Visible-light-promoted regioselective hydrocarboxylation of allenes with formate salt and CO2.

Visible-light-promoted hydrocarboxylation of allenes with formate salt and CO2 was developed for the first time using commercially available [Ir(ppy)2(dtbbpy)]PF6 as a photocatalyst. This strategy provides an efficient and practical method to access ß,γ-unsaturated linear carboxylic acids in moderate yields with complete regioselectivity.

Effects of Antarctic Krill Meal in Diet on Reproductive Performance and Embryo Quality of Eriocheir sinensis.

A 60-day feeding trial was conducted to evaluate the impact of dietary Antarctic krill meal on the reproductive performance and embryo quality of the Chinese mitten crab, Eriocheir sinensis. Three diets were formulated, incorporating varying levels of Antarctic krill meal at 0% (Diet K0), 10% (Diet K10), and 20% (Diet K20), with a control group fed razor clam Sinonovacula constricta. Each diet was randomly assigned to three replicate tanks, each stocked with 5 males and 10 females. Male and female weights were 145.38 ± 8.01 and 102.57 ± 9.73 g, respectively. The results revealed no significant differences in weight gain rate, specific growth rate, and survival rate. However, the hepatopancreatic weight and hepatopancreas index of female crabs in each group decreased, while gonadal weight and gonadosomatic index increased significantly after 60 days, with Diet K20 showing the highest values. Egg production and fecundity of female crabs reached their peak in Diet K20, with no significant differences in reproductive indices among all groups. The phospholipid content in Diet K20 was significantly higher than in the other groups (P < 0.05). Cholesterol contents in Diet K0 and the control group were significantly higher than in Diet K10 and K20 (P < 0.05). No significant differences were observed in egg diameter, egg weight, moisture, crude protein, and crude fat between the groups. The content of C20 : 2 and C20 : 4n6 was highest in Diet K0, with a significant difference compared to Diet K10 (P < 0.05). However, no significant differences were found in the total content of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids among all groups. Based on the research findings, it is recommended that the optimal level of Antarctic krill meal in diets is 20%.

Photoredox-Catalyzed Phosphonocarboxylation of Allenes with Phosphine Oxides and CO2.

Phosphonocarboxylation of allenes with diarylphosphine oxides and CO2 via visible-light photoredox catalysis was developed for the first time. This work provided practical and sustainable access to highly valuable but otherwise difficult-to-access linear allylic ß-phosphonyl carboxylic acids in moderate yields with exclusive regio- and stereoselectivity. This method was also characterized by step and atom economy and transition-metal free and mild conditions. Preliminary mechanistic studies suggested that allyl-methyl carbanion species are the key intermediates.

Integrating monthly spring tidal waves into estuarine carbon budget of meta-ecosystems.

The contribution of lateral carbon (C) to hydrological processes is well known for its ecological functions in the estuarine C budget across the terrestrial-aquatic interfaces. However, sampling of individual daily tides during multiple months or seasons in heterogeneous patches of landscape makes extrapolation from days to months or seasons challenging. In this paper, we examine the terrestrial-aquatic lateral hydrological C flux for an estuarine marsh where monthly tides, including consecutive daily spring tides, were measured over the course of an entire year. We found a significant correlation between imported and exported hydrological dissolved C, both dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC), although a similar correlation was not found for particulate organic carbon (POC). Based on a total of 44 sampling trips over a year, this saltmarsh appeared to be a net exporter of DOC and DIC but a net sink of POC. Furthermore, the lateral hydrological C budget functioned as a limited lateral C sink in terms of organic C (i.e., ΔPOC and ΔDOC), while the marsh functioned as a small lateral C source. Our findings highlight the importance of lateral hydrologic inflows/outflows in wetland C budgets of land-water interfaces, especially in those characterized by the meta-ecosystem framework. Surprisingly, different C species responded unequally to the lateral hydrological C budget, suggesting that a conceptual realization of meta-ecosystem is a powerful theoretical framework to extend the outwelling hypothesis.

Differences in subthalamic oscillatory activity in the two hemispheres associated with severity of Parkinson's disease.

Background: It is well known that motor features of Parkinson's disease (PD) commonly begin on one side of the body and extend to the other side with disease progression. The onset side generally remains more severely affected over the course of the disease. However, the pathophysiology underlying the asymmetry of motor manifestations remains unclear. The purpose of the present study is to examine whether alterations in neuronal activity in the subthalamic nucleus (STN) associate with PD severity. Methods: Microelectrode recording was performed in the STN during targeting for 30 patients in the treatment of deep brain stimulation. The mean spontaneous firing rate (MSFR), power density spectral analysis, and correlations were calculated. Characteristics of subthalamic oscillatory activity were compared between two hemispheres. UPDRS III scores during "Off" and "On" states were obtained for the body side of initial symptoms (BSIS) and the body side of extended symptoms (BSES). Results: There were significant differences of MSFR (41.3 ± 11.0 Hz vs 35.2 ± 10.0 Hz) and percentage of ß frequency oscillatory neurons (51.3% vs 34.9%) between BSIS and BSES. The percentage of ß frequency oscillatory neurons correlated with the bradykinesia/rigidity scores for both sides (p < 0.05). In contrast, the percentage of tremor frequency oscillatory neurons was significantly higher in the BSES than that in the BSIS. In particular, these neurons only correlated with the tremor scores of the BSES (p < 0.05). Conclusion: The results suggest that increased neuronal firing rate and ß frequency oscillatory neurons in the STN are associated with contralateral side motor severity and its progression. Tremor frequency oscillatory neurons are less observed in the STN of the BSIS suggesting that ß oscillatory activity dominates and tremor frequency oscillatory activity reciprocally declines.

Lithium Triethylborohydride (LiHBEt3)-Promoted Hydrosilylation of Allenes to Prepare (E)-Allylsilanes.

A transition-metal-free hydrosilylation of allenes is reported herein by using commercially available lithium triethylborohydride (LiHBEt3) as the catalyst. Both mono- and disubstituted allenes could be hydrosilylated with primary or secondary silanes effectively. This reaction represents an environmental and economic method to prepare (E)-allylsilanes in good yields along with decent selectivities.

Characterization of pneumococcal serotype 7F in vaccine conjugation.

Streptococcus pneumoniae is a highly invasive bacterial pathogen that can cause a range of illnesses. Pneumococcal capsular polysaccharides (CPS) are the main virulence factors that causes invasive pneumococcal disease (IPD). Pneumococcal CPS serotype 7F along with a few other serotypes is more invasive and likely to cause IPD. Therefore, 7F is a target for pneumococcal vaccine development, and is included in the two recently approved multi-valent pneumococcal conjugated vaccines, i.e. VAXNEUVANCE and PREVNAR 20.To support process and development of our 15-valent pneumococcal conjugated vaccine (PCV15), chromatographic methods have been developed for 7F polysaccharide and conjugate characterization. A size-exclusion chromatography (SEC) method with UV, light scattering and refractive index detections was employed for concentration, size and conformation analysis. A reversed-phase ultra-performance liquid chromatography (RP-UPLC) method was used for analysis of conjugate monosaccharide composition and degree of conjugation. The collective information obtained by these chromatographic analysis provided insights into the pneumococcal conjugate and conjugation process.

A Photosensitizer for N-O Bond Activation: 2,7-Br-4CzIPN-Catalyzed Difunctionalization of Alkenes with Oxime Esters.

We developed 2,4,5,6-tetrakis(2,7-dibromo-9H-carbazol-9-yl)isophthalonitrile (2,7-Br-4CzIPN) as a new photosensitizer for the energy-transfer-driven N-O bond dissociation of oxime esters. In the presence of 2,7-Br-4CzIPN, difunctionalization of alkenes with oxime esters, including oxyimination, aminocarboxylation, and amidylimination, could afford a variety of versatile molecules in good yields with excellent regioselectivity, which widely occur in natural products and drugs. Our theoretical investigations and experiments have demonstrated that 2,7-Br-4CzIPN has unique photophysical properties, favorable triplet energy, and excellent photocatalytic activity.

The effect of dexmedetomidine on expression of neuronal nitric oxide synthase in spinal dorsal cord in a rat model with chronic neuropathic pain.

BACKGROUND: Neuropathic pain typically refers to the pain caused by somatosensory system injury or diseases, which is usually characterized by ambulatory pain, allodynia, and hyperalgesia. Nitric oxide produced by neuronal nitric oxide synthase (nNOS) in the spinal dorsal cord might serve a predominant role in regulating the algesia of neuropathic pain. The high efficacy and safety, as well as the plausible ability in providing comfort, entitle dexmedetomidine (DEX) to an effective anesthetic adjuvant. The aim of this study was to investigate the effect of DEX on the expression of nNOS in spinal dorsal cord in a rat model with chronic neuropathic pain. METHODS: Male Sprague Dawley (SD) rats were randomly assigned into three groups: sham operation group (sham), (of the sciatic nerve) operation (CCI) group, and dexmedetomidine (DEX) group. Chronic neuropathic pain models in the CCI and DEX groups were established by sciatic nerve ligation. The thermal withdrawal latency (TWL) was measured on day 1 before operation and on day 1, 3, 7 and 14 after operation. Six animals were sacrificed after TWL measurement on day 7, and 14 days after operation, in each group, the L4-6 segment of the spinal cords was extracted for determination of nNOS expression by immunohistochemistry. RESULTS: Compared with the sham group, the TWL threshold was significantly decreased and the expression of nNOS was up-regulated after operation in the CCI and DEX groups. Compared with the CCI grou[, the TWL threshold was significantly increased and the expression of nNOS was significantly down-regulated on day 7 and 14 days after operation in the DEX group. CONCLUSION: Down-regulated nNOS in the spinal dorsal cord is involved in the attenuation of neuropathic pain by DEX.

ANTECEDENTES: A dor neuropática refere-se tipicamente à dor causada por lesões ou doenças do sistema somatossensorial. De modo geral, é caracterizada por dor à ambulação, alodinia e hiperalgesia. O óxido nítrico produzido pela enzima óxido nítrico sintase neuronal (nNOS) na medula espinhal dorsal pode ter um papel predominante na regulação da dor neuropática. A alta eficácia e segurança, bem como a plausível capacidade de proporcionar conforto, faz com que a dexmedetomidina (DEX) seja um adjuvante anestésico eficaz. O objetivo deste estudo foi investigar o efeito da DEX na expressão de nNOS na medula espinhal dorsal em um modelo de ratos com dor neuropática crônica. MéTODOS: Ratos Sprague Dawley (SD) machos foram distribuídos aleatoriamente em três grupos: grupo de cirurgia simulada (sham), grupo de cirurgia (do nervo ciático; CCI) e grupo dexmedetomidina (DEX). Os modelos de dor neuropática crônica nos grupos CCI e DEX foram estabelecidos por ligadura do nervo ciático. A latência de retirada térmica (TWL) foi medida no dia 1 antes da cirurgia e nos dias 1, 3, 7 e 14 após o procedimento. Seis animais de cada grupo foram eutanasiados após a medida de TWL nos dias 7 e 14 após a cirurgia e o segmento L4-6 da medula espinhal foi extraído para determinação da expressão de nNOS por imuno-histoquímica. RESULTADOS: Em comparação ao grupo sham, o limiar de TWL diminuiu significativamente e a expressão de nNOS foi regulada de maneira positiva após a cirurgia nos grupos CCI e DEX. Comparado ao grupo CCI, o limiar de TWL aumentou de forma significativa e a expressão de nNOS caiu significativamente diminuída nos dia 7 e 14 após a cirurgia no grupo DEX. CONCLUSãO: A regulação negativa de nNOS na medula espinhal dorsal está envolvida na atenuação da dor neuropática pela DEX.

The effect of dexmedetomidine on expression of neuronal nitric oxide synthase in spinal dorsal cord in a rat model with chronic neuropathic pain / O efeito da dexmedetomidina na expressão do óxido nítrico sintase neuronal na medula espinhal dorsal em um modelo rato com dor neuropática crônica

Abstract Background Neuropathic pain typically refers to the pain caused by somatosensory system injury or diseases, which is usually characterized by ambulatory pain, allodynia, and hyperalgesia. Nitric oxide produced by neuronal nitric oxide synthase (nNOS) in the spinal dorsal cord might serve a predominant role in regulating the algesia of neuropathic pain. The high efficacy and safety, as well as the plausible ability in providing comfort, entitle dexmedetomidine (DEX) to an effective anesthetic adjuvant. The aim of this study was to investigate the effect of DEX on the expression of nNOS in spinal dorsal cord in a rat model with chronic neuropathic pain. Methods Male Sprague Dawley (SD) rats were randomly assigned into three groups: sham operation group (sham), (of the sciatic nerve) operation (CCI) group, and dexmedetomidine (DEX) group. Chronic neuropathic pain models in the CCI and DEX groups were established by sciatic nerve ligation. The thermal withdrawal latency (TWL) was measured on day 1 before operation and on day 1, 3, 7 and 14 after operation. Six animals were sacrificed after TWL measurement on day 7, and 14 days after operation, in each group, the L4-6 segment of the spinal cords was extracted for determination of nNOS expression by immunohistochemistry. Results Compared with the sham group, the TWL threshold was significantly decreased and the expression of nNOS was up-regulated after operation in the CCI and DEX groups. Compared with the CCI grou[, the TWL threshold was significantly increased and the expression of nNOS was significantly down-regulated on day 7 and 14 days after operation in the DEX group. Conclusion Down-regulated nNOS in the spinal dorsal cord is involved in the attenuation of neuropathic pain by DEX.

Resumo Antecedentes A dor neuropática refere-se tipicamente à dor causada por lesões ou doenças do sistema somatossensorial. De modo geral, é caracterizada por dor à ambulação, alodinia e hiperalgesia. O óxido nítrico produzido pela enzima óxido nítrico sintase neuronal (nNOS) na medula espinhal dorsal pode ter um papel predominante na regulação da dor neuropática. A alta eficácia e segurança, bem como a plausível capacidade de proporcionar conforto, faz com que a dexmedetomidina (DEX) seja um adjuvante anestésico eficaz. O objetivo deste estudo foi investigar o efeito da DEX na expressão de nNOS na medula espinhal dorsal em um modelo de ratos com dor neuropática crônica. Métodos Ratos Sprague Dawley (SD) machos foram distribuídos aleatoriamente em três grupos: grupo de cirurgia simulada (sham), grupo de cirurgia (do nervo ciático; CCI) e grupo dexmedetomidina (DEX). Os modelos de dor neuropática crônica nos grupos CCI e DEX foram estabelecidos por ligadura do nervo ciático. A latência de retirada térmica (TWL) foi medida no dia 1 antes da cirurgia e nos dias 1, 3, 7 e 14 após o procedimento. Seis animais de cada grupo foram eutanasiados após a medida de TWL nos dias 7 e 14 após a cirurgia e o segmento L4-6 da medula espinhal foi extraído para determinação da expressão de nNOS por imuno-histoquímica. Resultados Em comparação ao grupo sham, o limiar de TWL diminuiu significativamente e a expressão de nNOS foi regulada de maneira positiva após a cirurgia nos grupos CCI e DEX. Comparado ao grupo CCI, o limiar de TWL aumentou de forma significativa e a expressão de nNOS caiu significativamente diminuída nos dia 7 e 14 após a cirurgia no grupo DEX. Conclusão A regulação negativa de nNOS na medula espinhal dorsal está envolvida na atenuação da dor neuropática pela DEX.

Antibody enhanced HPLC for serotype-specific quantitation of polysaccharides in pneumococcal conjugate vaccine.

Bacterial infection remains as one of the major healthcare issues, despite significant scientific and medical progress in this field. Infection by Streptococcus Pneumoniae (S. Pneumoniae) can cause pneumonia and other serious infectious diseases, such as bacteremia, sinusitis and meningitis. The pneumococcal capsular polysaccharides (CPS) that constitute the outermost layer of the bacterial cell are the main immunogens and protect the pathogen from host defense mechanisms. Over 90 pneumococcal CPS serotypes have been identified, among which more than 30 can cause invasive pneumococcal diseases that could lead to morbidity and mortality. Multivalent pneumococcal vaccines have been developed to prevent diseases caused by S. Pneumoniae. These vaccines employ either purified pneumococcal CPSs or protein conjugates of these CPSs to generate antigen-specific immune responses for patient protection. Serotype-specific quantitation of these polysaccharides (Ps) antigen species are required for vaccine clinical dosage, product release and quality control. Herein, we have developed an antibody-enhanced high-performance liquid chromatography (HPLC) assay for serotype-specific quantitation of the polysaccharide contents in multivalent pneumococcal conjugate vaccines (PCVs). A fluorescence-labeled multiplex assay format has also been developed. This work laid the foundation for a serotype-specific antigen assay format that could play an important role for future vaccine research and development.

Correlation analysis of migration in Eriocheir sinensis of the Yangtze River estuary based on salinity preference.

Reproduction and development are the most important stages in the life of aquatic animals, which are also the most sensitive stages to environmental stress. As a migratory crab, parent Eriocheir sinensis need to migrate to estuary (brackish water) for reproduction, and megalopas need to migrate to freshwater for development. Yangtze River estuary is located at the junction of the Yangtze River and the East China Sea, and the salinity of different regions varies greatly (salinity 0-30‰). Therefore, salinity is one of the key environmental factors affecting E. sinensis. In this study, the salinity preference of parent and megalopas E. sinensis was observed and analyzed by the six-chambered and seven-chambered devices of laboratory experiments. Two groups of alternative salinity were set for parent crabs (7, 14, 21, 28, and 35 ‰) and megalopas (0, 5, 10, 15, 20, 25, and 30‰). The results indicated that males showed no obvious preference for salinity, while females had obvious preference for different salinity and stronger dependence and tolerance to saltwater. Megalopas showed a significant preference for low salinity which was beneficial to migrating to freshwater quickly. It was speculated that the behavior of megalopas tending to freshwater was an inherited behavior in the evolutionary process rather than influenced by environment. The salinity preference of E. sinensis might change the position of spawning grounds and migratory routes, and then the annual fluctuation of salinity in Yangtze River estuary will affect the change of E. sinensis resources.

Optimizing co-combustion synergy of soil remediation biomass and pulverized coal toward energetic and gas-to-ash pollution controls.

The co-combustion synergy of post-phytoremediation biomass may be optimized to cultivate a variety of benefits from reducing dependence on fossil fuels to stabilizing heavy metals in a small quantity of ash. This study characterized the thermo-kinetic parameters, gas-to-ash products, and energetically and environmentally optimal conditions for the co-combustions of aboveground (PG-A) and belowground (PG-B) biomass of Pfaffia glomerata (PG) with pulverized coal (PC). The mono-combustions of PG-A and PG-B involved the decompositions of cellulose and hemicellulose in the range of 162-400 °C and of lignin in the range of 400-600 °C. PG improved the combustion performance of PC, with the blends of 30 % PG-A and 70 % (PAC37) and 10 % PG-B and 90 % PC (PBC19) exhibiting the strongest synergy. Both PG-A and PG-B interacted with PC in the range of 160-440 °C, while PC positively affected PG in the range of 440-600 °C. PC decreased the apparent activation energy (Eα) of PG, with PBC19 having the lowest Eα value (107.85 kJ/mol). The reaction order models (Fn) best elucidated the co-combustion mechanisms of the main stages. Adding >50 % PC reduced the alkali metal content of PG, prevented the slagging and fouling depositions, and mitigated the Cd and Zn leaching toxicity. The functional groups, volatiles, and N- and S-containing gases fell with PAC37 and PBC19, while CO2 emission rose. Energetically and environmentally multiple objectives for the operational conditions were optimized via artificial neural networks. Our study presents controls over the co-circularity and co-combustion of the soil remediation plant and coal.

Characterization of High Molecular Weight Pneumococcal Conjugate by SEC-MALS and AF4-MALS.

Infections by Streptococcus pneumoniae can cause serious pneumococcal diseases and other medical complications among patients. Polysaccharide-based vaccines have been successfully developed as prophylactic agents against such deadly bacterial infections. In the 1980s, PNEUMOVAX® 23 were introduced as the first pneumococcal polysaccharide vaccines (PPSV). Later, pneumococcal polysaccharides were conjugated to a carrier protein to improve immune responses. Pneumococcal conjugate vaccines (PCV) such as PREVNAR® and VAXNEUVANCE™ have been developed. Of the more than 90 pneumococcal bacteria serotypes, serotype 1 (ST-1) and serotype 4 (ST-4) are the two main types that cause invasive pneumococcal diseases (IPD) that could lead to morbidity and mortality. Development of a novel multi-valent PCV against these serotypes requires extensive biophysical and biochemical characterizations of each monovalent conjugate (MVC) in the vaccine. To understand and characterize these high molecular weight (Mw) polysaccharide protein conjugates, we employed the multi-angle light scattering (MALS) technique coupled with size-exclusion chromatography (SEC) separation and asymmetrical flow field flow fractionation (AF4). MALS analysis of MVCs from the two orthogonal separation mechanisms helps shed light on the heterogeneity in conformation and aggregation states of each conjugate.

Effect of Polishing on Lead and Cadmium Bioavailability in Rice and Its Health Implications.

Rice polishing is an important approach to reducing the concentrations of heavy metals in rice, but knowledge of its effect on the Pb and Cd bioavailability in produced rice and the related health risk remains limited. In this study, the effects of rice polishing on the bioaccessibility (BAC) and bioavailability (RBA) of Pb and Cd in rice are assessed using an in vitro method and an in vivo mouse bioassay. The Pb removal rate in brown rice (40%), lightly processed brown rice (62%), germinated rice (74%), and polished rice (79%) gradually enhanced with an increase in the polishing degree, while Cd was difficult to remove by polishing. The Pb and Cd BAC in germinated rice was the highest, while that in brown rice was the lowest. The polished rice Pb and Cd RBA in the liver and kidneys were significantly higher than those in the brown rice group. The Pb RBA in the livers and kidneys in the polished rice group was 26.6% ± 1.68% and 65.3% ± 0.83%, respectively, which was 1.6- and 2.6-times higher than that in the brown rice group, respectively. The Cd RBA values in both the livers and kidneys of the polished rice group were 1.3-times higher than those in the brown rice group. Although polishing reduced the total Pb in the polished rice, it was not enough to offset the increase in bioavailability, and its consumption risk was not weakened. This study highlighted the value of the oral-bioavailability-corrected health risk assessment for assessing the influence of rice polishing on Pb and Cd exposure via rice consumption.

Seasonal Changes of Growth, Immune Parameters and Liver Function in Wild Chinese Sturgeons Under Indoor Conditions: Implication for Artificial Rearing.

Seasonality has a significant effect on the physiology of fish, especially the effect of water temperature changes. In the present study, the growth, innate immune parameters and liver function indices of two rescued wild adult Chinese sturgeons under captive conditions were monitored for 1 year. The results showed that the total annual weight loss rate of the male was -4.58% and the total weight gain rate of the female was 24.12%, in which the weight of both individuals registered highly significant differences in summer, fall and winter (p < 0.01). The male Chinese sturgeon also exhibited negative specific growth rates (-0.1 to -0.8%) during spring to fall, whereas positive specific growth rates, ranging from 0.03 to 0.11%, were recorded in the female. Seasonality also affected the innate immune parameters of the two Chinese sturgeons, in which leukocytes had been increasing since spring and C-reactive protein (CRP) content was significantly higher (p < 0.05) in summer than fall in both individuals. The CRP level of the male Chinese sturgeon showed a significant increase from fall to winter (p < 0.05), suggesting that it may have contracted infection or inflammation during this study period. With the analysis of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), transaminase (AST:ALT) ratio, alkaline phosphatase, albumin to globulin ratio and triglycerides, it was found that the liver function of the captive Chinese sturgeons was adversely affected along seasonal changes, with the highest degree of liver impairment in winter. In combining observations from growth performance and changes in innate immune and liver function parameters, the present findings deduced that the male Chinese sturgeon under study was more susceptible to seasonal changes than the female. For better indoor culture of adult Chinese sturgeons, monitoring of hematological parameters to detect early signs of inflammation and liver function abnormality should be conducted with routine veterinary care during prolonged captivity.

Effectiveness of Patient-Controlled Intravenous Analgesia (PCIA) with Sufentanil Background Infusion for Post-Cesarean Analgesia: A Randomized Controlled Trial.

Purpose: To investigate the effectiveness of sufentanil patient-controlled intravenous analgesia pump (PCIA) and background infusion in patients of post-cesarean analgesia. Patients and Methods: This trial compared two groups of women undergoing cesarean section and receiving PCIA: no background infusion group (n=30), 6-min lockout time, and background infusion group (n=30), 2 mL/h infusion, 10-min lockout time. Both groups with 2 µg/kg sufentanil was diluted to 100 mL with normal saline. VAS scores at rest at 36 h was the primary endpoint. The secondary endpoints were the VAS scores at rest at 6, 12, and 24 h, the total amount of sufentanil consumed, the Ramsay sedation score (RSS) assessed at the same time points, postpartum bleeding within 24 h, the injection/attempt (I/A) ratio, BP and HR, PONV, side effects of sufentanil. Results: Compared with the no background infusion group, the background infusion group showed lower VAS pain scores at 6, 12, and 24 h (P<0.01), but no differences at 36 h (95% CI = -0.5-0.8. P>0.05). Attempts, injections, and total sufentanil consumption were significantly different between the two groups (P<0.001), but without difference in I/A. Bleeding was less in the background infusion group at 1 h (P=0.03). The minimal respiration rates were not significantly different between groups. Conclusion: Background infusion increased the total consumption of sufentanil within 36 h after cesarean section. Although it did not reduce uterine contraction pain and wound pain at 36 h, it significantly reduced the pain at 6, 12, and 24 h after cesarean section. It improved patient satisfaction and reduced the amount of bleeding after 1 h. Importantly, it did not increase the incidence of hypertension, PONV and respiratory depression.

Development of a derivatization RP-HPLC method for determination of sulfuryl chloride in chlorosulfonic acid for gefapixant citrate manufacture.

Control of process impurities during manufacturing of drug substance is critical to ensure quality and process robustness. During commercial process development for the gefapixant citrate drug substance, several process impurities were found to derive from sulfuryl chloride, an impurity in the raw material, chlorosulfonic acid (CSA). This made controlling the CSA quality essential for commercial production of this drug substance. Various direct analysis methods were evaluated and found unsuitable because of the highly reactive nature and structural similarity of sulfuryl chloride and CSA. Therefore, a robust derivatization reversed-phase high performance liquid chromatography (RP-HPLC) method was developed and validated to accurately quantify sulfuryl chloride in CSA. The derivatization method was utilized to evaluate many CSA batches from different commercial suppliers and to establish a correlation between sulfuryl chloride levels in CSA and the levels of process impurities in downstream materials. The methodology described herein informed the development of setting the specification on sulfuryl chloride for CSA to ensure a robust process for manufacturing high-quality gefapixant citrate drug substance. The derivatization method was successfully validated and transferred to the commercial commodity supplier for release testing of CSA as a raw material for gefapixant citrate commercial campaigns.

Identification and quantitation of isomeric pneumococcal polysaccharides by partial chemical degradation followed by mass spectrometry.

Quantitation of isomeric pneumococcal polysaccharides in vaccines is a challenging task due to mixture complexity, their low quantities, and identical monosaccharide compositions. Differentiation and quantitation of isomeric pneumococcal polysaccharides were investigated here based on a partial chemical degradation mass spectrometry approach to generate an oligosaccharide marker for one isomer, and not the other. Mild base conditions were successful at generating unique ions for the isomers with the weakest glycosidic bonds, while strong base and acid conditions were successful at generating unique ions for the more stable isomers. Linear relationships between the ion abundance of the oligosaccharide marker and the starting pneumococcal polysaccharides concentration were established for all isomers. Furthermore, precision measurements for each method were below 12% demonstrating good robustness. Therefore, partial chemical degradation followed by mass spectrometry was successful at differentiating and quantifying isomeric pneumococcal polysaccharides and may be adopted for other bacterial types.

Multi-attribute characterization of pneumococcal conjugate vaccine by Size-exclusion chromatography coupled with UV-MALS-RI detections.

Streptococcus pneumoniae bacterial infection can cause serious diseases. Among more than 90 known streptococcus pneumoniae serotypes, more than 30 can cause invasive pneumococcal diseases that could lead to morbidity and mortality. Initially, a 23-valent polysaccharide vaccines (PPSV) PNEUMOVAX®23, was developed to generate an antigen-specific immune response and prevent diseases caused by these pneumoniae serotypes. Later, pneumococcal conjugate vaccines (PCV), such as PREVNAR® and VAXNEUVANCE™ have been developed to offer a more robust immune response in the pediatric population. In our effort to develop novel pneumococcal conjugate vaccines, each serotype of pneumococcal polysaccharide (Ps) is conjugated to a detoxified diphtheria toxin carrier protein CRM197 to form a monovalent conjugate (MVC). MVCs from multiple serotypes are formulated with vaccine adjuvant to form a multi-valent vaccine drug product. During the product development, critical attributes including conjugate molecular weight (Mw), protein and polysaccharide concentration, have been used to monitor process and product quality. To measure these attributes, a size-exclusion chromatography (SEC) method was developed with a series of in-line detectors including UV, multi-angle light scattering (MALS) and refractive index (RI). This SEC-UV-MALS-RI method is employed to characterize and monitor process intermediates and product during process development and for product release and stability testing. With this, we have expanded the multi-attribute SEC method to a 15-valent pneumococcal conjugate vaccine.