已知同阶数字矩阵$A,B$的秩相同。若$A=A^{2},B=B^{2}$,则结论不正确的是( )。
C.
$\lambda E-A$与$\lambda E-B$的秩相同
Hershey and Chase use phage Viruses as working model. was used to label the DNA contained in the T2 phage, used to label the protein sections of the T2 phage.()
A.
Phosphorus-32, sulfur-35
B.
Phosphorus-30, sulfur-35
C.
Phosphorus-32, sulfur-32
D.
Phosphorus-30, sulfur-32
The central dogma of molecular biology describes the two-step process, transcription and translation, by which the information in genes flows into proteins: DNA → RNA → protein.()
若矩阵$A$的全部初等因子为(l-1)2,(l+1)2,则其有理标准形矩阵为( )。
Okazaki fragments are short sequences of DNA nucleotides which are synthesized discontinuously Okazaki fragments were later linked together by the enzyme DNA ligase to create the leading strand during...
RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, during the process of transcription.()
高分子材料的热导率很低,而金属是优良的导热体。()
Each of the three RNA polymerases in eukaryotes is responsible for transcribing a unique type of RNA.()
淋巴瘤错误的是()
B.
腹膜后淋巴结肿大,可融合成团,推移、包埋血管、
结构也是影响材料热膨胀系数的关键因素,键能越大,则膨胀系数()
神经节瘤强化方式()2. 神经母细胞瘤强化方式()A. 轻度均匀或不均匀强化B. 轻-中度均匀或不均匀强化C. 中-重度强化D. 重度强化
成熟畸胎瘤影像学特点()4. 未成熟畸胎瘤影像学特点()A. 囊性成分、钙化和脂肪成分较少,实性部分多不均匀强化B. 密度成分较混杂,可见较多脂肪、钙化、牙齿及毛发等成分C. 病变通常较大,周边水肿及出血少见D. 实性成分较多,呈均匀强化
氧指数越高的材料其阻燃特性越好,那么氧指数在22以下的属于()
RNA polymerase II is a multiprotein complex. It is one of the three RNAP enzymes found in the nucleus of eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and mo...
设$\alpha_{1},\alpha_{2},…,\alpha_{n}$是列向量空间$R^{n}$的标准正交基,若$A$是$n$阶可逆矩阵,则$A\alpha_{1},A\alpha_{2},…,A\alpha_{n}$还是$R^{n}$的标准正交基。
若$\alpha_{1},\alpha_{2},\alpha_{3}$是欧氏空间$V$的标准正交基,则下列向量组还是标准正交基的是( )。
A.
$\frac{1}{3}(2\alpha_{1}+2\alpha_{2}-\alpha_{3}),\frac{1}{3}(2\alpha_{1}-\alpha_{2}+2\alpha_{3}),\frac{1}{3}(\alpha_{1}-2\alpha_{2}-2\alpha_{3})$
B.
$2\alpha_{1}+2\alpha_{2}-\alpha_{3}, 2\alpha_{1}-\alpha_{2}+2\alpha_{3}, \alpha_{1}-2\alpha_{2}-2\alpha_{3}$
C.
$\frac{1}{3}(2\alpha_{1}-2\alpha_{2}-\alpha_{3}),\frac{1}{3}(2\alpha_{1}+\alpha_{2}+2\alpha_{3}),\frac{1}{3}(\alpha_{1}-2\alpha_{2}-2\alpha_{3})$
D.
$2\alpha_{1}-2\alpha_{2}-\alpha_{3}, 2\alpha_{1}+\alpha_{2}+2\alpha_{3}, \alpha_{1}-2\alpha_{2}-2\alpha_{3}$
子宫恶性肿瘤影像学特点()
A.
CT提示附件区或子宫直肠陷窝处得均一水样密度肿块,呈圆形或椭圆形,边缘光滑,壁薄,无内隔,增强扫描无强化
B.
子宫输卵管造影可见黏膜下肌瘤可产生圆形充盈缺损,大的肌瘤可致宫腔增大、变形
C.
当肿瘤晚期侵犯输尿管和膀胱时,尿路造影可发现输尿管、肾盂肾盏积水和膀胱壁不规则、僵硬
D.
CT提示子宫腔内可见软组织密度肿物,密度低于正常强化的子宫肌,肿瘤呈菜花状或结节状,周围可为更低密度的子宫腔内积液所环绕,也可填充全部子宫腔
A transfer RNA molecule is used in translation and consists of a single RNA strand that is only about 80 nucleotides long.()
Ribosomes are minute particles consisting of RNA and associated proteins that function to synthesize proteins.()
In eukaryotes and archaea, the amino acid encoded by the start codon is methionine.()
患者58岁。绝经后阴道出血3个月,妇科检查:阴道黏膜正常,宫颈光滑,子宫稍大。诊刮刮出内膜为烂肉样。盆腔CT平扫及增强示:子宫增大,子宫腔内可见软组织密度肿块,肿块呈菜花状,密度低于正常强化的子宫肌。()
3维欧氏空间R3 (取标准内积)中的向量(2, 3,-1), (1, 1, 0),(0, 1,-1)生成的子空间的正交补空间的维数是( )。
患者女性,绝经后不规则阴道流血,并有下腹部及腰部疼痛,CT提示子宫腔内可见软组织密度肿物,肿瘤呈菜花状或结节状,妇科检查宫颈口有突出物质,质脆,触之易出血。157.最可能的诊断为()
患者女性,绝经后不规则阴道流血,并有下腹部及腰部疼痛,CT提示子宫腔内可见软组织密度肿物,肿瘤呈菜花状或结节状,妇科检查宫颈口有突出物质,质脆,触之易出血。158.下面的CT表现错误的是()
若$\cal{A}$是有限维欧氏空间$V$的一个正交变换,则$\cal{A}$的不变子空间的正交补还是$\cal{A}$的不变子空间。
PCR primers for the qPCR step of RT-qPCR should ideally be designed to span an exon-exon junction, with one of the amplification primers potentially spanning the actual exon-intron boundary. ()
下列哪一项关于Ⅲ期和Ⅳ期子宫内膜癌MRI表现的描述是正确的()
A.
发生宫旁浸润时,显示肿瘤累及宫旁组织并使其信号发生改变
C.
肿瘤在T2WI上可显示中等信号的肿块延伸至宫颈,并扩张宫颈管
E.
腹膜种植表现为T1WI中等信号和T2WI高信号结节影
关于子宫解剖的MRI表现,描述不正确的是()
D.
子宫肌层T1加权像呈高信号 E 、子宫峡部位于宫颈和阴道交界处
In two-step RT-qPCR assays, the reverse transcription and PCR steps are performed in separate tubes, with different optimized buffers, reaction conditions, and priming strategies.()
A basic PCR set-up requires several components and reagents, Which of the following are included?()
已知三阶实对称方阵$A$有特征值2,2,3,且$(1,1,1)^{T}$是属于3的特征向量。则$A$的属于2的线性无关的特征向量是( )。
A.
$(1,-1,0)^{T},(1,0,-1)^{T}$
B.
$(-1,-1,2)^{T},(1,1,-1)^{T}$
C.
$(1,1,0)^{T},(1,0,-1)^{T}$
D.
$(1,-1,0)^{T},(2,1,-1)^{T}$
About step of gene clone, Which of the following are included?()
A.
Preparation of RNA to be cloned
B.
Creation of recombinant DNA with DNA ligase
C.
Introduction of recombinant DNA into host organism
D.
Screening for clones with desired DNA inserts and biological properties
已知三阶实对称矩阵$A$有特征值-1,且满足 $(1,1,0)A=(1,1,0),(0,0,1)A=(0,0,1)$,则$A$=( )。
患者女性,19岁,左下腹疼痛1个月。CT:左下腹111mm×120mm椭圆形囊性团块,边缘光滑,包膜完整,密度均匀,CT值26Hu,无强化,病变推移子宫、肠管。最先考虑()
Golden rice is a variety of rice produced through genetic engineering to biosynthesize beta-carotene, a precursor of vitamin A, in the edible parts of rice. It is intended to produce a food to be grow...
患者女性,40岁,一年前查体发现左下腹部直径约5cm实性肿物,未复查。一天前排尿时突然下腹痛,伴恶心,无发热。查体见子宫正常大,子宫左上方触及直径约14cm肿块,张力较大,不活动,有压痛。()
Most current GM crops have been engineered for resistance to insects, tolerance to herbicides or both.()
Mainly protein production includes three main steps, including().
C.
Protein quantification
关于卵巢囊性畸胎瘤的基本特征正确的是()
B.
液性脂肪部分呈短T1长T2信号,与皮下脂肪类似
设A是有限维欧氏空间$V$的一个对称变换,则下列结论正确的有( )。
Coding sequence is the candidate genes you are interested in, including().
A.
Herbicide residence gene
C.
Salt tolerance or nutritional enhancement gene
固体材料中原子的数量越多他们的相同原子能级分裂成的能级越多,即展宽成能带的带宽越大。()
若$A$是$3$阶实对称矩阵,且$A^{2}-E=0$。则$A$不能相似于( )。
People find that nearly all known enzymes are proteins. There are only a few RNA among them.()
The enzyme-catalyzed reaction is specific andan enzyme onlycatalyzes a single chemical reaction.()
光电导效应是通过何种手段使满带中的电子激发到导带的?()
Enzymes could accelerate the reaction rate and could alter the equilibrium of a chemical reaction.()
The most striking characteristics of enzymes are and .()
介电击穿是在强电场中,当电场强度超过某一临界值时,电介质就丧失其()
男,70岁,半年前出现尿频、尿急、尿流缓慢、尿流中断和排尿不尽,无血际。直肠指诊发现前列腺增大,质地硬,血清PSA为58ng/ml.TRUS检查发现前列腺体积增大,内部未见异常回声。为了进步鉴别诊断,应该选择下列哪种检查方法?()
The transition state is a transitory molecular structure that is no longer the substrate but is not yet the product.()
设$A$是$3$阶实对称矩阵,$r(A)=2$,$A^{2}=A$,则$\vert E+A+…+A^{5}\vert$=( )。
Much of the catalytic power of enzymes comes from their binding to and then altering the structure of the substrate to promote the formation of the transition state.()
男,67岁,临床表现为尿频、尿急、尿流缓慢、尿流中断和排尿不尽。直肠指论发现前列腺增大,质韧,边缘清楚,未触及不规则硬结。血清PSA为9ng/ml。最可能的诊断为:()
In enzyme–substrate binding induced-fit model, the active site of the unbound enzyme is complementary in shape to the substrate.()
男性,77岁。排尿困难多年。盆腔CT平扫前列腺为6.5cmx4.0cm,以中叶增大为主,并突入膀胱内。密度均匀。包膜完整。精囊腺境界清晰。最可能的诊断为:()
磁感应强度是描述磁场强弱和方向的物理量,用()表示,单位为特斯拉(符号为T)或(Wb·m-2)。
磁性大小,不仅取决于物质的原子结构,还取决于原子间的相互作用,它的键合情况和晶体结构。()
$P^{n\times n}$的对偶空间维数是( )。
Simple carbohydrates are called monosaccharides. These simple sugars serve not only as fuel molecules but also as fundamental constituents of living systems.()
The essence of catalysis is ().
A.
Speed up the rate of chemical reactions
B.
Alter the laws of thermodynamics
C.
Alter the equilibrium of a chemical reaction
D.
Facilitating the formation of the transition state
Glucose andfructosearean essential energy source for virtually all forms of life.()
某些物质中相邻原子磁矩同向排列,会发生自发磁化,这类物质为()物质
顺磁性物质的磁化率是抗磁性物质的()倍,所以在顺磁性物质中抗磁性被掩盖了。大多数金属都属于顺磁性物质。