甘肃陇南山区低品位氧化金矿的开发利用

甘肃陇南山区分布着较为广泛的低品位氧化金矿,其特点是带状分布、规模大、品位低。可采用就地产金方案(池浸、堆浸氰化提金工艺),投资少、见效快,当年投资当年还本,投资利润率高,具备开发利用的可行条件。     

甘肃陇南山区低品位氧化金矿的开发利用

甘肃陇南山区分布着较为广泛的低品位氧化金矿 ,其特点是带状分布、规模大、品位低。可采用就地产金方案 (池浸、堆浸氰化提金工艺 ) ,投资少、见效快 ,当年投资当年还本 ,投资利润率高 ,具备开发利用的可行条件。     

甘肃陇南山区低品位氧化金矿的开发利用

甘肃陇南山区分布着较为广泛的低品位氧化金矿，其特别是带状分布、规模大、品位低。可采用就地产金方案（池浸、堆浸氰化提金工艺），投资少、见效快，当年投资当年还本，投资利润率高，具备开发利用的可行条件。     

Lead impregnation in inhabitants of the Rabat region (Morocco)

OBJECTIVES: No current data is available on plumbism in Morocco. We conducted this work to evaluate blood lead levels in inhabitants of the Rabat region. PATIENTS AND METHODS: The study included 385 subjects, 300 men and 85 women, age range 18-55 years, who were volunteer blood donors at the Rabat blood bank. All subjects responded to a short questionnaire concerning type of lodging cigarette smoking, occupation. Blood lead levels were assayed by inductively coupled plasma-mass spectrometry (ICPMS). RESULTS: Mean blood lead levels for all subjects was 86.9 +/- 42.1 micrograms/l (92.9 +/- 51.7 micrograms/l for men and 80.9 +/- 32.6 micrograms/l for women). Blood lead levels increased more rapidly with age in women than in men. Levels in subjects who lived in residential urban areas were lower than those living in the old Arab center. Levels were higher in smokers than in non-smokers and in subjects with an employment than in those without. CONCLUSION: Mean blood lead levels in the Rabat region are similar to those currently observed in other countries where this same type of study has been conducted. Similar factors are associated with high mean blood lead levels.     

Estimation of the cytogenetic homeostasis in natural populations of small murine rodents from the Lower (Astrakhan') and Middle (Chapaevsk) Volga regions

Frequencies of chromosomal aberrations were estimated in the bone marrow of two background small rodent species, the bank vole (Clethrionomys glareolus) and the house mouse (Mus musculus) from the middle (Chapaevsk, Samarskaya oblast) and lower (Astrakhanskaya oblast) Volga regions. The majority of chromosomal aberrations were chromatid deletions. In the studied species, cytogenetic disturbances were most prevalent in areas where the anthropogenic environmental pollution was maximum. The lowest frequencies of disturbances were observed in the control areas, where the environmental pollution was insignificant. Thus, anthropogenic exposure caused disturbances of cytogenetic homeostasis in different small rodents living in different regions.     

Scorpion stings outbreaks in recently constructed urban dwellings inhabitants

Scorpion stings are unfrequent in Chile. Most of cases occur in rural areas during the warm season. Clinical manifestations have a low to moderate intensity and consist in local pain and inflammation, sometimes associated with headache and hyperthermia. Two autbreaks of scorpion stings--affecting six and five adult residents (18-42 years old) of recently built urban dwelling complexes--have been recorded in Chile in summertime of 1957 and 1998. The first took place in the town of Maipú and the second in Villa Alborada sites respectively 10 and 150 km South of the city of Santiago. The Maipú dwelling complex was constituted by 112 one story houses in which lived 504 people. In Villa Alborada live 1,050 persons distributed in 158 apartments, 86 of which are in the main floor and in 26 of these last the occupants have observed scorpions inside. All the 11 cases occurred into the dwelling: four when sleeping at night, three performing different activities (trying to find a tool, searching a kee, housekeeping), two when putting their shoes, and two walking with bare feet in dormitory. In all the cases the causative scorpion was observed, captured or destroyed. Identification of six specimens from Maipú corresponded to Brachistoternus ehrenbergi and of two from Villa Alborada to Bothriurus borrelianus. All the patients presented mild to moderate symptomatology. Treatment consisted basically in oral antihistamanic and/or antinflammatory tablets. Recovery was observed within one to seven days with a mean of three days. Prophylactic measures consisted in health education and physical destruction of scorpions in Maipú and insecticide spraying on floors of basement apartments and surrounding areas in Villa Alborada. Though the majority of accidents by scorpion stings happens in rural areas, also may occur in urban areas--rural in the near past--where dwellings have been constructed in fields which in not to much preterit times constituted the habitat of the referred arthropod, phenomenom that have occurred in summertime in the two dwelling complexes described in the present communication.     

Dynamics of morphometric parameters of skeletal bone in inhabitants of Saint-Petersburg

2102 roentgenograms of the left manus bones from both sexes subjects with normal health status aged up to 18 were studied to detect peculiarities of skeleton maturity of St. Petersburg inhabitants. TW-2 modified Tanner-Whitehouse method was used. It was demonstrated that children living in St. Petersburg are characterized with the excess of skeletal age over chronological one almost in all age groups, which is maximum typically during first years and minimum by the end of puberty. The process of bone maturity is not successive. Highest growth rate of skeletal maturity were found in prepubescent and puberty. Sex differences established are also noted. Girls were above boys in skeletal age at 7, 8, 9 and 10 years.     

Late changes in the body function of the inhabitants in the area of the eastern Urals radioactive trace

Using a mathematical methodology based upon the theory of pattern recognition, the adequacy of this methodology being confirmed by the corroborative results obtained with neuro-net non-parametric methods of analysis, it proved possible to discriminate reliably between generalized organism's statuses, as described with a big number of laboratory indices, of the inhabitants of different areas of a big industrial city which differ in levels of radioactive and non-radioactive environmental pollution.     

永磁磁系磁流体静力分选的研究

本文详细地论述了永磁磁系磁流体静力分选的基本原理。并介绍了ＴＭ－９３型磁流体单矿物分选仪的结构、特性以及分选介质的特点。通过使用该仪器分选四类矿物组合样，进一步说明了分选仪的应用范围和分选效果。     

Epidemiological evaluation of incidence of lung cancer in inhabitants of Warsaw in the period 1966--1975

Lung cancer is most frequent in men and occupies the first place among the causes of cancer deaths. In the period 1956--1975 in Poland the incidence rate of lung cancer increased about ten times in men and seven times in women. Analysis of age-specific incidence shows a significant increase in the group age of 35--39 years in men and in 45--49 in women. The absolute increase of incidence of lung cancer, the poor prognosis and the high mortality should call the attention of the whole population to canecerogenic factors, especially the noxious influence of smoking.     

Calcium homeostasis in aged neurones

Mechanisms of cytoplasmic calcium homeostasis were investigated in peripheral and central neurones isolated from neonatal, adult and old Wistar rats and in granule neurones in acutely prepared cerebellar slices of adult and old CBA mice. The cytoplasmic calcium concentration ([Ca2+]i) was measured by either indo-1-or fura-2-based microfluorimetry. The resting [Ca2+]i was significantly higher in senile neurones. The depolarization-induced [Ca2+]i transients were markedly altered in old neurones when compared with adult ones: the age-associated changes in stimulus-evoked [Ca2+]i signalling comprised of (i) significant decrease of the amplitudes of [Ca2+]i transients; (ii) prolongation of the rising phase and (iii) prominent deceleration of the recovery of the [Ca2+]i elevation towards the resting level after the end of depolarization. The amplitudes of calcium release from caffeine/Ca(2+)-sensitive endoplasmic reticulum calcium stores became significantly smaller in old central neurones, whereas they remained unaffected in peripheral neurones. Based on our observations we can conclude that ageing of the nervous system is associated with significant changes in mechanisms of [Ca2+]i homeostasis in individual neurones. These changes lead to a stable increase in the resting [Ca2+]i and to a substantial prolongation of stimulus-evoked [Ca2+]i signals. We could suggest also that the ability of the old neurones to handle Ca2+ loads is diminished, which may determine higher vulnerability of aged neurones to excess of calcium ions.     

Ten-year blood pressure trends in nonhypertensive inhabitants of La Plata, Argentina

OBJECTIVES: To compare, according to blood pressure (BP) categories, 10-year trends in BP measurements in nonhypertensive subjects and the relative risk of developing hypertension. DESIGN: Population study. BP was recorded as the average of two measures taken on a single occasion with a mercury sphygmomanometer and the auscultation method. SETTING: Residents of La Plata, aged 15 to 64 years. PARTICIPANTS: The study was based on randomly chosen individuals who, during a previous survey in 1985, were 15 to 64 years old and whose BP was below 140/90 mmHg. They were grouped according to sex and BP categories. Random age- and sex-stratified sampling of 151 men and 193 women was performed. Categories were high normal BP, optimal BP (as defined by the fifth report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure) and normal but not optimal BP defined as BP 120 to 129/80 to 84 mmHg. RESULTS: BP increased in all categories; this increase was significant (P < 0.01) except for diastolic BP in women with high normal BP. BP increases were higher in optimal BP subjects and lower in high normal BP subjects (P < 0.01 for women and not significant for men). The relative risk of developing hypertension in high normal BP subjects was triple that in optimal BP subjects (P < 0.01). CONCLUSIONS: Increases in BP observed in optimal BP subjects stress the importance of monitoring BP changes and recommending primary prevention in the whole population.     

Chernobyl accident: reconstruction of thyroid dose for inhabitants of the Republic of Belarus

The Chernobyl accident in April 1986 resulted in widespread contamination of the environment with radioactive materials, including (131)I and other radioiodines. This environmental contamination led to substantial radiation doses in the thyroids of many inhabitants of the Republic of Belarus. The reconstruction of thyroid doses received by Belarussians is based primarily on exposure rates measured against the neck of more than 200,000 people in the more contaminated territories; these measurements were carried out within a few weeks after the accident and before the decay of (131)I to negligible levels. Preliminary estimates of thyroid dose have been divided into 3 classes: Class 1 ("measured" doses), Class 2 (doses "derived by affinity"), and Class 3 ("empirically-derived" doses). Class 1 doses are estimated directly from the measured thyroidal (131)I content of the person considered, plus information on lifestyle and dietary habits. Such estimates are available for about 130,000 individuals from the contaminated areas of the Gomel and Mogilev Oblasts and from the city of Minsk. Maximum individual doses are estimated to range up to about 60 Gy. For every village with a sufficient number of residents with Class 1 doses, individual thyroid dose distributions are determined for several age groups and levels of milk consumption. These data are used to derive Class 2 thyroid dose estimates for unmeasured inhabitants of these villages. For any village where the number of residents with Class 1 thyroid doses is small or equal to zero, individual thyroid doses of Class 3 are derived from the relationship obtained between the mean adult thyroid dose and the deposition density of (131)I or 137Cs in villages with Class 2 thyroid doses presenting characteristics similar to those of the village considered. In order to improve the reliability of the Class 3 thyroid doses, an extensive program of measurement of (129)I in soils is envisaged.     

Acute mountain sickness in the Southern Alps of New Zealand

AIM: To assess the incidence and impact of acute mountain sickness in the Southern Alps of New Zealand. METHODS: Over a 22 month period, mountaineers in the Mount Cook region were asked to complete a questionnaire at the completion of their climbing excursions. The questionnaire recorded demographic data and incorporated the Lake Louise scoring system to assess the presence of acute mountain sickness. RESULTS: Of the 114 subjects who completed the questionnaire, 30 (26%) developed acute mountain sickness. The incidence was higher amongst those who slept above 2500 m (50%). Of those with acute mountain sickness, 33% reported that their symptoms resulted in no reduction in activity, while 13% reported a moderate or severe reduction in activity. CONCLUSION: Mountaineers climbing in New Zealand's Southern Alps should be aware of the risk of acute mountain sickness, especially for those sleeping above 2500 m.