High throughput exploration of the oxidation landscape in high entropy alloys.

High entropy alloys (HEAs) have gained interest for structural applications in extreme environments. With a potentially vast chemical and phase space, there are significant opportunities to discover superior performing alloys. Crucial for most high-temperature applications is understanding and mitigating the oxidation behavior of these chemically complex alloys. Most experimental and computational HEA studies have focused on a limited set of compositions and only a fraction of these compositions have been characterized for oxidation. We present a high-throughput framework that utilizes density-functional theory (DFT) in concert with a combined machine-learning model and grand-canonical linear programming for assessing phase stability, phase-fraction, chemical activity and high-temperature survivability of arbitrary HEAs. This framework considers temperature dependent contributions to the Gibbs energy of the competing phases arising from short-range order and vibrational entropy. We demonstrate the effectiveness of the framework by assessing the thermodynamic stability, oxidation behavior, chemical activity, and phase decomposition of body-centered cubic Mo-W-Ta-Ti-Zr refractory HEAs. A total of 51 compositions were analyzed and ranked in order of their survivability based on the Pareto-front analysis. Oxidation was performed at 1373 K on four samples in air showing the difference in oxidation behavior determined experimentally through scale thickness and their mass changes. The insights on oxidation behavior presented in this work will enable the fast assessment of technologically useful HEAs needed for future structural application in extreme conditions.

[Follow up analysis of 6 patients with severe trimethyltin chloride poisoning for 4 years].

Objective: Objective to investigate the health changes of patients with severe trimethyltin chloride (TMT) poisoning in four years. Methods: Six patients with severe TMT poisoning treated in the First Affiliated Hospital of Gannan Medical College in August 2016 were numbered 1, 2, 3, 4, 5 and 6 respectively. The patients were followed up 0.5, 2 and 4 years after poisoning and compared and analyzed. The follow-up contents include: symptom degree, score of simple mental intelligence examination scale (MMSE) and modified Rankin Scale (MRS) , cranial magnetic resonance imaging (MRI) , EEG, etc. Results: The symptoms of dizziness, headache, chest tightness, palpitation, nausea and vomiting decreased gradually in 6 patients. The symptoms of speech disorder and memory decline in No.1, 2 and 3 patients gradually increased, and the scores of MMSE and Mrs gradually decreased; Patients No.4, 5 and 6 had improved speech disorder, but their memory decreased, MMSE and Mrs scores were still flat, and mild cognitive impairment. The brain atrophy of No.1, 2 and 3 patients was aggravated, which showed obvious atrophy of hippocampus, temporal lobe, insular lobe and cerebellum and enlargement of ventricle; There was no significant change in brain atrophy in No.4, 5 and 6 patients. Conclusion: The neurotoxic symptoms in the later stage of severe TMT poisoning are still serious, and the neurotoxic time is long.

[Two cases of hypoxic encephalopathy caused by simple asphyxial gas poisoning].

This article analyzes the clinical manifestations and magnetic resonance imaging (MRI) data of 2 patients with hypoxic encephalopathy after simple asphyxia gas poisoning. Both patients were in a moderate coma after being poisoned, and the arterial blood lactic acid level and carbon dioxide partial pressure were higher than the normal range within 1 week after poisoning. Two patients were cured and discharged after being treated with oxygen therapy and glucocorticoids. The prognosis was good.

[Clinical analysis of sequelae of acute trimethyltin oxide poisoning].

Objective: Clinical analysis of sequelae of 16 patients with trimethyltin chloride (TMT) poisoning after 2 years. Methods: Sixteen patients with TMT poisoning from a waste recycling company in Ganzhou City in August 2016 were enrolled. They were investigated by questionnaires and assessed by various scales after two years. 6 cases of severe poisoning were examined by head MRI. The scale includes Hamilton Anxiety Scale (HAMA) , Depression Scale (HAMD) , Simple Mental State Examination Scale (MMSE) , Activity of Daily Living (ADL) , International Cooperative Ataxia Rating Scale (ICARS) . Results: 16 cases of TMT poisoning still have headache, dizziness and other symptoms. Instability of walking in 4 patients with severe poisoning, and the brain MRI manifestations included obvious atrophy of temporal lobe, hippocampus, insula lobe, cerebellum and ventricle enlargement. Two patients were rated as severe mixed anxiety and depression, one as moderate mixed anxiety and depression, and one as mild anxiety. 3 cases were diagnosed as dementia and 1 case as mild cognitive impairment. Two cases were totally dependent on living ability. ICARS scores were 66 points and 63 points respectively. Two cases were mildly dependent on living ability. ICARS scores were 28 points and 6 points respectively. There were 2 cases of mild mixed anxiety and depression in mild and moderate poisoning patients, and 1 case of mild cognitive impairment in each patient. They could live independently. ICARS scores were 0. Conclusion: After 2 years of TMT poisoning, some patients still have general clinical symptoms such as dizziness, headache and so on. There are also mental and intellectual symptoms such as anxiety, depression and cognitive impairment. Some of patients with severe poisoning presented with dementia and cerebellar ataxia, and even lost independent living ability.

Knockdown of HJURP inhibits non-small cell lung cancer cell proliferation, migration, and invasion by repressing Wnt/ß-catenin signaling.

OBJECTIVE: Holliday junction-recognizing protein (HJURP) was found to be upregulated in several tumors, including non-small cell lung cancer (NSCLC), and the effect of HJURP on NSCLC remains unknown. The objective of the present study was to explore the clinical significance of HJURP and its function in regulating the progression of NSCLC. PATIENTS AND METHODS: Reverse Transcriptions-Polymerase Chain Reaction (RT-PC) and Western blot were performed to detect the expression levels of HJURP in NSCLC tissues and cell lines. The association of HJURP expression level with various important clinicopathological parameters was evaluated. Then, the effects of HJURP expression on tumor cell behavior in vitro were analyzed by the Cell Counting Kit-8 (CCK-8), EdU assays, colony formation, flow cytometry, and transwell assays. The protein levels of related proteins of the Wnt/ß-catenin pathway were determined using the Western blot assay. RESULTS: Our study showed that HJURP was significantly upregulated in both NSCLC tissues and cell lines. The higher expression of HJURP was associated with advanced TNM stage, distant metastasis, and poor prognosis. Our data from in vitro assays confirmed that the knockdown of HJURP suppressed NSCLC cells proliferation, migration, invasion, epithelial-mesenchymal transition (EMT) progress, and induced cells apoptosis. Notably, through Western blot analysis, we found that HJURP suppression remarkably decreased ß-catenin, cyclin D1 and c-myc expression level in NSCLC cell lines. CONCLUSIONS: Our findings provide clues regarding the role of HJURP as a tumor promoter in NSCLC via the activation of the Wnt/ß-catenin pathway, indicating HJURP may be a promising therapeutic target for NSCLC.

[Analysis on efficacy and safety of total neoadjuvant therapy in patients with locally advanced rectal cancer with high risk factors].

Objective: To evaluate the safety and preliminary efficacy of total neoadjuvant therapy (TNT) in patients with locally advanced rectal cancer (LARC) with high risk factors. Methods: Data of 101 patients who were diagnosed with stage II-III rectal cancer with high risk factors and received TNT between March 2015 and January 2018 at West China Hospital of Sichuan University were analyzed retrospectively. Inclusion criteria: (1) patients were diagnosed with stage II-III rectal cancer by high-resolution MRI combined with CT and endorectal ultrasound; (2) at least one high risk factor: cT4a, cT4b, cN2, EMVI+, CRM+ and lateral lymph node+; (3) distance from tumor to anal verge was within 15 cm; (4) Eastern Collaborative Oncology Group (ECOG) performance status score was 0-1; bone marrow function, liver function and kidney function were suitable for chemoradiotherapy; (5) patients were treated with TNT strategy; (6) the follow-up data and postoperative pathological data were complete. Patients with previous rectal cancer surgery (except prophylactic colostomy), pelvic radiotherapy, and systemic chemotherapy, those with distant metastases, those without neoadjuvant radiotherapy, those receiving less than 4 cycles of neoadjuvant chemotherapy were excluded. The regimen of TNT: 3 cycles of induction CAPOX (oxaliplatin plus capecitabine) were followed by pelvic radiotherapy and concurrent CAPOX, then 3 cycles of consolidation CAPOX were delivered after radiotherapy. Total mesorectal resection (TME) or watch-and-wait strategy was selected according to the therapeutic effect and patients' wishes. Short-term efficacy, including tumor regression grade (TRG), pathological complete response (pCR), clinical complete response (cCR), postoperative complications within 30 days of surgery, and adverse events (AE) to radiotherapy and chemotherapy (measured using CTCAE 4.0) was analyzed. Results: The 101 patients included 68 males (67.3%) and 33 females (32.7%) with a median age of 54 years. The proportion of patients with cT4a, cT4b, cN2 and enlarged lateral lymph node was 13.9%, 29.7%, 56.4% and 43.6%, respectively. The mean cycle of neoadjuvant chemotherapy was 6.0±1.3. Seventy-five patients (74.3%) received at least 6 cycles of neoadjuvant chemotherapy and 100 (99.0%) completed radiotherapy. The mean cycle of induction and consolidation chemotherapy was 2.0±0.9 and 2.8±1.0 respectively. Most common grade 3 AE was leucopenia (n=13, 12.9%) and thrombocytopenia (n=7, 6.9%). Grade 3 diarrhea and radiation dermatitis were observed in 5 cases (5.0%) respectively. Grade 3 anemia and rectal pain were observed in 4 cases (4.0%) respectively. And rectal mucositis was observed in 2 cases (2.0%). Most of the AE was observed during concurrent chemoradiotherapy. No grade 4 or higher AE was observed. After TNT, 32 patients (31.7%) achieved pCR or cCR, and 62 patients (60.4%) achieved partial response (PR). Only 2 patients (2.0%) developed distant metastasis after chemoradiotherapy, while the other patients did not show disease progression. Seven patients (6.9%) with cCR refused surgery and selected watch-and-wait, while 7 patients without cCR still refused surgery. The other 87 patients (86.1%) underwent TME successfully. The mean interval from the completion of chemoradiotherapy to surgery was (20.1±8.5) weeks. The R0 resection rate was 97.7% (85/87).The morbidity of surgical complication was 16.1% (14/87), including pelvic infection or abscess in 6 cases (6.9%), anastomotic leakage in 3 (3.4%), hemorrhage in 2 (2.3%), and gastrointestinal dysfunction in 3 (3.4%). Pathological findings revealed that 24 cases (27.6%) had TRG 0, 20 (23.0%) had TRG 1, 30 (34.5%) TRG 2, and 13 (14.9%) TRG 3. Conclusion: TNT is safe and has good short-term efficacy for locally advanced rectal cancer patients with high risk factors.

[Characteristics of clinical, Magnetic Resonance Imaging and electroencephalogram after trimethyltin chloride poisoning].

Objective: Characteristics of clinical, MRI and electroencephalogram after trimethyltin chloride (TMT) poisoning. Methods: The clinical manifestations, MRI, EEG, treatment and prognosis of 16 patients with TMT poisoning were analyzed retrospectively. Results: Among the 16 cases of TMT poisoning, 6 cases were severe poisoning, 4 cases were moderate poisoning, and 6 cases were mild poisoning. All patients had dizziness, headache, general fatigue, loss of appetite, nausea, vomiting and other general clinical symptoms. Six patients with severe poisoning had psychobehavioral abnormalities, including 4 patients with mania, delirium, ataxia, epileptic seizures. Glasgow was 15 points in mild and moderate poisoning. Of the 6 cases of severe poisoning, 4 cases of Glasgow were 9~11 points, and 2 cases of Glasgow were 13 points. 2 patients with severe poisoning had abnormal MRI in head, and the total abnormal rate was 12.50%. Toxic encephalopathy was considered in 1 case with abnormal signal of corpus callosum pressure, and patchy ischemic foci of left cerebral foot and mild cerebral atrophy in 1 case. The total abnormal rate of EEG was 56.25%. The abnormal rate of electroencephalogram in severe poisoning was 83.33%. There were 2 cases of severe abnormal electroencephalogram, 2 cases of moderate abnormal electroencephalogram and 1 case of slight abnormal electroencephalogram. Twelve patients were recovered and discharged from hospital. 4 cases of severe poisoning are still getting better, and there are still cerebellar ataxia symptoms such as dizziness and unstable walking. Conclusion: In clinical work, attention should be paid to the identification of patients with mild and moderate TMT poisoning, and attention should be paid to the patients with severe TMT poisoning manifested by disturbance of consciousness. The positive rate of MRI test in TMT poisoning is low, and the lesion is nonspecific. Electroencephalogram test has a high positive rate in TMT poisoning, which can well reflect the degree of illness. Attention should be paid to the prevention and treatment of neurodegeneration caused by TMT poisoning.

Geometry-dependent band shift and dielectric modification of nanoporous Si nanowires.

In order to obtain a detailed understanding of the modulation of electronic properties in nanoporous Si (np-Si) nanowires with containing ordered, nanometer-sized cylindrical pores, we propose a theoretical method to clarify the band shift and associated with the dielectric modification determined by the geometrical parameters, including nanowire diameter, pore size, pore spacing and porosity, in terms of size-dependent surface energy and atomic-bond-relaxation correlation mechanism. Our results reveal that the self-equilibrium strain induced by the atoms located at inner and outer surfaces with high ratio of under-coordinated atoms as well as elastic interaction among pores in np-Si nanowires play the dominant role in the bandgap shift and dielectric depression. The tunable electronic properties of np-Si nanowires with negative curvature make them attractive for nanoelectronic and optoelectronic devices.

Cloning, characterization, and expression analysis of LGP2 cDNA from goose, Anser cygnoides.

Laboratory of genetics and physiology 2 ( LGP2: ) is a homologue of the retinoic acid inducible gene-I and melanoma differentiation associated gene 5 that lacks the caspase activation and recruitment domain required for signaling. It plays a pivotal role in host immune response. In this study, we cloned and characterized the full-length open reading frame ( ORF: ) sequence of LGP2 in the Qingyuan goose (Anser cygnoides) and evaluated the mRNA expression of this gene post infection with an H5N1 highly pathogenic avian influenza virus ( HPAIV: ). The full-length goose LGP2 ORF (2,028 bp) encoded a polypeptide of 675 amino acids. The deduced amino acid sequence contained 5 main overlapping structural domains-2 DEAD/DEAH box helicase domains, one conserved restriction domain of bacterial type III restriction enzyme, one helicase superfamily C-terminal domain and one C-terminal regulatory domain. Quantitative real-time PCR analysis indicated that goose LGP2 was constitutively expressed in all 19 investigated tissues, but the expression level was different among them. It was high expressed in the trachea, jejunum, bursa, kidney and heart, but low in the glandular stomach, lung, liver, spleen, crop and muscular stomach. A significant increase in the transcription of LGP2 was detected in the brain, spleen and lungs of geese post infection with H5N1 HPAIV versus uninfected tissues. These findings indicated that goose LGP2 was an important receptor that is involved in the host antiviral innate immune defense to H5N1 HPAIV in geese.

Size-dependent optical absorption modulation of Si/Ge and Ge/Si core/shell nanowires with different cross-sectional geometries.

We present an atomic-level and quantitative study of the absorption properties in Si/Ge and Ge/Si core/shell nanowires (CSNWs) along [110] direction with different cross-sectional geometries using the atomic bond relaxation method. We find that the strain existing in self-equilibrium state of CSNWs and associated with elastic energy originating from interface mismatch and surface relaxation affect the band shift and absorption properties. Compared to the CSNWs with tetragonal, hexagonal and circular shapes, the triangular CSNWs have the largest band gap shift at a fixed strain and the smallest absorption coefficient at a determinate incident light wavelength. The tunable absorption property, realized by controlling the size and geometry structure, could be helpful for nanoelectronic applications.

Reversible nanodiamond-carbon onion phase transformations.

Because of their considerable science and technical interest, nanodiamonds (3-5 nm) are often used as a model to study the phase transformation between graphite and diamond. Here we demonstrated that a reversible nanodiamond-carbon onion phase transformation can become true when laser irradiates colloidal suspensions of nanodiamonds at the ambient temperature and pressure. Nanodiamonds are first transformed to carbon onions driven by the laser-induced high temperature in which an intermediary bucky diamond phase is observed. Sequentially, carbon onions are transformed back to nanodiamonds driven by the laser-induced high temperature and high pressure from carbon onions as nanoscaled temperature and pressure cell upon the laser irradiation process in liquid. Similarly, the same bucky diamond phase serving as an intermediate phase is found during the carbon onion-to-nanodiamond transition. To have a clear insight into the unique phase transformation the thermodynamic approaches on the nanoscale were proposed to elucidate the reversible phase transformation of nanodiamond-to-carbon onion-to-nanodiamond via an intermediary bucky diamond phase upon the laser irradiation in liquid. This reversible transition reveals a series of phase transformations between diamond and carbon allotropes, such as carbon onion and bucky diamond, having a general insight into the basic physics involved in these phase transformations. These results give a clue to the root of meteoritic nanodiamonds that are commonly found in primitive meteorites but their origin is puzzling and offers one suitable approach for breaking controllable pathways between diamond and carbon allotropes.

Molecular screening and predation evaluation of the key predators of Conopomorpha sinensis Bradley (Lepidoptera: Gracilariidae) in litchi orchards.

Conopomorpha sinensis Bradley (Lepidoptera: Gracilariidae) is one of the major fruit borer pests of litchi and longan in Southern China. Although chemical control is effective, alternative, biorational strategies are preferable, and should be developed. Predators play an important role in the biological control of agricultural pests, but an accurate method for the evaluation of predation in agriculture has not yet been developed. Here, we report a new, specific primer pair to amplify a C. sinensis cytochrome c oxidase subunit I (COI) sequence fragment that can be used to detect consumption of C. sinensis by its predators. C. sinensis DNA was found in several arthropods collected in the field, including the important C. sinensis predators M enochilus sexmaculata (Coccinellidae), Leucauge magnifica (Tetragnathidae), Propylea japonica (Coccinellidae), and Oxyopes sertatus (Oxyopidae). The detection rates of C. sinensis COI DNA in these predators were 39.3, 36.4, 27.3, and 27.2%, respectively. Laboratory consumption and hunting capacity analysis of M. sexmaculata and P. japonica adults indicated that they exhibit a Holling type II functional response on C. sinensis eggs under field temperatures. A polymerase chain reaction digestion analysis of M. sexmaculata and P. japonica adults after consumption of a single C. sinensis egg indicated that positive detection decreased with the extension of digestion time, and estimated prey DNA half-lives were 16.3 h in M. sexmaculata and 6.0 h in P. japonica. These data serve to characterize two major predators of C. sinensis with potential for biological control of C. sinensis in litchi orchards.

Anomalous interface adhesion of graphene membranes.

In order to understand the anomalous interface adhesion properties between graphene membranes and their substrates, we have developed a theoretical method to calibrate the interface adhesion energy of monolayer and multilayer graphene on substrates based on the bond relaxation consideration. Four kinds of interfaces, including graphene/SiO2, graphene/Cu, graphene/Cu/Ni and Cu/graphene/Ni, were taken into account. It was found that the membrane thickness and the interface confinement condition determine the adhesion energy. The relationship between the critical interface separation and the graphene thickness showed that the interface separation in the self-equilibrium state drops with decreasing membrane thickness. The size-dependent Young's modulus of graphene membrane and the interfacial condition were responsible for the novel interface adhesion energy. The proposed theory was expected to be applied to the design of graphene-based devices.

Physical mechanism of surface roughening of the radial Ge-core/Si-shell nanowire heterostructure and thermodynamic prediction of surface stability of the InAs-core/GaAs-shell nanowire structure.

As a promising and typical semiconductor heterostructure at the nanoscale, the radial Ge/Si NW heterostructure, that is, the Ge-core/Si-shell NW structure, has been widely investigated and used in various nanodevices such as solar cells, lasers, and sensors because of the strong changes in the band structure and increased charge carrier mobility. Therefore, to attain high quality radial semiconductor NW heterostructures, controllable and stable epitaxial growth of core-shell NW structures has become a major challenge for both experimental and theoretical evaluation. Surface roughening is usually undesirable for the epitaxial growth of high quality radial semiconductor NW heterostructures, because it would destroy the core-shell NW structures. For example, the surface of the Ge-core/Si-shell NWs always exhibits a periodic modulation with island-like morphologies, that is, surface roughening, during epitaxial growth. Therefore, the physical understanding of the surface roughening behavior during the epitaxial growth of core-shell NW structures is essential and urgent for theoretical design and experimentally controlling the growth of high quality radial semiconductor NW heterostructures. Here, we proposed a quantitative thermodynamic theory to address the physical process of epitaxial growth of core-shell NW structures and surface roughening. We showed that the transformation from the Frank-van der Merwe mode to the Stranski-Krastanow mode during the epitaxial growth of radial semiconductor NW heterostructures is the physical origin of surface roughening. We deduced the thermodynamic criterion for the formation of the surface roughening and the phase diagram of growth and showed that the radius of the NWs and the thickness of the shell layer can not only determine the formation of the surface roughening in a core-shell NW structure, but also control the periodicity and amplitude of the surface roughness. The agreement between the theoretical results and the experimental data of the Ge-core/Si-shell NW structure implied that the established approach could be applicable to the understanding and design of various semiconductor core-shell NW structures. Consequentially, we used the established theoretical model to study the epitaxial growth of the InAs-core/GaAs-shell NW structure and predict the surface roughening formation, as well as the periodicity and amplitude of the surface roughness, which provided useful information to theoretically design and experimentally control the epitaxial growth of the radial InAs-core/GaAs-shell NW structure.

ZnO hollow quantum dot: a promising deep-UV light emitter.

We establish an analytic model to illustrate the energy bandgap of ZnO hollow quantum dots (HQDs) with negative curvature surface from the perspective of nanothermodynamics. It was found that the bandgap of ZnO HQDs shows a pronounced blue-shift as comparable to those of bulk counterpart and free nanocrystals. Furthermore, the photoelectric properties of ZnO HQDs can be effectively modulated by three independent dimensions, including the outer surface, the inner surface and the shell thickness. Strikingly, the emission wavelength of ZnO HQDs can be extended into the deep-ultraviolet (DUV) region, which suggests this kind of nanostructure could be expected to be applicable for the new-generation, compact, and environmentally friendly alternative DUV light emitter.

Twist2 contributes to breast cancer progression by promoting an epithelial-mesenchymal transition and cancer stem-like cell self-renewal.

The epithelial to mesenchymal transition (EMT) is a highly conserved cellular programme that has an important role in normal embryogenesis and in cancer invasion and metastasis. We report here that Twist2, a tissue-specific basic helix-loop-helix transcription factor, is overexpressed in human breast cancers and lymph node metastases. In mammary epithelial cells and breast cancer cells, ectopic overexpression of Twist2 results in morphological transformation, downregulation of epithelial markers and upregulation of mesenchymal markers. Moreover, Twist2 enhances the cell migration and colony-forming abilities of mammary epithelial cells and breast cancer cells in vitro and promotes tumour growth in vivo. Ectopic expression of Twist2 in mammary epithelial cells and breast cancer cells increases the size and number of their CD44(high)/CD24(low) stem-like cell sub-populations, promotes the expression of stem cell markers and enhances the self-renewal capabilities of stem-like cells. In addition, exogenous expression of Twist2 leads to constitutive activation of STAT3 (signal transducer and activator of transcription 3) and downregulation of E-cadherin. Thus, the overexpression of Twist2 may contribute to breast cancer progression by activating the EMT programme and enhancing the self-renewal of cancer stem-like cells.

Induction of θ-frequency oscillations in the rat medial septal diagonal band slice by metabotropic glutamate receptor agonists.

The aim of this study was to examine the role of metabotropic glutamate receptors (mGluR) in the generation of oscillatory field activity at theta frequency (4-12 Hz) in the medial septal slice prepared from rat brain. Bath application of mGluR agonists and antagonists showed that activation of mGluR1-type receptors produces persistent theta frequency oscillations in a dose-responsive manner. This activity, induced by the group I mGluR agonist (RS)-3,5-dihydroxyphenylglycine (DHPG), was reduced by ionotropic glutamate receptor antagonists and abolished by further addition of a GABAA receptor antagonist. However, addition of a GABAA receptor antagonist on its own converted the DHPG-induced oscillations to intermittent episodes of accentuated theta frequency activity following a burst. In a proportion of slices, DHPG induced large amplitude field population spiking activity (100-300 µV) which is correlated linearly with the field theta oscillations and is sensitive to glutamate receptor antagonists, suggesting a role of this type of spikes in theta generation induced by DHPG. These data demonstrate that DHPG-sensitive neuronal networks within medial septum generate theta rhythmic activity and are differentially modulated by excitatory and inhibitory ionotropic neurotransmissions.

Atomistic origin of lattice strain on stiffness of nanoparticles.

Lattice strain plays a crucial role on the properties of nanoparticles. Although the effect of lattice strain on nanoparticles has been widely studied in experimental measurements and calculations, its physical mechanism from the perfective of bond identities is still poorly understood. Herein we put forward an analytical solution of the size effect and external stimuli such as pressure and temperature dependence of lattice strain and bulk modulus of a nanoparticle from the perspective of atomistic origin. A shell-core configuration has been considered for the nanoparticle structure. It has been found that the lattice strain as well as quantum trapping and energy storage exerted by the compressive stress and thermal stress would be responsible for the mechanical behavior of nanoparticles. The theoretical predictions were well consistent with the experimental data and ab initio calculations, implying that the model could be expected to be a general approach to understand mechanical behavior in nanomaterials.