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Reported here is the comprehensive investigation on the formation of biphen[n]arenes by tailoring reaction modules. Five new macrocyclic arenes and four oligomers were synthesized by the condensation of monomers possessing different multimethoxyphenyl reaction modules and paraformaldehyde. We proved that the number and sites of methoxy on reaction modules greatly affected the reaction activity, shape, and connection mode of macrocycles. Moreover, the triangular and saddle-shaped configuration of macrocycles were revealed by single crystal structures. The results provided a typical and fundamental guidance in designing new macrocyclic arenes.

4-(tert-Butyl)-2-trityl-6-(di-(2-picolyl)amine)phenol, LH, was prepared from paraformaldehyde, 4-(tert-butyl)-2-tritylphenol, and di-(2-picolyl)amine. Reaction with Zn(N(SiMe3)2)2 gave LZnN(SiMe3)2. The complex was shown by X-ray diffraction study, variable temperature NMR, and DFT calculations to coordinate only one pyridine ligand, which allows for fast and facile complex isomerisation. LZnN(SiMe3)2 was active in rac-lactide polymerization, but in contrast to previous complexes of this type, it did not show any evidence for isotactic monomer enchainment via a catalytic-site mediated chain-end control mechanism. Addition of alcohol led to increased activity, but the complex was unstable in the presence of free alcohol.

A microwave-promoted multicomponent reaction of 3-formylchromones, amines, and paraformaldehyde was achieved under catalyst-free and solvent-free conditions, delivering 5H-chromeno[2,3-d]pyrimidin-5-one derivatives in good to excellent yields via an unexpected annulation pathway, which further expanded the synthetic application of paraformaldehyde as a C1 building block.

The spiro scaffold chiral organocatalyst of 3,2'-pyrrolidinyl spiro-oxindole amine was successfully prepared from racemic spiro-oxindole amine using l-menthol as a chiral pool in 4 steps in 28%-40% overall yields with at least 99% ee in scale-up preparation, and its catalytic activity was evaluated in the enantioselective aldol condensation between 3-(3-hydroxy-1H-pyrazol-1-yl)-oxindole and paraformaldehyde. The spiro organocatalyst showed superior catalytic activity and selectivity compared with its counterparts, and most substrates offered good to excellent results with up to 96% yield in 96% ee.

Benzoxazine polymers containing phenyleneethynylene and polypropylene glycol (PPG) in the main chain, poly(1)230, poly(1)400 and poly(1)2000, were synthesized by a Mannich reaction of the corresponding ethynylenebisphenol, paraformaldehyde and PPG diamines with Mn = 230–2,000. The curing temperature of poly(1) decreased from 212 to 182 °C as the Mn of the PPG chain decreased from 2,000 to 230. Poly(1)230–2000 was heated at 200–250 °C to obtain the corresponding polymers, and poly(1)′230–2000 was cured by ring-opening polymerization of the benzoxazine moieties. The structures of the polymers were elucidated by 1H-NMR and IR spectroscopies before and after curing. Poly(1)′230–2000 became flexible upon increasing the Mn of the PPG chain. Poly(1)′230 showed Tg as high as 253 °C. Poly(1)′230–2000 was thermally stable at approximately 300 °C, presumably due to the existence of rigid phenyleneethynylene moieties. We synthesized novel benzoxazine-polymers, poly(1)230–2000 consisting of rigid phenyleneethynylene and flexible polypropylene glycol (PPG) moieties in the main chain. Resins obtained by cross-linking reaction of poly(1)230–2000 were thermally as stable as a previously synthesized polybenzoxazine resin containing phenyleneethynylene moieties. Introduction of flexible PPG unit was effective to lower the curing temperature, and enhance mechanical toughness keeping thermal stability.

This study aimed to evaluate the effectiveness of ultraviolet light in reducing bacterial load of eggshells and the impact of experimental disinfection on hatching, embryo mortality, and time-borne distribution using broiler breeder hens of different ages (38, 42, and 48 weeks old). Fertile eggs were subjected to different exposure periods (5, 7, and 9 minutes) of UV light (UV-C) with a 254 nm wavelength. For controls, eggs disinfected with paraformaldehyde (5.3 g/m3) and eggs not disinfected (NC). After subjection to disinfection protocols, the eggs were placed into sterile plastic bags containing 20 mL of peptone saline solution (0.1% m:v) and massaged for 1 minute to release the bacterial load. Aliquots of this solution were incubated in specific medium for bacterial growth for 48 hours at 37ºC for subsequent CFU counts. To evaluate the effects of disinfection on production, eggs previously disinfected by UV-C (9 min) and paraformaldehyde and NC eggs were candled between incubation days 10 and 13 and at the end of the incubation period to assess embryonic mortality. Hatchability distribution was performed every 8 hours. The 9 minutes 254nm UV-C light exposure was able to disinfect viable eggs and matched the effectiveness of the paraformaldehyde technique. RESUMO Objetivou-se avaliar a eficácia da luz ultravioleta na redução da carga bacteriana de cascas de ovos e o impacto na eclosão e na mortalidade embrionária observando-se a idade das matrizes (38, 42 e 48 semanas). Os ovos foram submetidos a diferentes períodos de exposição (cinco, sete e nove minutos) à luz UV (UV-C) com comprimento de onda de 254nm. Os controles foram ovos desinfetados com paraformaldeído (5,3g/m³) e ovos não desinfetados (NC). Após a desinfecção, os ovos foram colocados em sacos plásticos estéreis contendo 20mL de solução salina peptonada (0,1% m:v) e massageados por um (1) minuto para descolamento das bactérias. Alíquotas dessa solução foram incubadas em meio para crescimento bacteriano por 48 horas a 37ºC e contagem de UFC. Para avaliar os efeitos da desinfecção, ovos previamente desinfetados por UV-C (nove minutos) e ovos com paraformaldeído e NC foram submetidos à ovoscopia entre os dias 10 e 13 de incubação e ao final do período de incubação, para avaliação da mortalidade embrionária. A distribuição da eclodibilidade foi realizada a cada oito horas. A exposição à luz UV-C de 25nm de nove minutos desinfetou os ovos férteis e coincidiu com a eficácia do paraformaldeído.

Cryptococcus neoformans is an important pathogen causing opportunistic fungal meningitis. The pathogenic mechanism of cryptococcal meningitis remains unclear. We aimed to describe a practical approach for studying the pathologic features of cryptococcal central nervous system infection by immunofluorescence on paraffin-embedded brain of mice using different antigen retrieval methods. After 14 days of intratracheal inoculation of green fluorescent protein-tagged C. neoformans (H99-GFP), C57BL/6J mice brains were fixed in 4% paraformaldehyde and embedded in paraffin. Antigen retrieval methods such as microwaves, 1% sodium lauryl sulfate, 1 N HCl, pepsase, and tryptase were used on 5-μm paraffin sections and the effects were compared. The green fluorescence of H99-GFP persisted with antigen retrieval using 1% sodium lauryl sulfate. After immunofluorescent staining, H99-GFP, glial fibrillary acidic protein-tagged astrocytes, and ionized calcium-binding adapter molecule 1-tagged microglia could be observed clearly. Based on our results, we provide a practical approach for the further study of the interaction between C. neoformans and brain cells.

With the continuous popularization of smart medicine, the protective effect of silibinin in the liver has attracted much attention. This study mainly explores the liver protection mechanism and absorption promotion technology of silybin based on intelligent medical analysis. Refining of silibinin: accurately weigh 1.0 g of silibinin in a three-necked flask; gradually add 50 mL of anhydrous methanol, reflux and filter the precipitated solid; and weigh it after drying. ICR male mice were taken as experimental subjects and randomly divided into groups of 10 each. The mice in the normal group and the model group were given intragastrically with 0.5% CMC-Na solution; the mice in the silibinin group were given intragastrically with SB/CMC-Na suspension; the mice in the remaining groups were given low, medium, and high-dose suspensions to their stomachs, and silibinin 23 acylate/CMC-Na suspension was administered at a dose of 10 mL/kg for 7 consecutive days. After that, the mice were fasted for 12 hours. After 6 hours of fasting (18 hours after modeling), the blood cells from their orbits were taken, placed in a 37°C water bath for 30 minutes, and centrifuged at 4000 rpm for 10 minutes, and then the serum was taken; the activity equivalent of AST and ALT in serum was measured; serum determination Medium AST and ALT vitality. The mice were killed by decapitation, fresh liver tissue was immediately collected, and part of it was frozen in liquid nitrogen for the RT-PCR test. The hepatocyte expansion and death were observed using a transmission electron microscope, and the oncosis index (OI) was calculated. Another part of the liver tissue was fixed in 4% paraformaldehyde solution, embedded in paraffin, dehydrated, and sliced at 4 μm. Some sections were stained with conventional HE, and the pathological changes of liver cells were observed under light microscope; some sections were subjected to immunohistochemistry. Only one mouse died when 240 mg/kg of silibinin was given 10 minutes after the model was modeled. However, when 240 mg/kg silibinin was given to the mice 20 minutes after modeling, the mortality rate of the mice rose to 50%, and the therapeutic effect was significantly weakened. This research is helpful to advance the research of silybin in liver protection.

Colombian sodium silicate was used as silicon source in the synthesis of MCM-41 with several surfactant: SiO2 molar ratios (MR = 0.12, 0.30, 0.50 and 0.70). Sn was incorporated on MCM-41 by incipient impregnation and by wetness impregnation using a rotaevaporador. The materials were characterized by AAS, XRD, N2 adsorption-desorption isotherms, TEM, adsorption of pyridine, NH3-TPD, UV–vis-DRS and XPS. Materials with Na2SiO3 (MR = 0.70) showed crystalline, textural and structural properties very similar to MCM-41 synthesized with tetraethyl orthosilicate (TEOS). The highest total acidity of materials synthesized with Na2SiO3 compared with materials synthesized with TEOS could be owing to the use of sulfuric acid in the synthesis or the presence of more silanol groups in the solid surface. TOF values obtained in nopol production over materials synthesized with TEOS and Na2SiO3 (MR = 0.70), using wetness impregnation with rotoevaporation, were 420 and 476 h−1, respectively. Low cost paraformaldehyde with larger polymerization degree than Sigma-Aldrich source of formaldehyde was characterized by XRF, XRD, FTIR, TGA and DSC. Polymerization degree seems to affect TOF for nopol production; lower TOF values were obtained with paraformaldehyde with larger polymerization degree. Depolymerization occurs by two parallel reactions: Avrami-Erofeyev (A4) and contracting area (R2) models, with activation energies of 19.8 and 77.5 kJ mol−1, respectively. Sn-MCM-41 synthesized with Na2SiO3 can be used four times without considerable loss of catalytic activity; furthermore, no Sn leaching was detected.

The effect of paraformaldehyde in the solution of 15% HCL as an inhibitor of C-steel corrosion has been studied using the weight loss method. It was found that the efficiency of inhibitor increased by increasing the inhibitor concentration and decreasing temperatures. Also, the action of paraformaldehyde as a corrosion inhibitor has been attributed to the insoluble complexes was adsorbed on the C-steel surface. The iron complexes were identified by FTIR spectrum and the mechanism of inhibition was explained as Langmuir adsorption. The thermodynamic parameters of the adsorption process were calculated and explained.

Melamine-formaldehyde (MF)rigid foams with high closed cell content were prepared via oven heating process, using MF prepolymer prepared from melamine and paraformaldehyde as a matrix, cyclohexane as the foaming agent, dimethyl silicon oil as the foam stabilizers, hydrochloric acid as the catalyst. The effect of MF prepolymer viscosity, foaming temperature, amount of catalyst on morphology, closed cell content, apparent density, water absorption and compressive strength of MF rigid foams were systematically studied. The optimized foaming conditions are as follows: the viscosity of MF prepolymer ranges from 35 Pa·s to 45 Pa·s, the foaming temperature is 125°C and the content of the catalyst is 0.65 wt%. The as-prepared MF foams showed the best comprehensive performance with closed cell content of 83.5%, apparent density of 62 kg·m−3, water absorption of 12.0%, compressive strength of 292kPa, thermal conductivity of 0.033 W m−1 K−1 and limiting oxygen index (LOI) of 36%. Compared to conventional organic foams, MF rigid foams possess low water absorption, excellent thermal insulation and flame retardancy due to high closed cell content, and can be expected to be used as thermal insulation material for building exterior walls.

α-Oxy ketones, easily accessible by conventional routes, can be selectively deprotonated generating an enolate intermediate, which upon treatment with paraformaldehyde undergoes an aldol–Tishchenko reaction, leading to relevant 1,2,3-triol fragments in a totally diastereoselective manner. The excellent stereocontrol in the generation of a quaternary stereocenter is attributed to stereoelectronic effects in the Evans intermediate. This methodology allows overcoming some limitations of our previously reported strategy, based on the reaction of α-lithiobenzyl ethers with esters and paraformaldehyde, broadening the scope of the obtained polyols. Synthetic applications of this process include the preparation of a new dilignol model and some functionalized oxetanes., Ministerio de Ciencia e Innovación and FEDER (CTQ2016-75023-C2-1-P), and Junta de Castilla y León and FEDER (BU291P18, BU049P20). The project leading to these results has also received funding from the “la Caixa” Foundation, under agreement LCF/PR/PR18/51130007) (CAIXA-UBU001). A postdoctoral contract (S.S.-P.) and a predoctoral contract (C.S.) were funded by Junta de Castilla y León and FEDER and Ministerio de Educación (FPU), respectively

SummaryOvine ovarian fragments (3 × 3 × 1 mm) were fixed in neutral buffered formalin (NBF), Carnoy’s solution (CAR), Davidson’s solution (DAV), or paraformaldehyde (PFA) for 12 h or 24 h. After this fixation time, each fragment was prepared for histological analysis. Although fixative and fixation period did not affect follicular and stromal cells density, the percentages of morphologically normal primordial and primary follicles was affected by the fixative type and period of fixation. Paraformaldehyde was not indicated as a fixative for ovarian fragments. Formalin was a suitable fixative only when the period of fixation was 12 h, while Carnoy was efficient after a fixation period of 24 h. In conclusion, the most indicated fixative for the morphological evaluation of ovarian preantral follicles was DAV, regardless of the fixation period, that is 12 or 24 h.

Human leukocyte antigen (HLA-G) participates in immunosuppression and is useful for prenatal diagnostics. Isolation of fetal cells positive for HLA-G by HLA-G antibody conjugated nanoparticles from the cervix of pregnant women is the basis for non-invasive prenatal testing. Endocervical specimens are fixed in transport medium before isolation using antibody conjugated nanoparticles. Staining of HLA-G using MEM-G/9 antibody, however, is restricted to unfixed cells. We investigated the effect of several fixatives on the interaction of HLA-G with MEM-G/9 in the HLA-G-positive cell line, JEG-3. We investigated absolute methanol, 1:1 acetate buffer:methanol, Pap solution and paraformaldehyde. The effects of these fixatives were evaluated using immunofluorescence. We found no MEM-G/9 surface staining of methanol fixed cells. Approximately 40% of JEG-3 cells fixed with paraformaldehyde failed to stain. Nearly all cells were stained with MEM-G/9 following fixation with acetate buffer:methanol or Pap solution. Our findings indicate the importance of using an appropriate fixative for preserving HLA-G cell surface antigen for studies using the MEM-G/9 antibody.

It has been well established that the early-stage interactions of nanoparticles with cells are governed by the extracellular protein corona. However, after entering into the cells, the evolving protein corona is the key to subsequent processing of nanoparticles by cells. To identify the protein corona around intracellular nanoparticles, it is essential to maintain its original compositions during cell treatment. Herein, we develop a paraformaldehyde (PFA) cross-linking strategy to stabilize corona compositions when extracting protein coronas from cells, providing original information on protein coronas around intercellular gold nanoparticles (AuNPs). The stability of the protein corona after PFA cross-linking was carefully investigated with several characterization methods, and the results demonstrate that PFA cross-linking successfully prevents the dissociation and exchange of corona proteins. Then the recovered intracellular protein corona around AuNPs from living HepG2 cells with a PFA cross-linking strategy was subjected to nanoHPLC-MS/MS for proteomic analysis. It was found that the compositions of intracellular protein coronas are dominated by cell-derived proteins and undergo significant variation of protein species and amounts over time during internalization. Time-resolved analysis provides relevant proteins involved in nanoparticle cellular uptake and transportation, indicating that AuNPs are endocytosed mainly by a clathrin-mediated uptake mechanism and directed into an endolysosomal pathway toward their final destination. Such proteomic-based results are verified by pharmacological inhibition and TEM imaging analysis. This work provides a universal strategy to study compositions of protein corona around intercellular nanoparticles and could be a footstone to link the formation of protein corona around nanoparticles to their biological function in cells.

A fluorescent probe with high selectivity for the detection of copper ions (Cu2+) is synthesized using 4-hydroxyhypoxidone, paraformaldehyde and proline via a one-step Mannich reaction. This Cu2+ fluorescent probe with large Stokes shift (129 nm) has good water solubility and could coordinate with Cu2+. It achieves fluorescence of this probe to be quenched linearly with the increasing concentration of Cu2+ from 10 to 800 nM. Since Cu2+ and pyrophosphate (PPi) have a stronger coordination ability, it promotes Cu2+ to coordinate with PPi preferentially and results in the fluorescence of the system being enhanced again. In this way, a novel fluorescence “turn-on” detection of PPi in the range from 2 to 40 μM within 2 min is developed using this Cu2+ fluorescent probe. It exhibits high selectivity in PPi detection towards other anions such as Cl−, NO3−, CO32−, PO43− and SO42−. It is worth noting that PPi can be hydrolyzed into phosphate (Pi) by alkaline phosphatase (ALP), and the coordination between Cu2+ and Pi is not as strong as that with the probe. Herein the fluorescence of the system can be quenched again after the addition of ALP. A fluorescence “turn-off” detection of ALP from 10 to 90 mU L−1 is achieved using this Cu2+ fluorescent probe. When it is used to detect ALP in serum samples, recoveries from 98.5% to 104.2% are obtained.

The aim of the study is to summarize the histology and morphometry of cortical neurons in acute clozapine and ethanol poisoning.Material and methods. Histological examination of the parietal cortical brain samples of 26 patients died during the Day 1 of acute clozapine and ethanol poisoning (23 males and 3 females aged 22-63 years) was performed. The blood ethanol level was 1.4-4.1%o. The level of clozapine in the blood ranged between 0.24 and 5.8 mg%, in the liver between 0.097 and 6.5 mg%, in kidneys between 0.03 and 3.5 mg%. The cortical samples for morphometric examination were placed in 10% neutral paraformaldehyde, the histological sections were done and stained with hematoxylin and eosin, as well as according to Niessl. The morphological analysis was performed using the video light microscopy. The number of damaged neurons (with separate quantification of reversible, intermediate, and irreversible damage) was assessed. The statistical analysis was done using the non-parametric methods.Results. The signs of brain neuronal damage in acute clozapine and ethanol poisoning, as well as forensic chemical tests, might be used for establishing the direct cause of death.

Accurate identification of the murine estrous cycle using vaginal exfoliative cytology is the initial and crucial step for controlled reproduction of this species. However, it is generally difficult to discriminate each stage of the cycle, and thus to select pro-estrous mice for mating. To increase the accuracy of identification of the pro-estrous stage, we re-evaluated the vaginal fold histology and modified the method of exfoliative cytology. Tissue fixation using methanol in Carnoy’s solution but not paraformaldehyde, combined with Alcian blue staining but not the conventional Giemsa staining, resulted in better manifestation of mucosal cell layers in the vaginal epithelium just above the keratinized layer. This mucous layer in the fold histology was found to form specifically in the pro-estrous and late di-estrous stages, and the mucous cells exfoliated in smear samples only in the pro-estrous stage. This novel method was found, by a blinded test, to increase the rate of accurate identification of the pro-estrous stage compared to the conventional method (80% vs 50%). Consistent with this finding, the mating experiment with “pro-estrous” females selected by the novel method revealed a significantly higher success rate than that with the conventional method (78.0% vs 47.5%). Thus, our study demonstrates vaginal exfoliative mucous cells as a better potential marker to detect the “receptive” state of female mice that leads to an improved success rate of mating.

A simple and highly efficient method for the preparation of 1,1-dimethoxymethane (DMM) is described using a molecularly defined NNN-Ni(II) complex (2 mol %). The reaction proceeds via the direct condensation reaction of methanol with paraformaldehyde under mild and neutral conditions. This atom-economical approach provides DMM in excellent yields in shorter reaction time. A simple and highly efficient method for the preparation of 1,1-dimethoxymethane (DMM) is described using a molecularly defined NNN-Ni(II) complex (2 mol%). The reaction proceeds via the direct condensation reaction of methanol with paraformaldehyde under mild and neutral conditions. This highly atom-economical approach provides DMM in excellent yields in shorter reaction time.

Three‐dimensional quantitative phase imaging is an emerging method, which provides the 3D distribution of the refractive index (RI) and the dry mass in live and fixed cells as well as in tissues. However, an insufficiently answered question is the influence of chemical cell fixation procedures on the results of RI reconstructions. Therefore, this work is devoted to systematic investigations on the RI in cellular organelles of live and fixed cells including nucleus, nucleolus, nucleoplasm, and cytoplasm. The research was carried out on four different cell lines using a common paraformaldehyde (PFA)‐based fixation protocol. The selected cell types represent the diversity of mammalian cells and therefore the results presented provide a picture of fixation caused RI changes in a broader context. A commercial Tomocube HT‐1S device was used for 3D RI acquisition. The changes in the RI values after the fixation process are detected in the reconstructed phase distributions and amount to the order of 10−3. The RI values decrease and the observed RI changes are found to be different between various cell lines; however, all of them show the most significant loss in the nucleolus. In conclusion, our study demonstrates the evident need for standardized preparation procedures in phase tomographic measurements. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals LLC. on behalf of International Society for Advancement of Cytometry.

Two novel benzoxazine monomers, oHMTI-a and oHMTI-pn, have been obtained via the modified Mannich condensation from ortho-4-methyltetrahydrophalimide functional phenol, paraformaldehyde, and aniline/4-aminophthalonitrile, respectively. The chemical structures of both benzoxazine monomers have been studied by Fourier transform infrared (FT-IR) and 1H and 13C nuclear magnetic resonance (NMR) spectra. Their polymerization processes are investigated using in-situ FT-IR and different scanning calorimetry (DSC). Specifically, the phthalonitrile group in oHMTI-pn can react at a relatively lower temperature without adding any catalysts, which suggests the presence of the thermal synergistic polymerization effect in this benzoxazine monomer. In addition, the thermal and fire related properties of the resulting polybenzoxazines are evaluated by thermogravimetric analysis (TGA) and micro-scale combustion calorimetry (MCC). The polybenzoxazine derived from oHMTI-pn shows both high thermal stability and outstanding flame retardancy, with a T g of 350°C, a T d10 value of 417°C, a high char yield value of 65%, and a very low heat release capacity value of 35.2 J/(g·K).

The reaction of pyrrolo[3,2,1-ij]quinoline-1,2-diones with methyl (het)aryl ketones gave the corresponding 1-(het)arylmethylidenepyrroloquinolin-2-ones, and 1,3-dipolar cycloaddition of the latter to azomethine ylide generated from sarcosine and paraformaldehyde afforded 4-acyl-1,4′,4′,6′-tetramethylspiro[pyrrolidine-3,1′-pyrrolo[3,2,1-ij]quinolin]-2′(4′H)-ones. The synthesized compounds were evaluated for inhibitory activity against blood coagulation factors Xa and XIa.

1,3-Indenedione has been reacted with p-aminobenzaldehyde to give the corresponding p-aminobenzylidine-1,3-indenedione, treatment of which with paraformaldehyde and trifluroacetic acid has led to the Troger’s base analogue. Treatment of that compound with dimethyl sulfate, acetic anhydride, benzoyl chloride, or trifluroacetic anhydride can afford the correspondingN,N′-disubstituted phenhomazines. Complexation of the Troger’s base with ferric nitrate trihydrate or nickel chloride hexahydrate has resulted in the corresponding complexes. The structures of all compounds have been confirmed by their elemental analyses and spectral data. All the newly synthesized Troger’s base and the derived N,N′-disubstituted phenhomazines have been tested for anticancer activity.

Pankreas merupakan jaringan labil karena terdiri dari sel-sel asinar yang selalu berproliferasi sepanjang hidupnya untuk menggantikan se l yang rusak. P roliferasi tersebut dapat diidentifikasi dengan pemeriksaan histologi s, yaitu mikroteknik dengan pewarnaan imunohistokmia (IHC). Penelitian ini bertujuan untuk membandingkan deteksi proliferasi sel dengan IHC anti-PCNA dan anti-BrdU pada pankreas. Tikus diinjeksi BrdU secara intraperitoneal sebanyak 4 kali dengan selang waktu 3 jam dengan dosis BrdU 0,125 ml, 0,375 ml, 0,250 ml, dan 0,250 ml dan dibiarkan selama 1 malam. Jaringan pankreas dipotong sepanjang ± 5 mm dan direndam dalam fiksatif paraformaldehid 4%, kemudian dibuat blok paraffin nya . Blok parafin diiris dengan ketebalan 6µm untuk pengecatan hematoksilin eosin (HE) dan 4 µm untuk pengecatan IHC. Pengecatan IHC dengan antibodi anti PCNA (antibodi monoklonal PCNA 1;1000 dalam PBS). Pengecatan IHC dengan antibodi anti BrdU menggunakan a ntibodi primer (antibodi anti BrdU 1:1000). P engecatan dianalisis secara kualitatif . IHC menggunakan antibodi anti-PCNA dan anti-BrdU menunjukkan adanya penyebaran warna coklat gelap yang menandakan proliferasi sel aktif , dimana s el yang terekspresi pada BrdU lebih sedikit dibandingkan PCN A. Penelitian ini menyimpulkan bahwa p roliferasi sel pankreas dapat terekspresi melalui perwarnaan IHC dengan antibodi anti PCNA dan anti BrdU . Kata kunci: Imunohistokimia, PCNA, Brdu, Proliferasi ABSTRACT The pancreas is a labile tissue because it consists of acinar cells which proliferate throughout their lives to replace damaged cells. The proliferation can be identified by histological examination, that is microtechnics with immunohistochmia (IHC) staining. This study aims to compare the detection of cell proliferation with anti-PCNA and anti-BrdU IHC in the pancreas. The rats were injected BrdU intraperitoneally 4 times with an interval of 3 hours with a dose of BrdU 0.125 ml, 0.375 ml, 0.250 ml, and 0.250 ml and left for 1 night. Pancreatic tissue were necropsy along ± 5 mm and soaked in 4% paraformaldehyde fixative, then made paraffin block. The paraffin block was sliced to a thickness of 6 µm for hematoxylin eosin (HE) and 4 μm for IHC painting. IHC used anti PCNA antibodies (PCNA monoclonal antibody 1; 1000 in PBS ) and anti BrdU antibodies (anti BrdU primary antibodies 1: 1000). Staining was analyzed qualitatively. IHC with anti-PCNA and anti-BrdU antibodies sho wed the spread of dark brown which indicates active cell proliferation , where as cells expressed in BrdU are less than PCNA. This study conclud ed that pancreatic cell proliferation can be expressed through the coloring of IHC with anti-PCNA and anti-BrdU antibodies . Keyword: Immunohistochemistry, PCNA, Brdu, Proliferation

Benzoxazine monomer (named as B-aptes) was synthesized from 3-aminopropyltriethoxysilane (KH-550), bisphenol A (BPA), and paraformaldehyde. Subsequently, functionalized halloysite nanotubes were obtained by introducing B-aptes onto the surface of halloysite nanotubes (HNTs). Then, benzoxazine-modified halloysite nanotubes (B-HNTs) were used to combine with BPA epoxy resin to prepare the diglycidyl ether of bisphenol-A (DGEBA)/B-HNTs composites. The homogeneous dispersion state of modified HNTs in the cured composite matrix was observed by scanning electron microscopy. Differential scanning calorimetry was used to investigate polymerization behaviors of ternary composites. The results showed that the ternary composite possessed lower polymerization temperature compared with the neat DGEBA/benzoxazine. According to the results of thermogravimetric analysis, the thermal stability of DGEBA/benzoxazine copolymers was improved by the modified HNTs, the char yield increased with the increase of HNTs mass ratio. The results of mechanical tests and dynamic mechanical analysis displayed that the DGEBA/B-HNTs composites possessed promoted mechanical properties.

The aim of the present study was to investigate the distribution of neuronal perikarya and nerve fibres and their chemical coding in the heart of 10-week-old porcine foetuses. The foetuses, obtained from a local slaughterhouse, were fixed by immersion in 4% buffered (pH 7.4) paraformaldehyde. Cryostat sections of the hearts were processed for single- or double-labelling immunofluorescence methods using antibodies against protein gene product (PGP) dopamine beta-hydroxylase (DβH), acetylcholine vesicular transporter (VAChT) and calcitonin gene-related peptide (CGRP). Numerous clusters of the PGP-positive nerve cells were observed throughout the heart wall. The majority of the clusters were found beneath the epicardium around the root of the aorta, pulmonary trunk and main veins. Some single PGP-positive neurons or small clusters of nerve cells were observed in the epicardium of heart atria and ventricles. The richest network of PGP-positive nerve fibres was observed in the base of the heart near the main cardiac blood vessel openings. Many bundles of PGP-positive nerve fibres were observed throughout the four cardiac chambers. Double-immunohistochemical staining revealed that the majority of the neurons contained immunoreactivity to VAChT, some of them stained for CGRP and the single neuronal somata were DβH-positive. The nerve fibres supplying the heart expressed immunoreactivity to DβH, VAChT or CGRP. The distribution and neurochemical coding of the nerve structures in ten-week-old foetuses are different from those observed in the hearts of juvenile pigs.

Aminomethylation of 1-(4-alkoxyphenyl)-2-phenyl(chlorophenyl)ethanones with paraformaldehyde and substituted piperazines in ethanol furnished 1-(4-alkoxyphenyl)-3-(4-R-piperazin-1-yl)-2-phenyl (chlorophenyl)propan-1-ones. Reaction of the latter with alkyl (aryl) magnesium halides resulted in the formation of tertiary amino alcohols of piperazine series, which were further converted to dihydrochlorides. The effect of synthesized compounds on the processes of tumor DNA methylation in vitro was studied.

Plant specimens for scanning electron microscopy (SEM) are commonly treated using standard protocols. Conventional fixatives consist of toxic chemicals such as glutaraldehyde, paraformaldehyde, and osmium tetroxide. In 1996, methanol fixation was reported as a rapid alternative to the standard protocols. If specimens are immersed in methanol for 30 s or longer and critical-point dried, they appear to be comparable in preservation quality to those treated with the chemical fixatives. A modified version that consists of methanol fixation and ethanol dehydration was effective at preserving the tissue morphology and dimensions. These solvent-based fixation and dehydration protocols are regarded as rapid and simple alternatives to standard protocols for SEM of plants.

Efficient approaches towards the synthesis of various N-substituted 1,3,5-triazinanes based on a transformation of N-alkyl-1,5,3-dioxazepanes or on a domino reaction involving condensation of various amines, amides, and paraformaldehyde are described for the first time. Mg(ClO4)2 was shown to be one of the most potent additives for the condensation. The proposed approaches permit the synthesis of a broad spectrum of substituted sym-triazinanes in good yields with relatively easy workup. In the case of the multicomponent reaction, the approach allows the preparation of the target substances from simple and easily accessible reagents. The representatives of the resulting compounds were found to possess no antimicrobial or cytotoxic activity in in vitro bioassays.

Paraformaldehyde is an easy-to-handle chemical for the in situ generation of formaldehyde and is, therefore, often used in chemistry, structural biology, or medicine. We have investigated the depolymerization process of paraformaldehyde at different temperatures for the application as C1 surrogate in "CO-free" carbonylation reactions using in situ Raman spectroscopy. Rather surprisingly, it was found that small amounts of commonly applied carbonylation catalysts slow down the depolymerization process significantly. By applying 1 H, 17 O, and 31 P NMR spectroscopy coupled with DFT calculations the inhibition process could be assigned to an electron-withdrawing coordination behavior of the Pd complex at the chain end of the paraformaldehyde chain. This inhibition process can be controlled by the utilized phosphine ligand.

Most attention has been focused on physiologically generated membrane blebs on the cellular cortex, whereas artificial membrane blebs induced by chemicals are studied to a lesser extent. We found that exposure of HeLa human cervical cancer cells to paraformaldehyde (PFA), followed by incubation in phosphate-buffered saline (PBS) efficiently induced large membrane blebs on the cellular cortex. Intriguingly, sequential exposure of the PFA-treated cells to PBS containing dimethyl sulfoxide (DMSO) facilitated shedding of the blebs from the cellular cortex, yielding a high quantity of large extracellular vesicles in the supernatant, which was applicable to assess the potentials of compounds and proteins as membrane influencers. Similar effects of PFA and DMSO were detected on the cellular cortex of other human, mouse, and fish cells. Our procedure to facilitate membrane blebbing and vesicle shedding by chemicals may be practical for the manipulation of membrane dynamics and the development of vesicle-inspired technologies using a wide variety of cell types.

New 1-aza-3,5-diphosphorinanes have been synthesized as a mixture of RR/SS- and RS-isomers via the reaction of bis(phenylphosphanyl)methane, paraformaldehyde, isopropylamine, of benzhydrylamine.

PURPOSE: Chemical fixation is a critical step to retaining cellular targets as naturally as possible. Recent developments in microscopy allow sophisticated detection and measuring techniques with which spatio-temporal molecular alterations are conceivable. In this study, we compare two members of aldehyde fixatives [i.e., glyoxal (Gly) and paraformaldehyde (PFA)] to determine whether Gly, a less toxic dialdehyde fixative that is considered to retain immunoreactivity could provide a successful and consistent cell fixation in favor of PFA in various cell preparations and types. METHODS: We document the fixation competence of Gly and PFA side-by-side (with or without Triton X-100 permeabilization) in live- and fixed-cell preparations in mouse oocytes, embryos, and human somatic cells (human umbilical cord-derived mesenchymal stromal cells) using protein quantification by Western blot assay and super-resolution microscopy. RESULTS: Although Gly seemed to act faster than PFA, catastrophic consequences were found not acceptable, especially in oocytes and embryos. Due to cell lysate and immunocytochemistry surveys, it was obvious that PFA is superior to Gly in retaining cellular proteins in situ with little/no background staining. In many samples, PFA revealed more reliable and consistent results regarding the protein quantity and cellular localization corresponding to previously defined patterns in the literature. CONCLUSION: Although the use of Gly is beneficial as indicated by previous reports, we concluded that it does not meet the requirement for proper fixation, at least for the tested cell types and proteins. However, PFA alone with no addition of TX displayed a significant cytoplasmic loss by generating membrane blebs during fixation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10815-019-01666-9) contains supplementary material, which is available to authorized users.

The centrohelid Raphidocystis contractilis is a heliozoan that has many radiating axopodia, each containing a bundle of microtubules. Although the rapid contraction of the axopodia at nearly a video rate (30 frames/s) is induced by mechanical stimuli, the mechanism underlying this phenomenon in R. contractilis has not yet been elucidated. In the present study, we described for the first time an adequate immunocytochemical fixation procedure for R. contractilis and the cellular distribution of α-tubulin before and after rapid axopodial contraction. We developed a flow-through chamber equipped with a micro-syringe pump that allowed the test solution to be injected at a flow rate below the threshold required to induce rapid axopodial contraction. Next, we used this injection method for evaluating the effects of different combinations of two fixatives (paraformaldehyde or glutaraldehyde) and two buffers (phosphate buffer or PHEM) on the morphological structure of the axopodia. A low concentration of glutaraldehyde in PHEM was identified as an adequate fixative for immunocytochemistry. The distribution of α-tubulin before and after rapid axopodial contraction was examined using immunocytochemistry and confocal laser scanning fluorescence microscopy. Positive signals were initially detected along the extended axopodia from the tips to the bases and were distributed in a non-uniform manner within the axopodia. Conversely, after the induction of a rapid axopodial contraction, these positive signals accumulated in the peripheral region of the cell. These results indicated that axopodial microtubules disassemble into fragments and/ or tubulin subunits during rapid axopodial contraction. Therefore, we hypothesize that the mechanism of extremely rapid axopodial contraction accompanied by cytoskeletal microtubule degradation in R. contractilis involves microtubule-severing at multiple sites.

A facile one-step reaction of [60]fullerene with cinnamaldehydes and amines promoted by magnesium perchlorate/ferric perchlorate under air conditions afforded a series of rare amino-substituted cyclopentafullerenes in moderate to good yields. Stereoselectivity was readily achieved. Secondary amines exclusively produced N,N-disubstituted cyclopentafullerenes as cis isomers, while arylamines gave N-monosubstituted cyclopentafullerenes with a preference of cis isomers as major products. N-Monosubstituted cyclopentafullerenes could be further converted into other scarce cyclopentafullerenes in the presence of acid chloride or paraformaldehyde. A possible reaction pathway was proposed to elucidate the formation of amino-substituted cyclopentafullerenes.

A novel one-pot approach for the synthesis of multi-substituted 2-imidazolylimidazoles, 2-pyrazolylimidazoles and 2-indazolylimidazoles was developed through a domino addition/A3 coupling/cyclization process under copper catalysis. A variety of aminoethyl- or hydroxylethyl-tethered 2-azolylimidazole derivatives were conveniently and efficiently assembled in one pot using N-propargylcarbodiimides, azoles, paraformaldehyde and secondary amines as starting materials. The products containing an o-iodoaryl group could be further converted to imidazo[1,2-c]imidazo[1,2-a]quinazoline derivatives through a copper-catalyzed intramolecular C-H arylation.

The first active catalyst system for the carbonylation of tri- and tetra-substituted olefins with paraformaldehyde and methyl formate is described. Specifically, using 1.0 mol% Pd(OAc)2 and 4.0 mol% 1,2-bis-(tert-butylpyridylphosphino)xylene L3 in the presence of 5.0 mol% PTSA·H2O, and 0.5 mol% Pd(OAc)2 and 2.0 mol% L3 in the presence of 8.0 mol% PTSA·H2O, respectively, allowed the corresponding linear esters to be obtained in good yields and selectivities.

The most common applications of flow cytometry (FC) include diagnostics of haemato-oncological disorders, based on analysis of bone marrow, peripheral blood (PB), or cerebrospinal fluid (CSF) samples. A proper diagnostic process requires standardisation in setting the optimal time frame between material collection and the assay. Unfortunately, this might be difficult to achieve in daily practice due to unintended shipment delays, which might compromise large-scale multicentre studies. Thus, material fixation should be considered as a solution. The most widely used fixative agents are: paraformaldehyde, TransFix®, Cyto-Chex®, and serum-containing media. In this review, we attempted to summarise the literature data on the influence of sample storage under different temperatures and times combined with different fixation conditions on the cell count and marker expression levels. Based on the findings of several extensive studies employing fixed PB samples, it can be concluded that the performance of particular fixative greatly depends on the analysed marker and specific PB cell population expressing a given antigen. Preservation of absolute cell count was usually better in Cyto-Chex®-fixed PB samples, whereas TransFix® tended to better stabilise marker expression levels. CSF-based studies reveal that both serum-containing media and TransFix® can prevent cellular loss and enhance FC-based detection of leptomeningeal localisations of haematological malignancies, the latter being more available and having longer shelf-life. As both cell count and marker expression level are the main determinants of quality of biological samples dedicated to FC analyses, it remains to be addressed by the investigators which is the fixative of choice for their specific research aims.

Many of medicaments used historically in root canal treatment have been shown to be cytotoxic. Paraformaldehid agents (such as Toxavit and Depulpin) are used to devitalize inflamed pulp when local anesthesia is ineffective. The misuse of pulp devitalizing agents may cause damage to gingiva and alveolar bone. This case report demonstrates complications arising after application of paraformaldehyde containing paste, necrosis of the gingiva and alveolar cortical bone, which resulted in great loss of supporting bone. Surgical intervention was required wherein necrotic bone was removed and bone defect was filled with xenograft of bovine origin. After three months endodontic treatment was performed. After the treatment, the patient's complaints were resolved. The use of paraformaldehyde-based agents during endodontic therapy requires special caution.

The discrimination of living and dead cells shows great importance in the development of biology, pathology, medicine, and pharmacology research. Herein, we synthesized a simple benzothiazole-based probe, EP, which was characterized via1H NMR (hydrogen nuclear magnetic resonance) spectroscopy, 13C NMR (carbon nuclear magnetic resonance) spectroscopy and HRMS (high-resolution mass spectroscopy). The fluorescence changes in response to esterase were characterized via fluorescence spectroscopy. EP exhibited a 70-fold fluorescence enhancement in the presence of esterase and possessed a very low limit of detection (4.73 × 10-5 U mL-1). EP also showed high selectivity to esterase compared to other biological species. Bright fluorescence appeared in living cells, which was activated by esterase when incubated with EP. In paraformaldehyde or H2O2 pretreated cells, the fluorescence became very weak since esterase became inactive in these cells. In summary, the EP probe can monitor esterase activity both in vitro and in living cells and can be used to evaluate the health status of cells and discriminate living and dead cells effectively.

β-Pinene and paraformaldehyde can be activated over catalyst to preferentially produce nopol. Tin supported over MCM-41 has shown high activity in this reaction, achieving complete conversion of pu...

A second-generation m-phenolsulfonic acid-formaldehyde resin (PAFR II) catalyst was prepared by condensation polymerization of sodium m-phenolsulfonate and paraformaldehyde in an aqueous H2SO4 solution. This reusable, robust acid resin catalyst was improved in both catalytic activity and stability, maintaining the characteristics of the previous generation catalyst (p-phenolsulfonic acid-formaldehyde resin). PAFR II was applied in the batchwise and continuous-flow direct esterification without water removal and provided higher product yields in continuous-flow esterification than any other commercial ion-exchanged acid catalyst tested.

Lignin is the second most abundant biopolymer and will be an important source for carbon-containing compounds in the future. Based on their similar phenolic structures, lignin has great potential to become a valuable substitute for phenol in phenol-formaldehyde resin adhesives. To meet this aim, the sodium hydroxide (NaOH)-catalyzed reaction of kraft lignin with formaldehyde was studied by using paraformaldehyde (PFA) as a formaldehyde source. The advantage of using PFA, the solid polymer of formaldehyde, is the simple composition of the depolymerized solution. According to the results of differential scanning calorimetry (DSC), the lignin reaction was found to require a high NaOH concentration in order for the reaction with PFA to proceed at reasonably low temperatures compared to the curing temperature of phenol-formaldehyde resins (approximately 150°C). On the other hand, high alkalinity conditions are known to favor the disproportionation of formaldehyde to formic acid and methanol. Due to the moderate reactivity of lignin, the Cannizzaro reaction can compete with the methylolation reaction of lignin. Based on the results of 13C, 31P and 1H-13C heteronuclear single quantum correlation nuclear magnetic resonance (HSQC NMR), methylolation was found to be the main reaction occurring in the lignin-formaldehyde reaction.

Despite their significant potential, catalytic asymmetric reactions of olefins with formaldehyde are rare and metal-free approaches have not been previously disclosed. Here we describe an enantioselective intermolecular Prins reaction of styrenes and paraformaldehyde to form 1,3-dioxanes, using confined imino-imidodiphosphate (iIDP) Brønsted acid catalysts. Isotope labeling experiments and computations suggest a concerted, highly asynchronous addition of an acid-activated formaldehyde oligomer to the olefin. The enantioenriched 1,3-dioxanes can be transformed into the corresponding optically active 1,3-diols, which are valuable synthetic building blocks.

In this paper, the microwave (MW)-assisted catalyst-free and mostly solvent-free Kabachnik&ndash, Fields reaction of amino alcohols, paraformaldehyde, and various &gt, P(O)H reagents (dialkyl phosphites, ethyl phenyl-H-phosphinate, and secondary phosphine oxides) is reported. The synthesis of N-2-hydroxyethyl-&alpha, aminophosphonate derivatives was optimized in respect of the temperature, the reaction time, and the molar ratio of the starting materials. A few by-products were also identified. N,N-Bis(phosphinoylmethyl)amines containing a hydroxyethyl group were also prepared by the double Kabachnik&ndash, Fields reaction of ethanolamine with an excess of paraformaldehyde and secondary phosphine oxides. The crystal structure of a 2-hydroxyethyl-&alpha, aminophosphine oxide and a bis(phosphinoylmethyl)ethanolamine was studied by X-ray analysis.

This paper reported a microfluidic platform which realized the characterization of inherent single-cell biomechanical and bioelectrical parameters simultaneously. Individual cells traveled through a constriction channel with deformation images and impedance variations captured and processed into cortical tension Tc , specific membrane capacitance Csm , and cytoplasmic conductivity σcy based on an equivalent biophysical model. These properties of thousands of individual cells of K562, Jurkat, HL-60, HL-60 treated with paraformaldehyde (PA)/cytochalasin D (CD)/concanavalin A (ConA), granulocytes of Donor 1, Donor 2, and Donor 3 were quantified for the first time. Leveraging Tc , Csm , and σcy , (1) high accuracies of classifying wild-type and processed HL-60 cells (e.g., 93.5% of PA treated vs. CD treated HL-60 cells) were realized, revealing the effectiveness of using these three biophysical parameters in cell-type classification; (2) low accuracies of classifying normal granulocytes from three donors (e.g., 56.4% of Donor 1 vs. 2), indicating comparable parameters for normal granulocytes. In conclusion, this platform can characterize single-cell Tc , Csm , and σcy concurrently and quantify multiple parameters in single-cell analysis.

Paraformaldehyde (PFA) fixation is a common fixation technique. However, current high-throughput single-cell RNA sequencing (scRNA-seq) methods are not compatible with PFA-fixed cells. Here we introduce FD-seq (Fixed Droplet RNA Sequencing), a method for droplet-based scRNA-seq of PFA-fixed, stained and sorted cells. FD-seq offers greater flexibility for researchers, and can readily be incorporated with existing Drop-seq experimental setup.