Cation Exchange in Colloidal Transition Metal Nitride Nanocrystals.

Transition metal nitride (TMN)-based nanostructures have emerged as promising materials for diverse applications in electronics, photonics, energy storage, and catalysis due to their highly desirable physicochemical properties. However, synthesizing TMN-based nanostructures with designed compositions and morphologies poses challenges, especially in the solution phase. The cation exchange reaction (CER) stands out as a versatile postsynthetic strategy for preparing nanostructures that are otherwise inaccessible through direct synthesis. Nevertheless, exploration of the CER in TMNs lags behind that in metal chalcogenides and metal phosphides. Here, we demonstrate cation exchange in colloidal metal nitride nanocrystals, employing Cu3N nanocrystals as starting materials to synthesize Ni4N and CoN nanocrystals. By controlling the reaction conditions, Cu3N@Ni4N and Cu3N@CoN core@shell heterostructures with tunable compositions can also be obtained. The Ni4N and CoN nanocrystals are evaluated as catalysts for the electrochemical oxygen evolution reaction (OER). Remarkably, CoN nanocrystals demonstrate superior OER performance with a low overpotential of 286 mV at 10 mA·cm-2, a small Tafel slope of 89 mV·dec-1, and long-term stability. Our CER approach in colloidal TMNs offers a new strategy for preparing other metal nitride nanocrystals and their heterostructures, paving the way for prospective applications.

Reference gene catalog and metagenome-assembled genomes from the gut microbiome reveal the microbial composition, antibiotic resistome, and adaptability of a lignocellulose diet in the giant panda.

The giant panda, a strict herbivore that feeds on bamboo, still retains a typical carnivorous digestive system. Reference catalogs of microbial genes and genomes are lacking, largely limiting the antibiotic resistome and functional exploration of the giant panda gut microbiome. Here, we integrated 177 fecal metagenomes of captive and wild giant pandas to construct a giant panda integrated gene catalog (GPIGC) comprised of approximately 4.5 million non-redundant genes and reconstruct 393 metagenome-assembled genomes (MAGs). Taxonomic and functional characterization of genes revealed that the captivity of the giant panda significantly changed the core microbial composition and the distribution of microbial genes. Higher abundance and prevalence of antibiotic resistance genes (ARGs) were detected in the guts of captive giant pandas, and ARG distribution was influenced by geography, for both captive and wild individuals. Escherichia, as the prevalent genus in the guts of captive giant pandas, was the main carrier of ARGs, meaning there is a high risk of ARG transmission by Escherichia. We also found that multiple mcr gene variants, conferring plasmid-mediated mobile colistin resistance, were widespread in the guts of captive and wild giant pandas. There were low proportions of carbohydrate-active enzyme (CAZyme) genes in GPIGC and MAGs compared with several omnivorous and herbivorous mammals. Many members of Clostridium MAGs were significantly enriched in the guts of adult, old and wild giant pandas. The genomes of isolates and MAGs of Clostridiaceae harbored key genes or enzymes in complete pathways for degrading lignocellulose and producing short-chain fatty acids (SCFAs), indicating the potential of these bacteria to utilize the low-nutrient bamboo diet. Overall, our data presented an exhaustive reference gene catalog and MAGs in giant panda gut and provided a comprehensive understanding of the antibiotic resistome and microbial adaptability for a high-lignocellulose diet.

Single-nucleus transcriptome inventory of giant panda reveals cellular basis for fitness optimization under low metabolism.

BACKGROUND: Energy homeostasis is essential for the adaptation of animals to their environment and some wild animals keep low metabolism adaptive to their low-nutrient dietary supply. Giant panda is such a typical low-metabolic mammal exhibiting species specialization of extremely low daily energy expenditure. It has low levels of basal metabolic rate, thyroid hormone, and physical activities, whereas the cellular bases of its low metabolic adaptation remain rarely explored. RESULTS: In this study, we generate a single-nucleus transcriptome atlas of 21 organs/tissues from a female giant panda. We focused on the central metabolic organ (liver) and dissected cellular metabolic status by cross-species comparison. Adaptive expression mode (i.e., AMPK related) was prominently displayed in the hepatocyte of giant panda. In the highest energy-consuming organ, the heart, we found a possibly optimized utilization of fatty acid. Detailed cell subtype annotation of endothelial cells showed the uterine-specific deficiency of blood vascular subclasses, indicating a potential adaptation for a low reproductive energy expenditure. CONCLUSIONS: Our findings shed light on the possible cellular basis and transcriptomic regulatory clues for the low metabolism in giant pandas and helped to understand physiological adaptation response to nutrient stress.

Surface acoustic wave manipulation of bioparticles.

The introduction of surface acoustic waves (SAWs) into lab-on-a-chip microfluidic systems has contributed to the development of a new cutting-edge technology-SAW-based micro/nano manipulation. Recently, the SAW technology has emerged as an important tool for manipulating micro/nano particles/cell populations by virtue of its simplicity, biocompatibility, non-invasiveness, scalability, and versatility. In custom-designed acoustic fields, this technology can be used to manipulate cells, bacteria, exosomes, and even worms precisely, and it has been used in applications such as biomedical and point-of-care diagnostic systems. In this review paper, we start by providing a comprehensive overview of the fundamental working principle and numerical simulation of SAW-based manipulation. Then, we introduce the recent advancements in the manipulation of organisms based on standing and traveling SAWs, including separation, concentration, and transport. At the end of the review, we discuss the current challenges to and future prospects of SAW-based manipulation. The conclusion is that the SAW technology will open up a new frontier in the microfluidics field and contribute significantly to the development of bioengineering research and applications.

Antimicrobial resistance of Escherichia coli, Enterobacter spp., Klebsiella pneumoniae and Enterococcus spp. isolated from the feces of giant panda.

BACKGROUND: Escherichia coli, Enterobacter spp., Klebsiella pneumoniae and Enterococcus spp., common gut bacteria in giant pandas, include opportunistic pathogens. The giant panda is an endangered species, classified as vulnerable by the World Wildlife Foundation. Continuous monitoring for the emergence of antimicrobial resistance (AMR) among bacterial isolates from giant pandas is vital not only for their protection but also for public health. RESULTS: A total of 166 E. coli, 68 Enterobacter spp., 116 K. pneumoniae and 117 Enterococcus spp. isolates were collected from fecal samples of 166 giant pandas. In the antimicrobial susceptibility tests, 144 E. coli isolates, 66 Enterobacter spp. isolates, 110 K. pneumoniae isolates and 43 Enterococcus spp. isolates were resistant to at least one antimicrobial. The resistant isolates carried antimicrobial resistance genes (ARGs), including sul3, blaTEM, blaSHV and tetA. The differences in the prevalence of the bla types implied that the genetic basis for ß-lactam resistance among the E. coli, Enterobacter spp. and K. pneumoniae isolates was different. The strain K. pneumoniae K85 that was resistant to sixteen antimicrobials was selected for whole genome sequencing. The genome contained Col440I, IncFIBK and IncFIIK plasmids and altogether 258 ARGs were predicted in the genome; 179 of the predicted ARGs were efflux pump genes. The genetic environment of the ß-lactamase genes blaCTX-M-3 and blaTEM-1 in the K. pneumoniae K85 genome was relatively similar to those in other sequenced K. pneumoniae genomes. In comparing the giant panda age groups, the differences in the resistance rates among E. coli, K. pneumoniae and Enterobacter spp. isolates suggested that the infections in giant pandas of different age should be treated differently. CONCLUSIONS: Antimicrobial resistance was prevalent in the bacterial isolates from the giant pandas, implying that the gut bacteria may pose serious health risks for captive giant pandas. The resistance genes in the genome of K. pneumoniae K85 were associated with insertion sequences and integron-integrase genes, implying a potential for the further spread of the antimicrobial resistance.

A Review on Coupled Bulk Acoustic Wave MEMS Resonators.

With the introduction of the working principle of coupled resonators, the coupled bulk acoustic wave (BAW) Micro-Electro-Mechanical System (MEMS) resonators have been attracting much attention. In this paper, coupled BAW MEMS resonators are discussed, including the coupling theory, the actuation and sensing theory, the transduction mechanism, and the applications. BAW MEMS resonators normally exhibit two types of vibration modes: lateral (in-plane) modes and flexural (out-of-plane) modes. Compared to flexural modes, lateral modes exhibit a higher stiffness with a higher operating frequency, resulting in a lower internal loss. Also, the lateral mode has a higher Q factor, as the fluid damping imposes less influence on the in-plane motion. The coupled BAW MEMS resonators in these two vibration modes are investigated in this work and their applications for sensing, timing, and frequency reference are also presented.

Photoelectrochemical Nitrate Reduction to Ammonia on Ordered Silicon Nanowire Array Photocathodes.

As a new path to "green" ammonia production, photoelectrochemical nitrate reduction reaction (PEC NO3 RR) is investigated for the first time. An Au-decorated ordered silicon nanowire (O_SiNW) array photocathode demonstrates 95.6 % of Faradaic efficiency (FE) to ammonia at 0.2 VRHE , which represents a more positive potential than the thermodynamic reduction potential of nitrate by utilizing photovoltage. The high FE is possible because both Si and Au surfaces are inactive for competing water reduction to hydrogen. The O_SiNW array structure is favorable to promote the PEC NO3 RR relative to planar Si or randomly-grown Si nanowire, by enabling the uniform distribution of small Au nanoparticles as an electrocatalyst and facilitating the mass transport during the reaction. The results demonstrate the feasibility of PEC nitrate conversion to ammonia and would motivate further studies and developments.

Metagenomic analysis revealed a wide distribution of antibiotic resistance genes and biosynthesis of antibiotics in the gut of giant pandas.

BACKGROUND: The gut microbiome is essential for the host's health and serves as an essential reservoir of antibiotic resistance genes (ARGs). We investigated the effects of different factors, including the dietary shifts and age, on the functional characteristics of the giant panda's gut microbiome (GPs) through shotgun metagenome sequencing. We explored the association between gut bacterial genera and ARGs within the gut based on network analysis. RESULTS: Fecal samples (n=60) from captive juvenile, adult, and geriatric GPs were processed, and variations were identified in the gut microbiome according to different ages, the abundance of novel ARGs and the biosynthesis of antibiotics. Among 667 ARGs identified, nine from the top ten ARGs had a higher abundance in juveniles. For 102 ARGs against bacteria, a co-occurrence pattern revealed a positive association for predominant ARGs with Streptococcus. A comparative KEGG pathways analysis revealed an abundant biosynthesis of antibiotics among three different groups of GPs, where it was more significantly observed in the juvenile group. A co-occurrence pattern further revealed a positive association for the top ten ARGs, biosynthesis of antibiotics, and metabolic pathways. CONCLUSION: Gut of GPs serve as a reservoir for novel ARGs and biosynthesis of antibiotics. Dietary changes and age may influence the gut microbiome's functional characteristics; however, it needs further studies to ascertain the study outcomes.

Gender-specified mediation of depression between sleep quality and short-term memory in older adults: Study in a semi-closed Island of Xiamen, China.

BACKGROUND: Both the quality of sleep and depression impact short-term memory (STM) while they influence each other. However, the underlying mechanisms are not yet clear. Herein, we aimed to explore the mediating effect of depression between sleep quality and STM in older adults and further test the gender differences in this relationship. METHODS: A cluster sampling survey was carried out among 903 residents that were aged 60+ years in a semi-closed island of Xiamen, China, in 2019. The subjects' sleep quality and depression were measured using the Pittsburgh Sleep Quality Index (PSQI) and the 15-item Geriatric Depression Scale (GDS-15), respectively. The three-item recall test was utilized to measure STM function. Mediation analyses were performed using the structural equation model and bias-corrected bootstrap method. Next, the Wald-test was utilized to determine gender differences in the pathway. RESULTS: Overall, 355 men and 508 women, with a mean age of 69.55 and 70.97, respectively, had valid data on the main variables. Depression was found to mediate the effect of sleep quality on STM (a*b = -0.076, p < 0.05). Interestingly, while this indirect effect existed in the female group (af *bf  = -0.126, p < 0.05), it did not in the male group (am *bm  = 0.017, p = 0.677). The Wald-test indicated no gender differences in the pathway from sleep quality to depression (p = 0.303). However, the pathway from depression to STM function was found to be significantly stronger for females than males (p = 0.0198). CONCLUSION: Higher sleep quality was found to be associated with improved STM function. Furthermore, the association was found to be regulate indirectly by lower depressive symptoms for females, but directly for males. Therefore, appropriate psychological interventions may be beneficial to the maintenance of STM for older adults, particularly for women.

The Fecal and Serum Metabolomics of Giant Pandas Based on Untargeted Metabolomics.

Little is comprehensively known or understood about giant panda fecal and serum metabolites, which could serve as important indicators of the physiological metabolism of giant pandas. Therefore, we determined the contents of fecal and serum metabolites of giant pandas based on an untargeted metabolome. Four hundred and 955 metabolites were detected in the feces and serum of giant panda, respectively. Glycerophospholipid and choline metabolism were the main metabolic pathways in feces and serum. A significant correlation between the gut microbiota and fecal metabolites was found (P < 0.01). Fecal metabolites were not greatly affected by the age or gender of giant pandas, but serum metabolites were significantly affected by age and gender. The majority of different metabolites caused by age were higher in serum of younger giant pandas, including fatty acids, lipids, metabolites of bile acids, and intermediate products of vitamin D3. The majority of different metabolites caused by gender included fatty acids, phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylethanolamine (PE). A separate feeding diet should be considered according to different ages and genders of giant panda. Therefore, our results could provide helpful suggestions to further protect captive giant pandas.

Diversity and Composition of Gut Bacterial Community in Giant Panda with Anorexia.

The giant panda (GP) is the most precious animal in China. Gastrointestinal tract disease, especially associated with dysbiosis of gut microbiota, is the leading cause of death in GPs. Here, we performed 16S rRNA high-throughput sequencing to investigate the gut microbiota of GPs having symptoms of anorexia. Results showed that gut microbiota of GP with anorexia had lower richness (Chao1 index) than the healthy GP. However, no significant differences in alpha diversity were observed. There is a significance in the microbial structure between anorexia and healthy GPs. The abundance of phylum Firmicutes (99.23% ± 7.1%), unidentified genus Clostridiales (24.75% ± 2.5%), was significantly higher in the subadult anorexia group (P < 0.01), and that of the unidentified genus Clostridiales (4.53% ± 1.2%) was also significantly higher in the adult anorexia group (P < 0.01). Weissella and Streptococcus were found to be decreased in both anorexia groups. The decreased abundance of Weissella (0.02% ± 0.0%, 0.08% ± 0.0%) and Streptococcus (73.89% ± 4.3%, 91.15% ± 7.6%) and increase in Clostridium may cause symptoms of anorexia in giant pandas. The correlation analysis indicated that there is a symbiotic relationship among Streptococcus, Leuconostoc, Weissella, and Bacillus which are classified as probiotics (r > 0.6, P < 0.05). Importantly, a negative correlation has been found between Streptococcus and unidentified_Clostridium in two groups (r > 0.6, P < 0.05). Our results suggested that Streptococcus might be used as probiotics to control the growth of Clostridium causing the anorexia.

Pharmacokinetics of levofloxacin mesylate in healthy adult giant panda after single-dose administration via different routes.

The pharmacokinetics of levofloxacin mesylate in healthy adult giant panda is unknown. In this study, the pharmacokinetics of levofloxacin after intramuscular administration at a dose of 2 mg/kg and oral administration at a dose of 3 mg/kg in healthy adult giant pandas was determined. Levofloxacin concentrations in plasma were determined using liquid chromatography. In the levofloxacin intramuscular administration group, the absorption and elimination half-lives of the drug were determined to be 0.123 (range: 0.02) hr and 5.402 (range: 0.70) hr, respectively. In the levofloxacin oral administration group, the absorption and elimination half-lives were determined to be 0.325 (range: 0.02) hr and 7.143 (range: 0.63) hr, respectively. Furthermore, the blood-drug concentration of levofloxacin was found to be above 1 µg/ml after 8 hr of intramuscular administration and above 0.5 µg/ml after 12 hr of oral administration. In this study, HPLC conditions and pretreatment methods of plasma samples were optimized and a detection method was established. Our results indicated that in healthy adult giant pandas, levofloxacin was rapidly absorbed and slowly eliminated. This study will therefore provide to be a guide in veterinary research and will be helpful in the rational use of levofloxacin in giant panda.

First Steps toward the Giant Panda Metabolome Database: Untargeted Metabolomics of Feces, Urine, Serum, and Saliva by 1H NMR.

Differences in the concentration of metabolites in the biofluids of animals closely reflect their physiological diversities. In order to set the basis for a metabolomic atlas for giant panda (Ailuropoda melanoleuca), we characterized the metabolome of healthy giant panda feces (23), urine (16), serum (6), and saliva (4) samples by means of 1H NMR. A total of 107 metabolites and a core metabolome of 12 metabolites was quantified across the four biological matrices. Through univariate analysis followed by robust principal component analysis, we were able to describe how the molecular profile observed in giant panda urine and feces was affected by gender and age. Among the molecules modified by age in feces, fucose plays a peculiar role because it is related to the digestion of bamboo's hemicellulose, which is considered as the main source of energy for giant panda. A metagenomic investigation directed toward this molecule showed that its concentration was indeed positively related to the two-component system pathway and negatively related to the amino sugar and nucleotide sugar metabolism pathway. Such work is meant to provide a robust framework for further -omics research studies on giant panda to accelerate our understanding of the interaction of giant panda with its natural environment.

Hybrid Microwave Annealing Synthesizes Highly Crystalline Nanostructures for (Photo)electrocatalytic Water Splitting.

Hydrogen is regarded as an ideal energy carrier for the hydrogen economy that could replace the current hydrocarbon economy in order to achieve global energy security and mitigate climate change. For this purpose, H2 has to be produced from renewable sources (e.g., solar and wind) without producing global-warming CO2. (Photo)electrolysis of water into H2 and O2 is one of the most promising technologies for the production of renewable H2, which requires (photo)electrocatalysts of high efficiency, chemical robustness, and scalability. An essential attribute required for high-efficiency (photo)electrodes is high crystallinity with few defects to facilitate charge transfer without recombination. To this end, fabrication of photoelectrodes is usually completed with high temperature thermal annealing in a furnace. However, conventional thermal annealing (CTA) always results in undesirable crystal sintering, which reduces the surface area, and damage to the transparent conducting oxide (TCO) substrate. An emerging alternative method, hybrid microwave annealing (HMA), offers the beneficial effect of the high-temperature annealing (crystallinity) while minimizing its negative effects of sintering and TCO damage, enabling the fabrication of efficient (photo)electrodes for water splitting. HMA combines direct microwave heating with additional heating from an effective microwave absorber (called a susceptor), thereby avoiding a nonuniform temperature distribution between the interior and exterior of the synthesized material. More importantly, an extremely high temperature of the entire sample can be reached in only a few minutes. Compared with CTA, HMA has several advantages in the preparation of (photo)electrodes: (i) formation of a high-purity phase; (ii) high crystallinity with fewer defects; (iii) preservation of the original nanostructure; (iv) less damage to the TCO substrate for photoelectrodes; (v) smaller nanocrystals and uniform dispersion of catalyst particles. Overall, HMA is a convenient, ultrafast, and energy-economical technology for the synthesis of efficient (photo)electrodes. In this Account, we discuss recent progress made in our laboratory on HMA for preparing photoanodes (Fe2O3, BiVO4, ZnFe2O4, and Fe2TiO5), photocathodes (Cu2O and CuFeO2), and a graphene-based electrocatalyst (MoS2/graphene composite), which exhibit distinctive behavior and efficient performance in (photo)electrocatalytic water splitting. In particular, we have advanced the HMA technique further to synthesize hematite-based photoanodes with core-shell heterojunction nanorods (Nb,Sn:Fe2O3@FeNbO4 and Ta,Sn:Fe2O3@FeTaO4) by solid-solid interface reaction, which simultaneously achieves multiple doping effects (Nb or Ta, Sn) to improve the photoelectrocatalysis of water splitting. Thus, this Account focuses on the synthetic aspects of HMA, which may offer new research opportunities for the synthesis of other metal oxide (photo)electrode materials and hybrid electrocatalysts in the fields of solar energy conversion and storage, secondary batteries, and H2 fuel production.

Label-free characterization of different kinds of cells using optoelectrokinetic-based microfluidics.

We report a novel, to the best of our knowledge, method to rapidly characterize different kinds of cells and drug-treated cancer cells using a label-free biomarker of self-rotation in an optoelectrokinetics (OEK)-based microfluidic platform. OEK incorporates optics and electrokinetics into microfluidics, thereby offering a contact-free, label-free, and rapid approach to the cellular manipulation community. Self-rotational behaviors of four different kinds of cells were experimentally investigated by the frequency-sweeping of an AC bias potential in an optically induced nonuniform and irrotational electric field. The results revealed that these kinds of cells displayed a Gaussian distribution versus the AC frequency as well as different self-rotational speeds under the same conditions. Furthermore, the peak self-rotational speed varied from one kind of cell to another, with that of cancer cells higher than that of normal cells. In addition, MCF-7 cells treated by various concentrations of drug showed remarkably different self-rotational speeds. This finding suggests a high potential of developing a new label-free biomarker to rapidly distinguish different kinds of cancer cells and quantitatively monitor the response of cancer patients to various treatments.

Recent advances in AFM-based biological characterization and applications at multiple levels.

Atomic force microscopy (AFM) has found a wide range of bio-applications in the past few decades due to its ability to measure biological samples in natural environments at a high spatial resolution. AFM has become a key platform in biomedical, bioengineering and drug research fields, enabling mechanical and morphological characterization of live biological systems. Hence, we provide a comprehensive review on recent advances in the use of AFM for characterizing the biomechanical properties of multi-scale biological samples, ranging from molecule, cell to tissue levels. First, we present the fundamental principles of AFM and two AFM-based models for the characterization of biomechanical properties of biological samples, covering key AFM devices and AFM bioimaging as well as theoretical models for characterizing the elasticity and viscosity of biomaterials. Then, we elaborate on a series of new experimental findings through analysis of biomechanics. Finally, we discuss the future directions and challenges. It is envisioned that the AFM technique will enable many remarkable discoveries, and will have far-reaching impacts on bio-related studies and applications in the future.

Intravenous sodium valproate for acute migraine in the emergency department: A meta-analysis.

The role of intravenous sodium valproate (iVPA) in acute migraine attack has not been completely established. The aim of this updated review was to evaluate the efficacy and safety of iVPA in patients with acute migraine in the emergency department. We searched the PubMed, Web of Science, and Cochrane Library databases for relevant randomized controlled trials (RCTs). The primary outcome was improvement of headache intensity and headache relief. The need for rescue therapy, recurrence of headache, and number of adverse events was also assessed. Seven double-blinded RCTs involving 682 patients were analyzed. Overall, patients receiving iVPA had less improvement of headache intensity (SMD: -0.39, 95% CI: -0.73 to -0.06, P = .02) and lower rate of headache relief (OR: 0.51, 95% CI: 0.33 to 0.77, P = .002) than those receiving other active comparators. In addition, iVPA increased the odds of rescue therapy compared with other active drugs (OR: 3.76; 95% CI: 1.96 to 7.20, P < .0001). Subgroup analysis showed that iVPA was comparable to dexamethasone, with similar improvement of headache intensity, and recurrence of headache. For migraine without aura, we found no significant difference in headache intensity improvement when iVPA was compared with active comparators (SMD: -0.00, 95% CI: -0.54 to 0.54, P = 1.00). iVPA was inferior to the studied comparators and was comparable to dexamethasone for aborting migraine attack. Based on the available evidence, iVPA may be a reasonable alternative or salvage therapy. In particular, iVPA might be a promising agent for migraine with aura and migraine status.

Accelerating Crystallization of Open Organic Materials by Poly(ionic liquid)s.

The capability to significantly shorten the synthetic period of a broad spectrum of open organic materials presents an enticing prospect for materials processing and applications. Herein we discovered 1,2,4-triazolium poly(ionic liquid)s (PILs) could serve as a universal additive to accelerate by at least one order of magnitude the growth rate of representative imine-linked crystalline open organics, including organic cages, covalent organic frameworks (COFs), and macrocycles. This phenomenon results from the active C5-protons in poly(1,2,4-triazolium)s that catalyze the formation of imine bonds, and the simultaneous salting-out effect (induced precipitation by decreasing solubility) that PILs exert on these crystallizing species.

A case of giant panda ovarian cancer diagnosis and histopathology.

BACKGROUND: Ovarian cancer is diagnosed clinically by detecting ovarian cancer-related factors and markers. Here, we report a case of giant panda ovarian tumor metastasis with a combination of clinical and histopathological diagnosis. CASE PRESENTATION: Histopathological studies revealed severe lesions and tumor cells in the ovaries, lungs, spleen, kidneys and perianal tissue. Immunohistochemistry staining showed that the ovarian cancer markers B7-H4, CA125, and HE4 were highly expressed in the lungs, kidneys, spleen, ovaries and perianal tissue. Tumor marker tests detected significantly high levels of AFP in serum. CONCLUSION: Clinical biomarkers combined with histopathology can provide a more accurate diagnosis of ovarian cancer metastasis and identification of ovarian cancer types than either method alone. The giant panda's death may be due to granulosa cell tumor and theca cell tumor metastasis causing multiple organ dysfunction or even failure.

Diagnosing Zygosity in Giant Panda Twins Using Short Tandem Repeats.

The giant panda, native to mountains of south-west China, is one of the world's rarest bear species and is subject to considerable conservation effort. In captivity, the proportion of twins accounts for 54% of the total number of births. To date, little is known about zygosity in panda populations - specifically, the proportion of monozygotic and dizygotic twins. In this study, we used 10 microsatellite markers for reliable zygosity testing, and the probability of monozygotic twins was 99.963% when all 10 markers were concordant. Out of 43 studied twin pairs, no MZ twins were found, indicating that there may be no identical panda twins (or the incidence is very low). We speculate that the fertilized eggs of giant pandas do not have the capability to split into two identical embryos, or that this ability is very poor, which is likely due to delayed implantation that is common in bear species. The results of this study deepen our understanding of giant panda breeding, yield insight into panda twins' likely mechanism of formation, and reduce the uncertainty of individual identity in wild population surveys.