Hydrogen-induced tunable remanent polarization in a perovskite nickelate.

Materials with field-tunable polarization are of broad interest to condensed matter sciences and solid-state device technologies. Here, using hydrogen (H) donor doping, we modify the room temperature metallic phase of a perovskite nickelate NdNiO3 into an insulating phase with both metastable dipolar polarization and space-charge polarization. We then demonstrate transient negative differential capacitance in thin film capacitors. The space-charge polarization caused by long-range movement and trapping of protons dominates when the electric field exceeds the threshold value. First-principles calculations suggest the polarization originates from the polar structure created by H doping. We find that polarization decays within ~1 second which is an interesting temporal regime for neuromorphic computing hardware design, and we implement the transient characteristics in a neural network to demonstrate unsupervised learning. These discoveries open new avenues for designing ferroelectric materials and electrets using light-ion doping.

Establishment of a Multiplex Detection Method for Common Bacteria in Blood Based on Human Mannan-Binding Lectin Protein-Conjugated Magnetic Bead Enrichment Combined with Recombinase-Aided PCR Technology.

Objective: Recombinase-aided polymerase chain reaction (RAP) is a sensitive, single-tube, two-stage nucleic acid amplification method. This study aimed to develop an assay that can be used for the early diagnosis of three types of bacteremia caused by Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA), and Acinetobacter baumannii (AB) in the bloodstream based on recombinant human mannan-binding lectin protein (M1 protein)-conjugated magnetic bead (M1 bead) enrichment of pathogens combined with RAP. Methods: Recombinant plasmids were used to evaluate the assay sensitivity. Common blood influenza bacteria were used for the specific detection. Simulated and clinical plasma samples were enriched with M1 beads and then subjected to multiple recombinase-aided PCR (M-RAP) and quantitative PCR (qPCR) assays. Kappa analysis was used to evaluate the consistency between the two assays. Results: The M-RAP method had sensitivity rates of 1, 10, and 1 copies/µL for the detection of SA, PA, and AB plasmids, respectively, without cross-reaction to other bacterial species. The M-RAP assay obtained results for < 10 CFU/mL pathogens in the blood within 4 h, with higher sensitivity than qPCR. M-RAP and qPCR for SA, PA, and AB yielded Kappa values of 0.839, 0.815, and 0.856, respectively ( P < 0.05). Conclusion: An M-RAP assay for SA, PA, and AB in blood samples utilizing M1 bead enrichment has been developed and can be potentially used for the early detection of bacteremia.

Methylation-regulated tumor suppressor gene PDE7B promotes HCC invasion and metastasis through the PI3K/AKT signaling pathway.

BACKGROUND: Hepatocellular carcinoma (HCC) has a high mortality rate, and the mechanisms underlying tumor development and progression remain unclear. However, inactivated tumor suppressor genes might play key roles. DNA methylation is a critical regulatory mechanism for inactivating tumor suppressor genes in HCC. Therefore, this study investigated methylation-related tumor suppressors in HCC to identify potential biomarkers and therapeutic targets. METHODS: We assessed genome-wide DNA methylation in HCC using whole genome bisulfite sequencing (WGBS) and RNA sequencing, respectively, and identified the differential expression of methylation-related genes, and finally screened phosphodiesterase 7B (PDE7B) for the study. The correlation between PDE7B expression and clinical features was then assessed. We then analyzed the changes of PDE7B expression in HCC cells before and after DNA methyltransferase inhibitor treatment by MassArray nucleic acid mass spectrometry. Furthermore, HCC cell lines overexpressing PDE7B were constructed to investigate its effect on HCC cell function. Finally, GO and KEGG were applied for the enrichment analysis of PDE7B-related pathways, and their effects on the expression of pathway proteins and EMT-related factors in HCC cells were preliminarily explored. RESULTS: HCC exhibited a genome-wide hypomethylation pattern. We screened 713 hypomethylated and 362 hypermethylated mCG regions in HCC and adjacent normal tissues. GO analysis showed that the main molecular functions of hypermethylation and hypomethylation were "DNA-binding transcriptional activator activity" and "structural component of ribosomes", respectively, whereas KEGG analysis showed that they were enriched in "bile secretion" and "Ras-associated protein-1 (Rap1) signaling pathway", respectively. PDE7B expression was significantly down-regulated in HCC tissues, and this low expression was negatively correlated with recurrence and prognosis of HCC. In addition, DNA methylation regulates PDE7B expression in HCC. On the contrary, overexpression of PDE7B inhibited tumor proliferation and metastasis in vitro. In addition, PDE7B-related genes were mainly enriched in the PI3K/ATK signaling pathway, and PDE7B overexpression inhibited the progression of PI3K/ATK signaling pathway-related proteins and EMT. CONCLUSION: PDE7B expression in HCC may be regulated by promoter methylation. PDE7B can regulate the EMT process in HCC cells through the PI3K/AKT pathway, which in turn affects HCC metastasis and invasion.

"To do or not to do", male nurses' experiences of providing intimate care to female patients in China, a constructivist grounded theory study.

BACKGROUND: Some studies suggest that female patients have more concerns about receiving intimate care from male than female nurses. Thus, providing intimate care to female patients is a challenging experience for male nurses. The purpose of this study was to explore Chinese male nurses' experiences and process of providing intimate clinical care to female patients. METHODS: A constructivist grounded theory approach was used to develop a theoretical understanding of male nurses' experiences. This study included participants from 3 hospitals in different locations in China. Twenty-five male nurses were recruited using purposive and theoretical sampling. Semi-structured interviews were conducted. Data analysis was completed using initial coding, focused coding, theoretical coding and memo writing to produce core concepts and categories, and theory development. RESULTS: Chinese male nurses' experiences of providing intimate care to female patients can be constructed as a three-stage process: (1) anticipation of the level of embarrassment, (2) deciding on the process: do it or not do it and (3) protecting both parties and dealing with embarrassment. Additionally, seven themes and associated categories were identified to represent the important factors in the process of male nurses providing intimate care to female patients in China. CONCLUSIONS: Chinese traditional culture may affect the embarrassment in Chinese male nurses providing intimate care to female patients. The embarrassing situation can be divided into three different stages, and male nurses have different main concerns in each stage. Hospital nursing administrators should consider the experiences and needs of male nurses in providing intimate care and provide them with psychological support, education and training.

[Clinical Value of Detecting ABL Kinase Domain Mutations in Patients with Chronic Myeloid Leukemia Based on High-Throughput Sequencing Technology].

OBJECTIVE: To compare the efficacy and clinical value of high-throughput sequencing (HTS) and Sanger sequencing in detecting ABL kinase domain mutations in patients with chronic myeloid leukemia (CML). METHODS: A total of 198 samples of 147 CML patients from July 2017 to March 2021 in Henan Cancer Hospital were collected and underwent high-throughput sequencing and Sanger sequencing to detect the mutations in ABL kinase domain, and the relevant clinical data were collected for comparative analysis. RESULTS: The proportion of total mutations and ≥2 mutations detected by high-throughput sequencing were significantly higher than those detected by Sanger sequencing (P =0.01; P =0.046). ≥2 mutations were detected in 22 cases, of which 5 cases (22.7%) had compound mutations. High-throughput sequencing can detect low level mutations that cannot be detected by Sanger sequencing. In 198 samples, 25 (12.6%) were low level mutations, 33 (16.7%) were high level mutations and 10 (5.1%) were mixed high and low level mutations. In the analysis of related clinical factors, the total mutation rate and the low level mutation rate in the optimal period, failure period and warning period were gradually increased (total mutation rate, P =0.016; low level mutation rate, P =0.005). The mutation rate of the samples with additional chromosomal abnormalities was also significantly increased (P =0.009). The mutation rate of patients who received first- and second-line treatment was significantly lower than that of patients who received third- or higher-line treatment (P =0.006). Analysis based on variant allele frequency (VAF) of the mutation site was helpful to visually evaluate the clonal evolution status of TKI-resistance CML cells. CONCLUSION: High-throughput sequencing is more sensitive and accurate than Sanger sequencing in mutation detection, which is helpful to accurately and visually evaluate TKI treatment response and optimize treatment strategy for CML.

Diverse modes of chromosome terminal deletion in spontaneous canavanine-resistant Schizosaccharomyces pombe mutants.

Canavanine resistance has been used to analyze mutation rates in the fission yeast Schizosaccharomyces pombe . However, the genetic basis of canavanine resistance in this organism remains incompletely understood. Here, we performed whole genome sequencing on five spontaneously arising canavanine-resistant S. pombe mutants, including the can2-1 mutant isolated in the 1970s. This analysis revealed that three mutants, including can2-1 , experienced terminal deletions of the left arm of chromosome II, leading to the loss of multiple amino acid transporter genes. Interestingly, these three mutants underwent chromosome terminal deletion through distinct mechanisms, including homology-driven translocation, homology-independent chromosome fusion, and de novo telomere addition. Our findings shed new light on the genetic basis of canavanine resistance and mechanisms underlying chromosome terminal deletions in fission yeast.

Oncology nurses' experiences of providing emotional support for cancer patients: a qualitative study.

BACKGROUND: A high percentage of cancer patients may experience emotional distress. Oncology nurses are expected to play an important role in recognizing emotional distress and planning and delivering care that meets the individual needs of each patient. However, few studies have focused on the experiences of clinical nurses in such cases. This study adopted a qualitative research method to gain an in-depth understanding of the experience of nursing staff in caring for cancer patients with emotional distress. METHODS: A qualitative descriptive design and semi-structured interviews were used in this study. Twenty-one oncology nurses were interviewed, and the qualitative content analysis suggested by Graneheim & Lundman (2004) was used to interpret the data. RESULTS: Six themes were identified, as follows: (1) dictating the abnormality of emotion, (2) soothing and comforting patients, (3) a lack of psychology knowledge and communication skills, (4) negative impacts of a lack of time, (5) managing emotional labor, and (6) reflecting on the experiences. CONCLUSION: Hospital administrators should arrange pre-employment education and training as well as on-the-job education to help nurses in caring for cancer patients with emotional distress. They should also focus attention on the personal emotional states of nursing staff in a timely manner and provide psychological support and emotional counseling as necessary.

Ligand and Strain Synergistic Effect in NiFeP0.32 LDH for Triggering Efficient Oxygen Evolution Reaction.

Developing efficient water-splitting electrocatalysts to accelerate the slow oxygen evolution reaction (OER) kinetics is urgently desired for hydrogen production. Herein, ultralow phosphorus (P)-doped NiFe LDH (NiFePx LDH) with mild compressive strain is synthesized as an efficient OER electrocatalyst. Remarkably, NiFePx LDH with the phosphorus mass ratio of 0.32 wt.% and compressive strain ratio of 2.53% (denoted as NiFeP0.32 LDH) exhibits extraordinary OER activity with an overpotential as low as 210 mV, which is superior to that of commercial IrO2 and other reported P-based OER electrocatalysts. Both experimental performance and density function theory (DFT) calculation demonstrate that the doping of P atoms can generate covalent Fe─P coordination bonds and lattice distortion, thus resulting in the consequent depletion of electrons around the Fe active center and the downward shift of the d-band center, which can lead to a weaker adsorption ability of * O intermediate to improve the catalytic performance of NiFeP0.32 LDH for OER. This work provides novel insights into the distinctive coordinated configuration of P in NiFePx LDH, which can result in superior catalytic performance for OER.

What influences newly graduated registered nurses' intention to leave the nursing profession? An integrative review.

BACKGROUND: Newly graduated registered nurses leaving the nursing profession in the early stages of their career have enormous financial and time implications for nursing organizations and affect the quality of nursing care. OBJECTIVE: To identify the factors influencing newly graduated registered nurses' intention to leave the nursing profession over the past 10 years. METHODS: The framework developed by Whittemore and Knafl was used to conduct this integrative review. An electronic search was conducted for English articles to identify research studies published between 2011-2022 using the following databases of PubMed, MEDLINE, CINAHL, PsycINFO, and Scopus. Eligible publications were critically reviewed and scored using the Critical Appraisal Skills Program Checklist and the Center for Evidence-Based Management appraisal. RESULTS: Twenty-one studies were analyzed. The main factors affecting newly graduated registered nurses' intention to leave the nursing profession included demographic factors (age, educational level, year of experience, professional title, employment status, health status, shift, hospital location and size), supervisor and peer support, challenges in the workplace, cognitive and affective response to work, work environment (collegial nurse-physician relations, insufficient staffing level, person-work environment fit), gender stereotypes, autonomous motivation, role models, and resilience. CONCLUSIONS: The factors affecting newly graduated registered nurses' intention to leave the nursing profession are multifaceted and should receive continuous attention from nurse managers. The findings provide more comprehensive for nurse administrators to develop intervention strategies to mitigate newly graduated registered nurses' turnover intention.

A Novel ASCT2 Inhibitor, C118P, Blocks Glutamine Transport and Exhibits Antitumour Efficacy in Breast Cancer.

BACKGROUND: The microtubule protein inhibitor C118P shows excellent anti-breast cancer effects. However, the potential targets and mechanisms of C118P in breast cancer remain unknown. METHODS: Real-time cellular analysis (RTCA) was used to detect cell viability. Apoptosis and the cell cycle were detected by flow cytometry. Computer docking simulations, surface plasmon resonance (SPR) technology, and microscale thermophoresis (MST) were conducted to study the interaction between C118P and alanine-serine-cysteine transporter 2 (ASCT2). Seahorse XF technology was used to measure the basal oxygen consumption rate (OCR). The effect of C118P in the adipose microenvironment was explored using a co-culture model of adipocytes and breast cancer cells and mouse cytokine chip. RESULTS: C118P inhibited proliferation, potentiated apoptosis, and induced G2/M cell cycle arrest in breast cancer cells. Notably, ASCT2 was validated as a C118P target through reverse docking, SPR, and MST. C118P suppressed glutamine metabolism and mediated autophagy via ASCT2. Similar results were obtained in the adipocyte-breast cancer microenvironment. Adipose-derived interleukin-6 (IL-6) promoted the proliferation of breast cancer cells by enhancing glutamine metabolism via ASCT2. C118P inhibited the upregulation of ASCT2 by inhibiting the effect of IL-6 in co-cultures. CONCLUSION: C118P exerts an antitumour effect against breast cancer via the glutamine transporter ASCT2.

[Effect of Pin Holes Location of Unicompartmental Knee Arthroplasty on Postoperative Tibial Plateau Mechanical Properties].

OBJECTIVE: The purpose of this study is to explore the biomechanical characteristics of the tibia after unicompartmental knee arthroplasty with different distributions of two-pin holes, and to optimize the two-pin holes scheme to reduce the risk of tibial fractures after unicompartmental knee arthroplasty. METHODS: Lower limbs model is segmented and reconstructed from computed tomography images. Four combinations of two pin holes created for tibial cutting guide placement are simulated with finite element analysis. RESULTS: In the third mode, the positioning hole at the proximal medial edge of the tibial plateau has the highest stress value, and the position of the positioning hole near the medial edge of the proximal tibial plateau appears stress concentration. CONCLUSIONS: The present study revealed that placing tibial cutting guide holding pins centrally would lower the risks of periprosthetic fracture of the medial tibial plateau.

Prevalence and influencing factors of hyperuricemia in middle-aged and older adults in the Yao minority area of China: a cross-sectional study.

Hyperuricemia (HUA) endangers human health, and its prevalence has increased rapidly in recent decades. The current study investigated HUA's prevalence and influencing factors in Gongcheng, southern China. A cross-sectional investigation was conducted; 2128 participants aged 30-93 years were included from 2018 to 2019. Univariate and multivariate logistic regression models were used to screen HUA variables. A Bayesian network model was constructed using the PC algorithm to evaluate the association between influencing factors and HUA. The prevalence of HUA was 15.6% (23.2% in men, 10.7% in women). After screening the variables using a logistic regression analysis model, fatty liver disease (FLD), dyslipidemia, abdominal obesity, creatinine (CREA), somatotype, bone mass, drinking, and physical activity level at work were included in the Bayesian network model. The model results showed that dyslipidemia, somatotype, CREA, and drinking were directly related to HUA. Bone mass and FLD were indirectly associated with HUA by affecting the somatotype. The prevalence of HUA in Gongcheng was high in China. The prevalence of HUA was related to somatotype, drinking, bone mass, physical activity level at work, and other metabolic diseases. A good diet and moderate exercise are recommended to maintain a healthy somatotype and reduce the prevalence rate of HUA.

Renal­rotation techniques in retroperitoneoscopic adrenalectomy for giant pheochromocytomas: a clinical intervention study with historical controls.

BACKGROUND: Dealing with the giant pheochromocytomas (maximum diameter ≥ 6 cm) has long been a tough challenge for urologists. We introduced a new retroperitoneoscopic adrenalectomy method modified with renal-rotation techniques to treat giant pheochromocytomas. METHODS: 28 diagnosed patients were prospectively recruited as the intervention group. Meanwhile, by referring to the historical records in our database, matched patients who had undergone routine retroperitoneoscopic adrenalectomy (RA), transperitoneal laparoscopic adrenalectomy (TA), or open adrenalectomy (OA) for giant pheochromocytomas were selected as controls. Perioperative and follow-up data were collected for comparative assessment. RESULTS: Among all the groups, the intervention group had the minimal bleeding volume (28.93 ± 25.94 ml, p < 0.05), the least intraoperative blood pressure variation (59.11 ± 25.68 mmHg, p < 0.05), the shortest operation time (115.32 ± 30.69 min, p < 0.05), the lowest postoperative ICU admission rates (7.14%, p < 0.05), and shortest drainage time length (2.57 ± 0.50 days, p < 0.05). Besides, compared with TA and OA groups, intervention group was also characterized by lower pain scores (3.21 ± 0.63, p < 0.05), less postoperative complications (p < 0.05), earlier diet initiation time (1.32 ± 0.48 postoperative days, p < 0.05) and ambulation time (2.68 ± 0.48 postoperative days, p < 0.05). Follow-up blood pressure and metanephrine and normetanephrine levels in all intervention group patients remained normal. CONCLUSION: Compared with RA, TA, and OA, retroperitoneoscopic adrenalectomy with renal-rotation techniques is a more feasible, efficient, and secure surgical treatment for giant pheochromocytomas. TRIAL REGISTRATION: This study has been prospectively registered on the Chinese Clinical Trial Registry website (ChiCTR2200059953, date of first registration: 14/05/2022).

Dual Integrating Oxygen and Sulphur on Surface of CoTe Nanorods Triggers Enhanced Oxygen Evolution Reaction.

The bottleneck of large-scale implementation of electrocatalytic water-splitting technology lies in lacking inexpensive, efficient, and durable catalysts to accelerate the sluggish oxygen evolution reaction kinetics. Owing to more metallic features, transition metal telluride (TMT) with good electronic conductivity holds promising potential as an ideal type of electrocatalysts for oxygen evolution reaction (OER), whereas most TMTs reported up to now still show unsatisfactory OER performance that is far below corresponding sulfide and selenide counterparts. Here, the activation and stabilization of cobalt telluride (CoTe) nanoarrays toward OER through dual integration of sulfur (S) doping and surface oxidization is reported. The as-synthesized CoO@S-CoTe catalyst exhibits a low overpotential of only 246 mV at 10 mA cm-2 and a long-term stability of more than 36 h, outperforming commercial RuO2 and other reported telluride-based OER catalysts. The combined experimental and theoretical results reveal that the enhanced OER performance stems from increased active sites exposure, improved charge transfer ability, and optimized electronic state. This work will provide a valuable guidance to release the catalytic potential of telluride-based OER catalysts via interface modulating engineering.

Long-term result of 125 I seed brachytherapy for pediatric desmoid tumor in the head and neck.

BACKGROUND: Desmoid tumor (DT) is rare and challenging, often affects the head and neck (HN) region in children, and its appropriate treatments are under-discussed. This study aimed to retrospectively evaluate the long-term effectiveness and safety of 125 I seed brachytherapy for pediatric DT in HN. PROCEDURE: Seven pediatric patients with a median age of three years who suffered from DT in HN treated with 125 I brachytherapy from January 2008 to June 2018 were included. Among these, five underwent sole brachytherapy and the others combined with surgery under prescription doses ranging from 10,000 to 12,000 cGy. The rate of local control (LC), complete response (CR), and partial response (PR) was calculated after evaluation by radiological and pathological means. Radiation-associated toxicities were also evaluated. RESULTS: The LC rate was 7/7 during the follow-up time ranging from 43 to 135 months and with a mean of 57 months. No recurrent lesion was found in the patients receiving surgery combined with brachytherapy. In patients treated with sole brachytherapy, the radiological PR rate and CR rate were 4/5 and 1/5, respectively. In those reaching radiological PR, 3/4 were pathological CR. Slight acute radiation-associated toxicities were observed in all patients, and no late or severe acute toxicity was observed. CONCLUSION: 125 I brachytherapy is effective and safe in the management of pediatric DT in HN as the sole modality or combined with surgery in the long term.

[Observation of preventive effect of intervention strategy based on Caprini risk evaluation model on venous thromboembolism after total knee arthroplasty].

OBJECTIVE: To observe preventive effect of Caprini based thrombosis risk evaluation model on venous thromboembolism (VTE) after total knee replacement (TKA). METHODS: Totally 257 TKA patients were admitted from May 2017 to December 2021 were selected. They were divided into conventional intervention strategies (121 patients in control group) and intervention strategies based on Caprini thrombosis risk evaluation model (136 patients in observation group), based on whether Caprini thrombosis risk evaluation model was introduced in May 2019. In normal gourp, there were 79 males and 42 females aged from 50 to 78 years old with an average of (63.10±11.86) years old;body mass index (BMI) ranged from 19 to 32 with an average of (25.21±4.95) kg/m2;55 patients on the left side and 66 on the right side. In observation group, there were 81 males and 55 females aged from 50 to 78 years old with an average of (64.35±10.54) years old;BMI ranged from 19 to 32 with an average of (24.43±5.18) kg/m2;87 patients on the left side and 49 on the right side. The incidence of VTE, visual analogue scale (VAS), Hospital for Special Surgery (HSS) score, affected limb swelling, mean velocity(Vm), peak velocity (PV), D-dimer (D-D), prothrombin time(PT), and incidence of complications were analyzed and compared. RESULTS: The incidence of VTE in observation group was 1.47%(2/136), and 9.09%(11/121) in control group, and there was statistically difference between two groups (χ2=6.976, P=0.008). At 7 days after operation, VAS, HSS score and the difference in circumference of the affected limb in observation group were significantly better than those in control group, and had statistically differences (P<0.05). Blood flow Vm and PV levels between two groups were significantly increased (P<0.001), and blood flow Vm and PV levels in observation group were significantly higher than those in control group on the 7th day after operation, and had differences (P<0.001). The serum D-D level in observation group was significantly lower than that of in control group on the 7th day after operation, and PT level was significantly higher than that of in control group, and had difference(P<0.05). There was no difference in total incidence of complications between two groups (χ2=4.488, P=0.034). CONCLUSION: Intervention strategy based on caprini thrombus risk evluation model could effectively reduce incidence of VTE and complications in TKA patients, improve swelling, hemodynamics and coagulation function of the affected limbs, and contribute to recovery of knee joint function.

Process and Eco-Environment Impact of Land Use Function Transition under the Perspective of "Production-Living-Ecological" Spaces-Case of Haikou City, China.

Land use function transition can change the eco-environment. To achieve an "Intensive and efficient production space, moderately livable living space, and beautiful ecological space", the ecological effects of land use function transition in the context of ecologically fragile areas and rapidly developing areas of socio-economic importance need to be studied. In this study, from the perspective of "production-living-ecological" spaces, we calculated the index of regional eco-environment quality, positive and negative effects of eco-environment impact, and the ecological contribution rate and analyzed the driving factors. We found the following: (1) The production space was greatly compressed, living space was expanded, and ecological space was significantly squeezed. Haikou underwent a rapid transformation from an agriculture-dependent city to an industrial city. Land supply for urban and rural living was guaranteed by the Chinese land management department. However, Haikou prioritized economic development over environmental protection. (2) The regional eco-environment quality index decreased from 2009 to 2018. The expansion of pasture-based ecological spaces is important for improving the quality of the eco-environment, and the reduction of forest ecological space strongly influences the deterioration of the eco-environment. (3) Resource base, historical level of utilization, suitability of land, the ecological value potentiality, and regional policies greatly affected land use function transition and its eco-environment. (4) Refining the planning of territorial space, comprehensively improving land and resources, and reforming the rural land system greatly influenced policy guidance and technical regulation for coordinating "production-living-ecological" spaces and improving the regional eco-environment. In this study, we tested the effect of regional policy regulation on land use function transition and provided a reference for coordinating "production-living-ecological" spaces.

[Behavioral and physiological responses to hypoxia stress in male and female Macrobrachium rosenbergii]. / 雌雄罗氏沼虾应对低氧胁迫的行为生理响应.

To explore the physiological and behavioral responses of male and female Macrobrachium rosenbergii under hypoxia stress, an experiment with three dissolved oxygen (DO) levels (6.46, 4.48 and 3.27 mg·L-1, 6.46 mg·L-1 as control) was conducted. The enzyme activities of energy metabolism in hepatopancreas and muscles of male and female M. rosenbergii were measured after six days of hypoxia stress. The results showed that the enzyme activities of aerobic metabolism in muscles and swimming abilities were significantly decreased as DO decreased from 6.46 mg·L-1 to 4.48 mg·L-1, with the decreases being less in males than females. There was no significant difference in enzyme activities of anaerobic metabolism. When DO was further decreased to 3.27 mg·L-1, the enzyme activities of aerobic metabolism and anaerobic metabolism in muscles significantly decreased. The activity of lactate dehydrogenase (LDH) in anaerobic metabolism of hepatopancreas and tail-flipping speeds significantly decreased in males and females, with less decrease in females than that in males for LDH activity of hepatopancreas. The swimming ability was positively correlated with the enzyme activities of aerobic metabolism in pleopods muscles. There was significant correlation between tail-flipping abilities and enzyme activities of anaerobic metabolism. M. rosenbergii could reduce its reliance on energy metabolism during hypoxia stress, but with negative consequences on locomotor abilities. The muscles were preferentially powered to meet energy requirements of locomotion in males, while females gave priority to energy supply for hepatopancreas under insufficient oxygen conditions.