Impact of temporal resolution in single particle tracking analysis.

Temporal resolution is a key parameter in the observation of dynamic processes, as in the case of single molecules motions visualized in real time in two-dimensions by wide field (fluorescence) microscopy, but a systematic investigation of its effects in all the single particle tracking analysis steps is still lacking. Here we present tools to quantify its impact on the estimation of diffusivity and of its distribution using one of the most popular tracking software for biological applications on simulated data and movies. We found important shifts and different widths for diffusivity distributions, depending on the interplay of temporal sampling conditions with various parameters, such as simulated diffusivity, density of spots, signal-to-noise ratio, lengths of trajectories, and kind of boundaries in the simulation. We examined conditions starting from the ones of experiments on the fluorescently labelled receptor p75NTR, a relatively fast-diffusing membrane receptor (diffusivity around 0.5-1 µm2/s), visualized by TIRF microscopy on the basal membrane of living cells. From the analysis of the simulations, we identified the best conditions in cases similar to these ones; considering also the experiments, we could confirm a range of values of temporal resolution suitable for obtaining reliable diffusivity results. The procedure we present can be exploited in different single particle/molecule tracking applications to find an optimal temporal resolution.

Communal conflicts in Nigeria: Assessment of the impacts on internally displaced persons and settlements amidst COVID-19 pandemic.

Acknowledging that violent communal conflicts can lead to increased displacement and overcrowding in IDP camps, this study investigates the impact of such conflicts on internally displaced persons (IDPs) and their camps in Benue State, Nigeria, amid the COVID-19 pandemic. Employing a mixed-method approach, 386 IDPs and 20 stakeholders were purposively selected. Based on the research objectives, descriptive and inferential statistics were employed to analyze the research objectives. Employing logistics and multi-linear regressions, the data reveal that unregulated access to IDP camps resulted in overcrowding, straining resources like food and shelter. The study identifies economic losses and various challenges stemming from communal conflict and COVID-19, causing chaos, anxiety, and uncertainty in the IDP camps. These findings highlight the urgent need for ongoing humanitarian assistance to alleviate the precarious conditions faced by IDPs and their camps nationwide and recommend that the IDPs camps across the country need constant humanitarian aid to mitigate the various precarious conditions in the camps.

Experimental study on failure mode and fracture evolution characteristics of red shale in Kaiyang Phosphorus mining area.

In order to study the failure mode and fracture evolution characteristics of red shale in Kaiyang Phosphorus mining area, conventional triaxial compression mechanical tests of red shale with different bedding dip angles were carried out by using DSTD-1000 electro-hydraulic servo rock mechanics experiment system. Based on the laboratory test results, the conventional triaxial particle flow simulation of red shale samples with different bedding dip angles was carried out using discrete element PFC2D. The results show that: (1) the failure mode of red shale is controlled by bedrock when the bedding dip angle is 0° and 60° ~ 90°. When the bedding dip angle is 15° ~ 45°, the rock failure mode is controlled by bedding. The compressive strength of rock is the minimum when the bedding dip angle is 30°and the maximum at 0°, which is about 2 times of the minimum. (2) In the failure process of red shale, the cracks with different bedding dip angles show slow growth stage, accelerated growth stage and stable stage with axial strain. The whole failure process is dominated by tensile cracks, accompanied by a few shear cracks. (3) The type of displacement field varies with the bedding dip angle: tensile failure and shear failure are the main displacement field types at 15° ~ 45°, and mixed failure is often the main mode at 60° ~ 90°and 0°. The research results provide the basis and reference for the safety control of red shale roadway.

Engineering a cell-free biosensor signal amplification circuit with polymerase strand recycling.

Cell-free systems are powerful synthetic biology technologies because of their ability to recapitulate sensing and gene expression without the complications of living cells. Cell-free systems can perform even more advanced functions when genetic circuits are incorporated as information processing components. Here we expand cell-free biosensing by engineering a highly specific isothermal signal amplification circuit called polymerase strand recycling (PSR) that leverages T7 RNA polymerase off-target transcription to recycle nucleic acid inputs within DNA strand displacement circuits. We develop design rules for PSR circuit components and use these rules to construct modular biosensors that can directly sense different RNA targets with limits of detection in the nM range and high specificity. We then use PSR for signal amplification within allosteric transcription factor-based biosensors for small molecule detection. We use a double equilibrium model of transcription factor:DNA and transcription factor:ligand binding interactions to predict biosensor sensitivity enhancement by PSR, and then demonstrate this approach experimentally by achieving 3.6-4.6-fold decreases in biosensor EC50 to sub micromolar ranges. We believe this work expands the current capabilities of cell-free circuits by incorporating PSR, which we anticipate will have a wide range of uses within biotechnology.

A conceptual framework on pre- and post-displacement stressors: the case of Syrian refugees.

Researchers have documented multiple stressors and mental health problems along the journey of refugees as they are displaced to seek refuge in nearby and remote host countries. This article examines published research on Syrian refugees to propose a framework to conceptualize Syrian refugees' pre- and post-stressors and their collective impact on their mental health. The proposed framework provides a comprehensive understanding of the interconnected pathways between pre-displacement stressors, post-displacement stressors, and mental health outcomes for Syrian refugees. Pre-displacement stressors are best captured by the concept of trauma centrality and emotional suppression. Post-displacement stressors, categorized under financial, political, and social themes, have a direct impact on the mental health of the refugees, but could also play a partial mediating role on the impact of pre-displacement stressors on mental health. The framework suggests a direct pathway between the experience of war-related traumatic events and mental health and introduces the country of residence as a potential moderator of the severity of mental health. The latter is primarily influenced by local policies and the host communities' acceptance of refugees. We believe that the proposed framework can guide the work of researchers, policymakers, and practitioners concerned with the mental health and well-being of Syrian refugees. Additionally, although based on the experience of Syrian refugees, it presents a holistic perspective that could be adapted in other refugee settings.

Treatment of phenolic wastewater in an anaerobic fluidized bed microbial fuel cell filled with graphene oxide-macroporous adsorption resin as multifunctional carrier.

A novel graphene oxide-modified resin (graphene oxide-macroporous adsorption resin) was prepared and used as a multifunctional carrier in an anaerobic fluidized bed microbial fuel cell (AFB-MFC) to treat phenolic wastewater (PW). The macroporous adsorption resin (MAR) was used as the carrier, graphene oxide was used as the modified material, the conductive modified resin was prepared by loading graphene oxide (GO) on the resin through chemical reduction. The modified resin particles were characterized by scanning electron microscopy (SEM), Raman spectroscopy (RS), specific surface area and pore structure analysis. Graphene oxide-macroporous adsorption resin special model was established using the Amorphous Cell module in Materials Studio (MS), and the formation mechanism of graphene oxide-macroporous adsorption resin was studied using mean square displacement (MSD) of the force module. Molecular dynamics simulation was used to study the motion law of molecular and atomic dynamics at the interface of graphene oxide-macroporous adsorption resin composites. The strong covalent bond between GO and MAR ensures the stability of GO/MAR. When the modified resin prepared in 3.0 mg/mL GO mixture was used in the AFB-MFC, the COD removal of wastewater was increased by 9.1% to 72.44%, the voltage was increased by 84.04% to 405.8 mV, and power density was increased by 765.44% to 242.67 mW/m2.

Growth and body composition of infants born moderate-to-late preterm fed an protein- and mineral-enriched postdischarge formula compared with a standard term formula up to 6 months corrected age, a randomized controlled trial.

BACKGROUND: Infants born moderate-to-late preterm (i.e., 32 0/7-35 6/7 weeks' gestation) are, analogous to those born very preterm, at risk of later obesity, hypertension, and diabetes. Appropriate early life nutrition is key for ensuring optimal growth and body composition, thereby mitigating potential cardiometabolic risks. OBJECTIVE: To compare growth and body composition between infants born moderate-to-late preterm fed isocaloric but protein- and mineral-enriched postdischarge formula (PDF) or standard term formula (STF) until 6 months corrected age (CA; i.e., after term equivalent age [TEA]). METHODS: After enrolment (≤7 days postpartum), infants received PDF if (fortified) mother's own milk (MOM) was insufficient. At TEA, those receiving >25% of intake as formula were randomized to either continue the same PDF (n=47) or switch to STF (n=50); those receiving ≥75% of intake as MOM (n=60) served as references. At TEA and 6 months CA, we assessed anthropometry and body composition using both dual-energy x-ray absorptiometry and air displacement plethysmography. RESULTS: Feeding groups had similar gestational age (median [p25;p75]: 34.3 [33.5;35.1] weeks), birthweight (mean ± SD: 2175 ± 412 g), anthropometry and body composition at TEA. At 6 months CA, infants fed PDF had slightly, but significantly, higher length (67.6 ± 2.5 and 66.9 ± 2.6 cm, p<0.05) and larger head circumference (43.9 ± 1.3 and 43.4 ± 1.5 cm, p<0.05) compared to infants fed STF. Also, infants fed PDF had higher lean mass and bone mineral content estimated by dual-energy x-ray absorptiometry (4772 ± 675 and 4502 ± 741 g; 140 ± 20 and 131 ± 23 g, respectively; p<0.05). Air displacement plethysmography estimates, however, were not statistically different between feeding groups. CONCLUSIONS: Infants born moderate-to-late preterm demonstrated modest increases in length, head circumference, lean mass, and bone mineral content when fed PDF compared to STF for 6 months after TEA. CLINICAL TRIAL REGISTER: International Clinical Trial Registry Platform (https://trialsearch.who.int) as: NTR5117 (old-NTR) and NTR NL4979 (new-NTR) .

Capitalist Heterotopia & Lost Social Utopia: Documenting Class, Work, and Migration in Post-Communist East-Central European Fiction.

Some of the most acclaimed novels from post-communist countries deal with communism through an anti-communist ethos. The emerging international canon of post-communist representations of communism and transition to capitalism has always sought to enfoce a convincing anti-communist ideal. Writers have only recently formulated critiques of the post-communist transition through what Boris Buden describes as post-communist cultures without social utopias. Those novels are not rooted in anti-communism but rather criticize the death of utopias following the fall of communism. Drawing on the Romanian case, we try to outline the heterotopias of capitalism in post-communism from the standpoint of novels on migration and work abroad, addressing contemporary understandings of capitalist realism, post-socialist realism, autofiction, and documented realism. Analysing novels by Liliana Nechit, Mihai Buzea, and Adrian Schiop, we reveal the subjective nature of the testimonial literature on migration and contrast it to the need to incorporate workers' agency into this literary process. While the description of Eastern European capitalism through novels about migration has become an indictment of communism and a subtle plea for a 'better' form of capitalism, the novels about internal migration recover a lost social utopia that ended with the 1989 collapse of Romanian communism.

Bayesian inference of atomic column positions in scanning transmission electron microscopy images.

Atomic-resolution scanning transmission electron microscopy combined with 2D Gaussian fitting enables the accurate and precise identification of atomic column positions within a few picometers. The measurement performance significantly depends on the signal-to-noise ratio of the atomic columns. In areas with low signal-to-noise ratios, such as near surfaces, the measurement performance was lower than that of the bulk. However, previous studies evaluated the accuracy and precision only in bulk areas, underscoring the need for a method that quantitatively evaluates the accuracy and precision of each atomic column position with various signal-to-noise ratios. This study introduced Bayesian inference to assess the accuracy and precision of determining individual atomic column positions under various signals. We applied this method to simulated and experimental images and demonstrated its effectiveness in identifying statistically significant displacements, particularly near surfaces with signal degradation. The use of vector maps and kernel density estimate plots obtained from Bayesian inference provided a probabilistic understanding of the atom displacement. Therefore, this study highlighted the potential benefits of Bayesian inference in high-resolution imaging to reveal material properties.

Comparative study of arthrocentesis with concentric-needle cannula with classic concentric needle: A randomized single-blind controlled clinical trial.

This study aimed to assess and compare the efficacy of two distinct single-puncture techniques in temporomandibular joint (TMJ) arthrocentesis for managing disk displacement without reduction (DDwoR). Sixty patients with DDwoR were randomly and blindly assigned to two treatment groups (n = 30 each): group 1 - TMJ arthrocentesis with the classic concentric needle; and group 2 - TMJ arthrocentesis with the concentric needle-cannula system. The following variables were recorded and compared across the groups: patient's pain perception (visual analog scale - VAS, 0-10); maximal interincisal distance (MID, mm); facial edema (FE, presence or absence); and operation duration (OP, minutes). Patients in group 2 presented significantly lower values of VAS score and presence of FE (p < 0.05) when examining the data at 24 and 48 h after the arthrocentesis. They also showed an increase in MID values (p = 0.024) after 6 months. With regard to OP, no significant difference was observed between the groups. Performing a single-puncture TMJ arthrocentesis using a concentric needle-cannula system significantly reduced the patients' pain perception, and mitigated the presence of facial edema during the immediate postoperative period (at 24 and 48 h). Furthermore, it resulted in a notable increase in the MID after 6 months.

Influence of ceramic waste powder on shear performance of environmentally friendly reinforced concrete beams.

This investigation considered the usability of ceramic waste powder (CWP) in altered quantities in reinforced concrete beams (RCBs). In this way, it was aimed to reduce the environmental impacts of concrete by using CWP as a raw material in RCBs. 12 small-scale shear RCBs with the dimensions of 100 × 150 × 1000 mm were tested in this study. The variations of stirrups spacing and CWP ratio were examined in these specimens. The percentages of CWP by weight utilized in RCBs were 10%, 20%, and 30%, and stirrups spacings were adopted as 270 mm, 200 mm, and 160 mm. At the end of the study, it was determined that more than 10% CWP additive negatively affected the RCBs' compressive strength. The load-carrying capacity reduced between 30.3% and 59.4% when CWP increased from 0% to 30% as compared to RCB with stirrups spacing of 270 mm without CWP. However, compared to RCB with stirrups spacings of 200 mm and 160 mm without CWP, there were decreases in the load-carrying capacity as 21.4%-54.3% and 18.6%-54.6%, respectively. While the CWP ratio increased, the specimens with 160 mm, 200 mm, and 270 mm stirrups spacings obtained a lower maximum load value. However, with the increase of the CWP ratio in the specimens with 160 mm stirrups spacing, RCBs reached the maximum load-carrying capacity at an earlier displacement value. When stirrups spacing was selected as 270 mm, it was observed that the maximum load-carrying capacity of RCBs reached at a similar displacement value as the CWP ratio increased. Besides, it was resulted that the bending stiffness of RCBs reduced as the quantity of CWP enhanced. The bending stiffness decreased by 29.1% to 66.4% in the specimens with 270 mm stirrups spacing, 36.3% to 20.2% with 200 mm stirrups spacing, and 10.3% to 36.9% with 160 mm stirrups spacing. As an implication of the experiments, the use of CWP up to 10% in RCBs was realized as an economical and environmental approach and is suggested. There is some evidence to report that making use of CWP may be considered to be ecologically benign. This is due to the fact that reusing CWP may significantly reduce CO2 emissions, save energy, and reduce total power consumption. Furthermore, the experimental results were compared to the analytical calculations.

Two-step periosteal releasing incision for tension-free flap closure after implant placement with simultaneous guided bone regeneration.

We evaluated the effect of periosteal-releasing incisions on flap displacement in anterior maxillary sites following implant placement and simultaneously guided bone regeneration. Thirty patients requiring a single dental implant and guided bone regeneration in the maxillary esthetic zone were recruited. After full-thickness flap elevation, the displacement of the flap was measured under a standardized tension of 1 Ncm. Then, a two-step periosteal releasing incision was placed in the internal aspect of the flap, and the displacement was remeasured using the same standardized tension. Keratinized tissue width and mucosal thickness at the surgical site were recorded. Patient-reported outcomes were assessed at the 7- and 14-day recall visits. Flap displacement (primary outcome) was calculated before and after periosteal-releasing incisions. Multivariable linear regression models were used to evaluate the influence of mucosal thickness on flap displacement and adjusted for Keratinized tissue width. Primary wound closure was achieved in all patients. The mean difference in flap coronal displacement before and after the periosteal-releasing incisions was 8.2 mm (p<0.0001). Adjusted regression models showed no association between mucosal thickness and keratinized tissue width with the amount of flap displacement (p=0.770). PROMs for pain, swelling, and bleeding amounted to 1.28 ± 1.93, 1.36 ± 1.87, and 0.0 ± 0.0 at seven days and 0.11 ± 0.57, 0.56 ± 1.03, and 0.0 ± 0.0 at 14 days, respectively. Periosteal-releasing incisions using the two-step procedure described here are a predictable technique to obtain coronal flap displacements > 8 mm without increased surgical complications.

Clinical effect of digitalized designed and 3D-printed repositioning splints in the treatment of anterior displacement of temporomandibular joint disc.

OBJECTIVE: To compare the treatment effectiveness of digitized and 3D-printed repositioning splints with that of conventional repositioning splints in the treatment of anterior displacement of the temporomandibular joint disc. METHODS: This retrospective study included 96 patients with disc displacement of the anterior temporomandibular joint. They were treated with either digitally designed and 3D-printed repositioning splints or traditional splints and followed up for at least six months. Changes in signs and symptoms such as pain and mouth opening before and after treatment were recorded to evaluate treatment outcomes. RESULTS: During the first month of treatment, both the digitally designed and 3D-printed repositioning splint groups (Group B) and the traditional repositioning splint group (Group A) showed significant increases in mouth opening, with increases of 4.93 ± 3.06 mm and 4.07 ± 4.69 mm, respectively, and there was no significant difference between the two groups. Both groups had a significant reduction in visual analog scale (VAS) pain scores, with Group B showing a greater reduction of 1.946 ± 1.113 compared to 1.488 ± 0.978 in Group A (P < 0.05). By the sixth month, Group B's mouth opening further improved to 38.65 ± 3.22 mm (P < 0.05), while Group A's mouth opening did not significantly improve. Regarding pain, Group A's VAS score decreased by 0.463 ± 0.778 after one month, and Group B's score decreased by 0.455 ± 0.715; both groups showed significant reductions, but there was no significant difference between the two groups. CONCLUSION: Compared with traditional repositioning splints, digitally designed and 3D-printed repositioning splints are more effective at reducing patient pain and improving mouth opening. 3D-printed repositioning splints are an effective treatment method for temporomandibular joint disc displacement and have significant potential for widespread clinical application.

Identifying gaps in healthcare: a qualitative study of Ukrainian refugee experiences in the German system, uncovering differences, information and support needs.

BACKGROUND: The 5.8 million Ukrainian refugees arriving in European countries must navigate varying healthcare systems and different and often unknown languages in their respective host countries. To date, there has been little exploration of the experiences, perceived differences, information and support needs of these refugees regarding the use of healthcare in Germany. METHODS: We conducted ten qualitative interviews with Ukrainian refugees living in Germany from February to May 2023, using Ukrainian, English and German language. The transcribed interviews were analysed using the qualitative content analysis method according to Kuckartz and Rädiker with the MAXQDA software. RESULTS: In general, participants consistently had a positive experience of the German healthcare system, particularly regarding the quality of treatments and insurance. Differences have been reported in the structure of the healthcare systems. The Ukrainian healthcare system is divided into private and state sectors, with no mandatory insurance and frequent out-of-pocket payments. Pathways differ and tend to focus more on clinics and private doctors. General practitioners, often working in less well-equipped offices, have only recently gained prominence due to healthcare system reforms. Initiating contact with doctors is often easier, with much shorter waiting times compared to Germany. Interviewees often found the prescription requirements for many medications in Germany to be unusual. However, the mentioned differences in healthcare result in unmet information needs among the refugees, especially related to communication, navigating the healthcare system, health insurance, waiting times and medication access. These needs were often addressed through personal internet research and informal (social media) networks because of lacking official information provided during or after their arrival. CONCLUSIONS: Despite the positive experiences of Ukrainian refugees in the German healthcare system, differences in the systems and language barriers led to barriers using healthcare and information needs among refugees. The dissemination of information regarding characteristics of the German health care system is crucial for successful integration but is currently lacking. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00030942, date of registration: 29.12.2022.

Strain rate-dependent failure mechanics of the intervertebral disc under tension/compression and constitutive analysis.

BACKGROUND: The intervertebral disc exhibits not only strain rate dependence (viscoelasticity), but also significant asymmetry under tensile and compressive loads, which is of great significance for understanding the mechanism of lumbar disc injury under physiological loads. OBJECTIVE: In this study, the strain rate sensitive and tension-compression asymmetry of the intervertebral disc were analyzed by experiments and constitutive equation. METHOD: The Sheep intervertebral disc samples were divided into three groups, in order to test the strain rate sensitive mechanical behavior, and the internal displacement as well as pressure distribution. RESULTS: The tensile stiffness is one order of magnitude smaller than the compression stiffness, and the logarithm of the elastic modulus is approximately linear with the logarithm of the strain rate, showing obvious tension-compression asymmetry and rate-related characteristics. In addition, the sensitivity to the strain rate is the same under these two loading conditions. The stress-strain curves of unloading and loading usually do not coincide, and form a Mullins effect hysteresis loop. The radial displacement distribution is opposite between the anterior and posterior region, which is consistent with the stress distribution. By introducing the damage factor into ZWT constitutive equation, the rate-dependent viscoelastic and weakening behavior of the intervertebral disc can be well described.

A biomechanical analysis of novel endovascular implants for aortic valve replacement and ascending aortic repair.

Advances in medical technology have enabled minimally invasive treatment of type A aortic dissection with accompanying aortic regurgitation. Implants include endovascular stent grafts (ESG) and heart valve substitute (HVS) modules. Traditional implants can be divided into two types based on the assembly relationship between ESG and HVS: separated z-shaped implants (SZ) and separated diamond-shaped implants (SD). This study proposes a novel linked diamond-shaped implant (LD). To evaluate the safety and effectiveness of this new implant, finite element simulation models were created to assess the risks of endoleak, migration, and vascular wall rupture under annulus displacement load. After the SZ, SD, and LD implants were grafted in virtual release method, all the implants can cover tear-entry located in the ascending aorta, but space distance (δ) which exposed to blood was 14.5, 13.1, and 7.4 mm, respectively; the maximum areas of contact gap was 76.5, 51.5 and 6.3 mm2; the maximum migration distance (ΔL1) were 1.27, 1.06, and 0.1 mm; the maximum stress on ascending aorta was 0.19, 0.24, and 0.51 MPa, which were lower than failure stress (0.9 MPa). This study showed that both SZ and SD implants had minimal effects on the ascending aorta; however, higher risks were associated with implant migration and proximal endoleak. In contrast, the LD implant can simplify the surgical procedure, has a lower risk of endoleak and migration, and limited stress stimulation of the aorta. This study validated the feasibility and effectiveness of this novel implant using the finite element method, indicating its potential as a secure and reliable treatment option.

Erasable and Field Programmable DNA Circuits Based on Configurable Logic Blocks.

DNA is commonly employed as a substrate for the building of artificial logic networks due to its excellent biocompatibility and programmability. Till now, DNA logic circuits are rapidly evolving to accomplish advanced operations. Nonetheless, nowadays, most DNA circuits remain to be disposable and lack of field programmability and thereby limits their practicability. Herein, inspired by the Configurable Logic Block (CLB), the CLB-based erasable field-programmable DNA circuit that uses clip strands as its operation-controlling signals is presented. It enables users to realize diverse functions with limited hardware. CLB-based basic logic gates (OR and AND) are first constructed and demonstrated their erasability and field programmability. Furthermore, by adding the appropriate operation-controlling strands, multiple rounds of programming are achieved among five different logic operations on a two-layer circuit. Subsequently, a circuit is successfully built to implement two fundamental binary calculators: half-adder and half-subtractor, proving that the design can imitate silicon-based binary circuits. Finally, a comprehensive CLB-based circuit is built that enables multiple rounds of switch among seven different logic operations including half-adding and half-subtracting. Overall, the CLB-based erasable field-programmable circuit immensely enhances their practicability. It is believed that design can be widely used in DNA logic networks due to its efficiency and convenience.

Analyzing the effects of polymeric dielectric materials on micro capacitive pressure sensors: A model incorporating displacement-dependent porosity.

Recently, the extensive utilization of porous polymeric materials to amplify the sensitivity of capacitive devices is noticeable. The absence of an effective mathematical model for studying these devices has spurred the development of a comprehensive mathematical model in the current work. This model is formulated to analyze the static and dynamic behavior of systems incorporating a porous polymer dielectric material within the gap between flexible and fixed microplates. The derived nonlinear governing equations encompass the effects of electrostatic force, von-Karman nonlinear strains, and displacement-dependent porosity. Employing spatial decomposition, the resulting nonlinear algebraic equations and ordinary differential equations are leveraged to study the static and transient dynamic behavior, as well as the frequency response of the sensor using a learning approach. Two scenarios are investigated to assess the impact of various geometrical and physical parameters on sensor sensitivity one with a polymeric material and another without, each with distinct parameter values. The results reveal that the inclusion of a polymeric dielectric material increases electrostatic force but concurrently elevates the equivalent stiffness of the structure. The effectiveness of using a polymeric dielectric material is contingent upon the specific geometrical and physical properties of the sensor. Moreover, the obtained results in simplified cases are compared to existing numerical and experimental data, demonstrating a high degree of agreement. This work significantly contributes to advancing the understanding of sensors incorporating porous polymer dielectric materials and underscores their potential for enhanced sensitivity across diverse applications.

Self-assembly of protein-DNA hybrids dedicated to an accelerated and self-primed strand displacement amplification for reinforced serum microRNA probing.

BACKGROUND: High-efficiency and highly reliable analysis of microRNAs (miRNAs) in bodily fluids highlights its significance to be extensively utilized as candidates for non-invasive "liquid biopsy" approaches. DNA biosensors based on strand displacement amplification (SDA) methods have been successfully designed to detect miRNAs given the efficiently amplified and recycled of the target sequences. However, the unpredictable DNA framework and heavy reliance on free diffusion or random reactant collisions in existing approaches lead to delayed reaction kinetics and inadequate amplification. Thus, it is crucial to create a modular probe with a controlled structure, high local concentration, and ease of synthesis. RESULTS: Inspired by the natural spatial-confinement effect based on a well-known streptavidin-biotin interaction, we constructed a protein-DNA hybrid, named protein-scaffolded DNA tetrads (PDT), which consists of four biotinylated Y-shaped DNA (Y-DNA) surrounding a streptavidin protein center via a streptavidin-biotin bridge. The streptavidin-biotin recognition system significantly increased the local concentration and intermolecular distance of the probes to achieve enhanced reaction efficiency and kinetics. The PDT-based assay starts with the target miRNA binding to Y-DNA, which disassembles the Y-DNA structures into three types of hairpin-shaped structures via self-primed strand displacement amplification (SPSDA) and generates remarkable fluorescence signal that is proportional to the miRNA concentration. Results demonstrated that PDT enabled a more efficient detection of miRNA-21 with a sensitivity of 1 fM. Moreover, it was proven reliable for the detection of clinical serum samples, suggesting great potential for advancing the development of rapid and robust signal amplification technologies for early diagnosis. SIGNIFICANCE: This simple yet robust system contributes to the early diagnosis of miR-21 with satisfactory sensitivity and specificity, and display a significantly improved nuclease resistance owing to their unique structure. The results suggested that the strategy is expected to provide a promising potential platform for tumor diagnosis, prognosis and therapy.

A fluorescent aptasensor for enzyme-free and sensitive detection of kanamycin based on entropy-driven strand displacement reaction.

BACKGROUND: Kanamycin is an antibiotic that can easily cause adverse side effects if used improperly. Due to the extremely low concentrations of kanamycin in food, quantitative detection of kanamycin becomes a challenge. As one of the DNA self-assembly strategies, entropy-driven strand displacement reaction (EDSDR) does not require enzymes or hairpins to participate in the reaction, which greatly reduces the instability of detection results. Therefore, it is a very beneficial attempt to construct a highly sensitive and specific fluorescence detection method based on EDSDR that can detect kanamycin easily and quickly while ensuring that the results are effective and stable. RESULTS: We created an enzyme-free fluorescent aptamer sensor with high specificity and sensitivity for detecting kanamycin in milk by taking advantage of EDSDR and the high specific binding between the target and its aptamer. The specific binding can result in the release of the promoter chain, which then sets off the pre-planned EDSDR cycle. Fluorescent label modification on DNA combined with the fluorescence quenching-recovery mechanism gives the sensor impressive fluorescence response capabilities. The research results showed that within the concentration range of 0.1 nM-50 nM, there was a good relationship between the fluorescence intensity of the solution and the concentration of kanamycin. Specificity experiments and actual sample detection experiments confirmed that the biosensor could achieve highly sensitive and specific detection of trace amounts of kanamycin in food, with a detection limit of 0.053 nM (S/N = 3). SIGNIFICANCE: To our knowledge, this is the first strategy to combine EDSDR with fluorescence to detect kanamycin in food. Accurate results can be obtained in as little as 90 min with no enzymes or hairpins involved in the reaction. Furthermore, our enzyme-free biosensing method is straightforward, highly sensitive, and extremely specific. It has many possible applications, including monitoring antibiotic residues and food safety.