Protein engineering via Bayesian optimization-guided evolutionary algorithm and robotic experiments.

Directed protein evolution applies repeated rounds of genetic mutagenesis and phenotypic screening and is often limited by experimental throughput. Through in silico prioritization of mutant sequences, machine learning has been applied to reduce wet lab burden to a level practical for human researchers. On the other hand, robotics permits large batches and rapid iterations for protein engineering cycles, but such capacities have not been well exploited in existing machine learning-assisted directed evolution approaches. Here, we report a scalable and batched method, Bayesian Optimization-guided EVOlutionary (BO-EVO) algorithm, to guide multiple rounds of robotic experiments to explore protein fitness landscapes of combinatorial mutagenesis libraries. We first examined various design specifications based on an empirical landscape of protein G domain B1. Then, BO-EVO was successfully generalized to another empirical landscape of an Escherichia coli kinase PhoQ, as well as simulated NK landscapes with up to moderate epistasis. This approach was then applied to guide robotic library creation and screening to engineer enzyme specificity of RhlA, a key biosynthetic enzyme for rhamnolipid biosurfactants. A 4.8-fold improvement in producing a target rhamnolipid congener was achieved after examining less than 1% of all possible mutants after four iterations. Overall, BO-EVO proves to be an efficient and general approach to guide combinatorial protein engineering without prior knowledge.

The HDAC6-RNF168 axis regulates H2A/H2A.X ubiquitination to enable double-strand break repair.

Histone deacetylase 6 (HDAC6) mediates DNA damage signaling by regulating the mismatch repair and nucleotide excision repair pathways. Whether HDAC6 also mediates DNA double-strand break (DSB) repair is unclear. Here, we report that HDAC6 negatively regulates DSB repair in an enzyme activity-independent manner. In unstressed cells, HDAC6 interacts with H2A/H2A.X to prevent its interaction with the E3 ligase RNF168. Upon sensing DSBs, RNF168 rapidly ubiquitinates HDAC6 at lysine 116, leading to HDAC6 proteasomal degradation and a restored interaction between RNF168 and H2A/H2A.X. H2A/H2A.X is ubiquitinated by RNF168, precipitating the recruitment of DSB repair factors (including 53BP1 and BRCA1) to chromatin and subsequent DNA repair. These findings reveal novel regulatory machinery based on an HDAC6-RNF168 axis that regulates the H2A/H2A.X ubiquitination status. Interfering with this axis might be leveraged to disrupt a key mechanism of cancer cell resistance to genotoxic damage and form a potential therapeutic strategy for cancer.

SIRT6 coordinates with CHD4 to promote chromatin relaxation and DNA repair.

Genomic instability is an underlying hallmark of cancer and is closely associated with defects in DNA damage repair (DDR). Chromatin relaxation is a prerequisite for DDR, but how chromatin accessibility is regulated remains elusive. Here we report that the histone deacetylase SIRT6 coordinates with the chromatin remodeler CHD4 to promote chromatin relaxation in response to DNA damage. Upon DNA damage, SIRT6 rapidly translocates to DNA damage sites, where it interacts with and recruits CHD4. Once at the damage sites, CHD4 displaces heterochromatin protein 1 (HP1) from histone H3 lysine 9 trimethylation (H3K9me3). Notably, loss of SIRT6 or CHD4 leads to impaired chromatin relaxation and disrupted DNA repair protein recruitment. These molecular changes, in-turn, lead to defective homologous recombination (HR) and cancer cell hypersensitivity to DNA damaging agents. Furthermore, we show that SIRT6-mediated CHD4 recruitment has a specific role in DDR within compacted chromatin by HR in G2 phase, which is an ataxia telangiectasia mutated (ATM)-dependent process. Taken together, our results identify a novel function for SIRT6 in recruiting CHD4 onto DNA double-strand breaks. This newly identified novel molecular mechanism involves CHD4-dependent chromatin relaxation and competitive release of HP1 from H3K9me3 within the damaged chromatin, which are both essential for accurate HR.

Development of modified integrated water quality index to assess the surface water quality: a case study of Tuo River, China.

Water quality evaluation is an important step in water environment control and management. The water quality index (WQI) is considered to be an effective method for water quality evaluation. However, when constructing the WQI, the contribution of the lower threshold limits of water quality parameters to water quality has received little attention. The principle of the modified integrated water quality index (IWQI) is that the concentration of any water quality parameter below the lower threshold limits as well as above the upper threshold limits will lead to an increase in the overall index value. Based on the concentration of water quality parameters, the modified IWQI classified water quality into five categories, i.e., bad (> 8), poor (5-8), medium (2-5), good (1-2), and excellent (< 1). Tuo River plays a crucial role in potable and irrigation water sources of Sichuan Province, and the assessment result of modified IWQI reveals that 67.8% of samples were classified as "medium," 29% "poor," and 3.2% "bad." The high concentrations of N and P from agricultural activities and industrial wastewater are the main contributors to the deterioration of water quality in the Tuo River. Additionally, the Tuo River presents the characteristics of worse water quality in the midstream. The evaluation results of the modified IWQI are consistent with that of the conventional WQI, which proves the accuracy of the modified IWQI as a surface water quality evaluation method.

Numerical Simulation of Heat and Mass Transfer in Sludge Low-Temperature Drying Process.

Based on the sludge mass transfer flux model, this paper conducts a simulation study on the drying characteristics of sludge under low-temperature environment and compares it with the previous experimental results. It is found that when the sludge moisture content is low, the change of its drying curve is basically consistent with the experimental results, but there is a large error when the sludge moisture content is 0.4-0.6. In order to better simulate sludge drying characteristics, a model of cracking and shrinkage coefficients based on sludge moisture content is proposed, and the effective diffusion coefficient and mass transfer coefficient are modified. The maximum error between simulation and experiment is reduced to 23.78%. Based on this model, the sludge drying mechanism was studied. It was found that heat transfer and diffusion played a major role in the initial stage of sludge drying, and diffusion played a major role in sludge drying 30 min later.

Microbial diversity accumulates in a downstream direction in the Three Gorges Reservoir.

Organic and inorganic materials migrate downstream and have important roles in regulating environmental health in the river networks. However, it remains unclear whether and how a mixture of materials (i.e., microbial species) from various upstream habitats contribute to microbial community coalescence upstream of a dam. Here we track the spatial variation in microbial abundance and diversity in the Three Gorges Reservoir based on quantitative PCR and 16S rRNA gene high-throughput sequencing data. We further quantitatively assess the relative contributions of microbial species from mainstem, its tributaries, and the surrounding riverbank soils to the area immediately upstream of the Three Gorges Dam (TGD). We found an increase of microbial diversity and the convergent microbial distribution pattern in areas immediately upstream of TGD, suggesting this area become a new confluence for microbial diversity immigrating from upstream. Indeed, the number of shared species increased from upstream to TGD but unique species decreased, indicating immigration of various sources of microbial species overwhelms local environmental conditions in structuring microbial community close to TGD. By quantifying the sources of microbial species close to TGD, we found little contribution from soils as compared to tributaries, especially for sites closer to TGD, suggesting tributary microbes have greater influence on microbial diversity and environmental health in the Three Gorges Reservoir. Collectively, our results suggest that tracking microbial geographic origin and evaluating accumulating effects of microbial diversity shed light on the ecological processes in microbial communities and provide information for regulating aquatic ecological health.

Histone H1 acetylation at lysine 85 regulates chromatin condensation and genome stability upon DNA damage.

Linker histone H1 has a key role in maintaining higher order chromatin structure and genome stability, but how H1 functions in these processes is elusive. Here, we report that acetylation of lysine 85 (K85) within the H1 globular domain is a critical post-translational modification that regulates chromatin organization. H1K85 is dynamically acetylated by the acetyltransferase PCAF in response to DNA damage, and this effect is counterbalanced by the histone deacetylase HDAC1. Notably, an acetylation-mimic mutation of H1K85 (H1K85Q) alters H1 binding to the nucleosome and leads to condensed chromatin as a result of increased H1 binding to core histones. In addition, H1K85 acetylation promotes heterochromatin protein 1 (HP1) recruitment to facilitate chromatin compaction. Consequently, H1K85 mutation leads to genomic instability and decreased cell survival upon DNA damage. Together, our data suggest a novel model whereby H1K85 acetylation regulates chromatin structure and preserves chromosome integrity upon DNA damage.

Spatial variation and source apportionment of surface water pollution in the Tuo River, China, using multivariate statistical techniques.

The increasingly serious water pollution of rivers has attracted wide attention from all countries in the world. Investigating spatial variations of water pollution and source apportionment is particularly important for the effective management of river quality. The water samples collected every two months at 31 sampling sites containing 12 water quality parameters during 2018 and 2019 were analyzed to investigate the spatial patterns and the apportionment of the pollutants in the Tuo River. Cluster analysis (CA), pollution index (PI), factor analysis (FA), principal component analysis (PCA), and absolute principal component score-multiple linear regression (APCS-MLR) were used in the current study. The PI found that the Tuo River was most severely polluted with phosphorus and nitrogen. Additionally, compared with that in 2018, the water quality in the Tuo River has significantly improved in 2019. The CA divided the sampling sites into three categories, which are defined as clean, low-polluted, and moderate-polluted areas, respectively. FA/PCA resulted in four latent pollution sources, explaining 74.09% of the total variance. The contributions of the identified pollution sources to pollutants were realized using APCS-MLR. Most variables were mainly affected by the pollution of agricultural runoff, industrial wastewater, domestic sewage, and soil weathering. According to the results, we can also find that agricultural runoff and industrial wastewater were dominating in the Tuo River. These results provide a scientific basis for formulating more reasonable and strict pollution control strategies for the Tuo River.

[Analysis of medication characteristics of traditional Chinese medicine in treating COVID-19 based on data mining].

OBJECTIVE: To analysis the medication characteristics of the prescriptions issued via open channel by the National and Provincial Health Committee and the State Administration of Traditional Chinese Medicine in treating coronavirus disease 2019 (COVID-19). METHODS: We collected the data of traditional Chinese medicine related to treatment plans published by the National and Provincial Health Committee and the State Administration of Traditional Chinese Medicine from the start of COVID-19 outbreak to February 19, 2020. The frequency analysis, cluster analysis and association analysis were performed. RESULTS: The study collected 4 national and 34 regional prevention and treatment plans, 578 items, 84 traditional Chinese formulations, 60 Chinese patent medicines, and 230 Chinese herbs. The high frequently used herbs were Liquorice, Scutellariabaicalensis, Semen armeniacaeamarae, and Gypsum. The commonly used traditional formulations included Maxing Shigan decoction, Yin Qiao powder, and Xuanbai Chengqi decoction. The Chinese patent drugs included Angong Niuhuang pill, Xuebijing injection, and Lianhua Qingwen capsule. The most common paired medications were Ephedra and Semen armeniacaeamarae, Fructusforsythiae and Liquorice. Two core combinations and one novel formula were discovered in the study. CONCLUSIONS: Yin Qiao powder and Huopo Xialing decoction are the basic formulations for Weifen syndrome of COVID-19. In addition, Maxing Shigan decoction, Liang Ge powder, Qingwen Baidu decoction and Da Yuan decoction are the basic formulations for Qifen syndrome of COVID-19. The main medication characteristics are clearing heat, entilating lung, removing toxicity and removing turbidity. It shows that removing toxicity and eliminating evil are the prescription thought in treating epidemic disease of traditional Chinese medicine.

Effect of the particle size and surface area on Escherichia coli attachment to mineral particles in fresh water.

The objective of this study was to assess the effects of the particle size and specific surface area (SSA) on the attachment of Escherichia coli to sediment particles. To exclude the effect of different sediment mineral compositions, pure minerals were used, and three typical suspended sediment (<62 µm) components, quartz, K-feldspar and calcite, were separated into four groups with different grain size distributions. Equilibrium attachment experiments covering common E. coli concentrations in surface water were conducted for each group. The results show that the finer fractions of each pure mineral had the greatest attachment capacity. Different mineral properties were measured, as well as an author-defined parameter (SSA_a), which was calculated by integrating the particle size distribution and only reflected the microscopic surface areas accessible to E. coli cells (∼1 µm) while excluding the effects of nanoscopic pores (5-10 nm). Pearson correlation and partial correlation analyses suggested that the partition coefficient (Kd) was positively correlated with the clay content (CC) and SSA_a (P < 0.01). Stepwise multiple regression analysis suggested that SSA_a was the dominant factor (P < 0.01) and was a better explanatory variable than CC. Moreover, in addition to SSA_a, the zeta potential and SSA also partially explained the results (P < 0.05).

Ubiquitin-specific peptidase 7 (USP7)-mediated deubiquitination of the histone deacetylase SIRT7 regulates gluconeogenesis.

Sirtuin 7 (SIRT7), a member of the NAD+-dependent class III histone deacetylases, is involved in the regulation of various cellular processes and in resisting various stresses, such as hypoxia, low glucose levels, and DNA damage. Interestingly, SIRT7 is linked to the control of glycolysis, suggesting a role in glucose metabolism. Given the important roles of SIRT7, it is critical to clarify how SIRT7 activity is potentially regulated. It has been reported that some transcriptional and post-transcriptional regulatory mechanisms are involved. However, little is known how SIRT7 is regulated by the post-translational modifications. Here, we identified ubiquitin-specific peptidase 7 (USP7), a deubiquitinase, as a negative regulator of SIRT7. We showed that USP7 interacts with SIRT7 both in vitro and in vivo, and we further demonstrated that SIRT7 undergoes endogenous Lys-63-linked polyubiquitination, which is removed by USP7. Although the USP7-mediated deubiquitination of SIRT7 had no effect on its stability, the deubiquitination repressed its enzymatic activity. We also showed that USP7 coordinates with SIRT7 to regulate the expression of glucose-6-phosphatase catalytic subunit (G6PC), a gluconeogenic gene. USP7 depletion by RNA interference increased both G6PC expression and SIRT7 enzymatic activity. Moreover, SIRT7 targeted the G6PC promoter through the transcription factor ELK4 but not through forkhead box O1 (FoxO1). In summary, SIRT7 is a USP7 substrate and has a novel role as a regulator of gluconeogenesis. Our study may provide the basis for new clinical approaches to treat metabolic disorders related to glucose metabolism.

Common 1H-MRS Characteristics in Patients With Alzheimer's Disease and Vascular Dementia Diagnosed With Kidney Essence Deficiency Syndrome: A Preliminary Study.

Context • Traditional Chinese medicine (TCM) indicates that both Alzheimer's disease (AD) and vascular dementia (VD) should be categorized as dementia and that they have a common etiology and pathogenesis under TCM classification of syndromes, such as with kidney essence deficiency syndrome (KEDS). The pathological location is mainly in the brain. However, it remains unclear whether AD and VD patients with KEDS exhibit a metabolic commonality in the same region of the brain. Objective • The study intended to investigate the metabolic characteristics of the brain using proton magnetic resonance spectroscopy (1H-MRS) in patients with AD and VD who had been diagnosed with KEDS. Design • The research team designed a pilot study, with the participants being allocated to 3 groups: (1) an AD group, (2) a VD group, and (3) a control group. All data analysis was carried out by a trained radiologist who was blinded to each participant's diagnosis. Setting • The study took place at the Tongde Hospital of Zhejiang Province (Zhejiang Sheng, China). Participants • Participants were patients at the Tongde Hospital with mild AD or VD who had been diagnosed with KEDS. The normal controls were patients' spouses or guardians with normal cognitive function. Outcome Measures • All participants underwent 1H-MRS. The N-acetyl aspartate (NAA)/myo-inositol (mI), NAA/creatine (Cr), choline (Cho)/Cr, and mI/Cr ratios were bilaterally measured in the posterior cingulate gyrus (PCG) and anterior cingulate gyrus (ACG) by the Syngo spectroscopy postprocessing package. Demographic characteristics and 1H-MRS data were assessed across the AD, VD, and normal control groups. Results • Thirteen patients with mild AD with KEDS, 15 patients with mild VD with KEDS, and 18 normal controls were recruited from May 2013 through May 2014. The AD and VD groups did not significantly differ in the NAA/mI, NAA/Cr, Cho/Cr, and mI/Cr ratios in either the PCG or the ACG, with the exception being the Cho/Cr ratio in the right ACG, for which the ratio of the AD group was significantly lower when compared with that of the VD group (P < .05). Conclusions • Mild AD and VD with KEDS showed similar patterns for the 1H-MRS on the cingulate cortex, providing evidence for a common pathogenesis for the KEDS that is associated with AD and VD, providing a modern biological basis for the philosophy of providing the same treatment for different diseases.

Biological function and regulation of histone and non-histone lysine methylation in response to DNA damage.

DNA damage response (DDR) signaling network is initiated to protect cells from various exogenous and endogenous damage resources. Timely and accurate regulation of DDR proteins is required for distinct DNA damage repair pathways. Post-translational modifications of histone and non-histone proteins play a vital role in the DDR factor foci formation and signaling pathway. Phosphorylation, ubiquitylation, SUMOylation, neddylation, poly(ADP-ribosyl)ation, acetylation, and methylation are all involved in the spatial-temporal regulation of DDR, among which phosphorylation and ubiquitylation are well studied. Studies in the past decade also revealed extensive roles of lysine methylation in response to DNA damage. Lysine methylation is finely regulated by plenty of lysine methyltransferases, lysine demethylases, and can be recognized by proteins with chromodomain, plant homeodomain, Tudor domain, malignant brain tumor domain, or proline-tryptophan-tryptophan-proline domain. In this review, we outline the dynamics and regulation of histone lysine methylation at canonical (H3K4, H3K9, H3K27, H3K36, H3K79, and H4K20) and non-canonical sites after DNA damage, and discuss their context-specific functions in DDR protein recruitment or extraction, chromatin environment establishment, and transcriptional regulation. We also present the emerging advances of lysine methylation in non-histone proteins during DDR.

Tap water microbiome shifts in secondary water supply for high-rise buildings.

In high-rise buildings, secondary water supply systems (SWSSs) are pivotal yet provide a conducive milieu for microbial proliferation due to intermittent flow, low disinfectant residual, and high specific pipe-surface area, raising concerns about tap water quality deterioration. Despite their ubiquity, a comprehensive understanding of bacterial community dynamics within SWSSs remains elusive. Here we show how intrinsic SWSS variables critically shape the tap water microbiome at distal ends. In an office setting, distinct from residential complexes, the diversity in piping materials instigates a noticeable bacterial community shift, exemplified by a transition from α-Proteobacteria to γ-Proteobacteria dominance, alongside an upsurge in bacterial diversity and microbial propagation potential. Extended water retention within SWSSs invariably escalates microbial regrowth propensities and modulates bacterial consortia, yet secondary disinfection emerges as a robust strategy for preserving water quality integrity. Additionally, the regularity of water usage modulates proximal flow dynamics, thereby influencing tap water's microbial landscape. Insights garnered from this investigation lay the groundwork for devising effective interventions aimed at safeguarding microbiological standards at the consumer's endpoint.

Deep Mutational Scanning of an Oxygen-Independent Fluorescent Protein CreiLOV for Comprehensive Profiling of Mutational and Epistatic Effects.

Oxygen-independent, flavin mononucleotide-based fluorescent proteins (FbFPs) are promising alternatives to green fluorescent protein in anaerobic contexts. Deep mutational scanning performs systematic profiling of protein sequence-function relationships but has not been applied to FbFPs. Focusing on CreiLOV from Chlamydomonas reinhardtii, we created and analyzed two comprehensive mutant collections: (1) single-residue, site-saturation mutagenesis libraries covering all 118 residues; and (2) a full combinatorial metagenesis library among 20 mutations at 15 residues, where mutation and residue selection was based on single-site mutagenesis results. Notably, the second type of library is indispensable to study higher-order epistasis but underrepresented in the literature. Using optimized FACS-seq assays, 2,185 (>92.5%) out of 2,360 possible single-site mutants and 165,428 (>89.7%) out of 184,320 possible combinatorial mutants were reliably assigned with fitness values. We constructed statistical and machine-learning models to analyze the CreiLOV data set, enabling accurate fitness prediction of higher-order mutants using lower-order mutagenesis data. In addition, we successfully isolated CreiLOV variants with improved fluorescence quantum yield and thermostability. This work provides new empirical data and design rules to engineer combinatorial protein variants.

Effects of Chlorella vulgaris on phosphorus release from ferric phosphate sediment by consecutive cultivations.

Iron phosphate (Fe-P) is a main phosphorus storage form, especially in phosphorus-polluted environments. The re-release of Fe-P is a problematic result during microalgal remediation. In this study, pre-incubated Chlorella vulgaris was cultured in a BG-11 culture medium with different amounts of Fe-P. The effects of Fe-P re-release on biomass, flocculation and removal of PO4 3- were investigated. The results indicated that C. vulgaris can promote the dissolution and release of Fe-P when the pH is 7, and the amount of Fe-P (ΔQ) released in 200 ml water reaches 0.055-0.45 mg d-1 under a C. vulgaris concentration of 5.6 × 105-8 × 105 cells ml-1. The growth of C. vulgaris was inhibited because of the flocculation behaviour of Fe3 + in the release stage, which is associated with a specific growth rate of 0.3-0.4 d-1 and a phosphorus removal rate below 30%. However, this process, in the long term, indicates a favourable transformation in which Fe-P becomes bioavailable under the action of C. vulgaris. Microalgae outbreaks may be triggered by persistent interactions between Fe-P and C. vulgaris. This study provides an important reference for the application of C. vulgaris in a Fe-P-rich environment.

Towards one sample per second for mass spectrometric screening of engineered microbial strains.

Microbial cell factories convert renewable feedstocks into desirable chemicals and materials. Due to the lack of predictive modeling, high-throughput screening remains essential for microbial strain engineering. Mass spectrometry (MS) is a label-free modality with superior sensitivity and chemical specificity. Critical advances in improving the throughput of MS assays on complex microbial samples include massively parallel cultivation, robotic sample preparation, and chromatography-free instrumentation. Here, we review the recent development and application of rapid MS assays in screening microbial libraries, achieving or approaching a rate of one sample per second. We conclude with unique challenges associated with MS screening of strain libraries and discuss future solutions.

A Systematic Review and Meta-Analysis of Acupuncture Treatment for Oral Ulcer.

Background: Oral ulcer (OU) is a common oral mucosal disease manifested with obvious pain. In some studies, the efficacy of acupuncture in OU has been confirmed, but systematic reviews and meta-analyses for them are lacking. Our aim is to evaluate the efficacy of acupuncture in the treatment of OU. Methods: We searched the literature from eight databases from their inception to December 2021. We included randomized controlled trials of acupuncture for the treatment of oral ulcer. The meta-analysis was carried out using Review Manager 5.3 and Stata 16.0. The main outcomes were the effective rate and the recurrence rate, the secondary outcomes were the visual analogue score (VAS) and the ulcer healing time. Results: Totally, 18 studies were finally included in the meta-analysis, including 1,422 patients. In meta-analyses, we found that in comparison with Western medicine, acupuncture can improve effective rate (OR = 5.40, 95% CI: 3.40 to 8.58), reduce the ulcer recurrence rate (OR = 0.21, 95% CI: 0.13 to 0.33), and relieve the ulcer pain (MD = -2.26, 95% CI: -4.27to-0.24). In addition, compared with Western medicine, acupuncture plus Western medicine also can improve effective rate (OR = 2.95, 95% CI: 1.48 to 5.85). Compared with the Chinese medicine, the acupuncture plus Chinese medicine can improve the effective rate (OR = 8.26, 95% CI: 3.61 to 18.88) and relieve the ulcer pain (MD = -1.85, 95% CI: -2.51 to -1.19). Conclusion: Acupuncture may be more effective than Western medicine in terms of efficacy rate, and acupuncture combined with Western or Chinese medicine may have the potential to reduce the recurrence of ulcer and relieve the ulcer pain. However, due to limited evidence, higher quality and more rigorously designed clinical trials with larger sample sizes will be needed to further confirm our findings.

Knowledge Domain and Emerging Trends of Chinese Medicine in Management of Pediatric Asthma: A Scientometric Study.

OBJECTIVE: To analyze the intellectual landscape and emerging research trends of Chinese medicine (CM) in the management of pediatric asthma through a scientometric study. METHODS: Publications related to CM in the management of pediatric asthma were retrieved from the Web of Science Core Collection using relevant keywords. A scientometric study was performed using CiteSpace and VOSviewer. RESULTS: A total of 1,673 original articles and reviews from 1991 to 2019 were included in the analysis. The amount of annual publications had a gradual increase with time. USA was the major contributor both in country and institution analyses. Based on the co-citation, the published journals were grouped into 4 clusters. Keyword analysis indicated that the main hotspots were: (1) comprehensive management; (2) risk factors, mechanism, and prevalence; (3) prevention and treatment; (4) inflammation; and (5) environmental research. Lastly, we predicted that three emerging trends were quality of life promotion, immune response, and combination therapy. CONCLUSIONS: CM research in the management of pediatric asthma will maintain the current trend of steady growth. This scientometric analysis may help scientists to identify the areas of interests and future directions in the field.

A workflow for spatio-seasonal hydro-chemical analysis using multivariate statistical techniques.

Multivariate statistical techniques are powerful in data interpretation and pattern recognition, which play a vital role in pollutant source identification for water environment management. Despite of their wide application in hydro-chemical analysis, absence of a comprehensive workflow hinders the practices and further studies. The present study constructed a workflow on the application of multivariate statistical techniques in spatio-seasonal hydro-chemical analysis, which provided a basic guidance for practices and a systematic support to future exploration. Selection of the methods and work paths for spatio-seasonal analysis largely depends on the structure of data set and the requirements of specific tasks. Trial and adjustment could be repeatedly performed to optimize the analysis strategy and identify more underlying patterns. Given a multiscale dataset concerning complex spatio-seasonal variations, temporal or spatial grouping using appropriate methods to reasonably divide the complicated data set contributes to data interpretation and pattern recognition. The upper Yangtze River basin (UYRB, China) was employed for case analysis to demonstrate how the workflow guides an efficient and effective data exploration. Efforts could be made in future works to continually improve the workflow to involve more complicated analysis and techniques and the integrated application in various fields.