Publications by authors named "Huankai Zhang"

6 Publications

  • Page 1 of 1

A new method for high-bandwidth servo control of the power ratio between two Raman beams for cold atom interferometer.

Rev Sci Instrum 2020 Oct;91(10):103109

National University of Defense Technology, College of Artificial Intelligence, Changsha, Hunan 410073, China.

Light shift produced by the AC Stark effect is one of the major factors limiting the accuracy and long-term stability of a cold atom interferometer. The first order light shift can be canceled by fixing the power ratio of the Raman beams at a specified value. We report here a new method to stabilize the power ratio of the two Raman lasers with ∼100 kHz locking bandwidth, suppressing the effect of the first order light shift. We first mixed the two Raman lasers (at different optical frequencies) with a reference beam and then used two Schottky diode detectors to extract the corresponding beat note signals for each beam, which are much easier to be manipulated and processed as they are in the microwave band. The stability of the power ratio is improved by three orders of magnitude from 5.84 × 10 to 3.51 × 10 at 1 s averaging time and reaches 1.59 × 10 at 10 000 s integrating time when the servo loop is engaged. This method can be used in other precise quantum measurement based on the stimulated Raman transition and can be applied to compact inertial sensors.
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October 2020

Whether Keratectasia Area Shown in Corneal Topography Is Appropriate for Evaluating the Effect of Corneal Cross-Linking for Keratoconus: A 12-Month Follow-Up Study.

Biomed Res Int 2019 3;2019:1762537. Epub 2019 Apr 3.

Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China.

Purpose: To analyze the keratectasia area (KEA) shown in corneal topography before and after corneal cross-linking (CXL) in patients with progressive keratoconus (KC) and figure out whether KEA is appropriate for evaluating the effect of CXL.

Methods: A retrospective analysis was conducted in 34 eyes from 24 progressive KC patients who have underwent CXL from 2015 to 2017. Area with value more than 47D shown in the corneal topography was marked and identified as KEA. Keratometry (1, 2, and max), KEA, thinnest corneal thickness (TCT), and endothelial cell density (ECD) were evaluated preoperatively or at months 3, 6, and 12 postoperatively. The changes of KEA before and after operation were evaluated. The relation of KEA and other parameters, including max and TCT, was analyzed.

Results: Linear regression model revealed the KEA, max, 1, and 2 decreased after CXL in model y = 0.9622 -0.02408 x (P<0.05), y = 0.9982 -0.003469 x(P<0.05), y = 0.9977 + -0.001347 x(P<0.05), y = 0.9992 + -0.001779 x(P<0.05) (y represents KEA, max, 1, or 2; x represents time (month)). The KEA is significantly decreased in early stage (before month 3) (P<0.05); however, the max, 1, and 2 have no significant decrease in early stage (P= 0.09, 0.19, 0.32).

Conclusions: The KEA is more sensitive than value in describing the morphological changes of cornea after CXL, especially in early stage after treatment.
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September 2019

Bilateral thoracic Paravertebral block for immediate postoperative pain relief in the PACU: a prospective, observational study.

BMC Anesthesiol 2017 07 5;17(1):89. Epub 2017 Jul 5.

Department of Anesthesiology, West China Hospital, Sichuan University, No37 Guoxue Street, Chengdu, Sichuan, 610041, People's Republic of China.

Background: To investigate the feasibility, effectiveness and safety of bilateral thoracic paravertebral block (TPVB) in the post anesthesia care unit (PACU) for pain relief in participants after laparotomy.

Methods: A single shot of bilateral TPVB with 25 ml of 0.2% ropivacaine and 5 mg dexamethasone in combination for both sides at the 8th thoracic transverse level (T8) was performed on 201 participants who complained moderate to severe pain on arrival to PACU after laparotomy. The visual analog scale (VAS) pain scores at rest and on cough, heart rate, blood pressure, and pulse oximetry before and after bilateral TPVB for up to 1 h were recorded. The VAS Pain scores at rest and on cough at 24 h after bilateral TPVB were also recorded.

Results: Bilateral TPVB was carried out successfully in all participants. The VAS pain scores at rest and on cough were 7.9 ± 1.6 and 8.7 ± 1.3 respectively pre-bilateral TPVB. The VAS pain scores at rest and on cough were significantly decreased to 1.1 ± 1.2 and 2.1 ± 1.6 respectively (P < 0.001) at 60 min after bilateral TPVB and to 2.1 ± 1.7 and 3.8 ± 1.9 at rest and on cough respectively ((P < 0.001) at 24 h after bilateral TPVB. At 10 min post-bilateral TPVB, only systolic blood pressure was reduced from 122 ± 19 mmHg to 111 ± 18 mmHg (P = 0.007) but then gradually became stable. No complications related to bilateral TPVB were observed.

Conclusion: Bilateral TPVB can be provided for pain relief to the participants who suffer from moderate to severe pain after upper laparotomy in the PACU.

Trial Registration: Chinese Clinical Trial Registry: ChiCTR-ONN-16009229 , Registered on 10 September 2016.
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July 2017

The association and significance of H3K27me3 and a folate metabolic gene ACat2 in neural tube defects.

Nutr J 2016 11 3;15(1):95. Epub 2016 Nov 3.

Department of Scientific Research, General Hospital of Ningxia Medical University, 804 South Victory Street, Yinchuan, Ningxia, China.

Aim: To study the association between the expression of H3K27me3 and ACat2 (a folate metabolic protein), in order to elucidate the protective mechanism of folic acid (FA) in neural tube defects (NTDs).

Methods: Eighteen female SD rats were randomly divided into normal, NTD and FA group. NTD group was induced by all-trans retinoic acid (ATRA) at E10d. FA group was fed with FA supplementation since 2 weeks before pregnancy, followed by ATRA induction. At E15d, FA level in the embryonic neural tube was determined by ELISA. Neural stem cells (NSCs) were isolated. Cell proliferation was compared by CCK-8 assay. The differentiation potency was assessed by immunocytochemical staining. H3K27me3 expression was measured by immunofluorescence method and Western blot. ACat2 mRNA expression was detected by qRT-PCR.

Results: Cultured NSCs formed numerous Nestin-positive neurospheres. After 5 days, they differentiated into NSE-positive neurons and GFAP-positive astrocytes. When compared with controls, the FA level in NTD group was significantly lower, the ability of cell proliferation and differentiation was significantly reduced, H3K27me3 expression was increased, and ACat2 mRNA expression was decreased (P <0.05). The intervention of FA notably reversed these changes (P <0.05). H3K27me3 expression was negatively correlated with the FA level (rs = -0.908, P <0.01) and ACat2 level (rs = -0.879, P <0.01) in the neural tube.

Conclusion: The increased H3K27me3 expression might cause a disorder of folate metabolic pathway by silencing ACat2 expression, leading to reduced proliferation and differentiation of NSCs, and ultimately the occurrence of NTD. FA supplementation may reverse this process.
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November 2016