Biomedical subjects

Zhi Zhao

Publications and source records attributed to Zhi Zhao.

17 recordsLinked to original sources

PubMed2024

Effects of different temperatures on chondrocyte growth: a transcriptomic analysis.

BACKGROUND: Our previous study demonstrated that temperature-related microwave ablation (MWA) can safely modulate growth plates of piglets' vertebrae. Therefore, this study is designed to investigate the effects of different temperatures on chondrocyte viability and the underlying molecular mechanisms in vitro. METHODS: Following a 10-minute treatment at different temperatures (37 °C, 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, and 50 °C), CCK-8 assay was used to examine the viability of ATDC5 cells at 12 h. Differentially expressed genes (DEGs) and the hub genes in ATDC5 cells treated at 37 °C, 40 °C and 44 °C were identified using RNA-seq. The expression of hub genes in ATDC5 cells was validated using RT-qPCR. RESULTS: Compared with 37 °C, exposure to 40 °C significantly increased the viability of ATDC5 cells, while 42 °C had no significant effect. Additionally, exposure to 44 °C, 46 °C, 48 °C, and 50 °C exhibited the opposite pattern, with ATDC5 cells being particularly less than 50% active after treatment at 46 °C, 48 °C, and 50 °C. Differential expression analysis identified 179, 374 and 221 DEGs in the comparisons of 40 °C vs. 37 °C, 44 °C vs. 37 °C, and 44 °C vs. 40 °C, respectively. These DEGs predominantly regulated proliferation, differentiation, necrosis, inflammatory and immune responses, and ECM synthesis/degradation. Furthermore, they were associated with the Ras, PI3K/AKT, mTOR, cAMP, and MAPK pathways. Agt, Hspa1a, Hspb1, and Nlrc4 were identified as hub genes in DEGs, and RT-qPCR confirmed that the mRNA expression patterns of these hub genes in ATDC5 cells were largely consistent with the RNA-seq results. CONCLUSION: The regulation of chondrocyte viability by temperature is associated with Ras, PI3K/AKT, mTOR, cAMP, and MAPK pathways. Additionally, Agt, Hspa1a, Hspb1, and Nlrc4 may be the key regulatory genes in this process.

Chondrocytes↗

PubMed2007

Application of spiral CT image 3D reconstruction in severe talar neck fracture.

OBJECTIVE: To explore the application of the spiral computerized tomography (CT) image three-dimensional (3D) reconstruction technique associated with the conventional radiography in the diagnosis and treatment of severe talar neck fracture. METHODS: Using the multi-slice spiral CT image 3D reconstruction technique, we analysed 11 cases of talar neck fracture. The fractures were reduced and fixed through a minimal incision and internal fixation with titanium cannulated lag screws. RESULTS: In the 11 cases, the results of CT image 3D reconstruction were in concordance with plain radiograph in 6 case of Hawkins type II. And the remaining 5 cases of Hawkins types III and IV could not be classified exactly only by radiographs, one of whom was misdiagnosed. After using the CT image 3D reconstruction, the 5 cases were classified exactly before osteosynthesis. The classifications of these 11 cases were confirmed finally by surgical findings. The duration of operation were 45-140 min, averaging 81 min (including the duration of C-arm fluoroscopy). X-ray exposure time was 6-58 seconds, averaging 22 seconds. The blood loss was less than 100 ml. The fracture union was achieved in 3 months. No nonunion, talus avascular necrosis or joint surface collapse occurred. Postoperative follow-up was from 1 to 25 months. According to Hawkins score, excellent result was found in 6 type II cases and 1 type III case; good result in 1 type III case with both medial and lateral malleolar fracture, 1 type III with medial malleolus fractures and 1 open type III; fair result in 1 open type IV with lateral malleolus fracture. CONCLUSIONS: By using the multi-slice spiral CT image 3D reconstruction associated with radiography to diagnose and treat severe talar neck fractures, the accuracy of diagnosis can be improved obviously. Based on this technique, more consummate operational plan can be designed and performed so as to achieve a better therapeutic effect.

Adult↗

PubMed2006

Experimental violation of Bell's inequality beyond Tsirelson's bound.

The correlations between two qubits belonging to a three-qubit system can violate the Clauser-Horne-Shimony-Holt-Bell inequality beyond Tsirelson's bound [A. Cabello, Phys. Rev. Lett. 88, 060403 (2002)]. We experimentally demonstrate such a violation by 7 standard deviations by using a three-photon polarization-entangled Greenberger-Horne-Zeilinger state produced by Type-II spontaneous parametric down-conversion. In addition, using part of our results, we obtain a violation of the Mermin inequality by 39 standard deviations.

Journal Article↗

PubMed2006

Experimental quantum error rejection for quantum communication.

We report an experimental demonstration of a bit-flip error-rejection protocol for error-reduced transfer of quantum information through a noisy quantum channel. In the experiment, an unknown state to be transmitted is encoded into a two-photon entangled state, which is then sent through an engineered noisy quantum channel. At the final stage, the unknown state is decoded by a parity measurement, successfully rejecting the erroneous transmission over the noisy quantum channel.

Journal Article↗

PubMed2006

[Cloning, sequence analysis and expression of alanine racemase gene in Pseudomonas putida].

Two distinct alanine racemase genes from Pseudomonas putida 200 were cloned and sequenced. DadX encodes a peptide of 357 amino acids with a calculated molecular weight of 38.82kDa. The putative product of alr gene is a peptide of 409 amino acids with molecular weight of 44.182kDa. A homology comparison revealed identities of 96.64%, 71.99%, 44.88% and 47.37% of the DadX alanine racemase to those from P. putida KT2440, Pseudomonas aeruginosa, Salmonella typhimurium and Escherichia coli, respectively. The amino acids sequence deduced from alr gene showed the homologies of 94.38%, 22.89%, 25.72% and 26.44% to those from the microorganisms above, respectively. Two motifs believed essential to the enzyme activity are found both in DadX and Alr, such as pyridoxal-5'-phosphate binding site. Both dadX and alr were expressed in E. coli TG1. Neither alanine racemase activity or serine racemase activity was detected in the host strain. Only alanine racemase activity was found in E. coli TG1/pCTD. But both E. coli TG1/pCTA and TG1/pCBA exhibit activity toward L-alanine and L-serine. Transcription of alr gene in E. coli is independent from extraneous promoter, a result confirmed by the significant enzyme activity observed in the E. coli TG1/pCBA, which indicates the presence of a possible promoter upstream the structure gene.

Alanine Racemase↗

PubMed2006

[Cloning, sequence analysis and expression of N-acetylglutamate kinase gene in Corynebacterium crenatum].

N-Acetylglutamate kinase (EC 2.7.2.8;NAGK) genes from wild-type Corynebacterium crenatum AS 1.542 and a L-arginine-producing mutant C. crenatum 971.1 were cloned and sequenced. Analysis of argB sequences revealed that only one ORF existed, which used ATG as the initiation codon and coded a peptide of 317 amino acids with a calculated molecular weight of 33.6kDa. Only one nucleotide difference was found in the structure gene and the difference did not cause a change of amino acid by comparison of the gene sequences between the wild type C. crenatum AS 1.542 and the mutant 971.1. The ORF sequence of argB from C. crenatum AS 1.542 showed homologies of 99.89%, 76.62%, 37.94% to those from Corynebacterium glutamicum ATCC 13032, Corynebacterium efficient YS-314 and Escherichia coli k12. And the amino acid sequence deduced from ORF displayed homologies of 100%, 78.55%, 25.25% to those from microorganisms above, respectively. An internal promoter was found in the upstream of the argB gene from C. crenatum. The argB gene from C. crenatum AS 1.542 was expressed both in C. crenatum AS 1.542 and 971.1. The NAGK activity of transformed C. crenatum AS 1.542 was greatly increased by the induction of IPTG. The NAGK activity of transformed C. crenatum 971.1 was almost twice as much as that of C. crenatum 971.1 under the same induction. The amplification of the NAGK activity yielded 25% increase of L-arginine production in C. crenatum 971.1.

Amino Acid Sequence↗

PubMed2005

All-versus-nothing violation of local realism by two-photon, four-dimensional entanglement.

We develop and exploit a source of two-photon, four-dimensional entanglement to report the first two-particle all-versus-nothing test of local realism with a linear optics setup, but without resorting to a noncontextuality assumption. Our experimental results are in good agreement with quantum mechanics while in extreme contradiction to local realism. Potential applications of our experiment are briefly discussed.

Journal Article↗

PubMed2005

Experimental quantum secret sharing and third-man quantum cryptography.

Quantum secret sharing (QSS) and third-man quantum cryptography (TQC) are essential for advanced quantum communication; however, the low intensity and fragility of the multiphoton entanglement source in previous experiments have made their realization an extreme experimental challenge. Here, we develop and exploit an ultrastable high intensity source of four-photon entanglement to report an experimental realization of QSS and TQC. The technology developed in our experiment will be important for future multiparty quantum communication.

Journal Article↗

PubMed2005

Experimental realization of optimal asymmetric cloning and telecloning via partial teleportation.

We report an experimental realization of both optimal asymmetric cloning and telecloning of single photons by making use of partial teleportation of an unknown state. In the experiment, we demonstrate that, conditioned on the success of partial teleportation of single photons, not only the optimal asymmetric cloning can be accomplished, but also one of two outputs can be transferred to a distant location, realizing the telecloning. The experimental results represent a novel way to achieve quantum cloning and may have potential applications in the context of quantum communication.

Journal Article↗

PubMed2005

Experimental demonstration of a nondestructive controlled-NOT quantum gate for two independent photon qubits.

Universal logic gates for two quantum bits (qubits) form an essential ingredient of quantum information processing. However, photons, one of the best candidates for qubits, suffer from a lack of strong nonlinear coupling, which is required for quantum logic operations. Here we show how this drawback can be overcome by reporting a proof-of-principle experimental demonstration of a nondestructive controlled-NOT (CNOT) gate for two independent photons using only linear optical elements in conjunction with single-photon sources and conditional dynamics. Moreover, we exploit the CNOT gate to discriminate all four Bell states in a teleportation experiment.

Journal Article↗

PubMed2005

[Analysis of clinical manifestations and surgical treatment of Crohn disease: a report of 82 cases].

OBJECTIVE: To elucidate the clinical types of Crohn disease and evaluate its surgical treatment. METHODS: Clinical data of 82 cases with Crohn disease were retrospectively analyzed from June 1972 to June 2003. RESULTS: Among 82 cases with Crohn disease,38 cases were diagnosed before operation,and 44 cases(53.7% ) were misdiagnosed. Main clinical manifestations included abdominal pain(96.3% ),diarrhea(89.0% ) and abdominal mass(28.0% ),other clinical manifestations included fistulation,intestinal hemorrhage and extra- intestinal manifestations such as ulcerative stomatitis,mycotic stomatitis. Patients received different surgical procedures as following: partial enterectomy in 57 cases,hemicolectomy and colostomy in 4 patients,partial ileectomy and ileostomy in 2,ileocolic bypass procedure in 3 patients,partial enterectomy and colectomy and anastomosis in 3 patients because of internal fistula,repair of ileal perforation in 2,lysis of adhesion in 6,drainage of intraperitoneal abscess and ostomy in 3,radical operation in 2 due to colon cancerization. Seventy- three cases(89.0% ) were cured by operation,postoperative complications occurred in 9 patients and 2 cases died. CONCLUSION: It is the key point to achieve successful operation that the corresponding operative modes respectively for varied types of Crohn disease should be adopted.

Adolescent↗

PubMed2005

[Expression of feedback-resistant aspartate kinase gene in Corynebacterium crenatum].

The AEC-resistant aspartate kinase gene from C. crenatum CD945 was cloned into vector pJC1. Its expression was investigated both in the wild type C. crenatum AS1.542 and its mutant C. crenatum CD945. The result showed that C. crenatum AS1.542 harboring AK(fbr) gene could grow on the defined medium with the co-existence of 12 mg/mL both of AEC and L-threonine respectively. Overexpression of AK(fbr) gene in C. crenatum CD945 results in a 4-fold increase of specific enzyme activity than the parental strain. The amplification of the activity of aspartate kinase yields 22% increase of L-lysine production and 23% increase of L-lysine productivity without affecting the growth rate.

Aspartate Kinase↗

PubMed2005

[Diagnosis and treatment of paraduodenal hernia: a report of 16 cases].

OBJECTIVE: To summarize the experience of diagnosis and treatment for paraduodenal hernia (PDH). METHODS: The clinical data of 16 cases with PDH surgically treated from 1962 to 2003 were analyzed retrospectively. RESULTS: The average age of the patients was 36 years old. There were 13 cases with left PDH (Landzerts hernia) and 3 cases with right PDH (Waldeyer's hernia). Ten patients usually had no symptoms, while acute abdominal pain occurred after full food in 3 case and after vigorous movement in 13 cases respectively. X-ray revealed complete or incomplete intestinal obstruction in 12 cases, while ultrasonography and CT revealed dilated cystic jejunal loop between the pancreas and the stomach in 6 cases. Fourteen cases (87.5%) were misdiagnosed before operation. The hospital stay ranged from 10 to 13 days. All patients were followed up from 2 to 4 years without recurrence. CONCLUSION: With high misdiagnostic rate, it is the key to perform exploratory operation for suspicious PDH.

Adolescent↗

PubMed2004

Experimental demonstration of five-photon entanglement and open-destination teleportation.

Quantum-mechanical entanglement of three or four particles has been achieved experimentally, and has been used to demonstrate the extreme contradiction between quantum mechanics and local realism. However, the realization of five-particle entanglement remains an experimental challenge. The ability to manipulate the entanglement of five or more particles is required for universal quantum error correction. Another key process in distributed quantum information processing, similar to encoding and decoding, is a teleportation protocol that we term 'open-destination' teleportation. An unknown quantum state of a single particle is teleported onto a superposition of N particles; at a later stage, this teleported state can be read out (for further applications) at any of the N particles, by a projection measurement on the remaining particles. Here we report a proof-of-principle demonstration of five-photon entanglement and open-destination teleportation (for N = 3). In the experiment, we use two entangled photon pairs to generate a four-photon entangled state, which is then combined with a single-photon state. Our experimental methods can be used for investigations of measurement-based quantum computation and multi-party quantum communication.

Journal Article↗

PubMed2003

Experimental violation of local realism by four-photon Greenberger-Horne-Zeilinger entanglement.

We report the first experimental violation of local realism by four-photon Greenberger-Horne-Zeilinger (GHZ) entanglement. In the experiment, the nonstatistical GHZ conflicts between quantum mechanics and local realism are confirmed, within the experimental accuracy, by four specific measurements of polarization correlations between four photons. In addition, our experimental results also demonstrate a strong violation of Mermin-Ardehali-Belinskii-Klyshko inequality by 76 standard deviations. Such a violation can only be attributed to genuine four-photon entanglement.

Journal Article↗

PubMed2003

Experimental realization of entanglement concentration and a quantum repeater.

We report an experimental realization of entanglement concentration using two polarization-entangled photon pairs produced by pulsed parametric down-conversion. In the meantime, our setup also provides a proof-in-principle demonstration of a quantum repeater. The quality of our procedure is verified by observing a violation of Bell's inequality by more than 5 standard deviations. The high experimental accuracy achieved in the experiment implies that the requirement of tolerable error rate in multistage realization of quantum repeaters can be fulfilled, hence providing a useful toolbox for quantum communication over large distances.

Journal Article↗

PubMed2002

[Constant scaled-energy spectroscopy of Rydberg atoms in a static electric field].

In the past years, scaled energy spectroscopy is under active investigation because this method can simplify the analysis of atomic spectra in the external field based on classic mechanics. A fully computer-controlled experimental system to study the constant scaled-energy spectroscopy was established and described in this paper. The excitation energy E and the strength of the external electric field F were controlled synchronously to keep the scaled-energy epsilon = E/square root of F constant. With this system, constant scaled-energy spectra of Strontium Rydberg atoms at epsilon = -3.0 in a static electric field were successfully recorded for the first time, and the recurrence spectra were obtained by a Fourier transform.

Electricity↗