior runner. Proportions that differ significantly from Distorted Humor’s expected proportion are so indicated. Only ancestors involving a group of at least 18 mares are considered to have inferential value on statistical grounds. Table 2: The sire Danzig is an ancestor of Positively Royal, along with 75 mares that produced foals by Distorted Humor, only five of which produced a superior runner by him, significantly fewer than expected. However, since Distorted Humor’s dam is by Danzig, the question of generational distance is relevant as a variable to the effect of inbreeding. The table below shows Danzig’s proportional distribution by genetic relation to those 75 mares as indicated by “Position.” Of the 64 mares in descent of Danzig within three generations, three mares produced a superior runner. It’s notable, though, that 2 of 6 mares with the same relation to Danzig as Positively Royal produced superior runners. Since Danzig is the only ancestor with a negative effect, further consideration is warranted. Table 3: In a population that tends to slough off unprofitable genetic resources, overspecialization is the main risk of close inbreeding. Some generational variations of an ancestor’s contribution can turn inbreeding to less specialized effect, but this depends on generational distance. Distorted Humor’s earliest opportunity with mares in descent of Danzig involved offspring closely inbred to Danzig, but later in his career he encountered mares for which variation was more likely. As the table shows, two of six mares descending from Danzig in position 25 (4th generation) produced Distorted Humor’s best runners inbred to Danzig, so it is of some interest that Positively Royal, the subject mare, is also a postion-25 descendant of Danzig. However, that those two mares happen to be full sisters whose breeding has little else in common with that of Positively Royal leaves the question of Distorted Humor’s fitness for this mare less certain than would be preferred.

What makes a better indicator? Taxonomic vs functional response of nematodes to estuarine gradient

Efficient implementation of nematodes-based indices for ecological quality assessment requires fundamental knowledge on their biodiversity and functional patterns along with the drivers that generate these patterns. Though, it is still unclear if nematodes taxonomical attributes are driven by the same environmental drivers as their functional (biological traits) counterparts, or if their taxonomical diversity is also enhanced by their functional diversity. To fill this knowledge gap, we investigated taxonomical (based on nematode genera abundances dataset) and functional attributes: trophic groups (TG) and life history strategies (LHS) of benthic nematodes collected from 35 sampling stations along the Sado Estuary, SW Portugal. Along with biological samples we measured environmental variables in the water and sediments as well as sediment grain size.Our results demonstrated that taxonomy-based assemblages were mainly structured by the salinity gradient and further by the interplay of granulometry and organic matter content. Contrastingly, trait-based distribution patterns were largely driven by the variations in the above sediment dissolved oxygen concentration. This finding largely draw attention to the role that above sediment dissolved oxygen concentration exerts on nematode assemblages and their functional distribution patterns. Consequently, our results demonstrate that biological traits introduce a new dimensionality in multivariate data that otherwise could not be detected using solely taxonomical information, thereby enhancing our knowledge on ecological gradients existing within an estuary.Additionally, we found a strong correlation between functional richness (based on the combination of TG and LHS traits) and diversity taxonomic metrics (species richness, Simpson and Shannon diversity), although no correlation was found between taxonomic diversity indices and single nematode ecological indices (ITD index of trophic diversity and MI Maturity Index). Therefore, the combined use of functional traits and its derived metrics was demonstrated to effectively reflect taxonomical diversity presenting reliable and highly complementary information for the assessment and monitoring of marine coastal sediments using benthic nematodes.

Efficient Differentiation of Human Induced Pluripotent Stem Cells into Endothelial Cells under Xenogeneic-free Conditions for Vascular Tissue Engineering

Tissue engineered vascular grafts (TEVGs) represent a promising therapeutic option for emergency vascular intervention. Although the application of small-diameter TEVGs using patient-specific primary endothelial cells (ECs) to prevent thrombosis and occlusion prior to implantation could be hindered by the long time course required for in vitro endothelialization, human induced pluripotent stem cells (hiPSCs) provide a robust source to derive immunocompatible ECs (hiPSC-ECs) for immediate TEVG endothelialization. To achieve clinical application, hiPSC-ECs should be derived under culture conditions without the use of animal-derived reagents (xenogeneic-free conditions), to avoid unwanted host immune responses from xenogeneic reagents. However, a completely xenogeneic-free method of hiPSC-EC generation has not previously been established. Herein, we substituted animal-derived reagents used in a standard method of xenogeneic hiPSC-EC differentiation with functional counterparts of human origin. As a result, we generated xenogeneic-free hiPSC-ECs (XF-hiPSC-ECs) with similar marker expression and function to those of human primary ECs. Furthermore, XF-hiPSC-ECs functionally responded to shear stress with typical cell alignment and gene expression. Finally, we successfully endothelialized decellularized human vessels with XF-hiPSC-ECs in a dynamic bioreactor system. In conclusion, we developed xenogeneic-free conditions for generating functional hiPSC-ECs suitable for vascular tissue engineering, which will further move TEVG therapy toward clinical application.

Xenogeneic-free generation of vascular smooth muscle cells from human induced pluripotent stem cells for vascular tissue engineering

Development of mechanically advanced tissue-engineered vascular grafts (TEVGs) from human induced pluripotent stem cell (hiPSC)-derived vascular smooth muscle cells (hiPSC-VSMCs) offers an innovative approach to replace or bypass diseased blood vessels. To move current hiPSC-TEVGs toward clinical application, it is essential to obtain hiPSC-VSMC-derived tissues under xenogeneic-free conditions, meaning without the use of any animal-derived reagents. Many approaches in VSMC differentiation of hiPSCs have been reported, although a xenogeneic-free method for generating hiPSC-VSMCs suitable for vascular tissue engineering has yet to be established. Based on our previously established standard method of xenogeneic VSMC differentiation, we have replaced all animal-derived reagents with functional counterparts of human origin and successfully derived functional xenogeneic-free hiPSC-VSMCs (XF-hiPSC-VSMCs). Next, our group developed tissue rings via cellular self-assembly from XF-hiPSC-VSMCs, which exhibited comparable mechanical strength to those developed from xenogeneic hiPSC-VSMCs. Moreover, by seeding XF-hiPSC-VSMCs onto biodegradable polyglycolic acid (PGA) scaffolds, we generated engineered vascular tissues presenting effective collagen deposition which were suitable for implantation into an immunodeficient mice model. In conclusion, our xenogeneic-free conditions for generating hiPSC-VSMCs produce cells with the comparable capacity for vascular tissue engineering as standard xenogeneic protocols, thereby moving the hiPSC-TEVG technology one step closer to safe and efficacious clinical translation.

Discrete weierstrass transform in discrete hermitian clifford analysis

The classical Weierstrass transform is an isometric operator mapping elements of the weighted L2−space L2(R,exp(−x2/2)) to the Fock space. It has numereous applications in physics and applied mathematics. In this paper, we define an analogue version of this transform in discrete Hermitian Clifford analysis, where functions are defined on a grid rather than the continuous space. This new transform is based on the classical definition, in combination with a discrete version of the Gaussian function and discrete counterparts of the classical Hermite polynomials. Furthermore, a discrete Weierstrass space with appropriate inner product is constructed, for which the discrete Hermite polynomials form a basis. In this setting, we also investigate the behaviour of the discrete delta functions and check if they are elements of this newly defined Weierstrass space.

Combined Genome and Transcriptome Analyses of the Ciliate Schmidingerella arcuata (Spirotrichea) Reveal Patterns of DNA Elimination, Scrambling, and Inversion.

Schmidingerella arcuata is an ecologically important tintinnid ciliate that has long served as a model species in plankton trophic ecology. We present a partial micronuclear genome and macronuclear transcriptome resource for S. arcuata, acquired using single-cell techniques, and we report on pilot analyses including functional annotation and genome architecture. Our analysis shows major fragmentation, elimination, and scrambling in the micronuclear genome of S. arcuata. This work introduces a new nonmodel genome resource for the study of ciliate ecology and genomic biology and provides a detailed functional counterpart to ecological research on S. arcuata.

Unravelling patterns of taxonomic and functional diversity of Amazon stream fish

Environmental filtering and dispersal limitation are essential processes affecting the variability of ecological communities. However, their relative contributions are highly debated and remain largely unknown in several systems, such as the hyperdiverse Amazon Basin. We determined the relative role of local, catchment, spatial, and biogeographical variables on the taxonomic and functional alpha and beta diversity of stream fish. We sampled 54 streams across six river basins in the Amazon. For each stream, we obtained 35 local habitat variables and 11 climate-catchment variables. Watercourse distances and basin identity were converted into spatial and biogeographical variables, respectively. We found that taxonomic alpha diversity responds both to spatial and local predictors, whereas its functional counterpart was mainly associated with local variables. Biogeography was the main factor structuring taxonomic and functional beta diversity, with a secondary contribution of catchment and local variables. Locally, substrate type and isolation determined the number and relative abundance of species and traits. The shared variation between biogeographical and environmental variables, especially altitude and slope, were strongly associated with beta diversity patterns, indicating a joint role of habitat filtering and dispersal limitation. Our results show the need to include both spatial and environmental variables in studies of stream communities at large spatial scales, as they are related to distinct processes that regulate community structure. We also encourage future studies to account for the responses of multiple facets of biodiversity to different drivers, as they provide essential and complementary information for community ecology and biogeography.

Sol\u2013gel synthesis and structural characterization of band gap engineered ferroelectric perovskite oxide potassium sodium barium nickel niobate

Ferroelectric materials with engineered thus visible-range optical band gaps are increasingly researched in recent years, triggering potentially new applications in solar cells, opto-ferroelectric devices, multifunctional sensors, and multisource energy harvesters. To date, most band gap engineered ferroelectrics have been discovered in form of ceramics fabricated via the solid-state route. Like other functional counterparts further research of these materials into nanoscale developments, e.g., nanocomposites and thin films, demands nanofabrication methods to be investigated. An emerging band gap engineered ferroelectric composition, (K,Na,Ba)(Ni,Nb)O3−δ (KNBNNO), discovered with solid-state route has allured research for novel applications as mentioned above. However, its nanofabrication via wet chemical routes has rarely been reported. In this paper, sol–gel method is used to fabricate KNBNNO nanoparticles. The developed method can successfully form the target perovskite phases, and is able to reduce the particle size from 300 to 400 nm made via the solid-state reaction to about 100 nm. In addition, the distributed particle size in the synthesized solutions averages at 4–6 nm, making the method suitable for potential thin film fabrication. Therefore, this paper offers a nanofabrication option to the emerging KNBNNO for prospective nanoscale research.

Human virus detection with graphene-based materials

Our recent experience of the COVID-19 pandemic has highlighted the importance of easy-to-use, quick, cheap, sensitive and selective detection of virus pathogens for the efficient monitoring and treatment of virus diseases. Early detection of viruses provides essential information about possible efficient and targeted treatments, prolongs the therapeutic window and hence reduces morbidity. Graphene is a lightweight, chemically stable and conductive material that can be successfully utilized for the detection of various virus strains. The sensitivity and selectivity of graphene can be enhanced by its functionalization or combination with other materials. Introducing suitable functional groups and/or counterparts in the hybrid structure enables tuning of the optical and electrical properties, which is particularly attractive for rapid and easy-to-use virus detection. In this review, we cover all the different types of graphene-based sensors available for virus detection, including, e.g., photoluminescence and colorimetric sensors, and surface plasmon resonance biosensors. Various strategies of electrochemical detection of viruses based on, e.g., DNA hybridization or antigen-antibody interactions, are also discussed. We summarize the current state-of-the-art applications of graphene-based systems for sensing a variety of viruses, e.g., SARS-CoV-2, influenza, dengue fever, hepatitis C virus, HIV, rotavirus and Zika virus. General principles, mechanisms of action, advantages and drawbacks are presented to provide useful information for the further development and construction of advanced virus biosensors. We highlight that the unique and tunable physicochemical properties of graphene-based nanomaterials make them ideal candidates for engineering and miniaturization of biosensors.