Is sperm cryopreservation at -150 degree C a feasible alternative?

A series of experiments was carried out to validate a -150 degree C ultra-low temperature freezer for its possible use to properly freeze and store semen. In the first part, crude sample handling was simulated to see whether temperature of stored samples was maintained within a safe range; also, the freezing point and latent heat of fusion plateau of a semen extender were monitored. In the second part, buck semen was (i) frozen in liquid nitrogen and stored in the ultra-low freezer, (ii) frozen and stored in the ultra-low freezer, and (iii) frozen and stored in liquid nitrogen, to compare sperm cryosurvival between freezing methods. Both, frequent removal of samples and long opening of the freezer door did not negatively affect stored sample temperature; latent heat of fusion plateau was 5 minutes long. Semen stored either at -150 degree C or at -196 degree C cryosurvived similarly after 2 days and after 2 months of cryopreservation.     

Biomolecular solid state NMR with magic-angle spinning at 25K

A magic-angle spinning (MAS) probe has been constructed which allows the sample to be cooled with helium, while the MAS bearing and drive gases are nitrogen. The sample can be cooled to 25 K using roughly 3 L/h of liquid helium, while the 4-mm diameter rotor spins at 6.7 kHz with good stability (±5 Hz) for many hours. Proton decoupling fields up to at least 130 kHz can be applied. This helium-cooled MAS probe enables a variety of one-dimensional and two-dimensional NMR experiments on biomolecular solids and other materials at low temperatures, with signal-to-noise proportional to 1/T. We show examples of low-temperature ¹³C NMR data for two biomolecular samples, namely the peptide Aβ_14–23 in the form of amyloid fibrils and the protein HP35 in frozen glycerol/water solution. Issues related to temperature calibration, spin–lattice relaxation at low temperatures, paramagnetic doping of frozen solutions, and ¹³C MAS NMR linewidths are discussed.     

A simple osmotic stress test to predict boar sperm cryosurvival

This work was carried out to test whether viability of pig spermatozoa subjected to an osmotic test is correlated to sperm cryosurvival. Spermatozoa were cooled from 22 degrees C to -5 degrees C, aliquots were exposed to a series of hyperosmotic solutions (300-2100 mOsm/kg) for 15 min, immediately spermatozoa were re-warmed to 37 degrees C and isosmolarity was restored. Spermatozoa were cooled from 22 degrees C to -5 degrees C and one aliquot was exposed to the osmotic test while diluted spermatozoa were frozen-thawed. Plasma membrane-intact spermatozoa decreased as osmolarity increased (P < 0.0001), a further decreased (P < 0.0001) was observed when isotonicity was restored. Proportions of plasma membrane-intact and acrosome-intact cells from the osmotic test were no different from those after freeze-thawing: 36% vs. 35%, 80% vs. 80%, respectively. A significant correlation was found between the proportion of acrosome-intact cells after freeze-thawing and that from the osmotic test (r = 0.81, P <0.01). This test provides a useful and economical mean to predict in vitro boar sperm cryosurvival.     

Measuring the quantum state of a large angular momentum

We demonstrate a general method to measure the quantum state of an angular momentum of arbitrary magnitude. The (2F+1)x(2F+1) density matrix is completely determined from a set of Stern-Gerlach measurements with (4F+1) different orientations of the quantization axis. We implement the protocol for laser cooled Cesium atoms in the 6S(1/2)(F = 4) hyperfine ground state and apply it to a variety of test states prepared by optical pumping and Larmor precession. A comparison of input and measured states shows typical reconstruction fidelities F >/~0.95.     

Effect of the extender supplement Equex-STM on cryopreserved semen in the Assaf sheep

This study was designed to evaluate the effect of adding the detergent Equex-STM to the extender used to dilute semen for cryopreservation on several indicators of sperm preservation. Two consecutive ejaculates per day were obtained from 5 Assaf sheep on two days out of every week over three alternate months. The freezing protocol involved diluting the semen in Fiser's extender, to which 0.7 percent Equex-STM was added or omitted before cryopreserving the semen in straws by exposure to nitrogen vapor. Equex-STM supplementation gave rise to significantly (p=0.05) improved sperm quality variables after different periods of freezing (0 hours, 1 week and 1 month). The variables examined were: individual motility, viability, acrosome integrity, plasma membrane integrity (HOS test) and morphological anomalies. This improvement was independent of the ram and month of testing. In a second experiment in which we incubated the semen (0 and 6 hours) at 37 degree C after thawing, Equex-STM also showed a beneficial effect on sperm quality.     

Simple and inexpensive method for cryopreservation of fish sperm combining straw and powdered dry ice

Here, we propose a simple and inexpensive method for fish sperm cryopreservation. Sperm samples of the loach Misgurnus anguillicaudatus (Teleostei: Cobitidae) were diluted 7-fold by an extender containing 63.5 mM NaCl, 114 mM KCl, 20 mM Tris and 10% methanol. The cryogenic straws were placed in three kinds of self-made tubes which diameter was changed by commercially available materials and then immersed into powdered dry ice for 2 min and plunged into liquid nitrogen. This procedure resulted in a cooling rate at -421.4 +/- 119.84 (control), -55.8 +/- 4.32 (tube 1), -40.2 +/- 3.43 (tube 2) and -33.3 +/- 2.09 C/min (tube 3). In the slowest cooling rate by the tube 3, total motility (72 +/- 3 %), duration (146 +/- 12 s) and hatching rates (29 +/- 04 %) were higher than those by other rates. Progressive motility (83 +/- 5 %) did not differ significantly from fresh samples.     

电感耦合等离子体发射光谱法测定有机染料油溶红中八个杂质元素

本文提出用电感耦合等离子体发射光谱法 (ICP- AES)同时测定有机染料油溶红产品中 Fe、Al、Cu、Pb、 Zn、 Cr、 Mn、 Ti等八个杂质元素的分析方法。试样前处理采用 H2 SO4、 HNO3分步炭化 ,5 0 0℃灰化 ,灰分用 HCl+ H2 O2 预溶解 ,再用 VHCl∶ VHNO3 =1∶ 1混酸提取。该法检出限 :0 .15 (mg· L- 1 ) Fe;1.7×10 - 2 (mg· L- 1 ) Al;5 .0× 10 - 3 (m g·L- 1 ) Cu;0 .2 0 (mg· L- 1 ) Pb;2 .7× 10 - 2 (mg· L- 1 ) Zn;5 .7×10 - 3 (m g· L- 1 ) Cr;1.3× 10 - 3 (m g·L- 1 ) Mn;2 .1× 10 - 3 (mg· L- 1 ) Ti。精密度 RSD(n =5 ) 0 .8%～ 2 1.5 %。加标回收率 84.6 %～ 118.6 %。     

核酸-桑色素-铝(Ⅲ)三元荧光体系的研究

基于核酸对桑色素 铝 (Ⅲ )配合物的荧光增强作用 ,以桑色素 铝 (Ⅲ )为荧光探针 ,考察该探针与核酸的结合反应 ,建立了新的准确测定核酸的方法 ,并研究了该三元荧光体系的作用机理。在 pH 8 5时 ,fsDNA ,ctDNA ,smDNA和 yRNA的浓度与桑色素 铝 (Ⅲ )的荧光强度成线性关系 ,响应范围分别为 0 2 5～1 5 0 ,0 2 5～ 2 0 0 ,0 10～ 1 6 0和 0 2 5～ 2 0 0 μg·mL-1,检测限 (3σ/K)分别为 3,2 ,2和 3ng·mL-1。测定了合成样品 ,回收率 93 3%～ 10 7 9% ,相对标准偏差小于 3 6 %     

High precision measurement of the static dipole polarizability of cesium

The cesium 6(2)S(1/2) scalar dipole polarizability alpha(0) has been determined from the time-of-flight of laser cooled and launched cesium atoms traveling through an electric field. We find alpha(0)=6.611+/-0.009 x 10(-39) C m(2)/V=59.42+/-0.08 x 10(-24) cm(3)=401.0+/-0.6a(3)(0). The 0.14% uncertainty is a factor of 14 improvement over the previous measurement. Values for the 6(2)P(1/2) and 6(2)P(3/2) lifetimes and the 6(2)S(1/2) cesium-cesium dispersion coefficient C6 are determined from alpha(0) using the procedure of Derevianko and Porsev [Phys. Rev. A 65, 053403 (2002)]].     

Cryopreservation of sea urchin (Evechinus chloroticus) sperm

A method was developed for cryopreserving sperm of the sea urchin, Evechinus chloroticus. Sperm fertilisation ability, mitochondrial function and membrane integrity were assessed before and after cryopreservation. Highest post-thaw fertilisation ability was achieved with lower concentrations (2.5%-7.5%) of dimethyl sulphoxide (DMSO). In contrast, post-thaw mitochondrial function and membrane integrity were higher for sperm frozen in intermediate and high DMSO concentrations (5%-15%). Surprisingly, some sperm frozen in seawater only, without DMSO, were able to survive post-thawing, although the fertilisation ability (10(6) sperm/ml; approximately 50% fertilisation), mitochondrial function and membrane integrity of these sperm were notably lower than of sperm frozen with DMSO (10(6) sperm cells/ml; 2.5%-7.5% DMSO; >85% fertilisation) at the concentrations tested. Amongst sperm from individual males, fertilisation ability varied before and after cryopreservation for both males frozen with and without cryoprotectant. Specific differences among males also varied. Sperm mitochondrial function and membrane integrity was similar among males before cryopreservation but differed considerably after cryopreservation. Cryopreserved sperm were able to fertilise eggs and develop to pluteus stage larvae. This study has practical applications and will provide benefits such as reduced broodstock conditioning costs, control of parental input and opportunities for hybridisation studies.     

五磷酸镧钕激光晶体发光的温度效应

研究了低温下Nd0.9 La0.1 P5O14晶体中,Nd3+离子在0.9,1.05,以及1.35μm附近发光光谱的精细结构及相应的跃迁过程,并与Nd:YAG晶体中Nd3+离子发光光谱及相应的跃迁作了比较。在77K-500K的温度变化范围内,研究了Nd3+在两种晶体中最强的发光线的温度依赖关系,发现相反的变化规律,指出这是与两种晶体的结构及跃迁过程有关。     

阿奇霉素含量的荷移光谱法测定

用分光光度法分别研究了阿奇霉素与7,7,8,8-四氰基对二次甲基苯醌(TCNQ)和氯冉酸(CL)之间的荷移反应。实验表明：阿奇霉素与TCNQ间的反应在丙酮介质中进行,形成的络合物在743和842 nm有两个吸收峰,表观摩尔吸光系数分别是2.7×104 L·mol-1·cm-1和5.0×104 L·mol-1·cm-1;阿奇霉素与氯冉酸的反应在丙酮介质中进行,形成的络合物在530 nm处有吸收峰,表观摩尔吸光系数2.4×103 L·mol-1·cm-1。用摩尔比法和等摩尔连续变化法测得荷移络合物中阿奇霉素与配体的摩尔比均为1∶2。用以上两种方法测定了阿奇霉素片剂中阿奇霉素的含量,相对标准偏差为1.0%～1.4%(n=6),回收率为97%以上,与标准方法比较结果准确。     

Highly efficient, 0.84 slope efficiency, 901 nm, quasi-two-level laser emission of Nd in strontium lanthanum aluminate

The possibility of using direct pumping into the emitting level of the Nd3+ ion in magnesium-compensated strontium lanthanum aluminate (Sr(1-x)La(x-y)Nd(y)Mg(x)Al(12-x)O19) to improve 900 nm 4F(3/2) --> 4I(9/2) laser emission is discussed. Selection of the composition parameters x and y for optimization of laser emission and reduction of heat generation is based on the spectroscopic and crystal growth characteristics. Pumping in the 865.5 nm absorption band 4I(9/2)(Z1) --> 4F(3/2)(R1) transforms the laser process into a quasi-two-level scheme of very low (below 4%) quantum defects. A very high slope efficiency (over 84%) for 901 nm continuous-wave laser emission is demonstrated with Ti:sapphire laser pumping in this band for a crystal with x = 0.4 and y = 0.05.     

DSC studies of freezing in terrestrial enchytraeids (Annelida: oligochaeta)

Specimens of six enchytraeid species from a wide range of terrestrial habitats were cooled to -25 degree C and rewarmed at 1 degree C/min and their cryobiological features measured by DSC. All were freezing intolerant, supercooling on average to c.-9 degree C. The quantity of frozen (osmotically active) water, calculated from the melt endotherm, varied considerably from 17 to 62% depending on the species and formed three groups. It is suggested that variation in the amount of water frozen in the worms reflects the acclimatisation of these species to the environmental conditions of their habitats.     

全氟羧酸钕2,2’-联吡啶配合物的合成及其光学特性

合成了一系列全氟羧酸钕2,2’-联吡啶配合物:Nd(CF3COO)3.Dipy,Nd(C2F5COO)3.Dipy和Nd(C3F7COO)3.Dipy,并通过红外光谱、元素分析、热分析、紫外可见近红外吸收光谱和荧光光谱对其进行了表征。配合物的分解温度都高于260℃,最大失重温度超过340℃,说明它们具有良好的热稳定性。全氟羧酸的碳链长度和钕离子配位结构的差异,引起配合物的吸收跃迁强度的变化。根据紫外可见近红外吸收图谱,计算获得了Judd-Ofelt参数和受激辐射跃迁特性。配合物的受激发射面积分别为:3.63×10-20,2.36×10-20和1.49×10-20 cm2,可以和文献报道的无机材料媲美,它们将是非常有潜力的液体激光介质。     

Sub-Hertz optical frequency comparisons between two trapped 171Yb+ ions

We compare the frequencies of the 6s2S(1/2)(F = 0)-->5d2D(3/2)(F = 2) reference transition in 171Yb+ for two single ions stored in independent traps. The quadrupole moment of the 5d2D(3/2) state is measured to be 9.32(48) x 10(-40) C m2 and from the quadratic Stark shift the relevant scalar and tensor polarizabilities are determined to be alphaS(S(1/2)) - alphaS(D(3/2)) = -6.9(1.4) x 10(-40) J m2/V2 and alphaT(D(3/2)) = -13.6(2.2) x 10(-40) J m2/V2, respectively. In the absence of external perturbations we find a mean frequency difference between the two trapped ions of 0.26(42) Hz, corresponding to a relative difference of 3.8(6.1) x 10(-16). This is comparable to the agreement found in the most accurate comparisons between cesium fountain clocks.     

Cryopreservation of rabbit spermatozoa with freezing media supplemented with reduced and oxidised glutathione

This study researches the effects of supplementation with reduced glutathione (GSH, 0.5 mm) and oxidised glutathione (GSSG, 0.5 mM) freezing extenders on different semen parameters after equilibration with DMSO preservation solution (45 min at 5 degrees C) and post-thawing. The main findings that emerged from this study are that (i) addition of GSH and GSSG to the freezing media did not result in any improvement in functional sperm tests after equilibrium phase. (ii) No differences were observed after cryopreservation in functional sperm tests and embryo recovery rate. In conclusion, the addition of 0.5 mM GSH or GSSG appears not to play an important role in sperm antioxidant defence during cooling and freezing in rabbit spermatozoa.     

Mössbauer studies of frozen aqueous solutions of iron-II chloride

This paper deals with Mössbauer measurements of frozen solutions of FeCl₂ in water in the temperature range from ?180 °C to their melting point. For thermally quenched solutions 3 different states, connected by irreversible transitions, are observed in quadrupole splittings and isomer shifts. For slowly cooled solutions two different phases, connected by an irreversible transition, are likewise observed. In both cases, those phases persistent until the melting point, are identical.     

掺Co钨酸镉单晶体的坩埚下降生长及光谱特性

应用坩埚下降法,采用70℃.cm-1的固液界面温度梯度与0.50 mm.h-1生长速度,生长出了初始Co掺杂摩尔百分浓度为0.5 mol%、尺寸为Ф25 mm×120 mm的钨酸镉单晶体。晶体呈透明深蓝色。用XRD表征了获得的晶体。观测到518,564和655 nm三个可见波段吸收带以及发光中心1 863 nm(1 323～2 220 nm)的超宽吸收带。可见波段的吸收归属于Co2+在八面晶格场中4T1(4F)→4A2(4F),4T1(4F)→4T1(4P)跃迁叠加,而红外波段的宽带吸收则为八面体场Co2+的4T1(4F)→4T2(4F)能级跃起所致。从吸收特性表明,Co离子掺杂于畸变的氧八面体中,呈现+2价态。根据吸收光谱计算出晶格场参数Dq=990 cm-1,Racah参数BC=726.3 cm-1。在520 nm波长光的激发下,观察到778 nm波段的荧光发射,归属于八面体晶格场中Co2+的4T1(4P)→4T1(4F)能级的跃迁。从吸收与荧光强度的变化推断:沿着晶体生长方向,Co2+浓度逐渐增加,有效分凝系数小于1。     

Low-temperature solution of the Sherrington-Kirkpatrick model

I propose a simple scaling ansatz for the full replica symmetry breaking solution of the Sherrington-Kirkpatrick model in the low energy sector. This solution is shown to become exact in the limit x --> 0, Bx --> infinity of the Parisi replica symmetry breaking scheme parameter . The distribution function of the frozen fields has been known to develop a linear gap at zero temperature. The scaling equations are integrated to find an exact numerical value for the slope of the gap thetaP(x,y)/delta|(y --> 0) = 0.301 046.... I also use the scaling solution to devise an inexpensive numerical procedure for computing finite time scale (x =1) quantities. The entropy, the zero field cooled susceptibility, and the local field distribution function are computed in the low-temperature limit with high precision, barely achievable by currently available methods.