Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires

Cd3As2 is a newly booming Dirac semimetal with linear dispersion along all three momentum directions and can be viewed as 3D analog of graphene. As breaking of either time reversal symmetry or spatial inversion symmetry, the Dirac semimetal is believed to transform into Weyl semimetal with exotic chiral anomaly effect, while the experimental evidence of the chiral anomaly is still missing in Cd3As2. Here we report the magneto-transport properties of individual Cd3As2 nanowires. Large negative magnetoresistance (MR) with magnitude of -63% at 60 K and -11% at 300 K are observed when the magnetic field is parallel with the electric field direction, giving the evidence of the chiral magnetic effect in Cd3As2 nanowires. In addition, the critical magnetic field BC, where there is an extremum of the negative MR, increases with increasing temperature. As the first observation of chiral anomaly induced negative MR in Cd3As2 nanowires, it may offer valuable insights for low dimensional physics in Dirac semimetals.Comment: 4 figure

Oxonium 2-carb­oxy-3-(2-fur­yl)acrylate

In the title compound, H3O+·C8H5O5 −, neighbouring cations and anions are linked by O—H⋯O hydrogen bonds, forming a one-dimensional chain framework along [001]. The crystal structure is further stabilized by π–π inter­actions, with centroid–centroid distances of 3.734 (3) Å

Ultrasonic frogs show extraordinary sex differences in auditory frequency sensitivity

Acoustic communication plays an important role in the reproductive behavior of anurans. Males of concave-eared torrent frog (_Odorrana tormota_) have ultrasonic communication capacity 1, 2, but it is unknown whether females communicate with ultrasound. Here we show that _O. tormota_ exhibits great sex differences in the auditory frequency sensitivity. Acoustic playback experiments demonstrated that the male's advertisement calls evoke gravid females' positive phonotaxis and vocal responses, whereas ultrasonic components of the male's calls (frequencies above 20 kHz) do not elicit female phonotaxis or vocalization. The behavioral study was complemented by electrophysiological recordings from the auditory midbrain and by laser Doppler vibrometer measurements of the tympanic membrane's response to acoustic stimuli. These measurements revealed that females have an upper frequency limit up to 16 kHz (threshold 107 dB SPL) and no ultrasound sensitivity, unlike males which have an upper frequency limit of up to 35 kHz (87 dB SPL). Single units in the female auditory midbrain have the best excitatory frequencies (BEFs) peaked around 5 kHz, corresponding to the fundamental frequency (F0) of male's most calls, whereas the male auditory midbrain units have BEFs mostly above 8 kHz, largely consistent with the F0 of female courtship calls. Females have a frequency sensitive bandwidth (10 dB above threshold) ranged from 2 to 6 kHz, narrower than that males have (5-20 kHz). The velocity amplitude of the tympanic membranes peaked around 5 kHz in females, whereas 7 kHz in males. The results suggest that the frog species O. tormota is an example of a vertebrate, which demonstrates well phonotaxis and extraordinary sex differences in hearing

高血压合并主动脉夹层患者高血压特征及院前降压治疗

Objective: To summarize hypertension characteristics and pre hospital antihypertensive therapy in patients with hypertension and aortic dissection, to explore the measures of prevention and control. Methods:  683 patients with hypertension complicated with aortic dissection patients (AD group), 8974 patients with hypertension (hypertension group), during the five years from October 2009 to October 2014, were analyzed retrospectively according to the hospital medical records data combined with outpatient clinical data.Retrospective analysis of hypertension characteristics and pre hospital antihypertensive therapy from the two groups of patients when first diagnosed was conducted. Results: The two groups ratio of diabetes, coronary heart disease, hyperlipidemia, renal insufficiency, have no statistical difference. Most patients in AD group have over 10 years’ history of hypertension (P <0.05).The incidence of aortic dissection in men of AD group is higher than the hypertensive group（P <0.05）. The ratio of 40～60 years in AD group is more than that in hypertensive group (P <0.05). The ratio of stage 3 hypertension in AD group is more than that in hypertension group (P < 0.05).The ratio of no antihypertensive treatment in patients in the AD group is more than that in hypertension group (P < 0.05).The average age of onset in AD group was lower than that in hypertension group (P<0.05). The ratio of patients in the AD group treated with ARB or ACEI antihypertensive was lower than that in hypertension group (P<0.05). Conclusion:  Hypertension complicated with aortic dissection is mostly accompanied by more than 10 years’ history of hypertension in most male patients of 40～60 age group, with grade 3 hypertension. Most did not receive antihypertensive treatment, the average age of onset is low, using ARB or ACEI for the treatment of patients is less.目的： 总结高血压合并主动脉夹层（aortic dissection,AD）患者入院时高血压特征及院前降压治疗，探讨防治措施。方法：根据住院病历资料结合门诊高血压微机管理病例资料分析2009年10月至２014年10月5年期间存活的683例高血压合并主动脉夹层患者（AD组），高血压病患者8974例（高血压组），对二组患者首诊时的高血压特征及院前降压治疗情况进行回顾性分析。结果：两组糖尿病、冠心病、高脂血症、肾功能不全比例无统计学差异。AD组多有10年以上的高血压病史（Ｐ＜0.0５）。AD组男性主动脉夹层发生率多于高血压组（Ｐ＜0.0５）。AD组40-60岁比例多于高血压组（Ｐ＜0.0５）。AD组高血压3级多于高血压组（Ｐ＜0.0５）。AD组未降压治疗者比例多于高血压组（Ｐ＜0.0５）。AD组发病平均年龄低于高血压病组（Ｐ＜0.0５）。AD组采用ARB或ACEI降压治疗者少于高血压组（Ｐ＜0.0５）。结论：高血压合并主动脉夹层多有10年以上高血压病史，男性患者多，在40-60岁年龄段多，3级高血压多，未接受降压治疗者多，发病平均年龄低，采用ARB或ACEI治疗者少