Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Alfalfa adapts to soil nutrient surplus and deficiency by adjusting the stoichiometric characteristics of main organs and nutrient reabsorption(BioMed Central Ltd, 2025-12-01) Sun Y; Hui J; Yang K; Wei K; Wang X; Cartmill AD; López IF; Qi Y; Ma C; Zhang QAccurate nutrient diagnosis is essential for simulating alfalfa (Medicago sativa L.) yield and optimizing resource-use efficiency under diverse soil nutrient conditions. However, limited knowledge exists about how fertilization impacts soil–plant nutrient stoichiometric constraints, especially in nutrient-deficient gray desert soils. This study conducted a field experiment with four nitrogen (N) application rates: 0, 60, 120, and 180 kg N∙ha−1 and four phosphorus (P) application rates: 0, 50, 100, and 150 kg P2O5∙ha−1. We assessed changes in the nutrient limitation characteristics of alfalfa and identified its primary driving factors, focusing on soil nutrient perspectives, nutrient distribution in main organs (leaves, shoots, and roots) and nutrient resorption. The results demonstrated that fertilization increased N and P concentrations in various alfalfa organs while reducing carbon (C) content. A strong synergy was observed in nutrient concentrations across the different alfalfa organs. With increasing application of single-nutrient fertilizers, the C:N and C:P ratios in alfalfa organs decreased, while the N:P ratio stabilized under conditions of sufficient or co-limiting soil N and P. Alfalfa N:P ratios under different fertilization treatments were 4.89–5.46 in roots, 6.19–8.45 in stems, and 9.10–15.16 in leaves. The C:N and C:P ratios were significantly negatively correlated with alfalfa yield, but the relationship between the N:P ratio and yield was not statistically significant. Soil nutrient status positively influenced N and P concentrations in leaves, stems, and roots, however, their effect on stoichiometric ratios was primarily mediated through indirect effects on corresponding organ-level nutrients. Moreover, soil nutrients directly or indirectly explained 98% of the variation in nutrient resorption in leaves. In conclusion, fertilization indirectly affects the stoichiometric characteristics of alfalfa organs via soil nutrients. Adjusting fertilizer nutrient ratios can mitigate nutrient limitations in both soil and alfalfa, providing valuable insights for fertilizer formulation, timing of fertilizer application, and fertilization application strategies. Highlights 1.Fertilization alters the C-N-P stoichiometry of the soil–plant system. 2.The stoichiometric characteristics and ratios of different organs exhibit a certain degree of synergy. 3.Stoichiometric ratios can represent nutrient limitation to a certain extent. 4.Soil nutrient changes affect the stoichiometric characteristics and ratios of alfalfa.Item The spatial effect of airport proximity on house prices: a quantile regression analysis for the New Zealand market(Taylor and Francis Group, 2025-08-19) Squires G; Ngo T; McCord MJ; Lo D; Wang XThis study contributes to understanding the link between the housing market and airport location proximity, whilst examining the entirety of the house price distribution. The research investigates this association across four key urban areas within New Zealand proximal to an international airport–Auckland, Wellington, Christchurch, and Queenstown. Applying hedonic and quantile regression, the analysis reveals that proximity to airports on house prices has a heterogeneous pricing effect. Results show that distance comprises a positive pricing effect within Auckland and Christchurch, whereas in Wellington and Queenstown the pricing effect is negative. The quantile regression findings further revealed differences between lower and higher priced properties value, given distance and proximity to airports within each city region. The Christchurch region reveals contrasting findings, showing there to be a higher positive pricing effect for higher-priced housing, which gradually decreases when moving down the quantiles. It is argued that this higher positive pricing for higher priced properties is due to particularities in the housing market close to Christchurch Airport.Item Impact of cell wall polysaccharide modifications on the performance of Pichia pastoris: novel mutants with enhanced fitness and functionality for bioproduction applications.(BioMed Central Ltd, 2024-02-17) Cheng B; Yu K; Weng X; Liu Z; Huang X; Jiang Y; Zhang S; Wu S; Wang X; Hu XBACKGROUND: Pichia pastoris is a widely utilized host for heterologous protein expression and biotransformation. Despite the numerous strategies developed to optimize the chassis host GS115, the potential impact of changes in cell wall polysaccharides on the fitness and performance of P. pastoris remains largely unexplored. This study aims to investigate how alterations in cell wall polysaccharides affect the fitness and function of P. pastoris, contributing to a better understanding of its overall capabilities. RESULTS: Two novel mutants of GS115 chassis, H001 and H002, were established by inactivating the PAS_chr1-3_0225 and PAS_chr1-3_0661 genes involved in β-glucan biosynthesis. In comparison to GS115, both modified hosts exhibited a looser cell surface and larger cell size, accompanied by faster growth rates and higher carbon-to-biomass conversion ratios. When utilizing glucose, glycerol, and methanol as exclusive carbon sources, the carbon-to-biomass conversion rates of H001 surpassed GS115 by 10.00%, 9.23%, and 33.33%, respectively. Similarly, H002 exhibited even higher increases of 32.50%, 12.31%, and 53.33% in carbon-to-biomass conversion compared to GS115 under the same carbon sources. Both chassis displayed elevated expression levels of green fluorescent protein (GFP) and human epidermal growth factor (hegf). Compared to GS115/pGAPZ A-gfp, H002/pGAPZ A-gfp showed a 57.64% higher GFP expression, while H002/pPICZα A-hegf produced 66.76% more hegf. Additionally, both mutant hosts exhibited enhanced biosynthesis efficiencies of S-adenosyl-L-methionine and ergothioneine. H001/pGAPZ A-sam2 synthesized 21.28% more SAM at 1.14 g/L compared to GS115/pGAPZ A-sam2, and H001/pGAPZ A-egt1E obtained 45.41% more ERG at 75.85 mg/L. The improved performance of H001 and H002 was likely attributed to increased supplies of NADPH and ATP. Specifically, H001 and H002 exhibited 5.00-fold and 1.55-fold higher ATP levels under glycerol, and 6.64- and 1.47-times higher ATP levels under methanol, respectively, compared to GS115. Comparative lipidomic analysis also indicated that the mutations generated richer unsaturated lipids on cell wall, leading to resilience to oxidative damage. CONCLUSIONS: Two novel P. pastoris chassis hosts with impaired β-1,3-D-glucan biosynthesis were developed, showcasing enhanced performances in terms of growth rate, protein expression, and catalytic capabilities. These hosts exhibit the potential to serve as attractive alternatives to P. pastoris GS115 for various bioproduction applications.Item Nitrogen and phosphorus fertilizer use efficiency improves alfalfa (Medicago sativa L.) production and performance in alkaline desert soil.(Frontiers Media S.A., 2025-02-18) Sun Y; Sun J; Wang X; Cartmill AD; López IF; Ma C; Zhang Q; Srivastava AKThe deficiency of nitrogen and phosphorus is a primary constraint on the normal growth of alfalfa (Medicago Sativa L.) in the alkaline desert soils of northern Xinjiang. Optimizing the combination of nitrogen and phosphorus fertilizers can maximally significantly enhance farmers' economic returns while concurrently mitigate soil environmental pollution. For this purpose, a field experiment based on a randomized complete block design was conducted over two consecutive years (2019 and 2020) in Shihezi, Xinjiang province, China. The WL366HQ variety of alfalfa was evaluated with four levels each of urea and monoammonium phosphate. The effects of fertilizer treatments were assessed on alfalfa yield, growth traits, nutritional quality, fertilizer use efficiency, and economic benefit. Application of nitrogen (N), phosphorus (P), and their interaction significantly (P< 0.05) affected cumulative alfalfa dry matter (DM) yield. In general, compared to no-fertilization treatment, the application of N and P fertilizers resulted in increased plant height, stem thickness, crude protein, and ether extract of alfalfa, while neutral detergent fiber (NDF) and acid detergent fiber (ADF) exhibited a decreasing trend. Additionally, while N and P fertilizer application reduced corresponding fertilizer use efficiency, it increased non-corresponding fertilizer use efficiency. During the two-year experimental period, the treatment involving the application of urea at 286.3 kg·ha-1 combined with monoammonium phosphate at 192 kg·ha-1 achieved the highest evaluation scores for production performance, fertilizer use efficiency, and total net profit, resulting in a net profit increase of 44.18% compared to the no-fertilizer treatment. These findings lay the groundwork for nuanced fertilization strategies in future alfalfa cultivation.Item Interfacial composition of coenzyme Q10 emulsions impacts coagulation of fortified milk during gastric digestion(Elsevier Ltd, 2025-02-01) Wang X; Zhu P; Ye A; Singh H; Acevedo-Fani AThis study aimed to investigate the gastric digestion behaviour of heat-treated enriched milk containing Coenzyme Q10-loaded emulsions with different interfacial compositions. Four enriched milk types were compared: pasteurized with a Tween 80 stabilised emulsion (PAST-TW80), or with a sodium caseinate-stabilised emulsion (PAST-NaCN), and UHT with a TW80-stabilised emulsion (UHT-TW80), or PAST with a NaCN-stabilised emulsion (UHT-NaCN); all loaded with Coenzyme Q10. An in vitro dynamic gastric digestion model (Human Gastric Simulator) was utilized and the kinetics of milk coagulation and emptying of protein, lipid and Coenzyme Q10 were monitored. Adding NaCN-stabilised emulsion to heated milk led to a largely fragmented curd with signs of extensive droplets coalescence, disintegrating rapidly and accelerating protein and lipid release. Heated milk with TW80-stabilised emulsion produced a compact and closely integrated curd with limited coalescence, slowing nutrient emptying. UHT milk showed more curd fragmentation than PAST milk, regardless of emulsion type. The release profiles of Coenzyme Q10 were similar between UHT-TW80 and PAST-TW80 or between PAST-NaCN and UHT-NaCN, indicating the emulsion's interfacial composition as a key factor in controlling lipophilic bioactive release from the food matrix, regardless of heat treatment. These findings demonstrate that the emulsion's interfacial composition (NaCN vs TW80) and the heat treatment (PAST vs UHT) can be combined as a strategy to modulate milk coagulation kinetics and the rate of nutrient delivery to the small intestinal stage. This study provides insights into the development of functional milk products fortified with lipophilic bioactive compounds, as well as strategies for optimizing the controlled release of these compounds upon consumption.Item An in-depth survey on Deep Learning-based Motor Imagery Electroencephalogram (EEG) classification(Elsevier BV, Netherlands, 2024-01) Wang X; Liesaputra V; Liu Z; Wang Y; Huang ZElectroencephalogram (EEG)-based Brain–Computer Interfaces (BCIs) build a communication path between human brain and external devices. Among EEG-based BCI paradigms, the most commonly used one is motor imagery (MI). As a hot research topic, MI EEG-based BCI has largely contributed to medical fields and smart home industry. However, because of the low signal-to-noise ratio (SNR) and the non-stationary characteristic of EEG data, it is difficult to correctly classify different types of MI-EEG signals. Recently, the advances in Deep Learning (DL) significantly facilitate the development of MI EEG-based BCIs. In this paper, we provide a systematic survey of DL-based MI-EEG classification methods. Specifically, we first comprehensively discuss several important aspects of DL-based MI-EEG classification, covering input formulations, network architectures, public datasets, etc. Then, we summarize problems in model performance comparison and give guidelines to future studies for fair performance comparison. Next, we fairly evaluate the representative DL-based models using source code released by the authors and meticulously analyse the evaluation results. By performing ablation study on the network architecture, we found that (1) effective feature fusion is indispensable for multi-stream CNN-based models. (2) LSTM should be combined with spatial feature extraction techniques to obtain good classification performance. (3) the use of dropout contributes little to improving the model performance, and that (4) adding fully connected layers to the models significantly increases their parameters but it might not improve their performance. Finally, we raise several open issues in MI-EEG classification and provide possible future research directions.Item Immobilization of Horseradish Peroxidase and Myoglobin Using Sodium Alginate for Treating Organic Pollutants(MDPI (Basel, Switzerland), 2024-03-15) Wang X; Ghanizadeh H; Khan S; Wu X; Li H; Sadiq S; Liu J; Liu H; Yue Q; Hung Y-TRemoving organic pollutants from wastewater is crucial to prevent environmental contamination and protect human health. Immobilized enzymes are increasingly being explored for wastewater treatment due to their specific catalytic activities, reusability, and stability under various environmental conditions. Peroxidases, such as horseradish peroxidase (HRP) and myoglobin (Mb), are promising candidates for immobilized enzymes utilized in wastewater treatment due to their ability to facilitate the oxidation process of a wide range of organic molecules. However, the properties of the carrier and support materials greatly influence the stability and activity of immobilized HRP and Mb. In this research, we developed immobilized HRP and Mb using support material composed of sodium alginate and CaCl2 as carriers and glutaraldehyde as a crosslinking agent. Following this, the efficacy of immobilized HRP and Mb in removing aniline, phenol, and p-nitrophenol was assessed. Both immobilized enzymes removed all three organic pollutants from an aqueous solution, but Mb was more effective than HRP. After being immobilized, both enzymes became more resilient to changes in temperature and pH. Both immobilized enzymes retained their ability to eliminate organic pollutants through eight treatment cycles. Our study uncovered novel immobilized enzyme microspheres and demonstrated their successful application in wastewater treatment, paving the way for future research.Item Investigation of the gastric digestion behavior of commercial infant formulae using an in vitro dynamic infant digestion model.(Frontiers Media S.A., 2024-12-05) Descallar FB; Roy D; Wang X; Zhu P; Ye A; Liang Y; Pundir S; Singh H; Acevedo-Fani A; Lambers TThe gastric digestion behavior of different commercial Stage 1 infant formulae (for 0-6 months) with different formulation backgrounds was investigated using an in vitro dynamic infant human gastric simulator (iHGS). The microstructural arrangements of the protein and lipid, colloidal stability and protein hydrolysis during digestion were elucidated. During gastric digestion, casein-dominant formulations showed a higher extent of aggregation due to their high proportion of casein micelles that underwent coagulation upon acidification and via the action of pepsin. The extensive protein coagulation/curd formation in casein-dominant infant formulae slowed the rate of protein hydrolysis and resulted in the retention of caseins in the iHGS for longer times. Confocal micrographs showed that oil droplets were entrapped in the curd particles of casein-dominant infant formulae, which consequently slowed the gastric emptying of lipids. Conversely, whey-dominant formulations showed a lower degree of protein aggregation that resulted in faster protein hydrolysis and rapid protein and lipid emptying from the iHGS. It was also revealed that whey-dominant infant formulae in the presence of biopolymers increased the viscosity of gastric chyme and induced the flocculation of oil droplets. This altered the rate of protein hydrolysis and emptying of lipids. Correlation analyses depicted the overall kinetics of gastric emptying of macronutrients during digestion and comprised two stages: (i) driven by the continuous stomach emptying and (ii) influenced by aggregation and coalescence indices. The present study highlights the similarities and differences in the digestion behaviors of commercial infant formulae based on important ingredients such as types of proteins and biopolymers, regardless of the formulation or processing histories.Item Unveiling the Effects of Phosphorus on the Mineral Nutrient Content and Quality of Alfalfa (Medicago sativa L.) in Acidic Soils(MDPI (Basel, Switzerland), 2024-10-02) Li Z; Hao Y; Wang X; He J; Zhao X; Chen J; Gu X; Zhang M; Yang F; Dong R; Yang JAlfalfa (Medicago sativa L.) grown in acidic soils is often affected by phosphorus (P) deficiency, which results in reduced mineral nutrient content and forage quality. In this context, the effects of phosphorus (P) fertiliser remain unclear. In this study, we analysed the effects of P application on mineral nutrient content and forage quality in aluminium (Al)-sensitive (Longzhong) and Al-tolerant (Trifecta) alfalfa cultivars cultivated in two acidic soil environments. Mineral nutrient content and quality were affected by genotype, soil type, and P treatment concentration (p < 0.001). In limestone soil, for Longzhong and Trifecta, the optimal potassium (K), calcium (Ca), and magnesium (Mg) contents as well as crude protein content (CP) and ether extract (EE) values were observed at 20 mg P kg−1, that of the P content was observed at 40 mg P kg−1, and the minimum neutral detergent fibre (NDF) acid detergent lignin (ADL) values were observed at 40 mg P kg−1. In yellow soil, the maximum K, Ca, Mg, and P contents in Longzhong and Trifecta were observed at 40 mg P kg−1, whereas the maximum CP, EE, and ADL values were observed at 20 mg P kg−1. Our study provides an empirically based framework for optimising alfalfa fertilisation programmes in acidic soils.Item Large-scale synthesis of N-doped carbon capsules supporting atomically dispersed iron for efficient oxygen reduction reaction electrocatalysis(Elsevier B.V. on behalf of Nankai University, 2022-05-17) Yang H; Liu Y; Liu X; Wang X; Tian H; Waterhouse GIN; Kruger PE; Telfer SG; Ma SThe large-scale synthesis of platinum-free electrocatalysts for the oxygen reduction reaction (ORR) remains a grand challenge. We report the large-scale production of stable and active ORR electrocatalysts based on iron, an earth-abundant element. A core–shell zeolitic imidazolate framework–tannic acid coordination polymer composite (ZIF-8@K-TA) was utilized as the catalyst precursor, which was transformed into iron atoms dispersed in hollow porous nitrogen-doped carbon capsules (H-Fe-Nx-C) through ion exchange and pyrolysis. H-Fe-Nx-C features site-isolated single-atom iron centers coordinated to nitrogen in graphitic layers, high levels of nitrogen doping, and high permeability to incoming gases. Benefiting from these characteristics, H-Fe-Nx-C demonstrated efficient electrocatalytic activity (E1/2 = 0.92 V, vs. RHE) and stability towards the ORR in both alkaline and acidic media. In ORR performance, it surpassed the majority of recently reported Fe-N-C catalysts and the standard Pt/C catalyst. In addition, H-Fe-Nx-C showed outstanding tolerance to methanol.