全冠黏固后出现龈缘炎,其可能的原因,除以下哪项() A.轴壁突度不良 B.冠边缘过长

题型:单项选择题 A1型题

问题:

全冠黏固后出现龈缘炎,其可能的原因,除以下哪项()

A.轴壁突度不良

B.冠边缘过长

C.冠边缘不密合

D.龈沟内黏固剂残留

E.咬合早接触

考点:口腔执业助理医师口腔执业助理医师资格考试模拟试题(二)第二单元
题型:单项选择题 A1型题

写出下列事物的发明者。

1.蒸汽机——_____________

2.飞机——_____________ 

3.电话——_____________

4.电灯——_____________

5.降落伞——_____________

题型:单项选择题 A1型题

用CH4催化还原NOx可以消除氮氧化物的污染。已知:

①CH4(g)+4NO2(g)=4NO(g)+CO2(g)+2H2O(l) △H=-574 kJ/mol

②CH4(g)+4NO(g)=2N2(g)+CO2(g)+2H2O(g) △H=-1160 kJ/mol

③H2O(g)=H2O(l) △H=-44kJ/mol。下列说法不正确的是

A.等物质的量的CH4参加反应,反应①②转移的电子数相同

B.CH4(g)+4NO2(g)=4NO(g)+CO2(g)+2H2O(g)△H=-530 kJ/mol

C.0.2 mol CH4还原NO2至N2,且生成H2O(g)放出的热量为164.6 kJ

D.若用4.48 L(标准状况)CH4还原NO2至N2且生成H2O(g),整个过程中转移电子1.60 mol

题型:单项选择题 A1型题

百会穴在头正中线上,其具体位置在()

A.入前发际7寸

B.入前发际5寸

C.入后发际6寸

D.头顶旋毛中

E.两耳连线上

题型:单项选择题 A1型题

Imagine eating everything delicious you want with none of the fat. That would be great, wouldn’t it

New "fake fat" products appeared on store shelves in the United States recently, but not everyone is happy about it. Makers of the products, which contain a compound called olestra, say food manufacturers can now eliminate fat from certain foods. Critics, however, say the new compound can rob the body of essential vitamins and nutrients and also cause unpleasant side effects in some people. So it’s up to consumers to decide whether the new fat-free products taste good enough to keep eating.

Chemists discovered olestra in the late 1960s, when they were searching for a fat that could be digested by infants more easily. Instead of finding the desired fat, the researchers created a fat that can’t be digested at all.

Normally, special chemicals in the intestines (肠道) "grab" molecules of regular fat and break them down so they can be used by the body. A molecule of regular fat is made up of three molecules of substances called fatty acids.

The fatty acids are absorbed by the intestines and bring with them the essential vitamins A, D, E and K. When fat molecules are present in the intestines with any of those vitamins, the vitamins attach to the molecules and are carried into the bloodstream.

Olestra, which is made from six to eight molecules of fatty acids, is too large for the intestines to absorb. It just slides through the intestines without being broken down. Manufacturers say it’s that ability to slide unchanged through the intestines that makes olestra so valuable as a fit substitute. It provides consumers with the taste of regular fat without any bad effects on the body. But critics say olestra can prevent vitamins A, D, E and K from being absorbed. It can also prevent the absorption of carotenoids (类胡萝卜素), compounds that may reduce the risk of cancer, heart disease, etc.

Manufacturers are adding vitamins A, D, E and K as well as carotenoids to their products now. Even so, some nutritionists are still concerned that people might eat unlimited amounts of food made with the fat substitute without worrying about how many calories they are consuming.

Olestra is different from ordinary fats in that ()。

A. it facilitates the absorption of vitamins by the body

B. it passes through the intestines without being absorbed

C. it helps reduce the incidence of heart disease

D. it prevents excessive intake of vitamins

题型:单项选择题 A1型题

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