An electrostatic cluster guides Aß40 fibril formation in sporadic and Dutch-type cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) is associated with the accumulation of fibrillar Aß peptides upon and within the cerebral vasculature, which leads to loss of vascular integrity and contributes to disease progression in Alzheimer's disease (AD). We investigate the structure of human-derived Aß40 fibrils obtained from patients diagnosed with sporadic or familial Dutch-type (E22Q) CAA. Using cryo-EM, two primary structures are identified containing elements that have not been observed in in vitro Aß40 fibril structures. One population has an ordered N-terminal fold comprised of two ß-strands stabilized by electrostatic interactions involving D1, E22, D23 and K28. This charged cluster is disrupted in the second population, which exhibits a disordered N-terminus and is favored in fibrils derived from the familial Dutch-type CAA patient. These results illustrate differences between human-derived CAA and AD fibrils, and how familial CAA mutations can guide fibril formation.

Complete Prevention of Bubbles in a PDMS-Based Digital PCR Chip with a Multifunction Cavity.

In a chamber-based digital PCR (dPCR) chip fabricated with polydimethylsiloxane (PDMS), bubble generation in the chambers at high temperatures is a critical issue. Here, we found that the main reason for bubble formation in PDMS chips is the too-high saturated vapor pressure of water at an elevated temperature. The bubbles should be completely prevented by reducing the initial pressure of the system to under 13.6 kPa to eliminate the effects of increased-pressure water vapor. Then, a cavity was designed and fabricated above the PCR reaction layer, and Parylene C was used as a shell covering the chip. The cavity was used for the negative generator in sample loading, PDMS degassing, PCR solution degassing in the digitization process and water storage in the thermal reaction process. The analysis was confirmed and finally achieved a desirable bubble-free, fast-digitization, valve-free and no-tubing connection dPCR.

The association between functional disability and depressive symptoms among older adults: Findings from the China Health and Retirement Longitudinal Study (CHARLS).

BACKGROUND: Previous research has shown that depressive symptoms in older adults was associated with functional disability, including basic activities of daily living (BADLs) and instrumental activities of daily living (IADLs). However, little is known about the impact of different patterns of functional disability and new-onset functional disability on subsequent depressive symptoms. OBJECTIVE: To determine the effect of various patterns of functional disability and new-onset functional disability on depressive symptoms among Chinese older adults aged 60 years and above. METHOD: The study included 3242 older adults from the China Health and Retirement Longitudinal Study (CHARLS), which was conducted from 2011 to 2018. Cox proportional hazards models were used to investigate the associations between patterns of functional disability and depressive symptoms. The associations were also examined in the population with new-onset functional disability. RESULT: During 15,321 person-years of follow-up, 946 depressive symptoms occurred. The hazard ratios (HRs) of depressive symptoms were 1.29 (95 % confidence intervals [CI]: 1.05-1.58) for IADLs disability, 1.22 (95 % CI: 0.75-1.55) for BADLs disability, and 1.78 (95 % CI: 1.41-2.22) for both IADLs and BADLs disabilities. In the analysis of new-onset functional disability, the HRs were 1.50 (95 % CI: 1.06-2.13) for onset IADLs disability, 1.28 (95 % CI: 0.85-1.91) for onset BADLs disability, and 1.69 (95 % CI: 1.03-2.76) for both onset BADLs and IADLs disabilities. LIMITATIONS: Depressive symptoms were assessed using the Centre for Epidemiological Studies Depression Scale, which has limitations in diagnosing clinical depression. CONCLUSION: Functional disability increases the risk of depressive symptoms, particularly impaired IADLs function. Psychological care for older adults with functional disability should be strengthened.

The causal relationship between 25-hydroxyvitamin D and serum lipids levels: A bidirectional two-sample mendelian randomization study.

Serum vitamin D levels were linked to lipid metabolism in observational studies, but the exact mechanism was unclear. Several studies have attempted to decipher the relationship between 25(OH)D and lipid levels. Conventional observational studies are vulnerable to confounding. Mendelian randomization (MR) analysis can better control for confounding factors and reverse causality, allowing for the inference of causal association. We, therefore, sought to use MR to investigate the possible causal relationship between 25(OH)D and blood lipid levels (HDL cholesterol, LDL cholesterol, triglycerides, and total cholesterol). A bidirectional two-sample Mendelian randomization (MR) was performed on data primarily from European ancestors. In addition, the potential causal effect of lipids on 25(OH)D was assessed by regressor-based multivariate magnetic resonance (MVMR). The single-nucleotide polymorphisms (SNPs) related to 25(OH)D were selected from a large-scale genome-wide association study (GWAS) database named IEU GWAS, and the SNPs associated with the four blood lipids were chosen from UK Biobank (UKB) lipid GWAS. When blood lipids were the outcome, the results of bidirectional two-sample MR demonstrated that 25(OH)D exhibited a negative causal association with TG, TC, and LDL-C: ß = - 0.23, 95% CI = -0.28 to -0.19, P<0.001; ß = - 0.16, 95% CI: - 0.30 to-0.03, P < 0.05; ß = - 0.11, 95% CI: - 0.23 to 0, P < 0.05. There was no causal relationship between 25(OH)D and HDL-C (ß = 0.05, 95% CI: - 0.11 to 0.20, P = 0.56). When setting blood lipids as exposure, TG and 25(OH)D, ß = -0.13, 95% CI: - 0.15 to -0.10, P < 0.05; TC and 25(OH)D, ß = -0.11, 95% CI: - 0.15 to -0.07, P < 0.05; HDL-C and 25(OH)D, ß = 0.02, 95% CI: 0 to 0.03, P = 0.07; LDL-C and 25(OH)D, ß = -0.08, 95% CI: - 0.11 to -0.05, P < 0.05). Our MVMR study also showed a significant relationship between genetically determined lipid traits and 25(OH)D levels (TG and 25(OH)D, P < 0.05; TC and 25(OH)D, P < 0.05). In all MR analyses, there was no horizontal pleiotropy (all P > 0.05), or statistical heterogeneity. The "Leave-one-out" sensitivity analysis confirmed the stability of our results. MR Studies have shown a bidirectional causal relationship between genetically-determined 25(OH)D levels and serum TG and TC levels. The findings have potential implications for etiological understanding and disease prevention.

SPA, a Stigma-style-transmitting tract Physical microenvironment Assay for investigating mechano-signaling in pollen tubes.

Accurate sensing and responding to physical microenvironment are crucial for cell function and survival, but the underlying molecular mechanisms remain elusive. Pollen tube (PT) provides a perfect single-cell model for studying mechanobiology since it's naturally subjected to complex mechanical instructions from the pistil during invasive growth. Recent reports have revealed discrepant PT behaviors between in vivo and flat, two-dimensional in vitro cultures. Here, we established the Stigma-style-transmitting tract (TT) Physical microenvironment Assay (SPA) to recapitulate pressure changes in the pistil. This biomimetic assay has enabled us to swiftly identify highly redundant genes, GEF8/9/11/12/13, as new regulators for maintaining PTs integrity during style-to-TT emergence. In contrast to normal growth on solid medium, SPA successfully phenocopied gef8/9/11/12/13 PT in vivo growth-arrest deficiency. Our results suggest the existence of distinct signaling pathways regulating in vivo and in vitro PT integrity maintenance, underscoring the necessity of faithfully mimicking the physical microenvironment for studying plant cell biology.

The association between the maternal pre-pregnancy platelet count and fecundability in mainland China: a population-based cohort study.

BACKGROUND: Currently, awareness about platelet count (PC) and its consequences for perinatal outcome have increased, but there is little reliable evidence on fecundability. METHODS: Based on the National Free Pre-conception Check-up Projects supported by the Chinese government, 5,524,886 couples met the inclusion criteria were included in this cohort study. Cox regression models were adopted to estimate fecundability ratios (FRs) and their 95% confidence intervals for pre-pregnancy PC quintiles. Restricted cubic splines were used to flexibly model and visualize the relationship of PC with FRs. Microsoft SQL server and R software were used for data management and analysis. RESULTS: The median of pre-pregnancy PC among women was 221.00×109/L. The first (<177.00 ×109/L) and second quintile (177.00-207.99 ×109/L) of PC showed slightly increased fecundability (Q1: adjusted FR 1.05, 95% CI 1.04-1.06; Q2: adjusted FR 1.04, 95% CI 1.03-1.05), while higher quintals (Q4: 236.00-271.99 ×109/L; Q5: ≥272.00 ×109/L) were related to reduction of fecundability, when compared with the third quintile of PC (208.00-235.99 ×109/L) (Q4: adjusted FR 0.96, 95% CI 0.95-0.97; Q5: adjusted FR 0.88, 95% CI 0.87-0.89). In the first quintiles (<177.00×109/L), only 20.93% women had PC below 129.94×109/L. An inverse-U shape association was consistently observed among women such that the lower PC of normal range (<118.03×109/L) and higher PC (>223.06×109/L) were associated with the risk of reduced female fecundability (P for non-linearity < 0.01). CONCLUSION: PC is associated with female fecundability. Further classification of PC levels may deepen our understanding of the early warnings and significance of female fecundability.

The rat frontal orienting field dynamically encodes value for economic decisions under risk.

Frontal and parietal cortex are implicated in economic decision-making, but their causal roles are untested. Here we silenced the frontal orienting field (FOF) and posterior parietal cortex (PPC) while rats chose between a cued lottery and a small stable surebet. PPC inactivations produced minimal short-lived effects. FOF inactivations reliably reduced lottery choices. A mixed-agent model of choice indicated that silencing the FOF caused a change in the curvature of the rats' utility function (U = Vρ). Consistent with this finding, single-neuron and population analyses of neural activity confirmed that the FOF encodes the lottery value on each trial. A dynamical model, which accounts for electrophysiological and silencing results, suggests that the FOF represents the current lottery value to compare against the remembered surebet value. These results demonstrate that the FOF is a critical node in the neural circuit for the dynamic representation of action values for choice under risk.

Expression of bone morphogenetic protein 10 and its role in biomineralization in Hyriopsis cumingii.

Shells and pearls are the products of biomineralization of shellfish after ingesting external mineral ions. Bone morphogenetic proteins (BMPs) play a role in a variety of biological function, and the genes that encode them, are considered important shell-forming genes in mollusks and are associated with shell and pearl formation, embryonic development, and other functions, but bone morphogenetic protein 10 (BMP10) is poorly understood in Hyriopsis cumingii. In this study, we cloned Hc-BMP10 and obtained a 2477 bp full-length sequence encoding 460 amino acids with a conserved TGF-ß structural domain. During the embryonic developmental stages, the cleavage stage had the highest expression of Hc-BMP10, followed by juvenile clams; the expression in the mantle gradually decreased with increasing mussel age. A strong signal was detected on epidermal cells on the mantle edge by in situ hybridization. In both the shell notching and inserting operations of the pearl fragment assay, we found that the expression of Hc-BMP10 increased after the above treatments. RNA interference assays showed that the silencing of Hc-BMP10 resulted in a change in the morphology of the prismatic layer and nacreous layer, with the prismatic layer less closely aligned and the disordered aragonite flakes in the nacreous layer. These findings indicate that Hc-BMP10 is involved in the growth and development of H. cumingii, as well as the formation of shells and pearls. Therefore, this study provides some reference for selecting superior species for growth and pearl breeding of H. cumingii at a molecular level and further investigation of the molecular mechanism for biomineralization of Hc-BMP10.

Study on the Role of Mitophagy Receptor PHB2 in Doubly Uniparental Inheritance of Hyriopsis cumingii.

In bivalves, the heterogeneity of mitochondrial DNA and its unique mode of transmission have been the focus of attention, which is called doubly uniparental inheritance (DUI). Prohibitin-2 (phb2) is a mitochondrial inner membrane protein that is a key mitophagy receptor for parental mitochondrial removal. Hyriopsis cumingii is a freshwater bivalve in China, the full-length cDNA of H. cumingii phb2 (named Hcphb2) is 2917 bp and encodes a total of 300 amino acids, a highly conserved sequence. Hcphb2 was highly expressed in the ovary. In the gonadal tissues of 5- to 8-month-old female mussels, the expression level of Hcphb2 continued to significantly increase. After Hcphb2 siRNA interference in 6-month-old female mussels, the expression of M-COII, a marker gene on M-type mitochondria, showed a considerable increase (p < 0.05). In contrast, the expression of autophagosome formation and maturation-related genes, atg4b, atg5, atg12, and atg16l, in the ATG family genes was significantly decreased (p < 0.01). Subcellular localization showed that Hcphb2 appeared in spermatogonia, spermatocyte, spermatid, and sperm, and its location changes synchronize with the behavior of M-type mitochondria location changes in DUI species. And it was found that miR-184 negatively regulated Hcphb2. The above results suggest that the mitochondrial autophagy receptor gene Hcphb2 may be associated with the degradation of M-type mitochondria in the freshwater mussel. This process requires multiple genes to participate, of which Hcphb2 and autophagy genes are only some of those that may play a role.

Vegetation restoration altered the soil organic carbon composition and favoured its stability in a Robinia pseudoacacia plantation.

Soil organic carbon (SOC) stabilization is vital for the mitigation of global climate change and retention of soil carbon stocks. However, there are knowledge gaps on how SOC sources and stabilization respond to vegetation restoration. Therefore, we investigated lignin phenol and amino sugar biomarkers, SOC physical fractions and chemical structure in one farmland and four stands of a Robinia pseudoacacia plantation. We observed that the content of SOC increased with afforestation, but the different biomarkers had different contributions to SOC. Compared to farmland, the contribution of lignin phenols to SOC decreased in the plantations, whereas there was no difference among the four stand ages, likely resulting from the balance between increasing lignin derivation input and increasing lignin degradation. Conversely, vegetation restoration increased the content of microbial necromass carbon (MNC) and the contribution of MNC to SOC, mainly because microbial residue decomposition was inhibited by decreasing the activity of leucine aminopeptidase, while microbial necromass preservation was promoted by adjusting soil variables (soil water content, clay, pH and total nitrogen). In addition, vegetation restoration increased the particulate organic carbon (POC), mineral-associated organic carbon (MAOC) pools and the O-alkyl C intensify. Overall, vegetation restoration affected SOC composition by regulating lignin phenols and microbial necromass and also altered SOC stabilization by increasing the physically stable MAOC pool during late afforestation. The results of this study suggest that more attention should be given to SOC sequestration and stability during late vegetation restoration.

MhCLC-c1, a Cl channel c homolog from Malus hupehensis, alleviates NaCl-induced cell death by inhibiting intracellular Cl- accumulation.

BACKGROUND: Overaccumulation of chloride (Cl) when plants suffer NaCl causes cell damage and death, and is regulated by Cl- channel protein (CLC). Apple roots are very sensitive to Cl-, but information associated with CLC is limited in apple crop that widely cultivated in the world. RESULTS: We identified 9 CLCs from the apple genome and divided them into two subclasses. Among them, MdCLC-c1 promoter contained the largest number of cis-acting elements associated with NaCl stress, and only the MdCLC-c1, MdCLC-d, and MdCLC-g were predicted that may be Cl- antiporters or channels. Expression analysis of MdCLCs homologs in the roots of Malus hupehensis showed that most of the MhCLCs expression were response to NaCl stress, especially MhCLC-c1 expression was upregulated continuously and rapidly expressed during NaCl treatment. Therefore, we isolated MhCLC-c1 and observed it was a plasma membrane-localized protein. The MhCLC-c1 suppression significantly increased sensitivity, reactive oxygen species content, and cell death of apple calli; while MhCLC-c1 overexpression decreased sensitivity, reactive oxygen species content, and cell death of apple calli and Arabidopsis by inhibiting intracellular Cl- accumulation under NaCl stress. CONCLUSIONS: The study selected and isolated a CLC-c gene MhCLC-c1 from Malus hupehensis based on identification of CLCs gene family in apple, and their homologs MhCLCs expression patterns during NaCl treatments, revealing that MhCLC-c1 alleviates NaCl-induced cell death by inhibiting intracellular Cl- accumulation. Our findings confer the comprehensive and in-depth upstanding of the mechanism that plants resist salt stress, and might also confer genetic improvement of salt tolerance in horticultural crops and the development and utilization of saline-alkali land.

Canonical Rab5 GTPases are essential for pollen tube growth through style in Arabidopsis.

Pollen tubes have dynamic tubular vacuoles. Functional loss of AP-3, a regulator of one vacuolar trafficking route, reduces pollen tube growth. However, the role of canonical Rab5 GTPases that are responsible for two other vacuolar trafficking routes in Arabidopsis pollen tubes is obscure. By using genomic editing, confocal microscopy, pollen tube growth assays, and transmission electron microscopy, we demonstrate that functional loss of canonical Rab5s in Arabidopsis, RHA1 and ARA7, causes the failure of pollen tubes to grow through style and thus impairs male transmission. Functional loss of canonical Rab5s compromises vacuolar trafficking of tonoplast proteins, vacuolar biogenesis, and turgor regulation. However, rha1;ara7 pollen tubes are comparable to those of wild-type in growing through narrow passages by microfluidic assays. We demonstrate that functional loss of canonical Rab5s compromises endocytic and secretory trafficking at the plasma membrane (PM), whereas the targeting of PM-associated ATPases is largely unaffected. Despite that, rha1;ara7 pollen tubes contain a reduced cytosolic pH and disrupted actin microfilaments, correlating with the mis-targeting of vacuolar ATPases (VHA). These results imply a key role of vacuoles in maintaining cytoplasmic proton homeostasis and in pollen tube penetrative growth through style.

Highly sensitive liquid chromatographic method combined with online ion suppression to remove interfering anions and mass spectrometry for impurity profiling of paromomycin sulfate.

A previously developed high-performance liquid chromatography method combined with pulsed amperometric detection allowed to separate many impurities of paromomycin. However, due to the presence of ion pairing agents and sodium hydroxide in the mobile phase, direct coupling to mass spectrometry for the identification of the chemical structures of the impurities was not an option. Indeed, ion suppression was encountered by trifluoroacetic acid and pentafluoroproponic acid in the mobile phase. A cation self-regenerating suppressor, which was originally designed for increasing analyte conductivity of ammonia and amines analysis in ion chromatography, was coupled between the liquid chromatography and ion trap-time of flight-mass spectrometry and almost all trifluoroacetic acid and pentafluoroproponic acid in the mobile phase was removed. The limit of detection of paromomycin in this integrated system improved significantly to 20 ng/ml (0.4 ng). The chemical structures of 19 impurities were elucidated and seven impurities were reported for the first time.

A transcriptional constraint mechanism limits the homeostatic response to activity deprivation in mammalian neocortex.

Healthy neuronal networks rely on homeostatic plasticity to maintain stable firing rates despite changing synaptic drive. These mechanisms, however, can themselves be destabilizing if activated inappropriately or excessively. For example, prolonged activity deprivation can lead to rebound hyperactivity and seizures. While many forms of homeostasis have been described, whether and how the magnitude of homeostatic plasticity is constrained remains unknown. Here, we uncover negative regulation of cortical network homeostasis by the PARbZIP family of transcription factors. In cortical slice cultures made from knockout mice lacking all three of these factors, the network response to prolonged activity withdrawal measured with calcium imaging is much stronger, while baseline activity is unchanged. Whole-cell recordings reveal an exaggerated increase in the frequency of miniature excitatory synaptic currents reflecting enhanced upregulation of recurrent excitatory synaptic transmission. Genetic analyses reveal that two of the factors, Hlf and Tef, are critical for constraining plasticity and for preventing life-threatening seizures. These data indicate that transcriptional activation is not only required for many forms of homeostatic plasticity but is also involved in restraint of the response to activity deprivation.

The human brain is made up of billions of nerve cells called neurons which receive and send signals to one another. To avoid being over- or under-stimulated, neurons can adjust the strength of the inputs they receive by altering how connected they are to other nerve cells. This process, known as homeostatic plasticity, is thought to be necessary for normal brain activity as it helps keep the outgoing signals of neurons relatively constant. However, homeostatic plasticity can lead to seizures if it becomes too strong and overcompensates for weak input signals. Regulating this process is therefore central to brain health, but scientists do not understand if or how it is controlled. To address this, Valakh et al. analyzed the genes activated in neurons lacking incoming signals to find proteins that regulate homeostatic plasticity. This revealed a class of molecules called transcription factors (which switch genes on or off) that constrain the process. In brain samples from mice without these regulatory proteins, neurons received twice as much input, leading to an increase in brain activity resembling that observed during seizures. Valakh et al. confirmed this finding using live mice, which developed seizures in the absence of these transcription factors. These findings suggest that this type of regulation to keep homeostatic plasticity from becoming too strong may be important. This could be especially vital as the brain develops, when the strength of connections between neurons changes rapidly. The discovery of the transcription factors involved provides a potential target for activating or restraining homeostatic plasticity. This control could help researchers better understand how the process stabilizes brain signaling.

Impact of Aß40 and Aß42 Fibrils on the Transcriptome of Primary Astrocytes and Microglia.

Fibrillar amyloid ß-protein (Aß) deposits in the brain, which are primarily composed of Aß40 or Aß42 peptides, are key pathological features of Alzheimer's disease (AD) and related disorders. Although the underlying mechanisms are still not clear, the Aß fibrils can trigger a number of cellular responses, including activation of astrocytes and microglia. In addition, fibril structures of the Aß40 and Aß42 peptides are known to be polymorphic, which poses a challenge for attributing the contribution of different Aß sequences and structures to brain pathology. Here, we systematically treated primary astrocytes and microglia with single, well-characterized polymorphs of Aß40 or Aß42 fibrils, and performed bulk RNA sequencing to assess cell-specific changes in gene expression. A greater number of genes were up-regulated by Aß42 fibril-treated glial cells (251 and 2133 genes in astrocyte and microglia, respectively) compared with the Aß40 fibril-treated glial cells (191 and 251 genes in astrocytes and microglia, respectively). Immunolabeling studies in an AD rat model with parenchymal fibrillar Aß42 plaques confirmed the expression of PAI-1, MMP9, MMP12, CCL2, and C1r in plaque-associated microglia, and iNOS, GBP2, and C3D in plaque-associated astrocytes, validating markers from the RNA sequence data. In order to better understand these Aß fibril-induced gene changes, we analyzed gene expression patterns using the Ingenuity pathway analysis program. These analyses further highlighted that Aß42 fibril treatment up-regulated cellular activation pathways and immune response pathways in glial cells, including IL1ß and TNFα in astrocytes, and microglial activation and TGFß1 in microglia. Further analysis revealed that a number of disease-associated microglial (DAM) genes were surprisingly suppressed in Aß40 fibril treated microglia. Together, the present findings indicate that Aß42 fibrils generally show similar, but stronger, stimulating activity of glial cells compared with Aß40 fibril treatment.

rTg-D: A novel transgenic rat model of cerebral amyloid angiopathy Type-2.

Background: Cerebral amyloid angiopathy (CAA) is common disorder of the elderly, a prominent comorbidity of Alzheimer's disease, and causes vascular cognitive impairment and dementia. Previously, we generated a transgenic rat model of capillary CAA type-1 that develops many pathological features of human disease. However, a complementary rat model of larger vessel CAA type-2 disease has been lacking. Methods: A novel transgenic rat model (rTg-D) was generated that produces human familial CAA Dutch E22Q mutant amyloid ß-protein (Aß) in brain and develops larger vessel CAA type-2. Quantitative biochemical and pathological analyses were performed to characterize the progression of CAA and associated pathologies in aging rTg-D rats. Results: rTg-D rats begin to accumulate Aß in brain and develop varying levels of larger vessel CAA type-2, in the absence of capillary CAA type-1, starting around 18 months of age. Larger vessel CAA was mainly composed of the Aß40 peptide and most prominent in surface leptomeningeal/pial vessels and arterioles of the cortex and thalamus. Cerebral microbleeds and small vessel occlusions were present mostly in the thalamic region of affected rTg-D rats. In contrast to capillary CAA type-1 the amyloid deposited within the walls of larger vessels of rTg-D rats did not promote perivascular astrocyte and microglial responses or accumulate the Aß chaperone apolipoprotein E. Conclusion: Although variable in severity, the rTg-D rats specifically develop larger vessel CAA type-2 that reflects many of the pathological features of human disease and provide a new model to investigate the pathogenesis of this condition.

Analysis of impurity profiling of arbekacin sulfate by ion-pair liquid chromatography coupled with pulsed electrochemical detection and online ion suppressor-ion trap-time off light mass spectrometry.

Ion-pair liquid chromatography with pulsed electrochemical detection (LC-PED) was established for the analysis of impurities in arbekacin (ABK) sulfate. APursuit pentafluorophenylpropyl (PFP) column was used as stationary phase. This novel method showed greater separation and sensitivity ability. In a representative ABK sample, 24 impurity peaks were detected in LC-PED, where of only 9 were monitored by a post-column derivatization method prescribed by the Japanese Pharmacopoeia (JP). For identification of the chemical structures of the impurities detected by LC-PED, LC-Mass Spectrometry (MS) was used. Two challenges had to be overcome in this work. The first was the transfer of the MS incompatible mobile phase to an MS compatibleone while maintaining the elution order of the peaks in the chromatograms. Previously reported approaches such as two-dimensional (2D)LC were hardly applicable in this case due to the lack of ultraviolet (UV) absorbing chromophores in ABK and its impurities. The sodium hydroxide solution was replaced by aqueous ammonia to adjust the pH of the mobile phase used in LC-PED. The other challenge encountered was the ion suppression effect caused by trifluoroacetic acid (TFA) and pentafluoroproponic acid (PFPA) in the mobile phase. Some strategies such as "TFA-fixed" and its modifications were tried, but they were inconvenient and severe contamination of the MS was observed. A cationself-regenerating suppressor (CSRS), which was originally designed for increasing analyte conductivityof ammonia and amines analysis in ion chromatography (IC), was coupled between the LC and Ion Trap-Time of Flight (IT-TOF)-MS and almost all TFA and PFPA in the mobile phase were removed. The limit of detection (LOD) of ABK in this integrated system improved significantly to 20 ng/mL. The chemical structures of the 28 impurities were elucidated and 15 impurities were reported for the first time.

Factors correlated with targeted prevention for prediabetes classified by impaired fasting glucose, impaired glucose tolerance, and elevated HbA1c: A population-based longitudinal study.

Background: There is still controversy surrounding the precise characterization of prediabetic population. We aim to identify and examine factors of demographic, behavioral, clinical, and biochemical characteristics, and obesity indicators (anthropometric characteristics and anthropometric prediction equation) for prediabetes according to different definition criteria of the American Diabetes Association (ADA) in the Chinese population. Methods: A longitudinal study consisted of baseline survey and two follow-ups was conducted, and a pooled data were analyzed. Prediabetes was defined as either impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or elevated glycosylated hemoglobin (HbA1c) according to the ADA criteria. Robust generalized estimating equation models were used. Results: A total of 5,713 (58.42%) observations were prediabetes (IGT, 38.07%; IGT, 26.51%; elevated HbA1c, 23.45%); 9.66% prediabetes fulfilled all the three ADA criteria. Among demographic characteristics, higher age was more evident in elevated HbA1c [adjusted OR (aOR)=2.85]. Female individuals were less likely to have IFG (aOR=0.70) and more likely to suffer from IGT than male individuals (aOR=1.41). Several inconsistency correlations of biochemical characteristics and obesity indicators were detected by prediabetes criteria. Body adiposity estimator exhibited strong association with prediabetes (D10: aOR=4.05). For IFG and elevated HbA1c, the odds of predicted lean body mass exceed other indicators (D10: aOR=3.34; aOR=3.64). For IGT, predicted percent fat presented the highest odds (D10: aOR=6.58). Conclusion: Some correlated factors of prediabetes under different criteria differed, and obesity indicators were easily measured for target identification. Our findings could be used for targeted intervention to optimize preventions to mitigate the obviously increased prevalence of diabetes.