PO Group Research Articles

Periodontitis Promotes the Progression of Oral Squamous Cell Carcinoma by Inducing Macrophage M2 Polarization

To investigate the role of periodontitis in the development of oral squamous cell carcinoma (OSCC) and to determine whether periodontitis microorganisms induce M2 macrophage (M2) polarization and promote tumor progression. The tumor tissues of OSCC patients with periodontitis and those without periodontitis were collected and immunohistochemistry tests were done to validate the trend of changes in M2 macrophages. A mouse model of OSCC accompanied by periodontitis was established by treating mice with drinking water containing four antibiotics for three consecutive days, applying in the mouths of the mice a coat of bacteria collected from the saliva of patients with periodontitis once every other day for five times, and injecting in their buccal mucosa OSCC cells (SCC7). We observed the effect of periodontitis on the development of OSCC, analyzed the M2 macrophage content in the tumor tissues, and analyzed salivary microbiota structure, and examined the pathological changes in the spleen and colon tissues of the mice. Finally, we collected saliva from patients with periodontitis, co-cultured it with mice peripheral blood mononuclear cells (PBMC) and SCC7 cells, and examined M2 macrophage percentage by flow cytometry. Immunohistochemical findings from the clinical samples showed that M2-polarized macrophages in OSCC patients with periodontitis were more enriched (27.01%±2.12%) compared with those of OSCC patients without periodontitis (17.00%±3.66%). The OSCC mice with periodontitis (PO group) had tumors of larger size and lower survival rate than OSCC mice (O group) did. Furthermore, the expression rate of Ki67-positive cells (35.49%±5.00%) was significantly higher than that of O group (23.89%±4.13%) ( P<0.05). According to the results of flow cytometry, M2 macrophage expression (24.97%±4.41%) in PO group was higher than that of O group (5.75%±0.52%) ( P<0.05). In addition, qPCR results showed that gene expression of M2 macrophage-related factors, Arg1, IL-10, and CD206, showed an overall upward trend. Immunohistochemistry results showed that the positive expression of M2 macrophages was significantly increased in the PO group (21.82%±4.16%) compared to that of the O group (9.64%±0.60%) ( P<0.05). Mice in the PO group showed changes in their oral flora structure, exhibiting increased bands and diversity. The white pulp in their spleen tissue decreased and the boundary of the red pulp became indistinct with severe bleeding. The morphology of the colon glands was abnormal and the U-shaped crypt was damaged rather seriously. According to the results of cell experiment, when co-culturing PBMC with SCC7 cells, the presence of periodontitis microorganisms increased the polarization of M2 macrophages (71.00%±0.66%). Periodontitis promotes the development of OSCC by inducing M2 polarization in tumor-associated macrophages. Hence, periodontitis treatment holds important values for OSCC patients.

Antibiotic prescribing for adults with group A streptococcal bacteremia in a large healthcare system.

Limited data exist regarding treatment of invasive group A streptococcal (GAS) infections, including safety and efficacy of oral (PO) step-down therapy. We sought to describe current prescribing practices and clinical outcomes for patients with GAS bacteremia across a large health system, including a prespecified subset of patients who stepped down to PO antibiotics. This retrospective cohort study included adult patients with a positive blood culture for GAS between July 2018 and July 2021. Primary outcomes included frequency of PO step-down, total duration of therapy, duration of intravenous (IV) therapy prior to PO switch, and antimicrobial selection. Secondary outcomes included length of stay (LOS), mortality, adverse events, and clinical failure leading to readmission within 90 days. In total, 280 patients met inclusion criteria. Of these, 46.7% were stepped down to PO antibiotics. Median total duration of therapy was 15 days. Median duration of IV therapy prior to PO switch was 5 days. The predominant definitive antibiotic choice was a beta-lactam. Median LOS was 5 days. Ninety-day mortality was 16.7%. One patient developed an occluded line and one developed Clostridioides difficile-associated diarrhea within 90 days. Ninety-day readmission due to clinical failure was 12.5%. Among cases of uncomplicated skin and soft tissue source, mortality (6.1% vs 2.4%) and readmission (15.2% vs 16.9%) were similar between definitive IV and PO groups. Group A streptococcal bacteremia is a severe infection with a high readmission and mortality rate. Use of PO step-down therapy was common with similar readmission and mortality rates compared with definitive IV therapy.

The molecular structure effects of starches and starch phosphates in the reverse flotation of quartz from hematite

Native starches and their phosphates with various molecular structures was introduced as the depressant to realize the flotation of quartz from hematite in this study. The present starch phosphates (WSP, NSP, GSP) were modified by the reaction between phosphate and three different corn starches (WS, NS, G50). The synthesis and characterization of starch phosphates found that starch with high amylopectin content was easily modified into starch phosphates. Microflotation tests showed that starch phosphates exhibited stronger depressing abilities of hematite flotation than native starches. Zeta potential measurement showed that both starches and starch phosphates could positively shift the zeta potential of hematite, while starch phosphates had more effects than starches. XPS and MDS indicated that the chemisorption occurred between Fe of hematite surface and CO groups of starch-based depressants. In addition, starch phosphates could adsorb onto the hematite surface through PO groups. MDS also presented that the adsorption strength of starch phosphate was mainly determined by the type and number of generating chelating rings, and the molecular structure of starch significantly affected the formation of chelate rings. The proposed adsorption model insights will significantly promote the development of starch-based depressants for iron ore flotation and other mineral processing applications.

Significance of medication discontinuation on bisphosphonate-related jaw osteonecrosis in a rat model

Bisphosphonate (BP) discontinuation has been advised as a measure to prevent the incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ), however, its efficacy remains controversial. This study aimed to analyze the efficacy of BP discontinuation in reducing BRONJ severity following tooth extraction in a rat model. Thirty-four male Sprague–Dawley rats were divided into two BRONJ model categories: oral administration (PO) of alendronate (1 mg/kg) for 3 and 8 weeks and intraperitoneal (IP) injection of pamidronate (3 mg/kg) and dexamethasone (1 mg/kg) for 20 days. The PO model was divided into five groups (a control group without BPs and four experimental groups with 1-week discontinuation). The IP model was divided into two groups consisting of group I (without discontinuation) and group II (1-week discontinuation). One molar from both sides of the mandible was extracted. After extraction, the PO models were sacrificed at 3 and 5 weeks, and the IP models were sacrificed either immediately or at 2, 4, 6, and 8 weeks. Micro-CT showed non-significant differences among PO groups but significant differences were observed between IP groups. Most bone remodeling parameters within group I of the IP model differed significantly (p-value < 0.05). Histologically, group I showed a significantly higher percentage of necrotic bone than group II (51.93 ± 12.75%, p < 0.05) and a higher number of detached osteoclasts in TRAP staining. With discontinuation of medication for at least 1 week in rats, the effects of BPs on alveolar bone are suppressed and bone turnover and osteoclast functions are restored.

The performance evaluation of high content bio-asphalt modified with polyphosphoric acid

In order to seek alternatives to petroleum asphalt and expand the practical engineering usage of castor oil bio-asphalt, the polyphosphoric acid (PPA) was applied to the modification of bio-asphalt in this research work. In this study, castor oil was mixed with neat asphalt to prepare high content (20 % – 26 %) castor oil bio-asphalt, and the PPA content was set to be 6 % – 10 %. The performance of CPMA was assessed by utilizing laboratory tests, including penetration, softening point, temperature sweeping, BBR, and FTIR tests. The changes of functional groups and chemical reaction between PPA and high content castor oil bio-asphalt were assessed by conducting Fourier transform infrared spectroscopy (FTIR). Besides, the CPMA mixture performance was evaluated with rutting test, low-temperature bending test, and immersion Marshall test. The test results indicated that the high-temperature behavior of CPMA was deteriorated with the increase of castor oil dosage. However, PPA could noticeably improve the high-temperature behavior. What’s more, CPMA could maintain excellent low-temperature crack resistance even at −18 °C. The chemical reaction between PPA and bio-asphalt generated PO, PO, and POC functional groups. The rutting deformation of the CPMA20-10 mixture decreases by 41.5 %, and the dynamic stability increases by 76.14 % contrast with the neat asphalt mixture. The flexural strength of the CPMA20-10 mixture increased by 76.14 %. The MS and MS1 of the CPMA20-10 mixture were 23 % and 24.68 % higher than neat asphalt mixture. Through this study, we proved that PPA modified high content bio-asphalt has better high and low temperature performance. This study proved the feasibility of high content bio-oil modified asphalt.

18b Comparative Safety and Efficacy of a Hybrid Intravenous and Oral Diltiazem Protocol for Acute Rate Control in the Emergency Department

18b Comparative Safety and Efficacy of a Hybrid Intravenous and Oral Diltiazem Protocol for Acute Rate Control in the Emergency Department

Efficient environmental recovery of Au(I) from thiosulfate solution on triphenylphosphine-oxide-modified vermiculite

Natural materials that are economical and environmentally benign are being explored as adsorbent bases for recovering Au(I) from thiosulfate solution via an efficient grafted functional group. In this work, natural vermiculite (VE) modified with triphenylphosphine oxide (TPPO) was used to adsorb Au(I) from thiosulfate solution, and it's gold recovery performance and adsorption mechanism. Fourier transform infrared spectroscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and nitrogen adsorption were used to characterize the adsorbents. TPPO-modified VE (VE-TPPO) showed improved gold adsorption ability at a pH of approximately 10, thiosulfate concentration of approximately 0.1 mol/L and temperature of approximately 25 °C. More than 95% of Au(I) could be recovered, and the loading capacity of Au on VE-TPPO increased with decreasing adsorption temperature, reaching an amount of 4.22 kg/t after once adsorption. TPPO was adsorbed on vermiculite through cationic-π bonds. Au(I) was adsorbed on VE-TPPO by a ligand-exchange mechanism involving charge transfer between PO groups and Au(I). Moreover, the interaction mechanism between TPPO and Au(I) was further validated by density functional theory calculations. The use of natural materials with low cost and environmental impact can make the process of leaching gold with thiosulfate safer and cleaner.

Variations of follicular fluid extracellular vesicles miRNAs content in relation to development stage and season in buffalo

In buffalo (Bubalus bubalis) reproductive seasonality, causing cycles of milk production, is one of the major factors affecting farming profitability. Follicular fluid (FF) contains extracellular vesicles (EVs) playing an important role in modulating oocyte developmental competence and carrying microRNAs (miRNAs) essential for in vitro fertilization outcomes. The aim of this work was to characterize the FF-EVs-miRNA cargo of antral (An) and preovulatory (pO) follicles collected in the breeding (BS) and non-breeding (NBS) seasons, to unravel the molecular causes of the reduced oocyte competence recorded in buffalo during the NBS. In total, 1335 miRNAs (538 known Bos taurus miRNAs, 324 homologous to known miRNAs from other species and 473 new candidate miRNAs) were found. We identified 413 differentially expressed miRNAs (DE-miRNAs) (FDR < 0.05) between An and pO groups. A subset of the most significant DE-miRNAs between An and pO groups targets genes which function is related to the lipid and steroid metabolism, response to glucocorticoid and oestradiol stimulus. Comparison between BS and NBS showed 14 and 12 DE-miRNAs in An-FF-EVs and pO-FF-EVs, which regulate IL6 release and cellular adhesion, respectively. In conclusion, these results demonstrated that the miRNA cargo of buffalo FF-EVs varies in relation to both follicular development and season.

A novel rhodamine phosphorus derivative as fluorescent and colorimetric sensor for highly selective detection of Fe3+ in solution

Based on Rhodamine moiety, a novel phosphorus fluorescent sensor as 2-(6-(diethylamino)-2-((diphenylphosphoryl) methyl)-3-oxo-3-3H-xanthen-9-yl) benzoic acid (ROAP) is firstly designed and synthesized for the detection of Fe3+ in solution. The recognition effect of ROAP sensor is investigated carefully in dimethyl sulfoxide-water (DMSO-H2O) (fw = 70%) dispersion system. Fe3+ ion can lead to the quenching fluorescence and fading color of ROAP sensor. The as-prepared ROAP sensor shows high sensibility, selectivity, and anti-interference for Fe3+ in the concentration range of 0–5 equivalents. The recognition mechanism of the sensor is attributed to the combination of Fe3+ ions with the ROAP sensor via O atoms of PO and OH groups. The stoichiometric ratio of ROAP and Fe3+ complexation is 2:1. The probe also exhibits good reversibility, and high potential commercial applications in the future.

P142. Single center, randomized controlled trial of intravenous vs oral acetaminophen administration in perioperative care of 1 and 2 level LLIFs with instrumented posterior lumbar fusion: a comparative effectiveness study

P142. Single center, randomized controlled trial of intravenous vs oral acetaminophen administration in perioperative care of 1 and 2 level LLIFs with instrumented posterior lumbar fusion: a comparative effectiveness study

Left bundle branch potential predicts better electrical synchrony in bradycardia patients receiving left bundle branch pacing

BackgroundLeft bundle branch pacing (LBBP) is a novel physiological pacing technology. We aim to explore the relation between LBB potential (LBB Po) and left ventricular (LV) electrical/mechanical synchrony in bradycardia patients without heart failure (HF) receiving LBBP.MethodsA total of 62 patients undergoing LBBP were categorized by LBB Po: the LBB Po positive (+) group and the LBB Po negative (−) group. The perioperative electrocardiographic and echocardiography parameters related to cardiac synchrony were analyzed.ResultsThere were 42 (67.74%) patients in the LBB Po (+) group and 20 patients in the LBB Po (−) group. Paced QRS duration (113.50 ± 17.65 ms vs. 123.40 ± 13.18 ms, P = 0.031) and stimulus left ventricular activation time (71.76 ± 3.53 ms vs. 74.45 ± 3.12 ms, P = 0.005) were shorter in the LBB Po (+) group than in the LBB Po (−) group. No significant differences in the LV mechanical synchrony (Ts-SD-12, 36.55 ± 19.76 vs. 39.95 ± 16.04, P = 0.505; PSD, 51.14 ± 17.69 vs. 45.65 ± 10.55, P = 0.205) between the two groups. There was not statistically difference in ventricular lead parameters measured intraoperative between the two groups. Compared with the LBB Po (−) group, the LBB Po (+) group showed a dramatically higher total procedure duration time (93.52 ± 9.18 min vs. 86.25 ± 10.54 min, p = 0.007) and fluoroscopy time for ventricle lead implantation (18.95 ± 3.43 min vs. 14.00 ± 3.16 min, p < 0.001).ConclusionsThe appearance of LBB Po may suggest better electrical synchrony during LBBP, but similar in LV mechanical synchrony. However, the total operation duration and fluoroscopy time of ventricular lead implantation in the LBB Po (+) group were longer. Therefore, it may be unnecessary to deliberately recognize the LBB Po when it is difficult to detect LBB Po and meet the LBBP criterion.

Protective effects of Portulaca oleracea and vitamin E on cardiovascular parameters in rats with subclinical hyperthyroidism

ABSTRACT Introduction Subclinical hyperthyroidism (SHT) is an endocrine disorder that is associated with abnormalities in heart structure and function. Oxidative stress plays an important role in the pathophysiology of cardiac disorders caused by SHT. Portulaca oleracea (P. Oleracea) is a herbaceous plant with many pharmacologic effects including antioxidant, and anti-inflammatory properties. In the present study, the effects of Portulaca oleracea and vitamin E on the biochemical, hemodynamic, and functional parameters of the cardiac tissue was studied in rats with subclinical hyperthyroidism. Methods Fifty-six male rats were divided into seven groups: 1-Control group: daily injection of saline, 2-SHT group: daily injection of levothyroxine sodium (LS) (20 µg/kg), 3- T4+Po groups were given LS and P. oleracea (100, 200, and 400 mg/kg in drinking water), 4- the T4+vit E groups received LS and a daily injection of vitamin E (100 and 200 mg/kg). Cardiac index, systolic blood pressure (SBP), also malondialdehyde and total thiol levels were measured in cardiac tissue. Results SBP and maximum dP/dt were significantly increased and minimum dP/dt was significantly decreased in SHT group. In P. oleracea groups, maximum dP/dt were significantly reduced and minimum dP/dt was increased. Malondialdehyde levels and cardiac index in groups receiving vitamin E and P. oleracea were significantly decreased. Maximum dP/dt was decreased in the group receiving LS+vitamin E. Minimum dP/dt was significantly higher in group received LS+ vitamin E. Conclusion This study showed that Portulaca oleracea has a positive effect on cardiac dysfunction caused by subclinical hyperthyroidism.

Lowering interfacial tension by extended surfactant containing EO and PO groups

Lowering interfacial tension by extended surfactant containing EO and PO groups

Does Early Oral Intake After Microvascular Free Flap Reconstruction of the Oral Cavity Lead to Increased Postoperative Complications?

Data on timing of oral intake (PO) after free flap reconstruction of the oral cavity have been limited. Recent studies have shown that early PO after free flap reconstruction does not lead to increased morbidity and has resulted in decreased hospital stay. The objective of this study is to assess postoperative complications associated with timing of PO after free flap reconstruction of the oral cavity and to define clinical predictors of postoperative complications. This was a retrospective comparative cohort study and comprised of patients who underwent free flap reconstruction of the oral cavity between January 2014 and December 2019 in the Department of Oral and Maxillofacial Surgery at the University of Alabama at Birmingham. The predictor variable was timing of PO grouped into early (<5days) and late (>5days), postoperatively. The primary and secondary outcomes were postoperative complications and hospital length of stay (LOS), respectively. Covariates included age, gender, pathology, reconstruction site, flap type, tracheostomy, neck dissection, defect volume (cm3), skin paddle size (cm2), and gastrostomy tube (g-tube). Student's t-test, Chi-squared test, and binary logistic regression models were computed using odds ratios (ORs) with 95% confidence intervals (CIs). For all statistical tests, P values of < .05 were regarded as statistically significant. The sample consisted of 415 patients (253 males and 162 females), with a mean age of 58.8years (range, 14.4-88.2 years). The majority had malignant pathology (68.9%) with defects involving the mandible (52.3%) and reconstructed with a radial forearm (43.6%), followed by fibula (39%), and osteocutaneous radial forearm (13%). Seventy one "early PO" and 344 "late PO" patients were analyzed. Early PO was associated with lower postoperative complications compared with the late PO group (RR=0.847, 95% CI 0.747-0.960, P=.031) and shorter hospital LOS (6 vs 9days, 95% CI 2.2459-3.720, P<.001). A regression model showed a 2% increase for postoperative complications with each unit (cm3) increase of defect volume (OR=1.002, 95% CI 1.000-1.004, P=.035) and 2.286 times higher odds for postoperative complication in patients with a g-tube (95% CI 1.271-4.110, P=.006). Early PO after free flap reconstruction of the oral cavity was not associated with increased postoperative outcomes or delayed hospital course. Variables such as defect location, defect volume, and tracheostomy may increase the risk for postoperative complications and can help guide surgeons in deciding the optimal timing for PO postoperatively.

Recovery of indium from sulfate solutions with D2EHPA in the presence of organic proton-donor additives

Di(2-ethylhexyl)phosphoric acid (D2EHPA, HR) is widely used for solvent extraction of indium from acidic leaching solutions, but indium stripping from the loaded organic phase is difficult because of the high affinity of indium for the extractant. Adding proton-donor additives (HA) to the D2EHPA solution is a way to achieve high stripping efficiency for indium. In this work, monocarboxylic acids, aliphatic alcohols, and phenol derivatives were used as additives. Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy of the organic phases confirm the formation of intermolecular associates (H-complexes) between all additives and D2EHPA. In the case of alcohols and substituted phenols, the interaction of oxygen atoms of alcohols or phenols with the proton of the hydroxyl group of D2EHPA is predominant, while in the case of monocarboxylic acids, an interaction between the hydroxyl proton of the acid and the PO group of D2EHPA mainly occurs. Despite the high In distribution ratio with D2EHPA (100−1000), in all cases investigated the introduction of additives into the organic phase led to an antagonistic extraction effect, however it facilitated efficient In stripping from the loaded organic phase. This effect depends significantly on the type and structure of the additive. Indium extraction in the presence of additives decreases in the series 4-bromophenol >4-t-butylphenol > octanol, 2-ethylhexanol >4-nitrophenol >2-nitrophenol >2,6-di-t-butylphenol, octanoic acid > Versatic 10. Extraction systems containing D2EHPA and 2-ethylhexanol can be used to recover indium from various industrial solutions, in particular, from those derived from lead‑zinc production and from liquid crystal display panel wastes.

Nano-calcium Powder Properties from Six Commercial Fish Bone Waste in Indonesia

Low daily calcium intake in Asia, especially in Indonesia, is still a serious problem. The abundant fish bone waste from the fishery fillet industries in Indonesia, can be employed as an alternative source of calcium to meet daily calcium needs. This research aimed to determine which of the six fish species (tilapia, catfish, grouper, snapper, tuna, kingfish mackerel) produces the best quality and the most cost-effective nano-calcium powder for a recommendation to the stakeholders. The calcium was extracted using an alkali treatment. The properties of the produced nano-calcium powders were analyzed for: proximate composition, calcium and phosphorus levels, color brightness level, XRD, FTIR, particle size, and SEM-EDX image analysis. The tilapia bone had the finest particle size of calcium (87.37 nm), while the grouper bone had the biggest particle size (281.4 nm). The brightness of all yields varied from 83.83 (beige-kingfish mackerel) to 90.64 (white-tilapia). The average calcium content from EDX analysis varied from 21.51% (snapper) to 34.37% (grouper). The average phosphorus levels ranged from 10.73% (kingfish mackerel) to 15.99% (grouper). The EDX Ca/P molar ratio was 1.41-1.66 across all samples. The FTIR spectra showed that all samples contained PO, CH, CO, NH, and OH groups. The XRD spectra pattern determined that the two main components of the fish bone nano-calcium powder were 90% hydroxyapatite and halite. All fish bone samples have the potential to be used as raw material for nano-sized calcium. However, grouper bone with the highest calcium content and the highest nano-calcium yield was the best choice for further study.

Effect of Porcine Placental Extract Mixture on Alcohol-Induced Hepatotoxicity in Rats.

This study was conducted to examine the effect of porcine placenta extract mixture (pPEM, enzymatic/acidic extract = 1/3) on alcoholic hepatotoxicity after pPEM dosing with alcohol in rats. The experimental groups were normal, control, silymarin, three pPEM (590, 1771, and 2511 mg/kg/day, po), and silymarin (100 mg/kg/day, po) groups (n = 10). Alcoholic hepatotoxicity was caused by a liquid ethanol diet for 4 weeks. The effect of pPEM and silymarin on alcoholic hepatotoxicity was evaluated by serology, hepatic ADH and ALDH activities, and histopathological findings. After oral dosing with alcohol for 4 weeks, ALT and AST were significantly increased to 33.7 → 115.6 and 81.37 → 235.0 in the alcohol group, respectively. These levels were decreased significantly to 83.9 and 126.7 in the silymarin group and dose-dependently to 73.6–56.9 and 139.2–122.8 in all pPEM groups. Hepatic ADH and ALDH might have been increased in the control and not in the silymarin and pPEM groups for hepatic ADH. All pPEM groups exhibited no effects on hepatic ALDH except for the high pPEM group. Mild inflammation and fatty lesions were observed in the alcohol group and were attenuated in the silymarin and pPEM groups. As a results, the pPEM showed protective activities against alcoholic hepatotoxicity on the serological markers, hepatic ADH and ALDH, and pathological findings.

Clinical performance of lithium disilicate crowns restoring endodontically treated teeth with two occlusal preparation schemes

Aim: To evaluate the clinical performance of lithium disilicate crowns restoring endodontically treated teeth with two occlusal preparation schemes. Materials and methods: Forty full coverage lithium disilicate restorations were fabricated for posterior endodontically treated teeth. Patients were divided into two groups according to the preparation design, Group PO (control group): Planar occlusal design and Group FO (intervention group): Flat occlusal design. The preparation was standardized with deep chamfer finish line for all teeth. The restorations were milled from e.max CAD blocks and proper adhesive protocol was followed. After final cementation, the clinical performance of the restorations was evaluated according to the USPHS criteria in terms of fracture, marginal adaptation, marginal discoloration and secondary caries. These measurements were recorded at baseline, after 3, 6, 9 and 12 months respectively. Results: No statistically significant difference was detected between both groups for all tested outcomes (Fracture, marginal adaptation, secondary caries and marginal discoloration) over one year. While comparison between follow-up periods revealed statistically significant difference within the PO group, regarding marginal discoloration (P ≤ 0.05). Conclusions: Both planar and flat occlusal design revealed successful clinical performance with lithium disilicate full coverage restorations.

Insight into the formation mechanism of N, P co-doped mesoporous biochar from H3PO4 activation and NH3 modification of biomass

Understanding the formation mechanism of N, P co-doped biochar is critical for preparation of ideal N, P co-doped biochar materials. In this study, N, P co-doped mesoporous biochar was prepared by H3PO4 activation and NH3 modification of biomass. Results showed that, during H3PO4 activation, H3PO4 preferentially reacted with active O-containing groups in biomass. With increase of H3PO4 amount, H3PO4 mainly reacted with carbon fragments. This process removed large amounts of oxygen and carbon of biomass, meanwhile formed lots of vacancies, and then H3PO4 introduced abundant phosphorus (8.95 wt%) and new oxygen into P-doped biochar, accompanying generation of developed mesoporous structure (1089.33 m2/g). P-containing groups introduced were mainly C3-P-O, C-P-O and C-O-P groups. During NH3 modification, NH3 preferentially reacted with PO groups to form amine/amide-N, and then most of them converted into stable pyridinic-N, pyrrolic-N, or NP groups, meanwhile some N-containing groups would further convert into more stable quaternary-N. This process promoted decrease of C3-P-O and C-P-O groups, and formed more PN groups. It introduced abundant nitrogen (12.21 wt%), accompanying generation of more mesopores. At last, possible chemical reaction pathways of H3PO4 activation, and chemical reaction pathways between NH3 and P-containing groups during NH3 modification were proposed for the first time.

Dinucleating ligands based on functionalized oxalamides: Lability of Re(I) coordination with the phosphorus pendant arms

The reactions of ortho-(thio)phosphorylated anilines with oxalyl chloride smoothly afforded new ditopic pincer ligands with an oxalamide core and phosphorus(V) pendant arms. The thiophosphoryl-functionalized oxalamide readily underwent direct cyclometalation under the action of Re(CO)5Br in the presence of a base, furnishing the expected ditopic Re(I) pincer complex. At the same time, its phosphoryl-containing counterpart, owing to the labile coordination of the PO groups, afforded a complicated mixture of products, which finally resulted in two binuclear complexes with either coordinated or uncoordinated phosphoryl arms. The structures of all the isolated complexes were elucidated using NMR and IR spectroscopy as well as X-ray diffraction analysis, which provided some insight into the mechanism of their formation. The results of the preliminary evaluation of cytotoxic properties of some of the Re(I) complexes are presented.