Acid Type Research Articles

Specific Response Assembly of 3D Space-Confined DNA Nanoaggregates for Rapid and Sensitive Detection of DNA Methyltransferase.

Rapid and sensitive detection of DNA adenine methyltransferase (Dam) activity is crucial for both research and clinical applications. Herein, we utilize two types of spherical nucleic acids (SNAs) to specific response assemble into 3D space-confined DNA nanoaggregates that enable the rapid and sensitive detection of Dam activity. The SNAs feature 3D order DNA scaffolds that serve as cores for anchoring signal hairpin probes (S-HPs) and target hairpin probes (T-HPs). Specifically, two distinct S-HPs are labeled with FAM fluorophores and BHQ1 quenchers and share identical hairpin sequences, while two types of T-HPs are designed with different linking sequences and specific recognition regions, resulting in the formation of two types of SNAs (SNA1 and SNA2). In the presence of Dam, the recognition region of the T-HPs is methylated and subsequently cleaved by auxiliary endonuclease, releasing the loop of the T-HP as a walking strand and exposing the linking sequence on the SNAs. Notably, the prior design of complementary linking sequences in the two types of SNAs facilitates their assembly into 3D DNA nanoaggregates, creating a confined space for walking strands to recover fluorescent signals. The 3D DNA nanoaggregate system not only provides highly ordered tracks but also enhances the spatial continuity of the walking strands, greatly improving the reaction kinetics for detecting Dam activity. This strategy enables the rapid and sensitive detection of Dam activity within 105 min, achieving a limit of detection of 2.9 × 10-4 U mL-1, demonstrating significant potential for advancing research in DNA methylation.

Trans-differentiation of Jdp2-depleted Gaba-receptor-positive cerebellar granule cells to Purkinje cells

The Jun dimerization protein (Jdp2) gene is active in mouse cerebellar granule cells and its protein product plays a crucial role in the formation of the cerebellum lobes through programmed cell death. However, the role of Jdp2 in cellular differentiation and pluripotency in the cerebellum, and the effect of the antioxidation reaction on cell plasticity, remain unknown. N-acetyl-l-cysteine (NAC) induced the early commitment of the differentiation of granule cell precursors (GCPs) to neurons, especially Purkinje cells, via the γ-aminobutyric acid type A receptor α6 subunit (Gabra6) axis; moreover, Jdp2 depletion enhanced this differentiation program of GCPs. The antioxidative effect of NAC was the main driving force of this decision toward the neural differentiation of the GCP population in the presence of Gabra6 in vitro. This implies that antioxidative drugs are effective agents for rescuing oxidative-stress-induced GCP damages in the cerebellum and commit this Gabra6-positive cell population toward differentiation into Purkinje cells.

Approach before alcoholic fermentation of mixtures with syrup in a Cuban distillery

Because of the competition with final molasses in different productions, it is necessary to look for other sources of sugar substrates to obtain ethanol. Streams derived from sugar production, such as final molasses, syrup, or filter juice, contain fermentable sugars, representing an opportunity for ethanol production. This work conducted a preliminary study in the alcoholic fermentation stage using a mixture of filter juice, molasses, and syrup. It also analyzed the feasibility of using syrup as a raw ferment material obtained from low-quality sugarcane. The experimental study was carried out using a 2k-1 experimental design, considering as variables: substrate (molasses or syrup), dilution agent (water and filter juice), and type of acid (H2SO4 and H3PO4), and the response variable was the alcoholic percentage obtained. Syrup, diluted with water using H3PO4, is a viable option when low-quality sugarcane is present, allowing the alcoholic degrees between 5.45 and 5.47%. With filter juice, alcoholic degrees between 5.22 and 5.30% were obtained, which are lower than in other studies with filter juices from sugarcane of adequate quality. The most influential variables were the dilution and acidifying agents in the statistical model obtained using Statgraphics Centurion XV 15.1.0.2 software. Keywords: experiment design; mixture; fermentation; syrup; substrate.

Evaluation of the Activation Energy for Pyrolytic Degradation of Poly-L-Lactide (PLA) During Artificially Accelerated Aging.

In the course of this study, the pyrolytic degradation characteristics of three poly(lactic acid) (PLA) types were investigated under inert conditions using dynamic thermogravimetric analysis (TGA) across the temperature range of 23°C-600°C with four heating rates. Specifically, the activation energy and its implications were determined at different stages of degradation. For this purpose, a comparative analysis of various isoconversional methods, including Kissinger, Flynn-Wall-Ozawa (FWO), Friedman, and Kissinger-Akahira-Sunnose (KAS) was undertaken to evaluate the reliability of each. The results indicate a decrease in thermal stability, indicated by a shift of the derived mass loss curves to lower temperatures, as confirmed by an increased water content and decreased crystallinity of the test specimen during aging. The study also highlights that if crystallinity and moisture content increase moderately, the thermal degradation curves remain unchanged. Additionally, kinetic analyses using mentioned models indicate a multi-step degradation process of PLA. The activation energy fluctuates with the conversion rate, suggesting complex underlying kinetics. These findings emphasize the need for dynamic adjustment of predictive models for material lifespan. The three PLA types were characterized by Differential Scanning Calorimetry (DSC), moisture absorption measurement and Gel permeation chromatography (GPC).

Research progress on the relationship between free fatty acid profile and type 2 diabetes complicated by coronary heart disease

Research progress on the relationship between free fatty acid profile and type 2 diabetes complicated by coronary heart disease

Understanding paralogous epilepsy–associated GABAA receptor variants: Clinical implications, mechanisms, and potential pitfalls

Recent discoveries have revealed that genetic variants in γ-aminobutyric acid type A (GABAA) receptor subunits can lead to both gain-of-function (GOF) and loss-of-function (LOF) receptors. GABAA receptors, however, have a pseudosymmetrical pentameric assembly, and curiously diverse functional outcomes have been reported for certain homologous variants in paralogous genes (paralogous variants). To investigate this, we assembled a cohort of 11 individuals harboring paralogous M1 proline missense variants in GABRA1, GABRB2, GABRB3, and GABRG2. Seven mutations (α1P260L, α1P260S, β2P252L, β3P253L, β3P253S, γ2P282A, and γ2P282S) in α1β2/3γ2 receptors were analyzed using electrophysiological examinations and molecular dynamics simulations. All individuals in the cohort were diagnosed with developmental and epileptic encephalopathy, with a median seizure onset age of 3.5 mo, and all exhibited global developmental delay. The clinical data for this cohort aligned with established GABAA receptor GOF but not LOF cohorts. Electrophysiological assessments revealed that all variants caused GOF by increasing GABA sensitivity by 3- to 23-fold. In some cases, this was accompanied by LOF traits such as reduced maximal current amplitude and enhanced receptor desensitization. The specific subunit mutated and whether the mutation occurred in one or two subunits within the pentamer influenced the overall effects. Molecular dynamics simulations confirmed similar structural changes from all mutations, but with position-dependent asymmetry. These findings establish that paralogous variants affecting the 100% conserved proline residue in the M1 transmembrane helix of GABAAR subunits all lead to overall GOF traits. The unexpected asymmetric and mixed effects on receptor function have broader implications for interpreting functional analyses for multimeric ion-channel proteins.

Piriform cortex is an ictogenic trigger zone in the primate brain.

Area tempestas, a functionally defined region in the anterior piriform cortex, was identified as a crucial ictogenic trigger zone in the rat brain in the 1980s. However, whether the primate piriform cortex can trigger seizures remains unknown. Here, in a nonhuman primate model, we aimed to localize a similar trigger zone in the piriform cortex and, subsequently, evaluated the ability of focal inhibition of the substantia nigra pars reticulata (SNpr) to suppress the evoked seizures. Focal microinjection of the γ-aminobutyric acid type A (GABAA) antagonist bicuculline methiodide into the piriform cortex was performed, in macaque monkeys, on a within-subject basis to map the ictogenic regions within this area. Glutamate antagonists were used to characterize the local circuit pharmacology. Focal inhibition of the substantia nigra by infusion of the GABAA agonist muscimol suppressed seizures evoked from piriform cortex. We documented a well-defined region highly susceptible to bicuculline-induced seizures in the piriform cortex, just posterior to the junction of the frontal and temporal lobes, indicating that a functional homolog to the rodent area tempestas is present in the primate brain. Focal infusion of glutamate receptor antagonists into the area tempestas revealed that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-mediated, but not N-methyl-D-aspartate-mediated, neurotransmission was necessary for the expression of seizures. Pharmacological inhibition of the SNpr robustly suppressed area tempestas-evoked seizures. Together, these data point to the area tempestas as a potent ictogenic zone in the primate brain and underscore the antiseizure effects of inhibition of the SNpr. Building on decades of studies in rodents, our present findings emphasize the relevance of these targets to the primate brain and provide further rationale for exploring these targets for clinical use.

MIRA/PfAgo-Mediated Biosensor for Multiplex Human Enteroviruses Virus Typing Detection on HFMD.

Hand, foot, and mouth disease (HFMD), caused by enteroviruses, mostly including EV71, CVA6, CVA10, and CVA16, is an acute infectious disease commonly found in children. Due to no approved antiviral therapies and available vaccines, except for EV71, developing accurate diagnostic methods of HFMD is essential for controlling its spread and mitigating its impact on public health. Here, we create a MIRA-HEV-PAND multiple nucleic acid typing method that utilizes PfAgo to identify enterovirus type A pathogens (EV71, CVA6, CVA10, and CVA16) and universal type EVU. The MDC (minimum detection concentration) level of MIRA-HEV-PAND is within the range of 1.66 aM (1.0 copy/μL), which was matched to that of qPCR assays and even more sensitive up to 10%. Importantly, the MIRA-HEV-PAND method exhibits higher sensitivity and less time-consuming efficiency compared to the approach that combines PCR amplification instead of MIRA amplification. Meanwhile, though the quintuple and single-tube multiple MIRA-HEV-PAND detection system can be used for one viral target or multiple viral target detection, the single-tube detection system detects more efficiently and rapidly than the quintuple-tube multiple detection system. Moreover, the diagnostic results obtained by evaluating clinical samples using MIRA-HEV-PAND show a complete consistency of 100% with qPCR assays. The MIRA-HEV-PAND method can screen a wider range of target regions using low-cost guide DNA without being limited to PAM sequences, compared to the MARPLES based on the CRISPR-Cas12a. The utilization of this correlation can be beneficial for the application of molecular testing for clinical diagnoses and the study of human enteroviruses A infection and virus typing on an epidemiological scale.

Bench to Any Side—The Pharmacology and Applications of Natural and Synthetic Alkylated Hydroxy Cinnamates and Cinnamides

Natural alkylated hydroxy cinnamates (AHCs) isolated from medicinal plants and the thereby designed and synthesized cinnamides are derivatives of hydroxy cinnamic acids such as p-coumaric, sinapic, ferulic, and caffeic acids, which are naturally derived from human dietary sources. The pharmacological properties displayed by AHCs based on their inherent structure range include antioxidant, antimicrobial, antiplasmodial, anti-tyrosinase, Alzheimer’s and Parkinson’s disease therapy, anticancer therapy, metabolic disease therapy, and biopesticides, which have not been reviewed together. Based on their inherent antioxidant, antimicrobial, and UV absorption and their structure–activity relationships, these cinnamyl esters and amides can be used for food preservation in emulsions and oils, as sun-protective components of skin care formulations, and in many other multifunctional applications. In conclusion, the fine-tuning of the structural features such as the type of hydroxy cinnamic acid used, the length of alkyl chains for variable lipophilicity, conversion from cinnamic to propanoic for antioxidants, the increase in methoxy or the change to amino groups to increase the molar absorption coefficient and loss of absorption values, the substitution by halides or amino groups for potent biopesticides, and conversion from esters to amide bonds leads to different AHCs for biomedical, cosmetic, and agriculture applications as an emerging field of investigation that can overall provide natural, safe, biodegradable, and sustainable molecules.

Formation and snake-eating like solubilization mechanisms of rhamnolipid vesicles for oil components and amino acids

Rhamnolipid vesicles hold significant potential across a wide range of applications, yet their formation mechanisms and selective solubilization of organic molecules remain elusive. Employing dissipative particle dynamics (DPD) simulations, this study delves deeply into these aspects, uncovering a stepwise formation pathway from dispersed monomers to complex multi-layer vesicle structures. The fusion and growth of three-layer structures were identified as crucial steps in the development of stacked vesicles. Notably, double-chain rhamnolipids (Rh-C10-C10) exhibited enhanced stability in self-assembled structures compared to their single-chain counterparts (Rh-C10). Through a detailed analysis of parameters such as relative concentration distribution, radial distribution function, and density fields, the solubilization process of rhamnolipid vesicles was found to resemble a “snake-eating” mechanism. We also analyzed the solubilization sites, amounts, and vesicle sizes, elucidating the selective solubilization mechanisms of rhamnolipids for representative polar and non-polar compounds in crude oil, anisole and 1-hexene. The selectivity of rhamnolipid vesicles in solubilizing organic molecules was primarily influenced by polar attraction and steric hindrance, which together determined their solubilization sites within the vesicles. Additionally, the solubilization behavior and properties of five types of amino acids within rhamnolipid vesicles were explored, demonstrating analogous solubilization patterns that correlated with amino acid polarity. These results provide a foundation for optimizing the application of rhamnolipid vesicles, paving the way for potential advancements in drug delivery, environmental remediation, and oil recovery processes.

A stearate-rich diet and oleate restriction directly inhibit tumor growth via the unfolded protein response.

Fatty acids are known to have significant effects on the properties of cancer cells. Therefore, these compounds have been incorporated into therapeutic strategies. However, few studies have examined the effects of individual fatty acids and their interactions in depth. This study analyzed the effects of various fatty acids on cancer cells and revealed that stearic acid, an abundant saturated fatty acid, had a stronger inhibitory effect on cell growth than did palmitic acid, which is also an abundant saturated fatty acid, by inducing DNA damage and apoptosis through the unfolded protein response (UPR) pathway. Intriguingly, the negative effects of stearate were reduced by the presence of oleate, a different type of abundant fatty acid. We combined a stearate-rich diet with the inhibition of stearoyl-CoA desaturase-1 to explore the impact of diet on tumor growth. This intervention significantly reduced tumor growth in both ovarian cancer models and patient-derived xenografts (PDXs), including those with chemotherapy resistance, notably by increasing stearate levels while reducing oleate levels within the tumors. Conversely, the negative effects of a stearate-rich diet were mitigated by an oleate-rich diet. This study revealed that dietary stearate can directly inhibit tumor growth through mechanisms involving DNA damage and apoptosis mediated by the UPR pathway. These results suggest that dietary interventions, which increase stearic acid levels while decreasing oleic acid levels, may be promising therapeutic strategies for cancer treatment. These results could lead to the development of new cancer treatment strategies.

Donnan Dialysis-based Approach for Reclamation of Waste Acid with a Low Concentration

This study provides a proof-of-concept investigation into the direct utilization of low-concentration recovered acid as a proton source for the efficient recovery of organic acids via Donnan dialysis, a scenario of particular significance in industrial parks. A primary objective is to examine the implications of waste acid concentration on the coupling process. To evaluate the technological feasibility, process simulations are performed utilizing a mathematical model grounded in the Nernst-Planck equation and associated equilibrium relationships. Furthermore, a variety of experimental conditions, encompassing different types of organic acids and varying concentrations of waste acid, are explored to analyze the ion substitution behaviors involved. The findings from both simulations and experiments indicate that weaker organic acids demonstrate superior performance, particularly regarding recovery rates and process efficiency. Additionally, it is revealed that merely increasing the concentration of the draw solution does not constitute an effective approach for improving the DD-based organic acid recovery process, thereby suggesting the potential for the direct application of low-concentration recovered acid. Given its significant advantages, the proposed DD-based coupling technology shows considerable promise for future applications.

Mass granulation of Al-promoted CaO-based sorbent via moulding-crushing methods for cyclic CO2 capture

Calcium looping (CaL) process, as an effective way to achieve CO2 mitigation from high-temperature flue gas streams, is one of the most promising alternatives to amine scrubbing (a well-established technology for industrial post-combustion CO2 capture). CaO sorbent is considered to be an ideal CO2 adsorption material. Moreover, the development of granulation/pelletization techniques along with the mass preparation of the CaO-based sorbent is imperative for realistic large-scale applications. This work proposes two practicable moulding-crushing techniques for the scale-up granulation of CaO-based sorbents, in which the kilogram-scale produced Al-promoted CaO-based sorbent powders were first moulded and subsequently crushed into the granules of target sizes. Three types of organic acids–acetic acid, citric acid and malonic acid were employed as peptizing agents to optimize the granulation process. As a result, the anti-attrition properties and compressive strength of the synthetic sorbents were elevated owing to the introduction of an appropriate amount of acetic or malonic acid, for it expedited the disintegration of the pseudo-boehmite (served as binder agent) particles into sol particles, which allowed for tighter bonding of sorbent particles. In addition, corncob powder acted as a pore-forming agent, enhancing the porous structure of the sorbent particles due to the gases released from the thermal decomposition of organic groups during calcination. Nevertheless, the results revealed that the porous and loose structure adversely affected the mechanical strength of the granules.

Towards understanding Trans-cleavage of natural and synthetic nucleic acids by Cas12a for sensitive CRISPR biosensing

CRISPR/Cas systems have been widely utilized for the development of biosensing platforms for precision molecular diagnostics. Their remarkable biosensing performance critically depends on the efficiency of sequence-independent trans-cleavage in type V and VI Cas effectors. Cas12a, a typical example of type V Cas effector exhibits varying trans-cleavage efficiency on different types of nucleic acids, and also in response to different nucleobase sequences. However, the underlying mechanism of Cas12a’s trans-cleavage characteristic remains unclear. To explore this mechanism, we introduced Xeno nucleic acids (XNA) as potential trans-cleavage substrates of Cas12a. XNAs are chemically modified nucleic acid analogues, which originate from chemical modifications of nucleobases, sugar moieties, and the backbone. We observed a progressive decrease in trans-cleavage rates by Cas12a across different types of XNAs, in the following sequence: nucleobase-modified XNA > sugar moiety-modified XNA > backbone-modified XNA. In addition, more complex chemical modifications on either of the three above locations led to the lowering of the trans-cleavage rate of Cas12a. These findings elucidate the mechanism behind Cas12a’ trans-cleavage characteristic, which is attributed to its higher affinity of Cas12a for substrates with simpler chemical structures, leading to increased trans-cleavage efficiency. Based on these findings, we also developed a colorimetric CRISPR/Cas12a biosensing system utilizing XNA for the detection of circulating tumor DNA (ctDNA), with a limit of detection of 10 pM and a 4 logs detection range from 10 pM to 100 nM. These results indicate that XNA can serve as a novel Cas12a trans-cleavage substrate for sensitive biosensing applications.

A Possible Neural Basis for Attentional Capture of Faces Revealed by Functional Magnetic Resonance Imaging and Causal Pharmacological Inactivation in Macaques.

In primates, the presence of a face in a visual scene captures attention and rapidly directs the observer's gaze to the face, even when the face is not relevant to the task at hand. Here, we explored a neural circuit that might potentially play a causal role in this powerful behavior. In our previous research, two monkeys received microinfusions of muscimol, a γ-aminobutyric acid type A (GABAA)-receptor agonist, or saline (as a control condition) in separate sessions into individual or pairs of four inferotemporal face patches (middle and anterior lateral and fundal), as identified by an initial localizer experiment. Then, using fMRI, we measured the impact of each inactivation condition on responses in the other face patches relative to the control condition. In this study, we used the same method and measured the impact of each inactivation condition on responses in the FEF and the lateral intraparietal area, two regions associated with attentional processing, while face and nonface object stimuli were viewed. Our results revealed potential relationships between inferotemporal face patches and these two attention-related regions: The inactivation of the middle lateral and anterior fundal face patches had a pronounced impact on FEF, whereas the inactivation of the middle and anterior lateral face patches had a noticeable influence on LIP. Together, these initial exploratory findings document a circuit that potentially underlies the attentional capture of faces. Confirmation of the role of this circuit remains to be accomplished in the context of a paradigm that explicitly tests the attentional capture of faces.

Upregulation of cAMP/PKA/CREB signaling mediated by GABABR might contribute to the amelioration effects of sea cucumber peptides (Acaudina leucoprocta) on cognitive dysfunction in mice

This study aimed to determine the effects and underlying mechanisms of sea cucumber peptides (SCP) obtained from Acaudina leucoprocta in mitigating induced by D-galactose cognitive dysfunction in mice. Additionally, it aimed to validate the cognitive-enhancing potential of peptides identified via in silico and peptidomics using SH-SY5Y cells. The results demonstrated significant improvement in behavioral performance with oral administration of SCP. Additionally, SCP normalized oxidative stress and neurotransmitter imbalances (especially gamma-aminobutyric acid, GABA). Also, SCP effectively rectified gut microbiota dysbiosis. Mechanistically, SCP activated the γ-aminobutyric acid type B receptors (GABABR)/ cyclic adenosine monophosphate (cAMP)/ cAMP-dependent protein kinase A (PKA)/ cAMP response element-binding protein (CREB) axis to promote GABA release and alleviate neuronal and oxidative stress damage, which subsequently ameliorated cognitive dysfunction. Furthermore, docking analysis predicted the binding of fourteen peptides with high abundance and PeptideRanker scores to GABABR. Notably, Lys-Gly-Phe-Pro (KGFP) had the strongest binding affinities and actively interacted with GABABR sites through hydrogen bonds, van der Waals, hydrophobic, and electrostatic interactions. The capacity of KGFP to improve cognitive function was further demonstrated when the SH-SY5Y cells were subjected to D-galactose. These results imply that the implementation of SCP intervention could be a useful tactic for improving cognitive function.

Anti-amyloid activity of amino acid functionalized magnetic nanoparticles on αLactalbumin aggregation

Protein amyloid aggregation involves structural changes in native protein conformers and the formation of amyloid fibrils that accumulate in deposits in the human body. This study explores the effect of magnetic nanoparticles functionalized with amino acids (aaMNPs)—cysteine (Cys), poly-L-lysine (PLL), or proline (Pro)—on the amyloid aggregation of α-lactalbumin (αLA) and its amyloid fibrils (LAF). Our results from thioflavin T fluorescence assay (ThT), atomic force microscopy (AFM), and infrared spectroscopy revealed that the studied aaMNPs inhibit αLA fibrillization and destruct LAF in a concentration-dependent manner. The type of amino acid used for nanoparticle functionalization significantly influences the anti-amyloid efficacy. ProMNPs exhibit the highest inhibitory activity, with the timing of their addition being crucial Conversely, CysMNPs demonstrate the highest destructing activity. AFM image analysis through grain mapping was employed to quantify the anti-amyloid effects of aaMNPs. Cytotoxicity testing on kidney cells identified PLLMNPs as the only cytotoxic nanoparticles in our study. These findings clarify the mechanisms of inhibition and destruction of LAF in the presence of aaMNPs, which could inform the design of nanoparticles for therapeutic purposes in the future.

GABRA1 frameshift variants impair GABAA receptor proteostasis.

The gamma-aminobutyric acid type A receptor (GABA A R) is the most common inhibitory neurotransmitter-gated ion channel in the central nervous system. Pathogenic variants in genes encoding GABA A R subunits can cause receptor dysfunction and lead to genetic epilepsy. Frameshift variants in these genes can result in a premature termination codon, producing truncated receptor subunit variants. However, the molecular mechanism as well as functional implications of these frameshift variants remains inadequately characterized. This study focused on four clinical frameshift variants of the α 1 subunit of GABA A R (encoded by the GABRA1 gene): K401fs (c.1200del), S326fs (c.975del), V290fs (c.869_888del), and F272fs (c.813del). These variants result in the loss of one to three transmembrane helices, whereas wild type α1 has four transmembrane helices. Therefore, these variants serve as valuable models to evaluate membrane protein biogenesis and proteostasis deficiencies. In HEK293T cells, all four frameshift variants exhibit significantly reduced trafficking to the cell surface, resulting in essentially non-functional ion channels. However, the severity of proteostasis deficiency varied among these four frameshift variants, presumably due to their specific transmembrane domain deletions. The variant α1 subunits exhibited endoplasmic reticulum (ER) retention and activated the unfolded protein response (UPR) to varying extents. Our findings revealed that these frameshift variants of GABRA1 utilize overlapping yet distinct molecular mechanisms to impair proteostasis, providing insights into the pathogenesis of GABA A R-associated epilepsy.

Nanoscale sintering of zinc micropowders for high conductivity and sensing applications of transient electronics

Abstract In the face of new social and environmental challenges, there is a need for an alternative approach to the fabrication of electronics. Increasing demand for smart healthcare applications or the growing e-waste problems inspired the work on new adaptations and materials for biodegradable, bioresorbable or even edible electronics. Such a trend is called transient electronics, which is a response to the mentioned problems, yet efficient and affordable fabrication of such elements is challenging. We report a broader approach to the application of zinc inks for printed electronics and a nanochemical sintering approach with several types of organic acids. Selectively spray-printed fine zinc microparticles subjected to acetic, lactic, malonic, ethylmalonic and citric acids were evaluated for obtaining the lowest electrical resistivity and its variations induced by the amount of applied acids. Resulting sintered Zn patterns exhibited sheet resistivity values as low as 15 · 10−2 Ω sq−1. Not all acids are suitable for fabricating stable, conductive paths, as in the case of citric and ethylmalonic acids. On the other hand, with malonic acid, there was a wide range of resistance changes in the function of applied acid doses (from one to fifteen), suggesting application as a chemical sensor for acid concentration. Such results suggest that with a low-cost zinc powder, absorbable by living organisms and disintegrating in the natural environment, using common organic acids, we can efficiently fabricate printed electronic circuits and sensors for transient electronics applications.

Root morphology, nitrogen metabolism and amino acid metabolism in soybean under low phosphorus stress.

Phosphorus deficiency is a major influence on growth and development of soybean. Therefore, improving phosphorus utilization efficiency in soybean is a research priority for the soybean community. In this experiment, Liaodou 13 (high phosphorus utilization: HPE) and Tiefeng 3 (low phosphorus utilization: LPE) were used as test varieties. We investigated changes in root morphology, amino acid content, and content of key substances of the nitrogen metabolic pathway with normal phosphorus (0.5 mM) and low phosphorus (0.005 mM) treatments. The results showed that the root length, root surface area and number of lateral roots of HPE roots were higher than those of LPE roots under normal and low phosphorus conditions. The contents of different types of amino acids showed different trends in two varieties. The HPE showed small change in the content of total hydrolyzed amino acids under the low phosphorus condition when compared to the normal phosphorus treatment by a 6.67% decrease, on the contrary LPE showed a drastic decrease by 20.36%. However, HPE exhibited similar decreasing trends in the contents of hydrolyzed and free aspartic acid with the low phosphorus treatment. Moreover, the contents of free histidine and valine in LPE were significantly increased by 657.84% and 149.29% respectively, in contrast to significant decreases in HPE. In aspects of major nutrient elements, the contents of phosphorus, total nitrogen and ammonia nitrogen in both HPE and LPE varieties decreased to dramatic levels. However, the nitrate nitrogen content significantly increased 78.51% for HPE and 65.12% for LPE. Compare to the normal condition, the GOGAT activity in HPE decreased by 5.18% but increased by 33.10% in LPE. Compare to the normal condition, the GS activity in HPE increased by 7.26% but decreased by 21.72% in LPE under phosphorus deficiency. In summary, the phosphorus-efficient soybean variety HPE exhibited superior tolerance to low phosphorus deficiency through advantageous root morphology, phosphorus uptake and transfer capability, and balanced amino acid metabolism and nitrogen metabolism pathways.