Investigation of unexpected silane ions caused by gas-phase reactions in Orbitrap gas chromatography-mass spectrometry.

RATIONALE: The mass spectra of compounds containing dimethyl (phenyl)silyl group (-SiMe2Ph) sometimes exhibit unusual ion peaks when measured using Orbitrap gas chromatography-mass spectrometry (GC-MS). This would complicate the mass spectra and may limit the matching of spectral data with preexisting resources for compound annotation. These peaks were identified as products from reactions with residual water. METHODS: A series of dimethyl (phenyl)silyl compounds were dissolved in methanol and investigated using Orbitrap GC-MS. Certain ions reacted with residual water in the C-trap. The reaction was confirmed using accurate mass and elemental composition analysis via MS studies, and the active center of the reaction was determined using density functional theory (DFT) calculations. RESULTS: Two types of gas-phase reactions between gaseous water and cations from a series of silanes were identified. DFT calculations indicate that silicon (Si) acts as the active center for these gas-phase water reactions. Compounds with multiple Si atoms generate a larger number of additional ions, which would complicate the mass spectra. The mass spectra of vinylsilanes and alkylsilanes with -SiMe2Ph indicate that the conjugated group linked to -SiMe2Ph can affect the water adduction process. CONCLUSIONS: Silane ions could react with residual water in the C-trap of an Orbitrap mass spectrometer. The mass spectra of these compounds may exhibit unexplained peaks arising from gas-phase reactions. Although these reactions may decrease spectral matching scores for compound annotation, they offer opportunities for systematic investigations into the mechanistic and kinetic aspects of high-energy ion reactivity.

A novel donor-acceptor fluorescent probe for the fluorogenic/ chromogenic detection and bioimaging of nitric oxide.

Nitric oxide (NO) plays an essential role in regulating various physiological and pathological processes. This has spurred various efforts to develop feasible methods for the detection of NO. Herein we designed and synthesized a novel donor-acceptor fluorescent probe Car-NO for the selective and specific detection of NO. Reaction of Car-NO with NO generated a new donor-acceptor structure with strong intramolecular charge transfer (ICT) effect, and led to remarkable chromogenic change from yellow to blue and dramatic fluorescence quenching. Car-NO exhibited high selectivity, excellent sensitivity, and rapid response for the detection of NO. In addition, the nanoparticles prepared from Car-NO (i.e., Car-NO NPs) showed strong NIR emission and high selectivity/sensitivity. Car-NO NPs was successfully employed to image both endogenous and exogenous NO in HeLa and RAW 264.7 cells. The present findings reveal that Car-NO is a promising probe for the detection and bioimaging of NO.

[Evolution Characteristics and Driving Forces of Carbon Dioxide Emissions and Sinks in the Pearl River Delta Region, China].

With the rapid economic and population growth, the Pearl River Delta(PRD) Region is one of the regions in China under the greatest pressure to be carbon neutral. This study analyzed the historical evolution characteristics of the carbon dioxide(CO2) emissions and sinks from 2006-2020 and identified the key drivers of the CO2 emissions and sinks based on the exponential decomposition method. The results showed that:① from 2006 to 2020, the total carbon emissions in the PRD Region increased from 218.22 million tons to 366.30 million tons, showing a fluctuating and rising evolution characteristic, with an overall increase of 67.86%. The carbon emission had not yet reached a peak. ② From 2006 to 2020, the total carbon sinks in the PRD Region decreased from 15.67 million tons to 15.53 million tons, showing a trend of fluctuation and decline, with an overall decrease of 0.94%. The carbon sinks were far lower than the carbon emissions, and there was still a large gap between carbon neutrality. ③ The main carbon emission sectors in the PRD Region were the energy sector(40.38%) and industrial sector(26.33%), and the carbon sinks mainly came from forestland(67.92%) and farmland(18.09%). ④ During the period from the "11th Five-Year Plan" to the "13th Five-Year Plan," the main positive driving factors for carbon emissions were economic growth and population size, whereas the main negative driving factor was energy intensity(energy use per unit GDP). However, since the "13th Five-Year Plan," the CO2 emission reduction potential released by reducing energy intensity has been weakening. In the future, the PRD Region needs to address the negative driving potential of the structural adjustment in energy, industry, transportation, and land use. ⑤ During the period from the "11th Five-Year Plan" to the "13th Five-Year Plan," the main positive driving factor for the carbon sink was the green scale, which was conducted by the increase in urban green space during the "11th Five-Year Plan." The main negative driving factor for the carbon sink was the carbon sink coefficient, which was caused by the natural disaster-induced yield reductions in crops with a high carbon sink coefficient, such as rice. Green space structure adjustment should be emphasized in the future. This study can provide scientific support for developing robust carbon-neutral policies in the PRD Region.

Association of subtle alterations in thyroid function with presarcopenia in patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: To investigate the association of subtle alterations in thyroid function with presarcopenia among patients with type 2 diabetes mellitus. MATERIALS AND METHODS: A total of 1,865 adult patients with type 2 diabetes mellitus were enrolled in this cross-sectional study, excluding patients with overt thyroid dysfunction. Skeletal muscle mass measured by dual energy X-ray absorptiometry was used to assess presarcopenia. Logistic regression models were used to estimate the effects of thyroid hormones on presarcopenia, and subgroup analyses were carried out in different strata of age, sex and body mass index, respectively. RESULTS: Compared with the euthyroid group (Euthy), the subclinical hyperthyroidism group had an increased odds of presarcopenia (multivariate-adjusted odds ratio 1.99, 95% confidence interval 1.09-3.63), but the subclinical hypothyroidism group did not (P > 0.05). In the subclinical hyperthyroidism group, age and body mass index <24 kg/m2 were independent risk factors for presarcopenia. In the overall Euthy group, an increased odds of presarcopenia was correlated with the elevated free thyroxine : free triiodothyronine ratio (all P for trend <0.05), whereas not with increment in free triiodothyronine level (P for trend >0.05). Additionally, in Euthy subgroup analyses stratified by middle-age, sex and body mass index, a similar association was noted (all P for trend <0.05), but not in the older-aged patients (P for trend >0.05). CONCLUSIONS: Subclinical hyperthyroidism was an independent risk factor for presarcopenia in patients with type 2 diabetes mellitus, but subclinical hypothyroidism was not. In the Euthy group with type 2 diabetes mellitus, a high free thyroxine : free triiodothyronine ratio was a good index of presarcopenia in addition to older age.

A Novel Nonsense INS Mutation Causes Inefficient Preproinsulin Translocation Into the Endoplasmic Reticulum.

Preproinsulin (PPI) translocation across the membrane of the endoplasmic reticulum (ER) is the first and critical step of insulin biosynthesis. Inefficient PPI translocation caused by signal peptide (SP) mutations can lead to ß-cell failure and diabetes. However, the effect of proinsulin domain on the efficiency of PPI translocation remains unknown. With whole exome sequencing, we identified a novel INS nonsense mutation resulting in an early termination at the 46th residue of PPI (PPI-R46X) in two unrelated patients with early-onset diabetes. We examined biological behaviors of the mutant and compared them to that of an established neonatal diabetes causing mutant PPI-C96Y. Although both mutants were retained in the cells, unlike C96Y, R46X did not induce ER stress or form abnormal disulfide-linked proinsulin complexes. More importantly, R46X did not interact with co-expressed wild-type (WT) proinsulin in the ER, and did not impair proinsulin-WT folding, trafficking, and insulin production. Metabolic labeling experiments established that, despite with an intact SP, R46X failed to be efficiently translocated into the ER, suggesting that proinsulin domain downstream of SP plays an important unrecognized role in PPI translocation across the ER membrane. The study not only expends the list of INS mutations associated with diabetes, but also provides genetic and biological evidence underlying the regulation mechanism of PPI translocation.