Twelve representative crude oil samples recovered from six oil fields in the Albertine Graben, Uganda were chosen for this study. The study aimed to understand the genetic relationships between the oils, the inferred ...Twelve representative crude oil samples recovered from six oil fields in the Albertine Graben, Uganda were chosen for this study. The study aimed to understand the genetic relationships between the oils, the inferred depositional environment of the source rocks, maturity of the crude oils, and to gain some insight on the expulsion of the oils from source rocks. The work involved geochemical bulk analysis （asphaltene and liquid chromatographic separations）, GC-FID （gas chromatography with a flame ionization detector）, and GC-MS （gas chromatography-mass spectrometry） of saturate and aromatic fractions. Bulk analysis shows that the oils are dominated by saturate hydrocarbon fractions （48.7%-62.0%） and are highly waxy （35-56.2 wt%） with low sulfur content （〈 0.1 wt%）. The high saturate hydrocarbon and high wax contents are probably due to organic matter input from land plants and/or long-chain alkanes from fresh water algae in lacustrine systems. The low sulfur contents alongside the high wax abundances are consistent with elastic-dominated source rock facies deposited in a non-stratified lacustrine environment. Data from GC-FID and GC-MS analyses such as n-alkane distributions, pristane/phytane ratios, biomarker terpane and sterane, dibenzothiophene and phenanthrene parameters show that the oils belong to a single family and were derived from a elastic predominantly algal source rock deposited under suboxic conditions in a non-stratified freshwater to brackish water lacustrine environment. The data further show that the oils have a very narrow range of maturities and are generated in the peak oil window. The observed narrow range of maturities and inferred lacustrine depositional setting for the source rocks suggest that the kerogen responsible for the generation of the oils is likely to be predominantly type-1 known to display narrow activation energies. This in turn implies that the expulsion of the oil from the source rock occurred as a quick single event hence, the filling of reservoirs in the Albertine Graben probably did not involve late stage expulsion and multiple charges of oil.展开更多
The identification of individual cells is crucial for advancements in single-cell analysis.Optically readable barcodes provide a means to distinguish and track cells through repeated,non-destructive measurements.Tradi...The identification of individual cells is crucial for advancements in single-cell analysis.Optically readable barcodes provide a means to distinguish and track cells through repeated,non-destructive measurements.Traditional fluorophore-based methods are limited by the finite number of unique barcodes they can produce.Laser particles(LPs),which emit narrowband peaks over a wide spectral range,have emerged as a promising technology for singlecell barcoding.Here,we demonstrate the use of multiple LPs to generate combinatorial barcodes,enabling the identification of a vast number of live cells.We introduce a theoretical framework for estimating the number of LPs required for unique barcodes and the expected identification error rate.Additionally,we present an improved LPtagging method that is highly effective across a variety of cell types and evaluate its biocompatibility.Our experimental results show successful barcoding of several million cells,closely matching our theoretical predictions.This research marks a significant step forward in the scalability of LP technology for single-cell tracking and analysis.展开更多
文摘Twelve representative crude oil samples recovered from six oil fields in the Albertine Graben, Uganda were chosen for this study. The study aimed to understand the genetic relationships between the oils, the inferred depositional environment of the source rocks, maturity of the crude oils, and to gain some insight on the expulsion of the oils from source rocks. The work involved geochemical bulk analysis （asphaltene and liquid chromatographic separations）, GC-FID （gas chromatography with a flame ionization detector）, and GC-MS （gas chromatography-mass spectrometry） of saturate and aromatic fractions. Bulk analysis shows that the oils are dominated by saturate hydrocarbon fractions （48.7%-62.0%） and are highly waxy （35-56.2 wt%） with low sulfur content （〈 0.1 wt%）. The high saturate hydrocarbon and high wax contents are probably due to organic matter input from land plants and/or long-chain alkanes from fresh water algae in lacustrine systems. The low sulfur contents alongside the high wax abundances are consistent with elastic-dominated source rock facies deposited in a non-stratified lacustrine environment. Data from GC-FID and GC-MS analyses such as n-alkane distributions, pristane/phytane ratios, biomarker terpane and sterane, dibenzothiophene and phenanthrene parameters show that the oils belong to a single family and were derived from a elastic predominantly algal source rock deposited under suboxic conditions in a non-stratified freshwater to brackish water lacustrine environment. The data further show that the oils have a very narrow range of maturities and are generated in the peak oil window. The observed narrow range of maturities and inferred lacustrine depositional setting for the source rocks suggest that the kerogen responsible for the generation of the oils is likely to be predominantly type-1 known to display narrow activation energies. This in turn implies that the expulsion of the oil from the source rock occurred as a quick single event hence, the filling of reservoirs in the Albertine Graben probably did not involve late stage expulsion and multiple charges of oil.
基金supported by the US National Institutes of Health research grants(R01-EB033155,R01-EB034687,R44CA281529,and K99HG013129).
文摘The identification of individual cells is crucial for advancements in single-cell analysis.Optically readable barcodes provide a means to distinguish and track cells through repeated,non-destructive measurements.Traditional fluorophore-based methods are limited by the finite number of unique barcodes they can produce.Laser particles(LPs),which emit narrowband peaks over a wide spectral range,have emerged as a promising technology for singlecell barcoding.Here,we demonstrate the use of multiple LPs to generate combinatorial barcodes,enabling the identification of a vast number of live cells.We introduce a theoretical framework for estimating the number of LPs required for unique barcodes and the expected identification error rate.Additionally,we present an improved LPtagging method that is highly effective across a variety of cell types and evaluate its biocompatibility.Our experimental results show successful barcoding of several million cells,closely matching our theoretical predictions.This research marks a significant step forward in the scalability of LP technology for single-cell tracking and analysis.
