Does working capital management improve financial performance in China's agri-food sector during COVID-19? A comparison with the 2008 financial crisis.

The objective of this study is to explore the impact of working capital management on firms' financial performance in China's agri-food sector from 2006 to 2021. In addition, we analyze whether this impact is the same during the 2008 financial crisis and the 2020 COVID-19 crisis. Working capital management is measured by working capital investment policy (measured by current assets to total assets ratio), working capital financing policy (measured by current liabilities to total assets ratio), cash conversion cycle, and net working capital ratio. The results reveal that current assets to total assets ratio and net working capital ratio positively influence financial performance measured through return on assets (ROA), while current liabilities to total assets ratio and cash conversion cycle negatively influence ROA. We also find that the relationship between working capital management and financial performance is more affected during COVID-19 than in the 2008 financial crisis. The findings might provide important implications for company managers to make optimal working capital management practices, depending on the economic environment.

Value of Molybdenum Target X-Ray and High-Frequency Color Doppler Flow Imaging in Early Diagnosis of Breast Carcinoma: A Comparative Analysis.

Background: Breast carcinoma (BC) threatens the physical and mental health of women worldwide, and early diagnosis is important for improving patient outcomes and ensuring successful treatment. Purpose: This research mainly aims to compare and analyze the value of molybdenum target X-ray and high-frequency color Doppler flow imaging (CDFI) in the early diagnosis of BC. Methods: First, 102 patients with suspected early-stage BC (ESBC) admitted to Henan Provincial People's Hospital were examined by molybdenum target X-ray and CDFI. Based on the pathological findings, the diagnostic efficiency data of the two diagnostic modalities such as positive detection rate (PDR), positive predictive value (PPV), negative predictive value (NPV), sensitivity (SEN), specificity (SPE), and accuracy (ACC), as well as imaging information like masses, microcalcifications (MCs), axillary lymph node (LN) metastases, and blood flow signal or vascular sign abnormalities were analyzed. Results: CDFI contributed to higher PDR, PRV, NPV, SEN, and ACC than molybdenum target X-ray in ESBC diagnosis, but similar SPE. The combined diagnosis of molybdenum target X-ray plus CDFI contributed to even higher PDR, PRV, NPV, SEN, and ACC than molybdenum target X-ray alone and higher ACC than CDFI. Imaging inspection revealed that the number of cases of masses, axillary LN metastases, and abnormalities in blood flow signals or vascular signs detected by CDFI was significantly higher than that by molybdenum target X-ray, while the number of MCs was significantly lower. Conclusion: Molybdenum target X-ray plus CDFI is more effective in the diagnosis of ESBC and plays a complementary role in imaging examination, which can synergistically improve the diagnostic ACC of ESBC and is worthy of clinical promotion.

A randomized controlled study for the treatment of middle-aged and old-aged lumbar disc herniation by Shis spine balance manipulation combined with bone and muscle guidance.

ABSTRACT: Ninety percent of elderly patients with lumbar disc herniation (LDH) have problems with the mechanics of the spine and muscle tissue. Shi-style spine balance manipulation combined with guidance (Daoyin) of muscle and bone as an alternative therapy for LDH can tone the muscle groups around the spine and maintain optimal mechanical and static sagittal balance of the spine. This study will be performed to investigate the effect of a combination of Shi-style spine balance manipulation and Daoyin therapy on LDH in middle-aged and elderly patients. In this non-blinded, randomized controlled trial, 72 eligible patients will be randomly divided into a treatment group (Shi-style spine balance manipulation combined with Daoyin therapy) and a control group (lumbar mechanical traction). Before and after the intervention, lumbar X-ray and magnetic resonance imaging examinations will be performed to observe the sagittal balance parameters of the spine and pelvis and the lumbar muscle strength. The visual analog scale score, Oswestry disability index score, and pressure pain threshold will be evaluated at baseline and at 2, 4, 12, and 24 weeks. During the treatment period, any signs of acute adverse events, such as paralysis of the lower extremities or cauda equina syndrome, will be recorded at each visit. Although Shi-style spine manipulation combined with Daoyin therapy has been used in the treatment of LDH in middle-aged and elderly people in China for many years, there is no consensus on its effectiveness. This experiment will provide convincing evidence of the efficacy of Shi-style spine manipulation combined with Daoyin therapy in the treatment of LDH in middle-aged and elderly people.

Development and Validation of a Novel Scoring System for Severity of Plantar Fasciitis.

OBJECTIVES: Plantar fasciitis (PF) is the most common cause of heel pain. Though PF is self-limited, it can develop into chronic pain and thus treatment is needed. Early and accurate prognostic assessment of patients with PF is critically important for selecting the optimal treatment pathway. Nevertheless, there is no scoring system to determine the severity of PF and no prognostic model in choosing between conservative or surgical treatment. The study aimed to develop a novel scoring system to evaluate the severity of plantar fasciitis and predict the prognosis of conservative treatment. METHODS: Data of consecutive patients treated from 2014 to 2018 were retrospectively collected. One hundred and eighty patients were eligible for the study. The demographics and clinical characteristics served as independent variables. The least follow-up time was 6 months. A minimal reduction of 60% in the visual analog scale (VAS) score from baseline was considered as minimal clinically important difference (MCID). Those factors significantly associated with achieving MCID in univariate analyses were further analyzed by multivariate logistic regression. A novel scoring system was developed using the best available literature and expert-opinion consensus. Inter-observer reliability and intra-observer reproducibility were evaluated. The appropriate cut-off points for the novel score system were obtained using receiver operating characteristic (ROC) curves. RESULTS: The system score = VAS (0-3 point = 1; 3.1-7 point = 3; 7.1-10 point = 5) + duration of symptoms (<6 months = 1; ≥1 6 months = 2) + ability to walk without pain (>1 h = 1; ≤1 h = 4) + heel spur in X-ray (No = 0; Yes = 2) + high intensity zone (HIZ) in MRI (No = 0; Yes = 2). The total score was divided in four categories of severity: mild (2-4 points), moderate (5-8 points), severe (9-12 points), and critical (13-15 points). Inter-observer agreement with a value of 0.84 was considered as perfect reliability. Intra-observer reproducibility with a value of 0.92 was considered as perfect reproducibility. The optimum cut-off value was 10 points. The sensitivity of predictive factors was 86.37%, 84.21%, 91.22%, 84.12%, and 89.32%, respectively; the specificity was 64.21%, 53.27%, 67.76%, 62.37%, and 79.58%, respectively; the area under curve was 0.75, 0.71, 0.72, 0.87, and 0.77, respectively. The Hosmer-Lemeshow test showed a good fitting of the score system with an overall accuracy of 90.6%. CONCLUSIONS: Based on prognostic factors, the present study establishes a novel scoring system which is highly comprehensible, reliable, and reproducible. This score system can be used to identify the severity of plantar fasciitis and predict the prognosis of conservative treatment accurately. The application of this scoring system in clinical settings can significantly improve the decision-making process.

A randomized, double-blind, placebo-controlled trial for Yi-Qi Hua-Yu tong-sui granule in the treatment of mild or moderate cervical spondylotic myelopathy.

BACKGROUND: Neck pain, sensory disturbance and motor dysfunction in most patients suffered cervical spondylotic myelopathy (CSM). However, some conservative treatments are limited by their modest effectiveness. In the other hand, surgical treatment is necessary when symptoms are refractory to conservative treatments and neurological function of the patients has deteriorated. Many patients use complementary and alternative medicine, including traditional Chinese medicine, to address their symptoms. The purpose of the present study is to examine effectiveness and safety of Yiqi-Huayu-Tongsui (YQHYTS) granule, a compound traditional Chinese herbal medicine, on symptoms in patients with mild or moderate CSM. METHODS/DESIGN: A randomized, double blinded, placebo-controlled clinical trial to evaluate the efficacy and safety of YQHYTS granule is proposed. 72 patients in Longhua Hospital with the diagnosis of mild or moderate CSM will be randomly allocated into 2 groups, and treated with YQHYTS granule or placebo. The prescription of the trial drugs (YQHYTS granule/placebo) is 20 grams twice a day for 3 months. The primary outcome measurements include visual analog scale, Japanese Orthopedic Association, and Neck Disability Index score. The secondary outcome measurements are electromyogram and Pfirrmann classification. DISCUSSION: YQHYTS granule has been established and applied in Longhua Hospital for many years. As it has a potential benefit in treating mild or moderate CSM, we designed a double-blind, prospective, randomized controlled trial and would like to publish the results and conclusions later. If YQHYTS granule can alleviate neck pain, sensory disturbance, and even motor dysfunction without adverse effects, it may be a unique strategy for the treatment of mild or moderate CSM. TRIAL REGISTRATION: Chinese Clinical Trial Registry ID: ChiCTR1900028192. Registered 15 December 2019, Available at: http://www.chictr.org.cn/edit.aspx?pid=46913&htm=4.

Clinical study on improving postoperative symptoms of cervical spondylotic myelopathy by Qishe pill.

BACKGROUND: Cervical spondylotic myelopathy (CSM) is the most serious type of cervical spondylosis, which is often treated surgically in patients with progressive neurological symptoms following ineffective conservative treatment. However, some patients have residual symptoms such as neck pain, stiffness, and C5 nerve palsy after surgery. The Qishe pill can effectively relieve the symptoms of neck pain and numbness, but there is no evidence showing the efficacy and safety of the Qishe pill in treating symptoms after spinal cord surgery. METHODS/DESIGN: A multicenter, randomized controlled clinical trial will be conducted to evaluate the efficacy and safety of the Qishe Pill. A total of 330 patients with CSM who receive surgical treatment will be randomly divided into 2 groups, treated for 12 weeks and with a 1-year follow-up. The primary outcome will be Japanese Orthopaedic Association score from the baseline to 4 weeks, 12 weeks, 24 weeks, and 48 weeks after surgery. Secondary outcomes will include Visual Analogue Scale score, Neck Disability Index, and imaging indicators (including magnetic resonance imaging and X-ray). Additionally, adverse reactions will be observed and recorded as safety indicators. DISCUSSION: Although the Qishe pill can effectively improve the discomfort of the neck and upper limbs in clinical applications, there is a lack of clinical research on postoperative patients. This study will investigate the efficacy and safety of the Qishe pill in treating postoperative symptoms of CSM. TRIAL REGISTRATION: Clinical Trials.gov ID: ChiCTR1900028173. Registered on 17 December 2019.

MicroRNA-497 is a potential prognostic marker in human cervical cancer and functions as a tumor suppressor by targeting the insulin-like growth factor 1 receptor.

BACKGROUND: Increasing evidence has shown that microRNAs function as oncogenes or tumor suppressors in human malignancies, but the roles of microRNA (miR)-497 in human cervical cancer still remain unclear. Our aim was to analyze the clinicopathologic and prognostic significance of miR-497 in human cervical cancer and to investigate the effects of miR-497 on the malignant phenotype of cervical cancer cells. METHODS: First, we detected miR-497 expression in the HPV-16-immortalized cervical epithelial cell lines and 4 other cervical cancer cell lines (HeLa, Caski, SiHa, and HeLa-S3). Then the expression of miR-497 was analyzed in cervical cancer tissues and paired nontumor tissues, and its correlation with clinicopathologic features and survival was analyzed. Finally, the roles of miR-497 in regulation of tumor proliferation, apoptosis, migration, invasion, and target gene expression were further investigated. RESULTS: MiR-497 was downregulated in cervical cancer cells or tissues compared with HPV-16-immortalized cervical epithelial cell lines or the paired nontumor tissues. Also, the decrease in miR-497 correlated closely with the criteria of the International Federation of Gynaecology and Obstetrics stage and lymph node metastases in patients with cervical cancer. Multivariate Cox analysis showed that low miR-497 expression appeared to be an unfavorable prognostic factor. Transient forced expression of miR-497 decreased the growth and colony-formation capacity of HeLa and SiHa cells by inducing Caspase-3-dependent apoptosis. Forced expression of miR-497 suppressed the migration and invasiveness of cervical cancer cells. By computational miRNA target prediction and functional analysis, miR-497 was demonstrated to bind to the 3' untranslated regions of IGF-1R mRNA, and upregulation of miR-497 downregulated IGF-1R protein expression. Further investigation showed that small interfering RNA-mediated IGF-1R knockdown could mimic the effect of enforced miR-497 expression on the malignant phenotypes of cervical cancer cells. CONCLUSION: MiR-497 may be a potential prognostic marker and functions as a tumor suppressor in human cervical cancer by post-transcriptionally targeting IGF-1R.

Analysis of muscle and ovary transcriptome of Sus scrofa: assembly, annotation and marker discovery.

Pig (Sus scrofa) is an important organism for both agricultural and medical purpose. This study aims to investigate the S. scrofa transcriptome by the use of Roche 454 pyrosequencing. We obtained a total of 558 743 and 528 260 reads for the back-leg muscle and ovary tissue each. The overall 1 087 003 reads give rise to 421 767 341 bp total residues averaging 388 bp per read. The de novo assemblies yielded 11 057 contigs and 60 270 singletons for the back-leg muscle, 12 204 contigs and 70 192 singletons for the ovary and 18 938 contigs and 102 361 singletons for combined tissues. The overall GC content of S. scrofa transcriptome is 42.3% for assembled contigs. Alternative splicing was found within 4394 contigs, giving rise to 1267 isogroups or genes. A total of 56 589 transcripts are involved in molecular function (40 916), biological process (38 563), cellular component (35 787) by further gene ontology analyses. Comparison analyses showed that 336 and 553 genes had significant higher expression in the back-leg muscle and ovary each. In addition, we obtained a total of 24 214 single-nucleotide polymorphisms and 11 928 simple sequence repeats. These results contribute to the understanding of the genetic makeup of S. scrofa transcriptome and provide useful information for functional genomic research in future.

Transcript variants, expression, and polymorphisms of the pig prosaposin gene.

Prosaposin (PASP) is a sphingolipid hydrolysis protein that plays roles in both the nervous and reproduction systems. In this study, we cloned the pig PASP gene and studied its genomic organization, polymorphism, and expression pattern. Two PASP transcripts, TV1 (HQ245644) and TV2 (HQ245646), were identified in pig. TV1 was the complete transcript that encoded 527 amino acids, whereas TV2 was 9 bp shorter due to an exon 8 deletion. The pig PASP gene spanned over 34 kb in length on chromosome 14 (SSC14), and consisted of 15 exons and 14 introns. The pig PASP gene (TV1 and TV2) expressed predominantly in the cerebellum, lymphnode, pituitary, abdominal fat, hypothalamus, and cerebrum in both females and males. PASP TV1 expressed mainly in teh cerebrum, cerebellum, hypothalamus, pituitary, heart, subcutaneous fat, and foreleg muscle, while TV2 was expressed in the liver, spleen, lung, kidney, and lymphnode. In foreleg muscle, the predominant transcript was TV2 in males and TV1 in females. Some potential transcriptional elements were predicted in 5' flanking region (~3000 bp) of the PASP gene, and they were TATA boxes, RORE, Sp1, SRY, oct-1, Cdx A, and cap. Additionally, we identified 68 single-nucleotide polymorphisms and 9 indels in the pig PASP gene, and three single-nucleotide polymorphisms (C77932320T or L15F; C77928094T or P191L; A77917401G or K522R) were nonsynonymous substitutions. These results provide useful information for future functional investigations of the pig PASP gene.

[Relationship between antioxidant activities and contents of active ingredients in Radix Scutellaria].

OBJECTIVE: To study the relationship between the antioxidant activities and the contents of active ingredients in Radix Scutellaria. METHOD: The antioxidant activities of extracts and active ingredients of Radix Scutellaria in NADPH-dependent lipid peroxidation in rat liver microsome were assayed. RESULT: Extracts of Radix Scutellaria showed a 50% inhibition of lipid peroxidation in the concentration range of 2.72-18.27 mg x L(-1). CONCLUSION: The antioxidant activities of extracts of Radix Scutellaria are not only related with the contents but also the ratio of the active ingredients.

Effects of organic matter on phosphorus release kinetics in different trophic lake sediments and application of transition state theory.

Sediments have a significant influence on the overlying water, and phosphorus (P) release from sediments is an important source for the lake eutrophication, particularly in shallow ones. In this study, effects of organic matter on P release from sediments in different trophic lakes from the middle and lower reaches of Yangtze River, China, were investigated, and the release kinetics of different P fractions at different temperature were studied. The results show that the release kinetics of soluble reactive phosphorus (SRP), dissolved organic phosphorus (DOP) and dissolved total phosphorus (DTP) were similar for the studied sediments, the release rate increased rapidly in the initial hours, and it increased gradually after 10h. The release kinetics of SRP, DOP and DTP followed the Power Function model. SRP was the major fraction among the released DTP, while DOP was an important fraction in the heavily polluted sediments. Organic matter restricted the SRP and DTP release while it promoted the DOP release. Both DOP and SRP release processes were endothermic. The thermodynamic properties in the P release kinetics were calculated and discussed.

[Determination of contents of the effective ingredients in root of Scutellaria baicalensis by HPLC-ECD].

OBJECTIVE: To develop an HPLC-electrochemical detection (HPLC-ECD) method for determination of contents of three effective ingredients baicalin, baicalein and wogonin in Scutellaria baicalensis simultaneously. METHOD: 70% ethanol extract of S. baicalensis was separated on a Kromasil C18 column (4.6 mm x 250 mm, 5 microm) using a mixture solution of CH3OH and H2O-THF-H3PO4(80:10:0.2) as mobile phase and detected by Waters2465 electrochemical detector at + 800 mV ( vs. ISAAC). Temperature of column was 30 degrees C. RESULT AND CONCLUSION: The linear ranges of baicalin, baicalein and wogonin were 0.045 6-1.14 microg (r = 0.999 6), 0.013-0.325 microg (r = 1) and 0.009 5-0.047 5 microg ( r = 0.999 9), respectively. The average recoveries of baicalin, baicalein and wogonin were 97.9% (n = 5, RSD 2.3%), 97.2% (n = 5, RSD 3.3%) and 103.5% (n = 5, RSD 3.5%), respectively. The contents of three effective ingredients from 14 different germplasm resourses and 9 different growing areas of S. baicalensis were determined, the quality of S. baicalensis was evaluated.

Effects of particle size, organic matter and ionic strength on the phosphate sorption in different trophic lake sediments.

The trophic status and development of lake system is significantly influenced by the phosphate sorption at the sediment-water interface. The effects of organic matter, particle size and ionic strength on the phosphate sorption by sediments were investigated in this study. The results show that maximum phosphate sorption capacity (Qmax), equilibrium phosphate concentration (EPC0), phosphate sorption efficiency (k) and phosphate sorption rate decreased as particle size increased for all the studied sediments. But the reliable desorbed phosphorus (RDP) increased. Qmax, EPC0, k and RDP of different particle size fractions varied and there were no obvious differences among different trophic lake sediments. Qmax, EPC0 increased while k and RDP decreased as the pollution level of lake sediment increased. The phosphate sorption mainly occurred within 0.5 h. Power function and simple Elovich models were the best kinetic models for the phosphate sorption of the different particle size fractions. Qmax and phosphate sorption rate decreased with the decreasing of organic matter content of sediments and the increasing of ionic strength. This study suggests that ionic strength and organic matter had similar effects on the phosphate sorption for different trophic lake sediments.

[Influences of submerged vegetation Hydrilla verticillata on the forms of inorganic and organic phosphorus and potentially exchangeable phosphate in sediments].

The influences of submerged vegetation Hydrilla verticillata on forms of inorganic and organic phosphorous forms and potentially exchangeable phosphate in sediments were investigated under indoors simulating condition. The results show that: (1) Hydrilla verticillata can decrease the amount of OM, CEC and TP evidently ( p < 0.05) and activate the phosphate in sediments. (2) In the forms of inorganic phosphorus, the NaOH-P was significantly influenced (p<0.01) and the labile organic P in the forms of organic P was influenced to a certainty (p < 0.1), while no significant differences were made to the other forms of phosphorous. (3) Hydrilla verticillata can affect the amount of potentially exchangeable phosphate of the sediments, which increased 11.5% for the vegetation-group and decreased 61.0% for the control group during the period of the experiments. The change orientation was oppositional and the degree of change was quite different. This testified that Hydrilla verticillata could increase the amount of potentially exchangeable phosphate of sediments.

Phosphorus fractions and phosphate sorption characteristics in relation to the sediment compositions of shallow lakes in the middle and lower reaches of Yangtze River region, China.

Phosphorus is recognized as the most critical nutrient limiting lake productivity. The trophic status and development of lake systems are also influenced by the phosphorus content and fractions and phosphate sorption characteristics of the lake sediments. The phosphorus fractions and phosphate sorption characteristics of sediments in shallow lakes from the middle and lower reaches of Yangtze River region in China were investigated. The results show that the phosphorus contents in the sediments ranged from 217.8 to 1640 mg kg(-1); inorganic phosphorus (IP) was the major fraction of total phosphorus (TP); phosphorus bound to Al, Fe, Mn oxides, and hydroxides (Fe/Al-P), and calcium bound phosphorus (Ca-P) were the main fractions of IP. Phosphate sorption on the sediments mainly occurred within 2 h and then reached equilibrium in 10 h. The phosphate sorption rate was closely related to the concentration of fine particles. The phosphate sorption capacity ranged from 128.21 to 833.33 mg kg(-1), showing a significant correlation with the contents of Fe, Fe+Al, total organic carbon (TOC), cationic exchange capacity, total nitrogen, TP, Ca, IP, and the ratio of P/(Al+Fe), and it was higher in the sediments of eutrophic lakes than in mesotrophic lakes. Phosphate was mainly sorbed onto Fe and Al particles. The phosphate sorption efficiency ranged from 26.74 to 312.50 L kg(-1), and had a strong positive correlation with Fe content. For the eutrophic lake sediments, there were no significant relationships between the phosphate sorption efficiency and the selected physical and chemical parameters. But for the mesotrophic lake sediments, the phosphate sorption efficiency was found to be positively related to the contents of Al and Fe+Al.

[Phosphate adsorption characteristics onto the sediments from shallow lakes in the middle and lower reaches of the Yangtze River].

Adsorption isotherms and kinetics of phosphate onto the 11 sediments taken from shallow lakes in the middle and lower reaches of the Yangtze River were determined in laboratory, and the effect of physical and chemical properties of the sediments on its phosphate adsorption characteristics was also analyzed. The results indicate that: (1) The process of phosphate adsorption onto sediments mainly occurred within 0-10 h, the maximum adsorption rates occurred within 0-0.5 h, and then attends to a dynamic equilibrium; (2) Between the NAP and its organic matter, CEC, total phosphorus, inorganic phosphorus, organic phosphorus, Fe/Al-phosphorus and total nitrogen have remarkable positive correlation; between the maximum adsorption of phosphate and its CEC, inorganic phosphorus, organic matter and total phosphorus have remarkable negative correlation; between the total maximum adsorption of phosphate and its organic matter, CEC, total phosphorus, inorganic phosphorus, organic phosphorus, Fe/Al-phosphorus and total nitrogen have remarkable positive correlation; (3) As regards water quality of the shallow lakes in the middle and lower reaches of the Yangtze River at present, its sediment exists desorption. Between the adsorption-desorption equilibrium concentrations of phosphate onto the sediments and its organic matter, CEC, total nitrogen, the total phosphorus and the content of every form phosphorous have a remarkable positive correlation. Even the sediment from heavily polluted lake also has the tendency to release phosphate into the overlying water in this study.

The study of the effect of pH on phosphate sorption by different trophic lake sediments.

This paper studies the effect of pH on phosphate sorption by the sediments of different trophic lakes, including sorption isotherms with different pH values, their effect on sorption rate, their impact on the kinetics of sorption and desorption. The following conclusions are drawn. (1) The phosphate sorption capacity of lake sediment is correlated with pH, but not with its trophic level; that is, pH at 7.0>5.5>9.0. The three isotherms models cannot well describe phosphate sorption by different trophic sediments with different pH, and its applicability seems irregular. (2) The power function equation is one of the best kinetic models, which can provide satisfactory fitting of the kinetic data of phosphate sorption by different trophic sediments, and there is no obvious difference between them. The quick phosphate sorption by the sediment takes place mainly at 0-0.5 h, the pH value has a remarkable effect on the rate of phosphate sorption by the sediment, and sediments in different trophic states tend to have similar trends of change, with pH 5.5>7.0>9.0. (3) The effect of pH on phosphate sorption shows a similar trend for different trophic sediments; namely, as pH increases phosphate sorption rate tends to increases sharply at first and then drop suddenly. After a while it increases slightly, and finally a slight decrease follows as the pH increases. The maximum and minimum of phosphate sorption capacity may be attributed to the rate of phosphate release. (4) Phosphate sorption by lake sediments is not completely reversible and strong bonding occurs between sediment particles and sorbed phosphate. This makes it difficult for the sorbed phosphate to be desorbed from the sediments. The amounts of desorbed phosphate are almost the same in different trophic sediments with different initial pH values; that is, the effect of pH on phosphate desorption is small.