综合医院门诊2型糖尿病患者骨质疏松风险及认知的现况调查

目的 调查门诊2型糖尿病患者是否存在骨质疏松风险,对骨质疏松症的认知水平及其影响因素。方法 以便利抽样的方法,采用骨质疏松症风险1 min测试题、FRAX骨折风险测评系统和自行设计的骨质疏松疾病认知水平问卷对2018年4月—2019年1月就诊于上海仁济医院的102例门诊2型糖尿病患者的骨质疏松风险及认知现况进行调查与分析。结果 102例2型糖尿病患者中,60例存在骨质疏松风险（58.8%）。未来10年,发生主要骨质疏松性骨折的概率和髋部骨折的概率男性和女性之间存在统计学差异[（3.99±1.80）% vs（8.94±6.30）%,P=0.000;（1.67±1.33）%vs（4.09±4.90）%,P=0.001];年龄≥60岁患者和＜60岁患者之间也有统计学意义[（7.57±5.75）% vs（3.68±2.00）%,P=0.000;（3.70±4.19）% vs（0.63±0.39）%,P=0.000]。受试者的骨质疏松认知得分为2~22分,平均（14.34±4.37）分,文化程度和有无骨质疏松家族史对其认知有影响,差异有统计学意义（P=0.000,P=0.013）。结论 半数以上2型糖尿病患者存在骨质疏松风险;未来10年发生骨折概率女性高于男性,老年人高于中年人;患者对骨质疏松相关知识掌握中等偏上,但对糖尿病合并骨质疏松的专科知识掌握不足。根据调查所得问题,采取针对性健康教育很有必要。     

2016-2019年南昌地区泌尿生殖道支原体感染现状及药敏分析

目的了解南昌地区泌尿生殖道支原体感染情况并进行药敏分析,为临床规范使用抗菌药物提供参考依据。方法对2016—2019年该院103254例疑似泌尿生殖道支原体感染患者的感染情况和药敏试验结果进行回顾性分析。结果103254例标本中共检出支原体阳性标本50970例,感染率为49.36%,其中解脲脲原体(Uu)感染41478例(40.17%),人型支原体(Mh)感染970例(0.94%),Uu+Mh混合感染8522例(8.25%);Uu感染率明显高于Mh和Uu+Mh,连续4年总体呈上升趋势,而Mh感染率呈下降趋势,Uu+Mh混合感染率相对稳定。女性Uu、Mh、Uu+Mh感染率分别为45.46%、1.08%、9.20%,明显高于男性的28.81%、0.64%、6.22%,差异有统计学意义(P<0.05)。≤20岁年龄段人群支原体感染率(51.32%)最高。Uu、Mh和Uu+Mh对强力霉素、美满霉素、四环素及交沙霉素敏感性较高,耐药率较低;Uu、Mh和Uu+Mh对喹诺酮类药物的敏感性均较低,耐药率较高;Uu对除交沙霉素外的大环内酯类药物阿奇霉素、克拉霉素和罗红霉素敏感性较高,对红霉素耐药率较高,而Mh和Uu+Mh对该类药物耐药率均较高;Uu、Mh和Uu+Mh对阿奇霉素、克拉霉素的耐药率连续4年逐年小幅下降。结论强力霉素、美满霉素、四环素及交沙霉素可首选用于该地区泌尿生殖道支原体感染的治疗。南昌地区Uu感染率总体呈上升趋势,应重视对该地区支原体感染的实时监控,加强临床对抗菌药物的合理使用。     

川芎龙蛭汤联合西医治疗急性脑梗死的疗效及其对血清CKLF1、CXCL16和FKN水平的影响

目的 探讨川芎龙蛭汤联合西医治疗急性脑梗死的疗效及其对机体血清趋化素样因子1(CKLF1)、CXC趋化因子配体16(CXCL16)和不规则趋化因子(FKN)水平的影响.方法 选择2019年1月至2020年12月在该院诊断为急性脑梗死患者102例为研究对象,按照随机数字表法将患者分为观察组和对照组,每组51例.对照组予以常规西医治疗,观察组在对照组的基础上使用川芎龙蛭汤治疗.观察两组治疗后的疗效和不良反应发生率,及治疗前后两组血管性痴呆的中医辨证量表(SDSVD)评分、美国国立卫生研究院卒中量表(NIHSS)评分、日常生活活动能力(ADL)评分、平均血流量(Qm)、平均血流流速(Vm)、血管阻力指数(RI)、动脉血氧饱和度(SaO2)、颈内静脉血氧饱和度(SjvO2)、脑氧摄取率(CERO2)、CKLF1、CXCL16和FKN水平的变化.结果 观察组的总有效率为90.20％,明显高于对照组的70.59％(χ2=5.038,P<0.05);治疗后观察组SDSVD评分、NIHSS评分、RI、SjvO2、CKLF1、CXCL16和FKN水平明显低于对照组(P<0.05),而ADL评分、Qm、Vm、SaO2和CERO2水平明显高于对照组(P<0.05).结论 川芎龙蛭汤联合西医治疗急性脑梗死的疗效显著,能够改善脑部血液供应和氧供应,值得临床推广应用.     

心脑血管疾病高危人群首发缺血性脑卒中的影响因素分析

目的 分析心脑血管疾病高危人群首发缺血性脑卒中的影响因素.方法 选取心脑血管疾病高危人群655例,按照是否首次发生缺血性脑卒中分为脑卒中组和非脑卒中组,采用一般情况调查表、半定量食物频率问卷、国际体力活动问卷、一般键康问卷、Morisky服药依从性量表、慢性病自我效能量表对两组进行分析.采用单因素分析、多元Lo-gistic回归分析探讨心脑血管疾病高危人群首发缺血性脑卒中的影响因素.结果 多元Logistic回归分析显示,膳食纤维(OR=0.333,95％CI=0.232～0.647)、胆固醇摄入(OR=3.535,95％CI=2.965～11.012)、体力活动(OR=0.100,95％CI=0.012～0.818)、服药依从性(OR=0.250,95％CI=0.102～0.337)和自我效能(OR=0.731,95％CI=0.604～0.884)是心脑血管疾病高危人群首发缺血性脑卒中的影响因素(P<0.05).结论 心脑血管疾病高危人群的服药依从性、生活方式、自我效能与首发缺血性脑卒中相关,医护人员应加强心脑血管疾病高危人群的健康宣教指导.     

朱丹溪气郁用药规律研究

目的:探究朱丹溪气郁的用药规律及其对临床的指导意义.方法:以《朱丹溪医学全书》作为方剂的基本信息来源,收集书中所涉所有相关方剂,运用excel将书中所有涉及方药进行数据库录入,建立数据库,通过数据挖掘技术对药物类别、使用频次、归经、性味进行统计.结果:朱丹溪著作共涉及治气方剂914个,其中出现频数大于100的常用药物有16味,分别是炙甘草、人参、白术、茯苓、陈皮、生姜、当归、香附、白芍、半夏、川芎等;在药物类别上补虚药和理气药使用频次最高;按药性划分使用频率较高依次为温性药57.29％、平性药22.24％、寒性药占20.48％;按归经划分使用频次较高的依次为脾经26.63％、肺经15.68％、胃经13.36％、心经占12.07％;按药味划分使用频次较高依次为苦味药36.27％、辛味药30.03％、甘味药29.46％,酸味药4.23％.结论:朱丹溪在治疗气证时,擅长应用炙甘草,以四君子汤为主方,配以补虚药,补母益子;同时,朱丹溪治气还往往佐以治血、治痰,扶正祛邪.通过对统计结果进行比较发现,朱丹溪在治气药物归经偏于脾胃两经,重视中焦脾胃之气的升提作用.     

Low-temperature operating ZnO-based NO2 sensors: a review

Owing to its excellent physical and chemical properties, ZnO has been considered to be a promising material for development of NO₂ sensors with high sensitivity, and fast response and recovery. However, due to the low activity of ZnO at low temperature, most of the current work is focused on detecting NO₂ at high operating temperatures (200–500 °C), which will inevitably increase energy consumption and shorten the lifetime of sensors. In order to overcome these problems and improve the practicality of ZnO-based NO₂ sensors, it is necessary to systematically understand the effective strategies and mechanisms of low-temperature NO₂ detection of ZnO sensors. This paper reviews the latest research progress of low-temperature ZnO nanomaterial-based NO₂ gas sensors. Several efficient strategies to achieve low-temperature NO₂ detection (such as morphology modification, noble metal decoration, additive doping, heterostructure sensitization, two-dimensional material composites, and light activation) and corresponding sensing mechanisms (such as depletion layer theory, grain boundary barrier theory, spill-over effects) are also introduced. Finally, the challenges and future development directions of low-temperature ZnO-based NO₂ sensors are outlined.

A comprehensive review on designs and mechanisms of ZnO-based NO₂ gas sensors operated at low temperature.     

Organic–inorganic hybrid liquid crystals of azopyridine-enabled halogen-bonding towards sensing in aquatic environment

In this study, organic–inorganic hybrid mesogens of silver nanoparticles (Ag NPs) and azopyridines (AzoPys) enabled by halogen bonding were prepared. Triple functions of the degree of orientation change, metal-enhanced fluorescence, and surface-enhanced Raman scattering were observed in Ag⋯Br–Br⋯AzoPy nanoparticles (12Br–Ag), which were induced by the in situ synthesis of Ag NPs in AzoPy. The bromine molecules were then linked by halogen bonding and electrostatic interaction resulting in the smectic A phase of 12Br–Ag. To demonstrate the potential of Br–Br⋯AzoPy (12Br) as a practical sensor, we used the 12Br compound to detect silver in an aqueous condition, and significant signals of the halogen-bonded complex-silver system were observed in the X-ray diffraction pattern and Raman spectra. Herein, we provide a novel perspective and design principle for the practical applications of organic–inorganic hybrid liquid crystals in environmental monitoring.

Organic–inorganic hybrid liquid crystals of azopyridines enabled by halogen bonding with the triple functions of degree of orientation change, MEF, and SERS towards sensing silver in aquatic environment.

Halogen bonding is an attractive intermolecular interaction for adjusting the interaction strength by choosing suitable halogen atoms that participate in the bond formation without significantly changing the electronic structure of the compound.¹ Azobenzene-containing composites are of great interest, having promising applications in various fields, such as, optical data storage, owing to the reversible trans–cis photoisomerisation of azobenzene chromophores.^2–5 The halogen-bonded liquid crystals of azobenzene were first reported in 2012.⁶ Currently, many studies describe halogen bonding using azobenzene in the field of organic-liquid crystals^7,8 and photoresponsive nanocomposites;^9–12 however, few studies have investigated the metal-containing azobenzene mesogens. Recently, azobenzene hybrid mesogen-capped thiolated ligands of gold and silver nanoparticles with lamellar and columnar superstructures were achieved and changed the phase transitions significantly; they can behave as intriguing photo-switched temperature sensors with storage and erase functionality with well-organised hybrid systems.¹³ The coupling of the azobenzene mesogen with inorganic nanoparticles has recently become an attractive approach as it can give rise to novel hybrid materials in which the properties of the two components are mutually enhanced.¹⁴ However, studies have not explored organic–inorganic hybrid liquid crystals of azobenzene-containing composites with intermolecular interactions for this purpose, not to mention exploring their applications for the next generation of liquid crystal sensors.Herein, we report azopyridine (AzoPy) mesogens embedded with silver nanoparticles (Ag NPs) obtained by halogen-bonding. Although the texture or degree of orientation remained unchanged in Ag⋯Br–Br⋯AzoPy (12Br–Ag) compared to that in Br–Br⋯AzoPy (12Br), a clear birefringence change was detected, which was attributed to the variation in the electronic properties of 12Br–Ag with a shorter d-spacing. Meanwhile, the halogen bonding intensified the metal-enhanced fluorescence (MEF) of the AzoPy ligand by inserting Br₂ between the Ag NPs and ligand molecules in the solution along with the Surface-enhanced Raman (SER) scattering but not in the condensed phases (crystal or mesophase). By taking advantage of the assisted enhancement of MEF and SER factors of halogen bonding, we report a new approach for the sewage detection by identifying the trace metals using a halogen-bonded liquid crystal as a sensor in water owing to its high sensitivity; it may possess the potential to transform the waste metal pollution into treasure.The organic–inorganic hybrid liquid crystals of azopyridines are shown in Scheme 1. Generally, there are two approaches for preparing nanoparticles: ex situ and in situ (direct growth). The in situ synthesis induces the morphology-controlled growth of nanoparticles.^15,16 Thus, we adopted the in situ synthesis of Ag NPs (10 wt%) with the ligand AzoPy, followed by a treatment with molecular Br₂ to obtain the organic–inorganic hybrid liquid crystals of Ag NPs and AzoPy. The synthesis protocols are given in the ESI.^† The resulting Ag⋯Br–Br⋯AzoPy nanoparticles were characterized by scanning transmission electron microscopy (STEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), UV-vis absorption, and Raman spectroscopy.Open in a separate windowScheme 1Schematic illustration of organic–inorganic hybrid liquid crystals (Ag⋯Br–Br⋯AzoPy).The STEM, TEM, and EDS elemental mapping were performed on the hybrid Ag NPs. As shown in Fig. 1(a), the Ag NPs were covered by an organic corona of the halogen-bonded complex Br–Br⋯AzoPy, which is a result of the interactions between Ag NPs and a pyridyl moiety in AzoPy linked molecular Br₂ by halogen bonding and electrostatic interactions. Moreover, the EDS mapping data support the presence of Ag and Br atoms in the hybrid nanoparticles (Fig. 1(b)). Fig. 1(c) shows an organic layer surrounding the Ag NPs with a small thickness, and the EDS mapping demonstrates the presence of Ag (Fig. 1(d)) and Br (Fig. 1(e)) in the hybrid nanoparticles. The HR-TEM images also showed distinct lattice fringe patterns, indicating the highly crystalline nature of the Ag nanocrystals. The obtained lattice spacing was 0.25 nm, which agrees with the (111) plane for the face-centred cubic (fcc) crystal structure of bulk Ag.¹⁷ The collective EDS mapping and STEM/TEM results provide a definitive evidence for the stabilised halogen-bonded complex of Ag NPs. However, a structure of Ag⋯AzoPy nanoparticles devoid of halogen bonding was not identified (Fig. S1(a)).^†Open in a separate windowFig. 1The STEM image (a), EDS Ag and Br elemental mapping image (b), and HR-TEM image (c) of the di-noncovalent bonded Ag⋯Br–Br⋯AzoPy nanoparticle compared to EDS elemental mapping images of Ag (d) and Br (e). Mapping of the Ag region is depicted in yellow, while the Br region is shown in red.The powder XRD was performed to confirm the structure of nanoparticles. The d-spacing, determined by the deconvolution of a specific diffraction peak in the XRD pattern following Vegard''s law, predicts a linear relationship between the crystal lattice parameter and the concentration of the constituent elements.^17,18 As shown in Fig. 2(a), the diffraction peaks of Ag (111), (200), (220), and (311) planes of Ag NPs were located at 2θ = 38°, 45°, 64°, and 77°, respectively. These distinct peaks are the structural features of Ag NPs, which also appear in the XRD pattern of Ag⋯AzoPy and Ag⋯Br–Br⋯AzoPy nanoparticles, confirming the successful formation of organic–inorganic hybrid complexes of Ag NPs.^19–21Open in a separate windowFig. 2The X-ray diffraction patterns (a), UV-vis absorption spectra of Ag NPs, AzoPy, Ag⋯AzoPy, Br–Br⋯AzoPy, and Ag⋯Br–Br⋯AzoPy in acetone (dashed line: predicted diffraction peaks for Ag metal) (b), and the Raman spectra of AzoPy, Br–Br⋯AzoPy, Ag⋯AzoPy, and Ag⋯Br–Br⋯AzoPy nanoparticles in the solid state (c).The UV-vis absorption spectra of Ag NPs, AzoPy, Ag⋯AzoPy nanoparticles, Br–Br⋯AzoPy, and Ag⋯Br–Br⋯AzoPy nanoparticles in acetone are shown in Fig. 2(b). The surface plasmon resonance (SPR) band of pristine Ag NPs is barely detectable because of the insolubility of Ag NPs in acetone. The absorption maximum (λ_max) of AzoPy and Ag⋯AzoPy nanoparticles are located in the same band at 352 nm, and the SPR band of Ag in Ag⋯AzoPy nanoparticles is absent because of the weak interaction between the electronic doublet of the nitrogen atom of the pyridyl moiety and the Ag surface.^22–24 However, compared to the Br–Br⋯AzoPy, the Ag⋯Br–Br⋯AzoPy nanoparticles showed a large redshift with λ_max at 393 nm because of the incorporation of Ag NPs to AzoPy, demonstrating a stronger interaction of Br–Br⋯AzoPy with Ag NPs than with Ag⋯AzoPy nanoparticles, leading to the formation of the Ag⋯Br noncovalent bond composites.In addition, the UV-vis absorption spectra of Ag⋯Br–Br⋯AzoPy nanoparticles at different concentrations of Ag NPs in acetone and a mixture of surface-stabilised Ag NPs and the AzoPy ligand in the solution were evaluated (Fig. S2^†).Further investigation of the Ag⋯Br–Br⋯AzoPy nanoparticles was corroborated by the Raman spectra. The Raman spectra of Ag⋯AzoPy nanoparticles showed a strong band at 249 cm⁻¹, characteristic of adsorbed pyridine groups compared to AzoPy (Fig. 2(c)), which is similar in frequency to the strong bands reported for pyridine adsorbed on Ag electrodes²⁵ and Ag sols.²⁶ However, the selective Raman enhancement by excitation at 785 nm was observed, corresponding to the characteristic Ag⋯Br vibrations at 151.8 cm⁻¹ in Ag⋯Br–Br⋯AzoPy nanoparticles, which is a result of the complexation between halogen-bonded azodye molecules Br–Br⋯AzoPy and Ag NPs after adding Br₂ to Ag⋯AzoPy nanoparticles.This extraordinary enhancement was caused by the metal–molecule interaction, which involves the exchange mixing of Ag electron–hole pairs and the HOMO–LUMO excited state of bromine molecules.^27,28 These results confirm that Ag⋯Br–Br⋯AzoPy nanoparticles were successfully assembled based on the interaction of Br₂ with the N atom of the pyridyl moiety by bromine bonding and the surface of Ag NPs by the electrostatic interaction. Furthermore, the XPS and ¹H NMR spectra were recorded to further ascertain the bonding between Br–Br⋯AzoPy ligand molecules and Ag NPs (Fig. S3–S5^†) Fig. 3(a) shows the mesophase produced by the organic–inorganic hybrid complexes via the in situ synthesis of Ag NPs in AzoPy, and then linked by the halogen bonding, which stabilised the mesophase with an increase of 10.3 °C in the liquid crystal to isotropic transition compared with 12Br in heating cycle owing to the chemisorption of mesogens on nanoparticles.²⁹ This is different from the physical mixture of liquid crystals and nanoparticle hybrid systems, which lower the temperature (destabilisation) of the liquid crystal phases with the metal nanoparticles. The POM images of 12Br–Ag show focal conic fan textures between plain glass slides (Fig. 3(b)) and a uniform dark image in a vertical-orientation cell at their liquid crystal temperatures (Fig. 3(c)), which is similar to the smectic A phase of the pristine materials (12Br).⁸ However, the photochemical phase transition in 12Br–Ag induced by UV irradiation was unlike that of the previously reported⁸ brominated compounds (12Br; Fig. 3(d)).Open in a separate windowFig. 3The DSC measurements of composites 12Br and 12Br–Ag in heating and cooling cycle (a), POM images of 12Br–Ag at 120 °C on cooling from the isotropic phase (b), in vertical orientation cell in liquid crystal temperature (c), and upon UV irradiation (d).After the annealing process, the SAXS experiments were employed to confirm the type of the smectic mesophase, as shown in Fig. 4. Two peaks with q values of 1.36 and 2.78 nm⁻¹ were detected for 12Br–Ag, similar to those observed for 12Br. The ratio of the scattering vectors of these two peaks was 1 : 2, indicating a smectic packing of 12Br–Ag. Using the MM2 force field method, it was determined that the d-spacings of the first diffraction peaks of 12Br and 12Br–Ag were 5.10 and 4.64 nm approximately, which is 1.67 and 1.41 times the length of the calculated molecular 12Br (l = 3.06 nm) and 12Br–Ag complexes (l = 3.26 nm, the length includes the non-interaction distance between the peripheral bromine atom and the Ag NPs), respectively. Thus, the structures of 12Br and 12Br–Ag could be interdigitated smectic A phase, in which parts of the 12Br–Ag molecules overlap (see the inset picture in Fig. 4). The d/l ratio of 12Br–Ag decreases compared to that of 12Br, probably because of the distinct electronic properties between them, which were induced by the in situ synthesis of Ag NPs in AzoPy.Open in a separate windowFig. 4The SAXS patterns of 12Br and 12Br–Ag after the annealing process with intensity in log scale. The inset picture is the schematic drawing of the smectic packing of 12Br–Ag.The directing abilities of the Ag NPs are selective to surpass those of the alignment layers of the cell according to the temperature condition, which implies that doping with Ag NPs in the liquid crystal plays a dominant role in changing the birefringence by decreasing the d-spacing and inhibiting the orientation, as shown in Fig. S6 and S7.^†Furthermore, when dyes are localised near either free or immobilised metal particles, their luminescence (i.e., fluorescence) intensifies, which is known as metal-enhanced fluorescence (MEF).^30–32 To investigate the occurrence and intensification of MEF in AzoPy, the fluorescence emission of the free AzoPy ligands and their corresponding complexes with Ag NPs were evaluated, as shown in Fig. S8(a).^† It is important to note that the fluorescence intensity of Ag⋯Br–Br⋯AzoPy nanoparticles was approximately three times higher than that of Ag⋯AzoPy nanoparticles. This implies that the insertion of Br₂ between the AzoPy ligand and Ag nanoparticles intensifies the MEF of the ligand. This interesting characteristic is attributed to the increased distance between the azodye molecule and the Ag NP surface due to the presence of the intervening Br₂. As shown in Fig. S9,^† the MM2 molecular mechanics calculations support this hypothesis.The influence of the concentration of Ag NPs, different excitation wavelengths, and doping method on the fluorescence enhancement effect was evaluated in detail (Fig. S8(b–d) and S10^†). The fluorescence quantum yield and fluorescence lifetime of the azodye functionalised Ag NPs were determined, as shown in Fig. S11, S12 and Table S1.^†To investigate the viability of halogen-bonded liquid crystals for application as sensors in metal pollution, inspired by the above-mentioned intensification phenomenon of the MEF and SERS of the organic and inorganic hybrid liquid crystal, 12Br was used for detecting silver components under realistic conditions, such as liquid waste produced in the preparation of conductive silver ink and tap water. As shown in Fig. 5(a), the diffraction peaks of Ag (200), (220), and (311) planes of Ag NPs in liquid waste are located at 45°, 64°, and 74°, respectively; thus, recovering silver from the waste liquid. Thereafter, trace amounts of silver were further detected in tap water. Although the content of silver in the tap water was extremely low, the detection signals of the Ag (111) and (200) planes at 2θ = 38° and 45° could also be detected by 12Br due to the interaction between 12Br and silver in water with high sensitivity.Open in a separate windowFig. 5The XRD pattern and Raman spectra of 12Br in liquid waste produced from the preparation of conductive silver ink and tap water (100 mg mL⁻¹), respectively.In addition to XRD characterisation, we studied the detection of silver in liquid waste and tap water via Raman spectroscopy. Compared to 12Br–Ag, the Raman peak of the bromine stretching vibration frequency of 12Br appeared at 222.4 cm⁻¹ and 166.8 cm⁻¹, but no SERS signals were detected because of weak interaction obtained by mixing them directly, as shown in Fig. 5(b). Instead, the N N stretching and azobenzene quadrant stretching at 1414 cm⁻¹ and 1452 cm⁻¹ became active due to the interaction of the azobenzene ring and N atom with silver. These results confirm that the 12Br halogen-bonded liquid crystal is capable of detecting silver in a water environment and has the potential to transform metal pollution into valuable organic–inorganic hybrid mesogenic materials.In conclusion, Br₂ was successfully introduced as a bridge between Ag NPs and the AzoPy ligand by electrostatic interaction and halogen bonding at the Ag NP surface and azodye end, respectively, thereby displaying liquid crystalline properties with the intensification of the MEF and SERS. The 12Br–Ag was difficult to orientate by the alignment layers of the cell in the liquid crystal temperature but could orientate after the annealing treatment at room temperature. More importantly, the bromine-bonded complex was used as a sensor for detecting silver in aqueous fluids and was capable of transforming waste metal pollution into valuable organic–inorganic hybrid liquid crystals for potential ultrasensitive detection in the water-environment monitoring and analytical chemistry.