[Effects of small GTP-binding protein GDP dissociation stimulator on adipocyte hypertrophy and glucose metabolism disorder in mice].

Objective: To explore the effect and mechanism of small GTP-binding protein GDP dissociation stimulator (SmgGDS) on the development of obesity. Methods: (1) 8-week-old C57BL/6J mice were randomly assigned to normal diet and high fat diet group, with 6 mice in each group. They were fed regular feed and a high fat diet containing 60% fat for 4 months, respectively. The expression of SmgGDS in epididymal adipose tissue (eWAT), liver, and skeletal muscle were measured using Western-blot. (2) 6-week-old wild-type (WT) and SmgGDS knockdown (KD) mice were divided into four groups, each receiving high fat diet for 4 months (7 in each group) and 7 months (9 in each group). Glucose tolerance test (GTT) and insulin tolerance test (ITT) were conducted; The weight, adipose tissue, and liver weight of mice were recorded; HE staining examined adipose tissue structural changes; Western-blot determined extracellular signal-regulated kinase (ERK) 1/2 phosphorylation levels in eWAT; Real time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect mRNA levels of CCAAT/enhancer binding protein α (C/EBPα), C/EBPß and peroxisome proliferator activated receptor γ (PPARγ) in eWAT. (3) Mouse embryonic fibroblasts (MEFs) extracted from WT and KD mice were induced for differentiation. Oil red O staining and Western-blot were used to detect lipid droplet and expression of SmgGDS and phospho-ERK; C/EBPα, C/EBPß and PPARγ mRNA levels were measured using RT-qPCR. (4) 10-week-old C57BL/6J mice were randomly assigned into two groups, with 7 mice in each group. Mice were infected with SmgGDS overexpressing adeno-associated virus (AAV-SmgGDS) or empty vector intraperitoneally, then fed with high fat diet. After 4 weeks, performed GTT and ITT; Recorded the weight and adipose tissue weight of mice; HE staining was used to analyze structural changes of eWAT; Western-blot was used to detect the phosphorylation level of ERK in eWAT. Results: (1) The expression of SmgGDS was significantly upregulated in eWAT of high fat diet fed mice (normal diet group: 0.218±0.037, high fat diet group:0.439±0.072, t=2.74, P=0.034). (2) At 4 months of high fat diet intervention, the glucose tolerance (60 minutes after glucose injection, WT group: 528 mg/dl±21 mg/dl, KD group: 435 mg/dl±17 mg/dl, t=3.47, P=0.030; 90 minutes, WT group: 463 mg/dl±24 mg/dl, KD group: 366 mg/dl±18 mg/dl, t=3.23, P=0.047;120 minutes, WT group: 416 mg/dl±21 mg/dl, KD group: 297 mg/dl±16 mg/dl, t=4.49, P=0.005) and insulin sensitivity (15 minutes after insulin injection, WT group: 77.79%±3.45%, KD group: 54.30%±2.92%, t=3.49, P=0.005; 30 minutes, WT group: 62.27%±5.31%, KD group: 42.25%±1.85%, t=2.978, P=0.024; 90 minutes, WT group: 85.69%±6.63%, KD group: 64.71%±5.41%, t=3.120, P=0.016) of KD mice were significantly improved compared to the WT group, with an increase in eWAT weight ratio (WT: 4.19%±0.18%, KD: 5.12%±0.37%, t=2.28, P=0.042), but a decrease in average adipocyte area (WT group: 5221 µm²±241 µm², KD group: 4410 µm²±196 µm², t=2.61, P=0.026). After 7 months of high fat diet, the eWAT weight ratio of KD mice decreased (WT: 5.02%±0.20%, KD: 3.88%±0.21%, t=3.92, P=0.001) and adipocyte size decreased (WT group: 6 783 µm²±390 µm², KD group: 4785 µm²±303 µm², t=4.05, P=0.002). The phospho-ERK1 in eWAT increased (WT group: 0.174±0.056, KD group: 0.588±0.147, t=2.64, P=0.025), and mRNA level of PPARγ significantly decreased (WT group: 1.018±0.128, KD group: 0.029±0.015, t=7.70, P=0.015). (3) The expression of SmgGDS was significantly increased in differentiated MEF (undifferentiated: 6.789±0.511, differentiated: 10.170±0.523, t=4.63, P=0.010); SmgGDS knock-down inhibited lipid droplet formation in MEF (WT group: 1.00±0.02, KD group: 0.88±0.02, t=5.05, P=0.007) and increased ERK1 (WT group: 0.600±0.179, KD group: 1.325±0.102, t=3.52, P=0.025) and ERK2 (WT group: 2.179±0.687, KD group: 5.200±0.814, t=2.84, P=0.047) activity, which can be reversed by ERK1/2 inhibitor. (4) SmgGDS over expression resulted in weight gain, increased eWAT weight (control group: 3.29%±0.36%, AAV-SmgGDS group: 4.27%±0.26%, t=2.20, P=0.048) and adipocyte size (control group: 3525 µm²±454 µm², AAV-SmgGDS group: 5326 µm²±655 µm², t=2.26, P=0.047), impaired insulin sensitivity(30 minutes after insulin injection, control group: 44.03%±4.29%, AAV-SmgGDS group: 62.70%±2.81%, t=3.06, P=0.019), and decreased ERK1 (control group: 0.829±0.077, AAV-SmgGDS group: 0.326±0.036, t=5.96, P=0.001)and ERK2 (control group: 5.748±0.287, AAV-SmgGDS group: 2.999±0.845, t=3.08, P=0.022) activity in eWAT. Conclusion: SmgGDS knockdown improves obesity related glucose metabolism disorder by inhibiting adipogenesis and adipose tissue hypertrophy, which is associated with ERK activation.

Anticoccidial evaluation of a traditional Chinese medicine--Brucea javanica--in broilers.

The traditional Chinese medicinal plant Brucea javanica has received much attention for its significant antiprotozoal effects in recent years; however, little is known about its potential anticoccidial functions. In the present study, a series of experiments was conducted to investigate the prophylactic and therapeutic effects of ethanol extract from B. javanica on coccidiosis induced by Eimeria tenella in broiler chickens. Chickens infected with E. tenella were treated with B. javanica extract and compared either with broilers treated with the anticoccidial halofuginone hydrobromide (Stenorol) or with control groups that consisted of infected-unmedicated and uninfected-unmedicated broilers. The experiments revealed that the B. javanica extract could significantly (P<0.05) reduce bloody diarrhea and lesion scores. Additional, OPG output in these plant extract treated groups was reduced in comparison with non-treated groups (P<0.05). However, there was no evidence to show that the extract could promote BWG. Histological data showed that the number of second-generation schizonts in the medicated groups was substantially less than that in the infected-unmedicated control. In summary, our work showed that B. javanica extract exerted considerable anticoccidial effects, supporting its use as a promising therapeutic in controlling avian coccidiosis.

Transcriptional analysis of the porcine TTID gene and association of different TTID genotypes with carcass traits.

The titin immunoglobulin domain (TTID) protein localizes to the Z line in muscle and binds to alpha-actinin and gamma-filamin. It plays an indispensable role in stabilizing and anchoring of thin filaments. In this study, the 5'-regulatory region of the porcine TTID gene was analyzed with bioinformatic methods. Another objective of this study was to further investigate the polymorphism in the intron 6 of the porcine TTID gene. We determined allele frequency among six Chinese porcine purebreds. The polymorphisms were genotyped in a population of 280 F2 pigs representing two Large White x Meishan reference families. Different TTID genotypes were significantly associated with carcass traits, including skin percentage (P < 0.05), loin eye area (P < 0.05), and average skin thickness (P < 0.01). Our study will continue to lay the groundwork for further investigations into the detailed function of the porcine TTID gene.

Differential expression and effect of the porcine ANGPTL4 gene on intramuscular fat.

In a previous study, we investigated differences in gene expression in backfat between Meishan and Large White pigs and their F1 hybrids, Large White x Meishan, and Meishan x Large White pigs. One potential differentially expressed sequence tag from the mRNA differential display was a homolog of the human angiopoietin-like 4 (ANGPTL4) gene, which encodes a protein that is secreted by both liver and white adipose tissues and can inhibit lipoprotein lipase activity and stimulate white adipose tissue lipolysis. Here, ANGPTL4 mRNA was found to be upregulated in the backfat of Large White compared with that in the Meishan pigs and the F1 hybrids, Meishan x Large White and Large White x Meishan, whereas expression was lowest both in the longissimus dorsi and the heart, as shown by the tissue distribution profile. Only one mutation, a G/A transition located in the third intron, was found. The ANGPTL4 G/A polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) showed a significant effect on intramuscular fat (IMF), water moisture of the longissimus dorsi, meat marbling of the longissimus dorsi, and pH of the longissimus dorsi (P < 0.05). This site seemed to be significantly (P < 0.05) additive in its actions on IMF, water moisture, and pH, whereas it showed significant dominance in its action on meat marbling (P < 0.05). This locus can be potentially considered as a marker for IMF improvement.

[Treacher Collins Syndrome 2 caused by a novel pathogenic variant in PLOR1D: clinical report and literature review].

Objective: To investigate the clinical features, molecular etiology, and treatment of a family with Treacher Collins Syndrome 2 (TCS2). Methods: Information of the proband (female, 8 years old) including medical history and family history was collected. Physical examination and examinations concerning laboratory, audiology, and radiology were performed on the proband. Physical examination was also performed on the family members. Genomic DNA of proband was extracted for whole exome sequencing, and then the genomic DNA of family members was extracted for Sanger sequencing. POLR1D and TCS2 related literatures published before August 31,2023 were searched and sifted in PubMed and CKNI databases. The clinical characteristics of TCS2 were summarized. Results: The proband had poor hearing since childhood, with pure tone audiometry indicating conductive hearing loss. She had a smaller jaw, bilateral preauricular fistulas and cup-shaped ear deformities. Temporal bone CT scan revealed deformities in the left external ear canal, bilateral middle ear and inner ear. A bone-conduction hearing aid device was surgically implanted, resulting in restoration of almost normal hearing levels. The proband's mother also had a slightly smaller jaw. Genetic analysis revealed a novel heterozygous variant NM_015972.4:c.38_47del in the POLR1D gene in the proband, which was inherited from her mother. A review of the literature revealed no clear evidence of genotype-phenotype correlation in TCS2. Conclusions: Molecular diagnosis plays a vital role in the diagnosis of TCS2. Patients with normal facial phenotype may be carriers of pathogenic variants in the POLR1D gene and have the risk of passing it to the offsprings with complete penetrance. Proper bone conductive hearing devices can improve the quality of life of TCS2 patients.

Molecular characterization, expression pattern and association analysis of the porcine BTG2 gene.

B-cell translocation gene 2 (BTG2), a member of the B-cell translocation gene family with anti-proliferative properties, have been characterized to be involved in cell growth, differentiation and survival. In this study, we cloned the full length sequences of cDNA and genomic DNA of BTG2 gene from the porcine skeletal muscle. Spatial expression analysis showed that the porcine BTG2 gene is expressed predominantly in muscle. Temporal expression analysis in longissimus dorsi muscle demonstrated that the expression of BTG2 gene has the highest expression at 60 days old in Large White while with a peak expression at 120 days old in Meishan. Temporal analysis also revealed that the expression of BTG2 gene is generally higher in Large White than in Meishan at all the developmental stages tested (65 days of conception and 3, 35, 60, 120, and 180 days of postnatal). A single nucleotide polymorphism (G417C) in the intron of BTG2 gene was then detected by PCR-RFLP in Large White × Meishan F2 resource population and association analysis suggested that this polymorphic site had significant association (P < 0.05) with the buttock fat thickness, fat percentage, lean muscle percentage, ratio of lean to fat and carcass length.

Real-time reverse transcription-PCR expression profiling of porcine troponin I family in three different types of muscles during development.

In this study, the expression profiling of three troponin I isoforms (TNNI1, TNNI2 and TNNI3) was investigated in two pig breeds differing in muscularity (Yorkshire and Meishan) at six stages (fetal 60 days and postnatal 3, 35, 60, 120, and 180 days) and three types of muscles (longissimus dorsi muscle, LD; semitendinosus, ST; cardiac muscle, CM) using relative real-time quantitative PCR. Significant differences of troponin I expression in three muscles were found between Yorkshire and Meishan breeds at some stages. The expression peak of TNNI1 and TNNI2 in LD and ST was at postnatal 35 or 60 days in Yorkshire and at postnatal 120 or 180 days in Meishan pigs, while it occurred in CM at postnatal 3 days in two pig breeds. The relative expression values of TNNI1 and TNNI2 were significantly higher in LD than ST at most of stages after birth. The expression ratio of TNNI2 versus TNNI1 favoured TNNI2 expression in ST and LD, but on the contrary in CM. The expression peak of TNNI3 occurred at postnatal 60 and 120 days in Yorkshire and Meishan pigs, respectively. TNNI1 and TNNI3 were co-expressed in CM during the fetal and earlier stages after birth.

Detection of novel SNPs and mapping of the fatness QTL on pig chromosome 7q1.1-1.4 region.

Many QTLs for fatness traits have been mapped on pig chromosome 7q1.1-1.4 in various pig resource populations. Eight novel markers, including seven SNPs and one insertion or deletion within BTNL1, COL21A1, PPARD, GLP1R, MDFI, GNMT, ABCC10, and PLA2G7 genes, as well as two previously reported SNPs in SLC39A7 and HMGA1 genes, were genotyped in Large White and Meishan pig breeds. Except for two SNPs in HMGA1 and ABCC10 genes, allele frequencies of the other eight markers are highly significant different between Chinese indigenous Meishan breeds and Large White pig breeds. Eight polymorphic sites were then used for linkage and QTL mapping to refine the fatness QTL in a Large White × Meishan F(2) resource population. Five chromosome-wise significant QTLs were detected, of which the QTLs for leaf fat weight, backfat thickness at 6-7th rib and rump, and mean backfat thickness were narrowed to the interval between PPARD and GLP1R genes and the QTL for backfat thickness at thorax-waist between GNMT and PLA2G7 genes on SSC7p1.1-q1.4.

Identification of three novel SNPs and association with carcass traits in porcine TNNI1 and TNNI2.

In this study, two novel SNPs (EU743939:g.5174T>C in intron 4 and EU743939:g.8350C>A in intron 7) in TNNI1 and one SNP (EU696779:g.1167C>T in intron 3) in TNNI2 were identified by PCR-RFLP (PCR restriction fragment length polymorphism) using XbaI, MspI and SmaI restriction enzyme, respectively. The allele frequencies of three novel SNPs were determined in the genetically diverse pig breeds including ten Chinese indigenous pigs and three Western commercial pig breeds. Association analysis of the SNPs with the carcass traits were conducted in a Large White × Meishan F(2) pig population. The linkage of two SNPs (g.5174T>C and g.8350C>A) in TNNI1 gene had significant effect on fat percentage. Besides these, the g.5174T>C polymorphism was also significantly associated with skin percentage (P < 0.05), shoulder fat thickness (P < 0.05) and backfat thickness between sixth and seventh ribs (P < 0.05). The significant effects of g.1167C>T polymorphism in TNNI2 gene on fat percentage (P < 0.01), lean meat percentage (P < 0.05), lion eye area (P < 0.05), thorax-waist backfat thickness (P < 0.01) and average backfat thickness (P < 0.05) were also found.

Association of 3 polymorphisms in porcine troponin I genes (TNNI1 and TNNI2) with meat quality traits.

The contractile protein troponin I (TnI), a constituent protein of the troponin complex located on the thin filaments of striated muscle, is involved in inhibition of calcium-induced myosin ATPase activity (and thus contraction). TnI-slow (slow-twitch skeletal muscle isoform, named TNNI1) and TnI-fast (fast-twitch skeletal muscle isoform, named TNNI2) are muscle-fiber-type-specific proteins, and expression of their genes may affect the composition of muscle fiber, thereby influencing the meat quality traits. Thus, the TnI genes are potential candidate genes for traits related to meat quality in animals. Association of 2 SNPs (EU743939:g.5174T>C in intron 4, and EU743939:g.8350C>A in intron 7) of the TNNI1 gene and a SNP (EU696779:g.1167C>T in intron 3) of the TNNI2 gene with 11 meat quality traits were studied on 334 Large White x Meishan F(2) pigs. In the TNNI1 gene, g.5174T>C and g.8350C>A were found to be significantly associated with intramuscular fat content and meat color value of biceps femoris. The g.5174T>C also showed significant effects on meat color value and marbling score of longissimus dorsi, as well as pH of longissimus dorsi and semispinalis capitis. The g.1167C>T polymorphism in the TNNI2 gene affected significantly the pH of longissimus dorsi, meat color value of longissimus dorsi and semispinalis capitis, marbling score of longissimus dorsi, and intramuscular fat.

Genetic polymorphisms and preliminary association analysis with production traits of the porcine SLC27A4 gene.

Solute carrier family 27 (fatty acid transporter), member 4 (SLC27A4) is a fatty acyl-CoA synthetase producing very long chain fatty acid-CoA for lipid metabolic pathways, suggesting that the SLC27A4 gene is a potential candidate gene for traits related to fat deposition in animals. This study was conducted to sequence the genomic region from exon 6 to 12 of porcine SLC27A4 and detect polymorphisms by comparative sequencing. In silico mapping assigned SLC27A4 gene between gene COQ4 (coenzyme Q4 homolog) and URM1 (ubiquitin related modifier 1 homolog) on pig chromosome 1q24-q2.12 where significant QTL affecting backfat depth had previously been identified. Thirty six putative sites of variation were detected, of which 31 polymorphisms including 28 SNPs and 3 indels were located in the intronic region, and 5 in the exonic regions. The g.1777G>A (EU703769) in intron 8 was confirmed by PCR-RFLP using HpaII restriction enzyme and further genotyped in four Chinese native pig breeds (Meishan, Erhualian, Tongcheng and Qingping) and three western meat-type pig breeds (Duroc, Large White and Landrace). Allele G was exclusively present in Tongcheng and Qingping pigs and predominant in the other pig populations analyzed. Significant differences of backfat at rump, body weight at birth and average daily gain on weaning between the AG and GG genotype were observed in Landrace pig population (P < 0.05).

Molecular characterization and association with carcass traits of the porcine SLC39A7 gene.

In this study, the molecular characterization and potential association of SLC39A7 gene with carcass traits were investigated in pigs. The sequence of SLC39A7 cDNA was obtained by in silico cloning and RT-polymerase chain reaction (PCR). Two transcripts, variant 1 (2398 bp) and variant 2 (2088 bp), of the SLC39A7 gene were identified. Expression analysis of SLC39A7 in 10 different tissues by RT-PCR showed that variant 1 was ubiquitously expressed in all tissues analysed, but variant 2 was not found in fat tissue. The cDNA regions of variant 1 and 2 were organized in seven and eight exons respectively. A c.205G>A substitution in exon 3, which changes a codon for glycine into a codon for arginine, (p.Gly69Arg) and a c.1138-216T>C substitution in intron 6 were detected by PCR-HpaII-restriction fragment length polymorphisms (RFLP) and PCR-cofI-RFLP respectively. Significant differences were found in the allele frequencies of c.205G>A among six Chinese indigenous pig breeds and two commercial pig breeds. Linkage analysis showed that the c.205G>A polymorphism within the SLC39A7 gene was closely linked to the marker Sw1856 on pig chromosome 7 in a Large White x Meishan F(2) resource population. The QTL and association studies between polymorphisms of the SLC39A7 gene and carcass traits were carried out. Significant associations of the SLC39A7 polymorphisms with backfat thickness at thorax-waist (p < 0.05), average backfat thickness (p < 0.05) and leaf fat weight (p < 0.01) were found. Additional F-drop test or marker assisted association analyses also supported the association of the mutation in SLC39A7 with the above traits. Together, the present study provided the useful information for the characterization of SLC39A7 gene and potential association with carcass traits in pigs.

Prevalence and drug resistance of avian Eimeria species in broiler chicken farms of Zhejiang province, China.

In this study, coccidia were isolated and identified from 5 main poultry farms located in Zhejiang province, eastern China. The overall prevalence of Eimeria spp. was 30.7% (95 of 310). Five common species were observed: E. tenella, E. acervulina, E. maxima, E. necatrix, and E. mitis. Two isolates (HZ and QZ) were tested for sensitivity to 8 anticoccidial drugs using 4 indexes including anticoccidial index (ACI), percent of optimum anticoccidial activity (POAA), reduction of lesion scores (RLS), and relative oocyst production (ROP): sulfachloropyrazine, toltrazuril, diclazuril, sulfamonomethoxine/trimethoprim, and amprolium; sulfaquinoxaline/sulfadimethoxine, nicarbazin, and halofuginone. The results showed that the 2 isolates have developed various degrees of resistance to most of the tested drugs. The multi-resistance coccidia are a potential threat to local poultry farming. Rotation of anticoccidial drugs and shuttle programs are recommended to prevent further economic losses caused by coccidiosis.

[Possible reasons for cerebrospinal fluid gusher in cochlear implantation with inner ear abnormality].

Objective: To discuss the possible reasons for cerebrospinal fluid (CSF) gusher in cochlear implantation (CI) with inner ear abnormality. Method: A retrospective analysis was performed on 340 cases who underwent CI from January 2013 to December 2016 in Division of Otology, Otorhinolaryngology Hospital, the First Affiliated Hospital of Zhengzhou University. Among them, 96 cases had inner ear abnormalities. Imaging examinations were performed on these patients, and classification of inner ear malformation was done according to the results. Results: Among the cases with inner ear abnormality, 9.4% (9/96) suffered from CSF gusher during CI. The inner ear abnormalities were found to be as follows: 3 cases had incomplete partition type Ⅰ; 1 case had incomplete partition type Ⅰ with semicircular canal dysplasia; 1 case had common cavity deformity; 1 case had enlarged vestibular aqueducts and common cavity deformity; 2 cases had Mondini deformity. All of these cases had bony defect in the fundus of the internal acoustic meatus observed on CT scans. Another case was type 1 cochlear aqueduct with round window aplasia. Conclusions: Defects in the modiolus or fundus of the internal acoustic meatus is the main reason for CSF gusher during CI. A patent cochlear aqueduct is another possible reason.

[Prediction of round window visibility in cochlear implantation with temporal bone high resolution computed tomography].

Objective: To discuss the prediction of round window(RW) visibility in cochlear implantation(CI) with temporal bone high resolution computed tomography(HRCT). Methods: From January 2013 to January 2017, 130 cases underwent both HRCT and CI in our hospital were analyzed. The distance from facial nerve to posterior canal wall(FWD), the angle between facial nerve and inner margin of round window(FRA), and the angle between facial nerve and tympanic anulus to inner margin of round window(FRAA) were detected at the level of round window on axial temporal bone HRCT. A line parallel to the posterior wall of ear canal was drawn from the anterior wall of facial nerve at the level of round window on axial temporal bone HRCT and its relationship with round window was detected (facial-round window line, FRL): type0-posterior to the round window, type1-between the round window, type2-anterior to the round window. Their(FWD, FRA, FRAA, FRL) relationships with intra-operative round window visibility were analyzed by SPSS 17.0 software. Results: FWD(F=18.76, P=0.00), FRA(F=34.57, P=0.00), FRAA (F=14.24, P=0.00) could affect the intra-operative RW visibility significantly. RW could be exposed completely during CI when preoperative HRCT showing type0 FRL. RW might be partly exposed and not exposed when preoperative HRCT showing type1 and type2 FRL respectively. Conclusion: FWD, FRA, FRAA and FRL of temporal bone HRCT can predict intra-operative round window visibility effectively in CI surgery.

A general dynamic force distribution algorithm for multifingered grasping.

A general dynamic force distribution (DFD) algorithm for multifingered grasping is presented. Based on the convexity and cone property of contact constraints, the optimal internal force is defined. Determination of the contact force is divided into two phases: (1) determine the direction of the optimal internal force during grasp planning and (2) determine the manipulation force and compensation factor during task manipulation. The total computation cost consists of off-line numerical iterations and on-line analytical computations. Only the latter is related to the real-time control. The algorithm can directly deal with the nonlinear and/or coupled constraints and well overcome the temporal discontinuity.

[Flotation spectrophotometric determination of platinum on isochromatic dye ion pair with tetrabromofluorescein and rhodamine 6G].

The flotation spectrophotometric method for the determination of platinum with isochromatic dye ion-pair is described. Rhodamine 6G (R6G) was produced and entered into aqueous phase when pH = 5.5 buffer solution was added to the Pt (SnCl3)5 (R6G)3 by isopropyl ether flotation. And then R6G. TBF was floated by tetrabromofluorescein(TBF)with toluene. The floatation was dissolved in acetone and absorbance of the solution was measured at 530nm. The sensitivity was raised because of the six dyes (Pt : R6G : TBF = 1 : 3 : 3) assistant effect. The molar absorptivity of this method is 5.92 x 10(5)L x mol(-1) x cm(-1). Beer's law was obeyed in the range of 0-2 microg/10mL with a relative standard deviation of 3.8%. The method was applied satisfactorily to the determination of platinum contained in catalysts without separation.

[Flotation spectrophotometric determination of copper on isochromatic dye ion pair with crystal violet and bromopnenol blue].

Bromophenol blue (BPB) was produced and entered into the aqueous phase when NaOH solution of pH = 10 was added to Cu(biq)2BPB by trichloromethane and isoamyl alcohol (20:1) extractive. And then CV x BPB was floated by crystal violet (CV) with benzene solution. The flotation was dissolved in ethanol and the absorbance of the solution measured at 590 nm. The sensitivity was raised because of the two dyes assistant effect. The molar absorptivity was 1.45 x 10(5) L x mol(-1) x cm(-1). Copper in the sample was separated first by extracting the Cu(biq)2BPB complex with trichloromethane and isoamyl alcohol, thus achieving a high selectivity. Beer's law was obeyd in the range of 0-0. 4 mg/L with a relative standard deviation of 3.6%. For 4.8 x 10(-8) g/mL copper solution, the recoveries were 97.8%-101.7%.