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The purposes of this study are to evaluate the tropical fruit (banana, kiwi, pineapple) preferences of consumers in Turkey and their willingness to pay and to assess the factors that affect this willingness to pay. In this context, tropical fruit products were presented in packages of 50 grams to 386 individuals who had never tasted these products before, and after the products had been tasted, surveys were administered. The findings revealed that dried banana has sensory issues related to hardness and taste and that dried kiwi has sensory issues related to taste and odour. The results show that improving the taste characteristics and increasing the emphasis on health while promoting the products could have a positive impact on increasing the demand for these products in Turkey. [ABSTRACT FROM AUTHOR]

From 2005 to 2008, high volatility in the markets affected grain prices significantly. This high volatility in grain prices made many researchers curious, and many discussions aroused from this topic. This study analyzes wheat price behavior during this period of high volatility. We estimate a return index for wheat using spot and futures wheat prices with the help of a present value model. To analyze the cointegration between the wheat prices and return index, a new cointegration test with multiple structural breaks, developed by Daiki Maki (2012), is used. The long-run cointegration coefficients are estimated using the Dynamic Ordinary Least Squares methodology. The empirical results show that there is cointegration between the spot and futures wheat prices, which tends to change at breakpoints. In other words, there is an equilibrium relation between spot prices and futures prices; however, it becomes unstable during the crisis in 2008. The results may help in understanding the dynamics of wheat prices, especially during high-volatility periods.

The purpose of this study was to determine the socio-economic and intellectual factors affecting the imported meat preferences of consumers and to reveal the personal prioritized preferences of buyers consuming domestic meat and imported meat. The study was carried out in Izmir, the third city of Turkey, where face-to-face interviews were conducted in 300householdswhose occupants shop at hypermarkets where domestic and imported meat is sold. 28.7% of those participating in the study prefer imported meat. As a result of logistic regression, the approach related to the share of cattle meat in the total meat spend, the age factor and the belief that the price of imported cattle meat is low positively affect the probability of consuming imported meat. The consumption of chicken and lamb and marital status has negative effects. The religious belief factor and the perception of taste in those consuming imported meat take priority in the personal preferences of domestic meat consumers. Long-term policies that will ensure stability in the market as a whole are needed in the livestock sector in Turkey. Improvement of meat quality, classification and the rising awareness of consumers regarding quality and farming according to nutritional requirements and the development of certification also have significant importance. [ABSTRACT FROM AUTHOR]

Coronavirus Disease-19 (COVID-19) is a highly contagious infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The development of rapid antigen tests has contributed to easing the burden on healthcare and lifting restrictions by detecting infected individuals to help prevent further transmission of the virus. We developed a state-of-art rapid antigen testing system, named DIAGNOVIR, based on immune-fluorescence analysis, which can process and give the results in a minute. In our study, we assessed the performance of the DIAGNOVIR and compared the results with those of the qRT-PCR test. Our results demonstrated that the sensitivity and specificity of the DIAGNOVIR were 94% and 99.2%, respectively, with a 100% sensitivity and 96.97% specificity, among asymptomatic patients. In addition, DIAGNOVIR can detect SARS‑CoV‑2 with 100% sensitivity up to 5 days after symptom onset. We observed that the DIAGNOVIR Rapid Antigen Test's limit of detection (LoD) was not significantly affected by the SARS‑CoV‑2 variants including Wuhan, alpha (B1.1.7), beta (B.1.351), delta (B.1.617.2) and omicron (B.1.1.529) variants, and LoD was calculated as 8 × 10 2 , 6.81 × 10 1.5 , 3.2 × 10 1.5 , 1 × 10 3 , and 1 × 10 3.5 TCID50/mL, respectively. Our results indicated that DIAGNOVIR can detect all SARS-CoV-2 variants in just seconds with higher sensitivity and specificity lower testing costs and decreased turnover time., (© 2023. The Author(s).)

Livestock manure management systems can be significant sources of nitrous oxide (N 2 O), methane (CH 4 ), and ammonia (NH 3 ) emissions. Many studies have been conducted to improve our understanding of the emission processes and to identify influential variables in order to develop mitigation techniques adapted to each manure management step (animal housing, outdoor storage, and manure spreading to land). The international project DATAMAN (http://www.dataman.co.nz) aims to develop a global database on greenhouse gases (N 2 O, CH 4 ) and NH 3 emissions from the manure management chain to refine emission factors (EFs) for national greenhouse gas and NH 3 inventories. This paper describes the housing and outdoor storage components of this database. Relevant information for different animal categories, manure types, livestock buildings, outdoor storage, and climatic conditions was collated from published peer reviewed research, conference papers, and existing databases published between 1995 and 2021. In the housing database, 2024 EFs were collated (63% for NH 3 , 19.5% for CH 4 , and 17.5% for N 2 O). The storage database contains 654 NH 3 EFs from 16 countries, 243 CH 4 EFs from 13 countries, and 421 N 2 O EFs from 17 countries. Across all gases, dairy cattle and swine production in temperate climate zones are the most represented animal and climate categories. As for the housing database, the number of EFs for the tropical climate zone is under-represented. The DATAMAN database can be used for the refinement of national inventories and better assessment of the cost-effectiveness of a range of mitigation strategies., (© 2022 The Authors. Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)

Influenza A viruses (IAV), including the pandemic 2009 (pdm09) H1N1 or avian influenza H5N1 virus, may advance into more pathogenic, potentially antiviral drug-resistant strains (including loss of susceptibility against oseltamivir). Such IAV strains fuel the risk of future global outbreaks, to which this study responds by re-engineering Interferon-α2a (IFN-α2a) bioconjugates into influenza therapeutics. Type-I interferons such as IFN-α2a play an essential role in influenza infection and may prevent serious disease courses. We site-specifically conjugated a genetically engineered IFN-α2a mutant to poly(2-ethyl-2-oxazoline)s (PEtOx) of different molecular weights by strain-promoted azide-alkyne cyclo-addition. The promising pharmacokinetic profile of the 25 kDa PEtOx bioconjugate in mice echoed an efficacy in IAV-infected ferrets. One intraperitoneal administration of this bioconjugate, but not the marketed IFN-α2a bioconjugate, changed the disease course similar to oseltamivir, given orally twice every study day. PEtOxylated IFN-α2a bioconjugates may expand our therapeutic arsenal against future influenza pandemics, particularly in light of rising first-line antiviral drug resistance to IAV.

Conjugation of poly(ethylene glycol) (PEG) to biologics is a successful strategy to favorably impact the pharmacokinetics and efficacy of the resulting bioconjugate. We compare bioconjugates synthesized by strain-promoted azide-alkyne cycloaddition (SPAAC) using PEG and linear polyglycerol (LPG) of about 20 kDa or 40 kDa, respectively, with an azido functionalized human Interferon-α2a (IFN-α2a) mutant. Site-specific PEGylation and LPGylation resulted in IFN-α2a bioconjugates with improved in vitro potency compared to commercial Pegasys. LPGylated bioconjugates had faster disposition kinetics despite comparable hydrodynamic radii to their PEGylated analogues. Overall exposure of the PEGylated IFN-α2a with a 40 kDa polymer exceeded Pegasys, which, in return, was similar to the 40 kDa LPGylated conjugates. The study points to an expanded polymer design space through which the selected polymer class may result in a different distribution of the studied bioconjugates., (Copyright © 2022. Published by Elsevier B.V.)

Hydrodynamic and light scattering methods are urgently required for accurate characterization of nanoparticles (NPs) in the field of nanomedicine to unveil their sizes and distributions. A fundamental characterization approach in the field of nanomedicines is, next to standard batch dynamic light scattering (DLS) and increasingly more applied (asymmetrical flow) field-flow fractionation (FFF) coupled to multi-angle laser light scattering (MALLS), the utilization of an analytical ultracentrifuge (AUC). Here, we demonstrate the power of an AUC in comparison to batch DLS and FFF-MALLS to decipher, in detail, the size and dispersity of pharma-relevant, commercial and in-house prepared soft matter NPs, suitable for life science applications. In this study, size and dispersity of poly(lactic-co-glycolic acid) (PLGA) NPs and in-house prepared NPs, consisting of the commercially available pharmapolymer Eudragit® E or of a polymer of similar composition synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, were investigated. Simultaneously, an insight on the presence of the utilized surfactant on the NP formulations, which is usually limited with other techniques, could be achieved by multi-speed experiments with the AUC in one experimental setting. While the repeatability and ruggedness of observations with modern AUC instruments of the newest generation is demonstrated, the results are further underpinned by the classical relations of hydrodynamics. Investigations aiming at hydrodynamic diameters (from DLS) and radii of gyration (from FFF-MALLS) are critically discussed and compared to the repeatable and rugged investigations by an AUC. The latter is proven to provide a self-sufficient experimental approach for NP characterization in the field of nanomedicine based on absolute principles, compares well to FFF-MALLS, and can unravel issues in NP sizing that arise when more common techniques, such as DLS, are used., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: Cytomegalovirus infection is an important complication in immunocompromised patients. As few studies have shown that cyclophosphamide treatment is a risk factor for cytomegalovirus infection in patients with glomerulonephritis, we aimed to describe the frequency and risk factors of cytomegalovirus infection in glomerulonephritis patients treated with cyclophosphamide., Methods: We prospectively recruited 43 cytomegalovirus seropositive patients with glomerulonephritis treated with cyclophosphamide. We screened all patients for viral DNA monthly during treatment. Patients were compared for age, sex, glomerular pathology, renal function and clinical status regarding development of cytomegalovirus infection before and after the treatment., Results: Cytomegalovirus infection was detected in 10 (23.3%) patients, most commonly within the first 2 months of cyclophosphamide treatment. All patients recovered without any cytomegalovirus-related complications. Patients with cytomegalovirus infection had higher serum creatinine (4.2 ± 3.2 vs. 1.9 ± 1.8 mg/dl, p = 0.006) and lower estimated glomerular filtration rate (29 ± 11 vs. 65 ± 8 ml/min/1.73 m 2 , p = 0.016) at diagnosis compared with cytomegalovirus infection non-occurred patients. In addition, number of patients presented with rapidly progressive glomerulonephritis were higher in cytomegalovirus infection group (80.0% vs. 27.3%, p = 0.007). Moreover, cytomegalovirus infection was associated with prolonged hospital stay (54 ± 7 vs. 29 ± 6 days, p = 0.027)., Conclusion: Cytomegalovirus infection is a common complication in glomerulonephritis patients treated with cyclophosphamide in this prospective study. Routine monitoring and prophylaxis should be considered for these high-risk patients., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

Competing Interests: The authors report no conflicts of interest.

Leukotrienes are pro-inflammatory lipid mediators generated by 5-lipoxygenase aided by the 5-lipoxygenase-activating protein (FLAP). BRP-201, a novel benzimidazole-based FLAP antagonist, inhibits leukotriene biosynthesis in isolated leukocytes. However, like other FLAP antagonists, BRP-201 fails to effectively suppress leukotriene formation in blood, which limits its therapeutic value. Here, we describe the encapsulation of BRP-201 into poly(lactide-co-glycolide) (PLGA) and ethoxy acetalated dextran (Ace-DEX) nanoparticles (NPs), aiming to overcome these detrimental pharmacokinetic limitations and to enhance the bioactivity of BRP-201. NPs loaded with BRP-201 were produced via nanoprecipitation and the physicochemical properties of the NPs were analyzed in-depth using dynamic light scattering (size, dispersity, degradation), electrophoretic light scattering (effective charge), NP tracking analysis (size, dispersity), scanning electron microscopy (size and morphology), UV-VIS spectroscopy (drug loading), an analytical ultracentrifuge (drug release, degradation kinetics), and Raman spectroscopy (chemical attributes). Biological assays were performed to study cytotoxicity, cellular uptake, and efficiency of BRP-201-loaded NPs versus free BRP-201 to suppress leukotriene formation in primary human leukocytes and whole blood. Both PLGA- and Ace-DEX-based NPs were significantly more efficient to inhibit leukotriene formation in neutrophils versus free drug. Whole blood experiments revealed that encapsulation of BRP-201 into Ace-DEX NPs strongly increases its potency, especially upon pro-longed (≥ 5 h) incubations and upon lipopolysaccharide-challenge of blood. Finally, intravenous injection of BRP-201-loaded NPs significantly suppressed leukotriene levels in blood of mice in vivo. These results reveal the feasibility of our pharmacological approach using a novel FLAP antagonist encapsulated into Ace-DEX-based NPs with improved efficiency in blood to suppress leukotriene biosynthesis., (© 2021. The Author(s).)

Stimuli-responsive block copolymer micelles can provide tailored properties for the efficient delivery of genetic material. In particular, temperature- and pH-responsive materials are of interest, since their physicochemical properties can be easily tailored to meet the requirements for successful gene delivery. Within this study, a stimuli-responsive micelle system for gene delivery was designed based on a diblock copolymer consisting of poly( N , N -diethylacrylamide) (PDEAm) as a temperature-responsive segment combined with poly(aminoethyl acrylamide) (PAEAm) as a pH-responsive, cationic segment. Upon temperature increase, the PDEAm block becomes hydrophobic due to its lower critical solution temperature (LCST), leading to micelle formation. Furthermore, the monomer 2-(pyridin-2-yldisulfanyl)ethyl acrylate (PDSAc) was incorporated into the temperature-responsive PDEAm building block enabling disulfide crosslinking of the formed micelle core to stabilize its structure regardless of temperature and dilution. The cloud points of the PDEAm block and the diblock copolymer were investigated by turbidimetry and fluorescence spectroscopy. The temperature-dependent formation of micelles was analyzed by dynamic light scattering (DLS) and elucidated in detail by an analytical ultracentrifuge (AUC), which provided detailed insights into the solution dynamics between polymers and assembled micelles as a function of temperature. Finally, the micelles were investigated for their applicability as gene delivery vectors by evaluation of cytotoxicity, pDNA binding, and transfection efficiency using HEK293T cells. The investigations showed that core-crosslinking resulted in a 13-fold increase in observed transfection efficiency. Our study presents a comprehensive investigation from polymer synthesis to an in-depth physicochemical characterization and biological application of a crosslinked micelle system including stimuli-responsive behavior.

Associations between inherited Killer Immunoglobulin-like Receptor (KIR) genotypes and the severity of multiple RNA virus infections have been reported. This prospective study was initiated to investigate if such an association exists for COVID-19. In this cohort study performed at Ankara University, 132 COVID-19 patients (56 asymptomatic, 51 mild-intermediate, and 25 patients with severe disease) were genotyped for KIR and ligands. Ankara University Donor Registry (n:449) KIR data was used for comparison. Clinical parameters (age, gender, comorbidities, blood group antigens, inflammation biomarkers) and KIR genotypes across cohorts of asymptomatic, mild-intermediate, or severe disease were compared to construct a risk prediction model based on multivariate binary logistic regression analysis with backward elimination method. Age, blood group, number of comorbidities, CRP, D-dimer, and telomeric and centromeric KIR genotypes (tAA, tAB1, and cAB1) along with their cognate ligands were found to differ between cohorts. Two prediction models were constructed; both included age, number of comorbidities, and blood group. Inclusion of the KIR genotypes in the second prediction model exp (-3.52 + 1.56 age group - 2.74 blood group (type A vs others) + 1.26 number of comorbidities - 2.46 tAB1 with ligand + 3.17 tAA with ligand) increased the predictive performance with a 92.9% correct classification for asymptomatic and 76% for severe cases (AUC: 0.93; P < 0.0001, 95% CI 0.88, 0.99). This novel risk model, consisting of KIR genotypes with their cognate ligands, and clinical parameters but excluding earlier published inflammation-related biomarkers allow for the prediction of the severity of COVID-19 infection prior to the onset of infection. This study is listed in the National COVID-19 clinical research studies database., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Cationic polymers are promising gene delivery vectors due to their ability to bind and protect genetic material. The introduction of hydrophobic moieties into cationic polymers can further improve the vector efficiency, but common formulations of hydrophobic polymers involve harsh conditions such as organic solvents, impairing intactness and loading efficiency of the genetic material. In this study, a mild, aqueous formulation method for the encapsulation of high amounts of genetic material is presented. A well-defined pH-responsive hydrophobic copolymer, i.e. poly((n-butylmethacrylate)-co-(methylmethacrylate)-co-(2-(dimethylamino) ethylmethacrylate)), (PBMD) was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. Exploiting the pH-dependent solubility behavior of the polymer, stable pDNA loaded nanoparticles were prepared and characterized using analytical ultracentrifugation (AUC), cryo-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). This novel formulation approach showed high transfection efficiencies in HEK293T cells, while requiring 5- to 10-fold less pDNA compared to linear polyethylenimine (LPEI), in particular at short incubation times and in serum-containing media. Furthermore, the formulation was successfully adopted for siRNA and mRNA encapsulation and the commercially approved polymer Eudragit® E(PO/100). Overall, the aqueous formulation approach, accompanied by a tailor-made hydrophobic polymer and detailed physicochemical and application studies, led to improved gene delivery vectors with high potential for further applications., (Copyright © 2020 Elsevier B.V. All rights reserved.)

From the perspective of future translation, medical, biodegradable nanoparticles (NPs) have been investigated using an analytical ultracentrifuge in fluids of various complexity, including human serum, in the temperature range of 6 to 40 °C, and timescales relevant for a nanomedical targeting and clearance application. These studies provided salient insights into the integrity and degradation aspects of the NPs, imposed by varying solution environmental conditions. This was enabled by selective monitoring of the targeting dye moiety, cell-specifically directing the NPs to the desired location of interest, i.e. considering a future translative in vivo application. Our study provides experimental insights that are believed to be of key importance to gauge the feasibility of such translative applications in terms of (i) compatibility with patient sera, (ii) timescales of targeting success, and (iii) timescales of desired erosion enabling clearance from the target. All such aspects are provided a priori any in vivo implementation.

The large volume and diversified nanomedicine market, undergoing a rapid growth, relies not only on the creation and applicative exploration of nanocarrier-based medicines showing significant potential, but in particular, demands a quantitative assessment of their physicochemical properties. In this study, we demonstrate the in situ assessment of multifunctional biodegradable nanoparticle (NP) entries as core components of nanoscale drug delivery systems (NDDSs) by making use of analytical ultracentrifugation (AUC). We determine and elucidate the following characteristics of NPs in NDDSs: NP density and size, targeting dye functionality, encapsulated and free drug, surfactant, and also NP drug release dynamics, quantitatively interconnected to NP degradation. In concept, we demonstrate this by multidetection AUC experiments at variable speed and time profiles. We could verify the quantitative and accurate nature of AUC for assessment of NDDSs, that is, also future nanomedicines. This concerns modeled and real life solution application formats such as cell culture media and human serum.

The interrelation of experimental rotational and translational hydrodynamic friction data as a basis for the study of macromolecules in solution represents a useful attempt for the verification of hydrodynamic information. Such interrelation originates from the basic development of colloid and macromolecular science and has proven to be a powerful tool for the study of naturally- and synthetically-based, i.e., artificial, macromolecules. In this tutorial review, we introduce this very basic concept with a brief historical background, the governing physical principles, and guidelines for anyone making use of it. This is because very often data to determine such an interrelation are available and it only takes a set of simple equations for it to be established. We exemplify this with data collected over recent years, focused primarily on water-based macromolecular systems and with relevance for pharmaceutical applications. We conclude with future incentives and opportunities for verifying an advanced design and tailored properties of natural/synthetic macromolecular materials in a dispersed or dissolved manner, i.e., in solution. Particular importance for the here outlined concept emanates from the situation that the classical scaling relationships of Kuhn-Mark-Houwink-Sakurada, most frequently applied in macromolecular science, are fulfilled, once the hydrodynamic invariant and/or sedimentation parameter are established. However, the hydrodynamic invariant and sedimentation parameter concept do not require a series of molar masses for their establishment and can help in the verification of a sound estimation of molar mass values of macromolecules.

Carbapenemase-producing Enterobacteriacea (CPE) cause serious and life-threatening infections. They are resistant to carbapenems and many other classes of commonly used antimicrobial agents; therefore, managing infections caused by them poses a substantial challenge in clinical practice. They can also cause morbidity and mortality in patients with liver transplant. A retrospective analysis of CPE culture-positive patients with a history of liver transplant can help to examine the epidemiology and microbiology of these bacteria, as well as gain information on the possible infection sources, susceptibility patterns, and expected mortality in infected populations. In addition, study of these bacteria could help formulate a consensus on the appropriate use of empirical and directed antibiotic therapy, which can effectively reduce infections in these patients. We reviewed the medical records of 142 subjects who underwent liver transplantation at Ankara University Hospital, a 1900-bed tertiary care university hospital, in Ankara, Turkey, between January 2014 and August 2018. Patients showing signs of infection with culture positivity for CPE-producing organisms were included from the study. Statistical analysis was performed and a value of P < .05 is considered statistically significant. In most cases, the source of infection was the abdomen. Klebsiella species was also predominant in these cases. Model for End-Stage Liver Disease scores and length of hospital stay were higher and statistically significant when compared to patients who were CPE negative. Mortality was highest in the CPE-positive group. Infection is the most important cause of mortality and morbidity after liver transplantation and increases the cost of treatment. Regarding the culture sensitivity patterns and resistance mode, empirical therapy with carbapenems does not produce a solid result. The high mortality observed with these infections reflects very limited therapeutic options., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Owing to impaired immune function, surgical procedures, and multiple hospitalizations, patients with end-stage liver disease are at risk for numerous infectious complications while waiting for transplantation. Infection in transplant recipients remains the main cause of mortality and morbidity, despite advances in surgical techniques and the development of new repressive agents. The purpose of this study is to examine the infections that develop during the pretransplantion period in live donor liver transplant recipients and their effect on post-transplant clinical outcomes. The retrospective analysis of adult live donor liver transplant recipients in the last 4 years was conducted at Ankara University Hospital, a 1900-bed tertiary-care university hospital, in Ankara, Turkey. Demographic characteristics, preoperative infections, and clinical outcomes were analyzed. Patients were divided into 2 groups according to whether they had developed an infection before transplantation. The diagnoses were based on clinical, laboratory, and microbiological findings. Statistical analyses were performed using Stata version 9.0 (StataCorp, College Station, Tex., United States), and P < .05 were considered statistically significant. In univariate analyses, having diabetes mellitus or a pretransplant infection, the number of pretransplant infection attacks, the need for a reoperation, and developing a post-transplant infection were the statistically significant factors associated with 1-year mortality (P < .001, χ 2 test). In multivariate analyses, diabetes mellitus (Odds ratio [OR] = 7.44, 95% confidence interval [CI], .03-45.79; P = .013), reoperation (OR = .33, 95% CI, .25-2.20; P < .001), having a pretransplantation infection (OR = 12.47, 95% CI, .011-87.67; P = .013), and the number of pretransplantation infection attacks (OR = .028, 95% CI, .013-.47; P < .001) were found to be statistically significant risk factors for 1-year mortality. Our study showed the effect of pretransplantation infections on post-transplant morbidity but not on rejection or mortality. According to the situation of patients, manageable pretransplantation infection is not an absolute contraindication for liver transplantation. Awareness of the increased risk for post-transplant infections and fast-acting antimicrobial coverage are the most important facts for patient survival., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Guidance of neurite extension and establishment of neural connectivity hold great importance for neural tissue regeneration and neural conduit implants. Although bioactive-epitope functionalized synthetic or natural polymeric materials have been proposed for the induction of neural regeneration, chemical modifications of these materials for neural differentiation still remain a challenge due to the harsh conditions of chemical reactions, along with non-homogeneous surface modifications. In this study, a facile noncovalent functionalization method is proposed by exploiting host-guest interactions between an adamantane-conjugated laminin derived bioactive IKVAV epitope and electrospun cyclodextrin nanofibers (CDNFs) to fabricate implantable scaffolds for peripheral nerve regeneration. While electrospun CDNFs introduce a three-dimensional biocompatible microenvironment to promote cellular viability and adhesion, the bioactive epitopes presented on the surface of electrospun CDNFs guide the cellular differentiation of PC-12 cells. In addition to materials synthesis and smart functionalization, physical alignment of the electrospun nanofibers guides the cells for enhanced differentiation. Cells cultured on aligned and IKVAV functionalized electrospun CDNFs had significantly higher expression of neuron-specific βIII-tubulin and synaptophysin. The neurite extension is also higher on the bioactive aligned scaffolds compared to random and non-functionalized electrospun CDNFs. Both chemical and physical cues were utilized for an effective neuronal differentiation process.

Peptide amphiphiles (PAs) self-assemble into supramolecular nanofiber gels that provide a suitable environment for encapsulation of both hydrophobic and hydrophilic molecules. The PA gels have significant advantages for controlled delivery applications due to their high capacity to retain water, biocompatibility, and biodegradability. In this study, we demonstrate injectable supramolecular PA nanofiber gels for drug delivery applications. Doxorubicin (Dox), as a widely used chemotherapeutic drug for breast cancer treatment, was encapsulated within the PA gels prepared at different concentrations. Physical and chemical properties of the gels were characterized, and slow release of the Dox molecules through the supramolecular PA nanofiber gels was studied. In addition, the diffusion constants of the drug molecules within the PA nanofiber gels were estimated using fluorescence recovery after the photobleaching (FRAP) method. The PA nanofiber gels did not show any cytotoxicity and the encapsulation strategy enhanced the activity of drug molecules on cellular viability through prolonged release compared to direct administration under in vitro conditions. Moreover, the local in vivo injection of the Dox encapsulated PA nanofiber gels (Dox/PA) to the tumor site demonstrated the lowest tumor growth rate compared to the direct Dox injection and increased the apoptotic cells within the tumor tissue for local drug release through the PA nanofiber gels under in vivo conditions.

Nature is an important inspirational source for scientists, and presents complex and elegant examples of adaptive and intelligent systems created by self-assembly. Significant effort has been devoted to understanding these sophisticated systems. The self-assembly process enables us to create supramolecular nanostructures with high order and complexity, and peptide-based self-assembling building blocks can serve as suitable platforms to construct nanostructures showing diverse features and applications. In this review, peptide-based supramolecular assemblies will be discussed in terms of their synthesis, design, characterization and application. Peptide nanostructures are categorized based on their chemical and physical properties and will be examined by rationalizing the influence of peptide design on the resulting morphology and the methods employed to characterize these high order complex systems. Moreover, the application of self-assembled peptide nanomaterials as functional materials in information technologies and environmental sciences will be reviewed by providing examples from recently published high-impact studies.

Characterization of amyloid-like aggregates through converging approaches can yield deeper understanding of their complex self-assembly mechanisms and the nature of their strong mechanical stability, which may in turn contribute to the design of novel supramolecular peptide nanostructures as functional materials. In this study, we investigated the coassembly kinetics of oppositely charged short amyloid-inspired peptides (AIPs) into supramolecular nanostructures by using confocal fluorescence imaging of thioflavin T binding, turbidity assay and in situ small-angle X-ray scattering (SAXS) analysis. We showed that coassembly kinetics of the AIP nanostructures were consistent with nucleation-dependent amyloid-like aggregation, and aggregation behavior of the AIPs was affected by the initial monomer concentration and sonication. Moreover, SAXS analysis was performed to gain structural information on the size, shape, electron density, and internal organization of the coassembled AIP nanostructures. The scattering data of the coassembled AIP nanostructures were best fitted into to a combination of polydisperse core-shell cylinder (PCSC) and decoupling flexible cylinder (FCPR) models, and the structural parameters were estimated based on the fitting results of the scattering data. The stability of the coassembled AIP nanostructures in both fiber organization and bulk viscoelastic properties was also revealed via temperature-dependent SAXS analysis and oscillatory rheology measurements, respectively.

Synthetic vaccines utilize viral signatures to trigger immune responses. Although the immune responses raised against the biochemical signatures of viruses are well characterized, the mechanism of how they affect immune response in the context of physical signatures is not well studied. In this work, we investigated the ability of zero- and one-dimensional self-assembled peptide nanostructures carrying unmethylated CpG motifs (signature of viral DNA) for tuning immune response. These nanostructures represent the two most common viral shapes, spheres and rods. The nanofibrous structures were found to direct immune response towards Th1 phenotype, which is responsible for acting against intracellular pathogens such as viruses, to a greater extent than nanospheres and CpG ODN alone. In addition, nanofibers exhibited enhanced uptake into dendritic cells compared to nanospheres or the ODN itself. The chemical stability of the ODN against nuclease-mediated degradation was also observed to be enhanced when complexed with the peptide nanostructures. In vivo studies showed that nanofibers promoted antigen-specific IgG production over 10-fold better than CpG ODN alone. To the best of our knowledge, this is the first report showing the modulation of the nature of an immune response through the shape of the carrier system.

Natural extracellular matrix (ECM) consists of complex signals interacting with each other to organize cellular behavior and responses. This sophisticated microenvironment can be mimicked by advanced materials presenting essential biochemical and physical properties in a synergistic manner. In this work, we developed a facile fabrication method for a novel nanofibrous self-assembled peptide amphiphile (PA) and poly(ethylene glycol) (PEG) composite hydrogel system with independently tunable biochemical, mechanical, and physical cues without any chemical modification of polymer backbone or additional polymer processing techniques to create synthetic ECM analogues. This approach allows noninteracting modification of multiple niche properties (e.g., bioactive ligands, stiffness, porosity), since no covalent conjugation method was used to modify PEG monomers for incorporation of bioactivity and porosity. Combining the self-assembled PA nanofibers with a chemically cross-linked polymer network simply by facile mixing followed by photopolymerization resulted in the formation of porous bioactive hydrogel systems. The resulting porous network can be functionalized with desired bioactive signaling epitopes by simply altering the amino acid sequence of the self-assembling PA molecule. In addition, the mechanical properties of the composite system can be precisely controlled by changing the PEG concentration. Therefore, nanofibrous self-assembled PA/PEG composite hydrogels reported in this work can provide new opportunities as versatile synthetic mimics of ECM with independently tunable biological and mechanical properties for tissue engineering and regenerative medicine applications. In addition, such systems could provide useful tools for investigation of how complex niche cues influence cellular behavior and tissue formation both in two-dimensional and three-dimensional platforms.

Background: To establish sonographic (US) criteria for the diagnosis of internal jugular phlebectasia (IJP) in children and to determine reliable cutoff values of US measurements with high specificity and sensitivity., Methods: We used B-mode US for the measurement of internal jugular vein transverse (T) and anteroposterior (AP) diameter, and cross-sectional area (CSA) at rest and during the Valsalva maneuver (VM) in 21 patients, aged 15 months to 16 years, diagnosed with IJP, and compared the results with those of 88 healthy children. Receiver operating characteristics curves were used to determine the optimal cutoff values., Results: Patients with IJP had higher T, AP diameters, and CSA at rest and during VM than controls on the same side (p < 0.001). Receiver operating characteristics curves showed that CSA during the VM on both sides yielded the best results (cutoff value 220 mm(2) with 92.3% sensitivity, 92% specificity on the right side; 188 mm(2) with 90% sensitivity, 87.5% specificity on the left side). AP diameter offered better specificity and sensitivity (≥85%) than T diameter during VM on both sides., Conclusions: We suggest using an AP diameter >15 mm as a cutoff point for both sides for the diagnosis of IJP in daily practice. US measurement of the jugular vein diameter might help increasing clinicians' awareness of clinically unrecognized cases of IJP and identifying borderline cases that require follow-up., (Copyright © 2013 Wiley Periodicals, Inc.)