Raman spectroscopic study of frustrated ferroelectric phase in hydroxyl salts Co2(OH)3Br/Co2(OD)3Br.

We report on an investigation of the temperature-dependent ordering of the hydrogen/deuterium atoms in geometrically frustrated magnets Co2(OH)3Br and its deuterated Co2(OD)3Br, to shed light on the origin of the newly-identified ferroelectricity using Raman spectroscopy. Significant changes in the Raman frequencies and line-widths of the Raman-active modes were observed below ∼260 K in Co2(OD)3Br and ∼240 K in Co2(OH)3Br, respectively, the analysis of which revealed strong spin-phonon couplings in this system. Further, for Co2(OD)3Br, six new phonon bands appeared below around 260 K, with the corresponding intensities obeying a power-law equationI∝1-T/Tc2ßwhereinTc= 260 K, suggesting that an ordering process occurred below ∼260 K. The ordering process subsequently affected the local structure and brought out the reported ferroelectric phase, which is considered as frustrated. Meanwhile, in Co2(OH)3Br, only one new band was observed below ∼240 K, followed by two 'softened' modes correlated to the [OH] sub-lattice below ∼185 K, wherein an incomplete ordering was suggested. The present work reveals a new multiferroic system combining geometrically frustrated magnetism and deuterium ordering-type ferroelectricity.

Ferroelectric Sr3 Sn2 O7 :Nd3+ : A New Multipiezo Material with Ultrasensitive and Sustainable Near-Infrared Piezoluminescence.

Ultrasensitive and sustainable near-infrared (NIR)-emitting piezoluminescence is observed from noncentrosymmetric and ferroelectric-phase Sr3 Sn2 O7 doped with rare earth Nd3+ ions. Sr3 Sn2 O7 :Nd3+ (SSN) with polar A21 am structure is demonstrated to emit piezoluminescence of wavelength of 800-1500 nm at microstrain levels, which is enhanced by the ferroelectrically polarized charges in the multipiezo material. These discoveries provide new research opportunities to study luminescence properties of multipiezo and piezo-photonic materials, and to explore their potential as novel ultrasensitive probes for deep-imaging of stress distributions in diverse materials and structures including artificial bone and other implanted structures (in vivo, in situ, etc).

Hydrogen/Deuterium Dynamics in Hydroxyl Salts Co2(OH)3Br/Co2(OD)3Br Revealed by Muon Spin Relaxation.

The temperature-dependent dynamics of the hydrogen/deuterium atoms in geometrically frustrated magnets Co2(OH)3Br and its deuterated form Co2(OD)3Br were investigated by muon spin relaxation (µSR). The deuterium atoms in Co2(OD)3Br were found to be rapidly fluctuating at high temperatures, which should be arising as a quantum atomic effect due to the small mass of deuterium, then they drastically slowed down toward Tc = 250 K where a broad anomaly appeared in the dielectric response, and finally became quasi-static at around 180 K. Meanwhile, the hydrogen atoms in Co2(OH)3Br also exhibited a two-step slowing at ~240 K and ~180 K, respectively. The revealed properties in Co2(OH)3Br/Co2(OD)3Br are reminiscent of relaxor-type ferroelectrics. The present study suggested the effectiveness of the µSR technique on revealing the hydrogen/deuterium (H/D) dynamics in Co2(OH)3Br/Co2(OD)3Br. Furthermore, magnetic coupling was found to be existing at high temperatures in this system. This work provides clear evidence to the mechanism of ferroelectric responses in the hydroxyl salts, i.e., the slowing of protons (deuterium ions) is directly related to the newly revealed ferroelectricity.

[Effects of Continuous Intravenous Intraoperative Lidocaine Infusion on Opioids Consumption and Postoperative Recovery in Patients Undergoing Video-assisted Thoracoscopic Lobectomy].

Objective To investigate whether continuous intravenous intraoperative lidocaine infusion can reduce the opioids dosage and improve postoperative recovery in patients undergoing video-assisted thoracoscopic(VATS) lobectomy. Methods Totally 60 patients undergoing VATS lobectomy were enrolled in this single-center randomized controlled study.The patients were equally randomized into lidocaine continuous pumping group(lidocaine group) and control group by computer-based random numbers.The patients had double-lumen catheter intubation,and total intravenous anesthesia was administrated intraoperatively.In the lidocaine group,patients continuously received intravenous pumping of lidocaine [2 mg/(kgdh) ] after a loading doses(1 mg/kg) until the end of the operation.We recorded the basic characteristics,preoperative examination,intraoperative medications,and postoperative recovery of both groups.Results The basic characteristics and preoperative examination findings were comparable between these two groups(all P>0.05).Compared with the control group,the intraoperative sufentanil consumption significantly decreased in the lidocaine group [(32.3±7.5) µg vs.(40.9±10.2) µg,P<0.001].Significantly more patients were given esmolol intraoperatively in the control group to lower heart rate(P=0.010).The incidence of postoperative nausea within 24 hours was significantly lower in the lidocaine group(P=0.045).There was no significant difference between the two groups in postoperative recovery(all P>0.05).Conclusion Intravenous continuous pumping of lidocaine during operation can reduce opioids consumption and lower the incidence of postoperative nausea without extra adverse or toxic reaction in patients undergoing VATS lobectomy.

Starch accumulation in hulless barley during grain filling.

BACKGROUND: Starch consists of two types of molecules: amylose and amylopectin. The objective of this study was increase understanding about mechanisms related to starch accumulation in hulless barley (Hordeum vulgare L.) grain by measuring temporal changes in (i) grain amylose and amylopectin content, (ii) starch synthase activity, and (iii) the relative expressions of key starch-related genes. RESULTS: The amylopectin/amylose ratio gradually declined in both Beiqing 6 and Kunlun 12. In both cultivars, the activities of adenosine diphosphate glucose pyrophosphorylase, soluble starch synthase (SSS), granule bound starch synthase (GBSS), and starch branching enzyme (SBE) increased steadily during grain filling, reaching their maximums 20-25 days after anthesis. The activities of SSS and SBE were greater in Ganken 5 than in either Beiqing 6 or Kunlun 12. The expression of GBSS I was greater in Beiqing 6 and Kunlun 12 than in Ganken 5. In contrast, the expression of SSS I, SSS II and SBE I was greater in Ganken 5 than in Beiqing 6 and Kunlun 12. The peak in GBSS I expression was later than that of SSS I, SSS II, SBE IIa and SBE IIb. The GBSS I transcript in Kunlun 12 was expressed on average 90 times more than the GBSS II transcript. CONCLUSIONS: The results suggest that SBE and SSS may control starch synthesis at the transcriptional level, whereas GBSS I may control starch synthesis at the post transcriptional level. GBSS I is mainly responsible for amylose synthesis whereas SSS I and SBE II are mainly responsible for amylopectin synthesis in amyloplasts.

LiNbO3 :Pr3+ : A Multipiezo Material with Simultaneous Piezoelectricity and Sensitive Piezoluminescence.

Red-emitting piezoluminescence (elasticoluminescence) is achieved by doping rare earth Pr3+ into the well-known piezoelectric matrix, LiNbO3 . By precisely tuning the Li/Nb ratio in nonstoichiometric Li x NbO3 :Pr3+ , a material that exhibits an unusually high piezoluminescence intensity, which far exceeds that of any well-known piezoelectric material, is produced. Li x NbO3 :Pr3+ shows excellent strain sensitivity at the lowest strain level, with no threshold for stress sensing. These multipiezo properties of sensitive piezoluminescence in a piezoelectric matrix are ideal for microstress sensing, damage diagnosis, electro-mechano-optical energy conversion, and multifunctional control in optoelectronics.

Raman spectroscopic study of the frustrated spin 1/2 antiferromagnet clinoatacamite.

Raman spectroscopy is a valuable and complementary tool for studying geometrically frustrated magnetic systems due to the intrinsic spin-phonon coupling. Here, we report on a Raman spectroscopic study of the geometrically frustrated spin 1/2 antiferromagnet microcrystalline clinoatacamite Cu2(OH)3Cl, focusing on the anomalous transition into the intermediate phase at T(c1) = 18.1 K. By measuring the temperature-dependent (295-4 K) full spectral profiles and main representative modes in spectral regions from 4000 to 95 cm(-1), we observed probable signatures of successive magnetic transitions near T(c1) = 18 K and T(c2) = 6.4 K in the Raman band frequencies and peak widths of the representative modes. Further, we observed a pronounced Raman spectroscopy background featuring a broad continuum at all temperatures. A quantitative analysis reveals that spin fluctuations may exist on a picosecond time scale in the intermediate phase. The short time scale falls out of the µSR time window; therefore, in the intermediate phase, the µSR study as reported in (2005 Phys. Rev. Lett. 95 057201) apparently only probed the local field of the ordered spins but overlooked the quickly fluctuating ones. This is likely to give a reasonable explanation of the fact that only a small entropy release occurs at T(c1) = 18 K although a long-range order is formed.

[Mid-infrared and Raman spectral analysis of geometrically frustrated natural atacamite].

At room temperature, the mid-infrared spectra of geometrically frustrated natural atacamite (hydroxyl copper chloride, beta-Cu2(OH)3Cl) in the range of 4 000-400 cm(-1) were measured by FTIR spectrometers, and meanwhile its Raman spectrum in the range of 4 000-95 cm(-1) was obtained by Jobin Yvon LabRAM HR800 Raman spectrometer. According to its crystal structure parameters, the authors confirmed the characteristic peaks of sample 4 000-2 500-1 000 cm(-1) in the functional group region and 1 000-550-200-95 cm(-1) in the fingerprint region, and also explored its microscopic origin Five distinct regions were assigned: the hydroxyl stretching vibration v(O-H) determined by the overall environment around the hydroxyl group; the overtones generated by the sum or multiplication of fundamental frequencies of hydroxyl bending vibration; the hydroxyl bending vibration modes delta(O-H) of the combination of delta(Cu-O-H) and delta(O-H...HCl); the vibration modes of strongly bonded planar CuO4 units; the vibration modes of weakly bonded linear-triatomic chain Cl-Cu-O/Cl. The bands were assigned in accordance with its crystal structure parameters, which is more reasonable to establish the relationship between its molecular structure and its respective spectral properties.