Beauty of Explicit Dispersity (Đ) Equations in Controlled Polymerizations

Dispersity (Đ) as a critical parameter indicates the level of uniformity of the polymer molar mass or chain length. In the past several decades, the development of explicit equations for calculating Đ experiences a continual revolution. This viewpoint tracks the historical evolution of the explicit equations from living to reversible-deactivation polymerization systems. Emphasis is laid on displaying the charm of explicit Đ equations in batch reversible-deactivation radical polymerization (RDRP), with highlights of the relevant elegant mathematical manipulations. Some representative emerging applications enabled by the existing explicit equations are shown, involving nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (RAFT) polymerization systems. Stemming from the several outlined challenges and outlooks, sustained concerns about the explicit Đ equations are still highly deserved. It is expected that these equations will continue to play an important role not only in traditional polymerization kinetic simulation and design of experiments but also in modern intelligent manufacturing of precision polymers and classroom education.

[Efficacy of Barbed reposition pharyngoplasty combined with Han-Uvulopalatopharyngoplasty for the treatment of OSAHS patients]

Objective: To study the efficacy of Barbed reposition pharyngoplasty (BRP) combined with Han-Uvulopalatopharyngoplasty (H-UPPP) in surgical treatment of OSAHS patients. Methods: OSAHS patients admitted to our department from June 2021 to February 2022 who met the surgical enrollment criteria were divided into two groups by surgical procedure: H-UPPP operation group [Control group, 47 cases, including 42 males and 5 females, aged 18-64 (37.77±11.65)years, and H-UPPP+BRP group [Study group, 48 cases, including 45 males and 3 females, aged 23-60 (39.10±9.86) years]. The surgical efficacy 6 months after operation was retrospectively analyzed. Meanwhile, the relationship between the surgical efficacy and modified Friedman pharyngeal anatomical stages was analyzed. The postoperative pain VAS score at first 3 days and the incidence of foreign body sensation in pharynx after 6 months of operation were compared between the two groups. Statistical analysis was conducted by SPSS 23.0. Results: There were no significant differences in gender, age, BMI, Friedman pharyngeal anatomical stages, ESS score, AHI and LSpO2 between the two groups, preoperatively (P>0.05). There was significant difference between the two groups in ratio of cumulative time of oxygen saturation below 90% to total sleep time(CT90), preoperatively. Surgical efficacy of H-UPPP operation group was 48.9% (23/47), while H-UPPP+BRP operation group was 70.8% (34/48), which was statistically significant (χ2=4.74, P=0.029). H-UPPP+BRP group seemed to have a higher surgical efficacy than H-UPPP group in patients with Friedman Ⅱb (87% vs. 61.9%) and Ⅲ stage (44.4% vs. 15%), but there was no statistically significant difference (P>0.05). H-UPPP+BRP group had a higher pain VAS score in first three days (t=-3.10, P=0.003), also had higher incidence of pharyngeal foreign body sensation after 6 months of operation (χ2=4.727, P=0.030). Conclusions: In the surgical treatment of OSAHS patients, the overall efficacy of BRP combined H-UPPP surgery is higher than that of H-UPPP surgery alone. It may be more suitable for OSAHS patients with modified Friedman type Ⅱb and type Ⅲ stage.

Long-Term Stable Hydrogen Production from Water and Lactic Acid via Visible-Light-Driven Photocatalysis in a Porous Microreactor

Photocatalytic hydrogen (H2) production is significant to overcome challenges like fossil fuel depletion and carbon dioxide emission, but its efficiency is still far below commercialization need. Herein we achieve long-term stable H2 bubbling production from water (H2O) and lactic acid via visible-light-driven photocatalysis in a porous microreactor (PP12) benefit for photocatalyst dispersion, charge separation, mass transfer and dissociation of O-H bonds of H2O. With the widely used platinum/cadmium-sulfide (Pt/CdS) as photocatalyst, PP12 leads to a H2 bubbling production rate of 602.5 mmol h-1 m-2, which is 1000 times higher than that in traditional reactor. Even when amplifying PP12 into a flat-plate reactor with an area as large as 1 m2 and elongating reaction time to 100 h, H2 bubbling production rate still remains at around 600.0 mmol h-1 m-2, offering a great potential for commercialization.

Ring Repeating Unit: An Upgraded Structure Representation of Linear Condensation Polymers for Property Prediction

Unique structure representation of polymers plays a crucial role in developing models for polymer property prediction and polymer design by data-centric approaches. Currently, monomer and repeating unit (RU) approximations are widely used to represent polymer structures for generating feature descriptors in the modeling of quantitative structure-property relationships (QSPR). However, such conventional structure representations may not uniquely approximate heterochain polymers due to the diversity of monomer combinations and the potential multi-RUs. In this study, the so-called ring repeating unit (RRU) method that can uniquely represent polymers with a broad range of structure diversity is proposed for the first time. As a proof of concept, an RRU-based QSPR model was developed to predict the associated glass transition temperature (T_g) of polyimides (PIs) with deterministic values. Comprehensive model validations including external, internal, and Y-random validations were performed. Also, an RU-based QSPR model developed based on the same large database of 1321 PIs provides nonunique prediction results, which further prove the necessity of RRU-based structure representation. Promising results obtained by the application of the RRU-based model confirm that the as-developed RRU method provides an effective representation that accurately captures the sequence of repeat units and thus realizes reliable polymer property prediction by data-driven approaches.

[Prevalence of Echinococcus infection in small mammals captured from Shiqu County, Sichuan Province from 2015 to 2020]

OBJECTIVE

To investigate the prevalence of Echinococcus infection in small mammals in Shiqu County, Sichuan Province from 2015 to 2020, so as to provide insights into echinococcosis control in Shiqu County.

METHODS

One setting with frequent activity of small mammals was sampled as the survey site from each of 9 townships where human alveolar echinococcosis was hyperendemic, in Shiqu County, Sichuan Province from 2015 to 2020. Two quadrats measuring 50 m × 50 m were assigned in each survey site during the period between July and August from 2015 to 2020 to capture all small mammals in quadrats, and the species of small mammals were identified by morphological characteristics. All captured small mammals were dissected in the field and Echinococcus infection was identified by visual examinations. The affected organs of Echinococcus - infected small mammals were collected, and Echinococcus infection was detected using PCR assay, with Echinococcus species characterized. The prevalence of Echinococcus infection was calculated in small mammals, and the trends in the prevalence of Echinococcus infection were analyzed during the period from 2015 to 2020. In addition, the prevalence of Echinococcus infection was compared in small mammals using visual examinations and PCR assay.

RESULTS

A total of 2 692 small mammals were captured in the survey sites of Shiqu County from 2015 to 2020, and morphology characterized 1 360 Microtus fuscus (50.52%) and 1 332 Plateau pika (49.48%). The prevalence rates of Echinococcus infection were 35.63%, 19.16%, 21.41%, 8.40%, 7.68% and 4.44% by visual examinations and 18.96%, 5.36%, 5.61%, 4.58%, 3.30% and 0.37% by PCR assay in small mammals in Shiqu County from 2015 to 2020, both showing a tendency towards a decline year by year (χ² = 215.024 and 117.045, both P values < 0.001). The prevalence of Echinococcus infection was significantly higher in small mammals by visual examinations than by PCR assay during the period from 2015 to 2020 except in 2018 (χ²= 33.597, 21.815, 51.373, 17.268 and 9.537, all P values < 0.01). PCR assay detected a reduction in the prevalence of E. multilocularis infection from 10.21% to 0.37% and a reduction in the prevalence of E. shiquicus infection from 8.75% to 0 in small mammals in Shiqu County from 2015 to 2020, both appearing a tendency towards a decline year by year (χ² = 117.045 and 43.436, both P values < 0.001). In addition, the prevalence of E. multilocularis and E. shiquicus infections reduced from 15.19% to 0.45% and from 8.23% to 0 in M. fuscus, and the prevalence of E. multilocularis and E. shiquicus infections reduced from 7.76% to 0 and from 9.01% to 0 in P. pika in Shiqu County from 2015 to 2020.

CONCLUSIONS

M. fuscus and P. pika were dominant species of small mammals in Shiqu County, Sichuan Province from 2015 to 2020, and E. multilocularis infection was mainly found in M. fuscus and E. shiquicus infection mainly found in P. pika. The prevalence of Echinococcus infection appeared a tendency towards a decline in both M. fuscus and P. pika year by year during the period from 2015 to 2020.

[Mechanism of hepatic fibrosis associated with Echinococcus: a review]

Echinococcosis is a zoonotic parasitic disease caused by Echinococcus infections, and this disorder may cause fibrosis of multiple vital organs, which may further progress into cirrhosis. Early-stage hepatic fibrosis is reversible, and unraveling the mechanisms underlying hepatic fibrosis induced by Echinococcus infections is of great significance for the prevention and treatment of early-stage hepatic fibrosis. Recently, the studies pertaining to hepatic fibrosis associated with Echinococcus infections focus on cytokines and immune cells. This review summarizes the advances in the mechanisms underlying host immune cells- and cytokines-mediated hepatic fibrosis in humans or mice following Echinococcus infections.

Advances in the study of molecular identification technology of Echinococcus species

The larvae of Echinococcus (hydatidcyst) can parasitize humans and animals, causing a serious zoonotic disease-echinococcosis. The life history of Echinococcus is complicated, and as the disease progresses slowly after infection, early diagnosis is difficult to establish. Due to the limitations of imaging and immunological diagnosis in this respect, domestic and foreign scholars have established a variety of molecular detection techniques for the pathogen Echinococcus over recent years, mainly including nested polymerase chain reaction (PCR), multiplex PCR, real-time quantitative PCR, and nucleic acid isothermal amplification technology. In this article, the research progress of molecular detection technology for Echinococcus infection currently was reviewed and the significance of these methods in the detection and diagnosis of hydatid and hydatid diseases was also discussed.

[Clinical effects of transplantation of turbocharged bipedicle deep inferior epigastric perforator flap in breast reconstruction]

Objective: To explore the clinical effects of transplantation of turbocharged bipedicle deep inferior epigastric perforator (DIEP) flap in breast reconstruction. Methods: A retrospective observational study was used. From December 2008 to December 2016, 24 patients who met the inclusion criteria were treated in the Department of Plastic Surgery of Hunan Cancer Hospital, all patients were female, aged 28-51 (36.5±1.6) years. All cases received turbocharged bipedicle DIEP flap for two-staged breast reconstruction. According to the patterns of turbocharged vessels anastomosis, the turbocharged bipedicle DIEP flaps with length of (27.5±0.3) cm and width of (12.8±1.4) cm, were divided into three types: distal end of pedicle anastomosis type, main branch of pedicle anastomosis type, and muscular branch of pedicle anastomosis type. After complete hemostasis in the donor region, the anterior sheath was repaired with intermittent suture, and umbilical reconstruction was completed. Two negative pressure drainage tubes were indwelled, and subcutaneous tissue and skin were sutured layer by layer. The specific ways of vascular anastomosis of the flap pedicle with the internal thoracic vessels of recipient site included anastomosing the proximal end of one artery and one vein, anastomosing the proximal and distal end of one artery and one vein, and anastomosing the proximal end of one artery and two veins. Postoperatively, the survival and blood supply of flaps were observed. The patients were followed up to observe the reconstructed breast shape satisfaction, donor site complications, abdominal wall function, and scar hyperplasia. Results: All turbocharged bipedicle DIEP flaps for two-staged breast reconstruction survived well, with good blood supply. During follow-up for 14 to 56 (20±6) months, the shape of reconstructed breasts was satisfied. Only linear scar was left in the donor sites of abdomen with no complications, and the function of abdominal wall was not affected. Conclusions: For patients with clear indications, transplantation of free turbocharged bipedicle DIEP flap is a safe, reliable, and satisfactory choice for breast reconstruction with autologous tissue.

Coupled matrix kinetic Monte Carlo simulations applied for advanced understanding of polymer grafting kinetics

An innovative coupled matrix-based Monte Carlo (CMMC) concept has been applied to successfully assess the detailed description of the molecular build-up of linear and non-linear chains in the free-radical induced grafting of linear precursors chains.

[A 5-year follow-up study of pneumoconiosis patients with positive autoantibody]

Objective: To explore the progress of small shadow and the change of lung function in pneumoconiosis with positive autoantibody, so as to provide basis for clinical treatment of pneumoconiosis. Methods: A total of 756 patients were admitted to the pneumoconiosis department of the Guangzhou Occupational Disease Prevention Hospital from January 1, 2013 to June 1, 2019. The patients with combined infection were excluded. According to whether the autoantibody was positive, they were divided into positive group and negative group, 25 cases in each group. Follow-up observation of X-ray chest radiographs, chest CT, forced expiratory volume in one second (FEV(1)) and forced expired flow at 50% of FVC (MEF(50)) of pneumoconiosis patients for 5 years, to analyze the influence of positive autoantibody on the morphology of X-ray chest film, the pneumoconiosis promotion in 5 years and lung function. Results: There were 22 males and 3 females in the autoantibody positive group, aged 53.14±10.51 years. In the autoantibody negative group, there were 23 males and 2 females, aged 53.88±8.10 years. During the 5-year observation period, there was no significant difference of small shadow shape, pneumoconiosis stage, and the pneumoconiosis promotion in 5 years between the autoantibody positive group and the autoantibody negative group (P>0.05). However, the increment of small shadow area in the autoantibody positive group was higher than that in the autoantibody negative group (P<0.05). FEV(1) and MEF(50) of the autoantibody positive group were significantly lower than those of the autoantibody negative group in the fourth and third years, respectively (P<0.05). Positive autoantibody was negatively correlated with FEV(1) and MEF(50) (P<0.05). Conclusion: The positive autoantibody can't promote the progress of X-ray, but show more small shadows on chest CT; the positive autoantibody may aggravate the decline of lung function.

[Endemic situation of schistosomiasis in national surveillance sites of Hunan Province from 2015 to 2019]

OBJECTIVE

To analyze the changes in the endemic situation of schistosomiasis in national surveillance sites of Hunan Province, so as to provide scientific basis for the development of the schistosomiasis elimination programme in the province.

METHODS

According to the requirements of the National Guidelines for Schistosomiasis Surveillance in China (2014 version), a total of 41 national schistosomiasis surveillance sites were assigned in all disease-endemic counties (districts) across Hunan Province. During the period between 2015 and 2019, Schistosoma japonicum infections were monitored in local residents, mobile populations and livestock, and snail status was monitored. The morbidity due to schistosomiasis and snail status was compared between years.

RESULTS

The sero-prevalence of S. japonicum infections was 2.57% and 1.56% in local residents and mobile populations in national surveillance sites of Hunan Province from 2015 to 2019, respectively, and the sero-prevalence appeared a tendency towards a decline over years. A higher sero-prevalence rate of S. japonicum infections was seen in men than in women (P < 0.01). During the 5-year study period, the sero-prevalence rate of human S. japonicum infections appeared a tendency towards a decline in the marshland, embankment, inner embankment and hilly types of endemic areas over years. There were 44 and 19 egg -positives detected in local residents and 5 and 1 egg-positives in mobile populations in 2015 and 2016 respectively. A total of 9 346 domestic animals were monitored from 2015 to 2019, and 6 egg-positives were detected in 2015 and 2016 (all were bovine). A total of 0.155 billion m² settings were surveyed from 2015 to 2019, and the mean density of living snails appeared a tendency towards a decline over years, with a 45.79% reduction in 2019 as compared to 2015. However, no S. japonicum infections were identified in snails during the 5-year period. A total of 1 469 mixed snail samples were detected using loop-mediated isothermal amplification (LAMP), and 6 positive snail samples were identified in 2015 (one sample) and 2017 (5 samples).

CONCLUSIONS

The overall endemic situation of schistosomiasis appears a tendency towards a decline in Hunan Province, and the prevalence of S. japonicum infections is at a low level in humans and livestock; however, there is still a risk of schistosomiasis transmission. Improvements of health education, intensification of schistosomiasis examinations in mobile populations and reinforcement of the surveillance-response system is required to consolidate the achievements of schistosomiasis control in Hunan Province.

[Survey of the capacity building of the county-level schistosomiasis diagnosis network laboratory in Hunan Province]

OBJECTIVE

To examine the construction and operation of the schistosomiasis diagnostic network platform in Hunan Province, so as to provide insights into the improvements of the schistosomiasis diagnostic network laboratory system in the province.

METHODS

According to the criteria and requirements for the construction of the county-level schistosomiasis diagnostic network laboratory in China, the establishment and operation of the laboratory were assessed using self-assessment and field review in national schistosomiasis surveillance sites of Hunan Province.

RESULTS

A total of 41 county-level schistosomiasis diagnostic network laboratories were built in national schistosomiasis surveillance sites of Hunan Province, and 36 met the requirements for the construction of the national schistosomiasis diagnostic network laboratory in China, which were approved for inclusion in the province-level schistosomiasis diagnostic network laboratory. During the six inter-laboratory comparisons performed by the national schistosomiasis diagnostic reference center of China, full consistency was achieved by 3 county-level schistosomiasis diagnostic network laboratories in Hunan Province, and the coincidence rates for re-review of serological and pathogenic detection samples were 98.40% and 100%, respectively.

CONCLUSIONS

The county-level schistosomiasis diagnostic network laboratory system has been preliminarily built and under effective operation in Hunan Province; however, the building capability remains to be improved.

Role of External Field in Polymerization: Mechanism and Kinetics

The past decades have witnessed an increasing interest in developing advanced polymerization techniques subjected to external fields. Various physical modulations, such as temperature, light, electricity, magnetic field, ultrasound, and microwave irradiation, are noninvasive means, having superb but distinct abilities to regulate polymerizations in terms of process intensification and spatial and temporal controls. Gas as an emerging regulator plays a distinctive role in controlling polymerization and resembles a physical regulator in some cases. This review provides a systematic overview of seven types of external-field-regulated polymerizations, ranging from chain-growth to step-growth polymerization. A detailed account of the relevant mechanism and kinetics is provided to better understand the role of each external field in polymerization. In addition, given the crucial role of modeling and simulation in mechanisms and kinetics investigation, an overview of model construction and typical numerical methods used in this field as well as highlights of the interaction between experiment and simulation toward kinetics in the existing systems are given. At the end, limitations and future perspectives for this field are critically discussed. This state-of-the-art research progress not only provides the fundamental principles underlying external-field-regulated polymerizations but also stimulates new development of advanced polymerization methods.

A polyelectrolyte-containing copolymer with a gas-switchable lower critical solution temperature-type phase transition

A polyelectrolyte-containing copolymer with a CO₂/N₂-switchable cloud point, resulting from the gas-induced alternation of hydrophilicity, was prepared.

A PBM-CFD Model with Optimized PBM-Customized Drag Equations for Chemisorption of CO2 in a Bubble Column

In this work, a computational fluid dynamics (CFD) approach based on two-fluid model (TFM) is introduced to describe the reversible two-step reactions found in the chemisorption process of ${\text{C}}{{\text{O}}_2}$ by an aqueous ${\text{NaOH}}$ solution in a lab-scale bubble column reactor. The population balance model (PBM) is applied to track the bubble size distribution with considering the coalescence and breakage terms, which then leads to a CFD-PBM model for describing the chemisorption of CO2 in an aqueous ${\text{NaOH}}$ solution. Drag force is considered for the interfacial momentum transfer and a modified PBM-customized drag model with the correction factor is subsequently adopted, in which the contribution of different bubble size groups in each computational cell is computed. The tested boundary conditions include superficial gas velocities, gas-inlet sparger and the reactor dimension. Detailed and comprehensive investigations are done in the evolution of gas holdup, pH value, concentration distribution and bubble diameter distribution which are essential in optimizing the reactor performance in terms of yield and selectivity. Importantly, the current CFD-PBM model is able to predict the entire reaction process.