Nonvolatile Modulation of Bi2O2Se/Pb(Zr,Ti)O3 Heteroepitaxy

The pursuit of high-performance electronic devices has driven the research focus toward 2D semiconductors with high electron mobility and suitable band gaps. Previous studies have demonstrated that quasi-2D Bi2O2Se (BOSe) has remarkable physical properties and is a promising candidate for further exploration. Building upon this foundation, the present work introduces a novel concept for achieving nonvolatile and reversible control of BOSe's electronic properties. The approach involves the epitaxial integration of a ferroelectric PbZr0.2Ti0.8O3 (PZT) layer to modify BOSe's band alignment. Within the BOSe/PZT heteroepitaxy, through two opposite ferroelectric polarization states of the PZT layer, we can tune the Fermi level in the BOSe layer. Consequently, this controlled modulation of the electronic structure provides a pathway to manipulate the electrical properties of the BOSe layer and the corresponding devices.

Discovery of new genetic loci for male sexual orientation in Han population

Epidemiological studies have demonstrated that the genetic factors partly influence the development of same-sex sexual behavior, but most genetic studies have focused on people of primarily European ancestry, potentially missing important biological insights. Here, we performed a two-stage genome-wide association study (GWAS) with a total sample of 1478 homosexual males and 3313 heterosexual males in Han Chinese populations and identified two genetic loci (rs17320865, Xq27.3, FMR1NB, Pmeta = 8.36 × 10-8, OR = 1.29; rs7259428, 19q12, ZNF536, Pmeta = 7.58 × 10-8, OR = 0.75) showing consistent association with male sexual orientation. A fixed-effect meta-analysis including individuals of Han Chinese (n = 4791) and European ancestries (n = 408,995) revealed 3 genome-wide significant loci of same-sex sexual behavior (rs9677294, 2p22.1, SLC8A1, Pmeta = 1.95 × 10-8; rs2414487, 15q21.3, LOC145783, Pmeta = 4.53 × 10-9; rs2106525, 7q31.1, MDFIC, Pmeta = 6.24 × 10-9). These findings may provide new insights into the genetic basis of male sexual orientation from a wider population scope. Furthermore, we defined the average ZNF536-immunoreactivity (ZNF536-ir) concentration in the suprachiasmatic nucleus (SCN) as lower in homosexual individuals than in heterosexual individuals (0.011 ± 0.001 vs 0.021 ± 0.004, P = 0.013) in a postmortem study. In addition, compared with heterosexuals, the percentage of ZNF536 stained area in the SCN was also smaller in the homosexuals (0.075 ± 0.040 vs 0.137 ± 0.103, P = 0.043). More homosexual preference was observed in FMR1NB-knockout mice and we also found significant differences in the expression of serotonin, dopamine, and inflammation pathways that were reported to be related to sexual orientation when comparing CRISPR-mediated FMR1NB knockout mice to matched wild-type target C57 male mice.

[Analysis of drug - resistant gene polymorphisms in Plasmodium falciparum imported from Equatorial Guinea to Shandong Province in 2015 and 2016]

OBJECTIVE

To investigate the drug-resistant gene polymorphisms in Plasmodium falciparum imported from Equatorial Guinea to Shandong Province.

METHODS

From 2015 to 2016, blood samples were collected from imported P. falciparum malaria patients returning from Equatorial Guinea to Shandong Province, and genome DNA of the malaria parasite was extracted. The drug-resistant Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, and K13 genes of P. falciparum were amplified using a PCR assay, followed by DNA sequencing, and the sequences were aligned.

RESULTS

The target fragments of all 5 drug-resistant genes of P. falciparum were successfully amplified and sequenced. There were 72.8%, 18.6%, and 8.6% of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfcrt gene, respectively, and all mutant haplotypes were CVIET (the underline indicates the mutation site). There were 20.0%, 61.4% and 18.6% of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfmdr1 gene, respectively, and the mutant haplotypes mainly included YF and NF (the underlines indicate the mutation sites). There were 1.4%, 98.6%, and 0 of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfdhfr gene, respectively, and AIRNI was the predominant mutant haplotype (the underline indicates the mutation site). There were 1.4%, 94.3%, and 4.3% of P. falciparum parasites carrying the wild-, mutant-, and mixed-type Pfdhps gene, respectively, and SGKAA was the predominant mutant haplotype (the underline indicates the mutation site). The complete drug-resistant IRNGE genotype consisted of 8.6% of the Pfdhfr and Pfdhps genes, and the K13 gene A578S mutation occurred in 1.4% of the parasite samples.

CONCLUSIONS

There are mutations in the Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, and K13 genes of P. falciparum imported from Equatorial Guinea to Shandong Province, with a low frequency in the Pfcrt gene mutation and a high frequency in the Pfmdr1, Pfdhfr, and Pfdhps gene mutations, and the K13 gene A578S mutation is detected in the parasite samples.

Efficacy of internet-based integrated intervention on depression and anxiety symptoms in patients with COVID-19

Public health crises, such as the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) since Dec. 2019, are widely acknowledged as severe traumatic events that impose threats not only because of physical concerns but also because of the psychological distress of infected patients. We designed an internet-based integrated intervention and evaluated its efficacy on depression and anxiety symptoms in patients infected by SARS-CoV-2.

Photodriven Dipole Reordering: Key to Carrier Separation in Metalorganic Halide Perovskites

Photodriven dipole reordering of the intercalated organic molecules in halide perovskites has been suggested to be a critical degree of freedom, potentially affecting physical properties, device performance, and stability of hybrid perovskite-based optoelectronic devices. However, thus far a direct atomically resolved dipole mapping under device operation condition, that is, illumination, is lacking. Here, we map simultaneously the molecule dipole orientation pattern and the electrostatic potential with atomic resolution using photoexcited cross-sectional scanning tunneling microscopy and spectroscopy. Our experimental observations demonstrate that a photodriven molecule dipole reordering, initiated by a photoexcited separation of electron-hole pairs in spatially displaced orbitals, leads to a fundamental reshaping of the potential landscape in halide perovskites, creating separate one-dimensional transport channels for holes and electrons. We anticipate that analogous light-induced polarization order transitions occur in bulk and are at the origin of the extraordinary efficiencies of organometal halide perovskite-based solar cells as well as could reconcile apparently contradictory materials' properties.

Atomically Resolved Electronic States and Correlated Magnetic Order at Termination Engineered Complex Oxide Heterointerfaces

We map electronic states, band gaps, and interface-bound charges at termination-engineered BiFeO₃/La_0.7Sr_0.3MnO₃ interfaces using atomically resolved cross-sectional scanning tunneling microscopy. We identify a delicate interplay of different correlated physical effects and relate these to the ferroelectric and magnetic interface properties tuned by engineering the atomic layer stacking sequence at the interfaces. This study highlights the importance of a direct atomically resolved access to electronic interface states for understanding the intriguing interface properties in complex oxides.

A Metal-Insulator Transition of the Buried MnO2 Monolayer in Complex Oxide Heterostructure

A novel artificially created MnO₂ monolayer system is demonstrated in atomically controlled epitaxial perovskite heterostructures. With careful design of different electrostatic boundary conditions, a magnetic transition as well as a metal-insulator transition of the MnO₂ monolayer is unveiled, providing a fundamental understanding of dimensionality-confined strongly correlated electron systems and a direction to design new electronic devices.

Dopant Diffusion and Activation in Silicon Nanowires Fabricated by ex Situ Doping: A Correlative Study via Atom-Probe Tomography and Scanning Tunneling Spectroscopy

Dopants play a critical role in modulating the electric properties of semiconducting materials, ranging from bulk to nanoscale semiconductors, nanowires, and quantum dots. The application of traditional doping methods developed for bulk materials involves additional considerations for nanoscale semiconductors because of the influence of surfaces and stochastic fluctuations, which may become significant at the nanometer-scale level. Monolayer doping is an ex situ doping method that permits the post growth doping of nanowires. Herein, using atom-probe tomography (APT) with subnanometer spatial resolution and atomic-ppm detection limit, we study the distributions of boron and phosphorus in ex situ doped silicon nanowires with accurate control. A highly phosphorus doped outer region and a uniformly boron doped interior are observed, which are not predicted by criteria based on bulk silicon. These phenomena are explained by fast interfacial diffusion of phosphorus and enhanced bulk diffusion of boron, respectively. The APT results are compared with scanning tunneling spectroscopy data, which yields information concerning the electrically active dopants. Overall, comparing the information obtained by the two methods permits us to evaluate the diffusivities of each different dopant type at the nanowire oxide, interface, and core regions. The combined data sets permit us to evaluate the electrical activation and compensation of the dopants in different regions of the nanowires and understand the details that lead to the sharp p-i-n junctions formed across the nanowire for the ex situ doping process.

Parallel p-n junctions across nanowires by one-step ex situ doping

The bottom-up synthesis of nanoscale building blocks is a versatile approach for the formation of a vast array of materials with controlled structures and compositions. This approach is one of the main driving forces for the immense progress in materials science and nanotechnology witnessed over the past few decades. Despite the overwhelming advances in the bottom-up synthesis of nanoscale building blocks and the fine control of accessible compositions and structures, certain aspects are still lacking. In particular, the transformation of symmetric nanostructures to asymmetric nanostructures by highly controlled processes while preserving the modified structural orientation still poses a significant challenge. We present a one-step ex situ doping process for the transformation of undoped silicon nanowires (i-Si NWs) to p-type/n-type (p-n) parallel p-n junction configuration across NWs. The vertical p-n junctions were measured by scanning tunneling microscopy (STM) in concert with scanning tunneling spectroscopy (STS), termed STM/S, to obtain the spatial electronic properties of the junction formed across the NWs. Additionally, the parallel p-n junction configuration was characterized by off-axis electron holography in a transmission electron microscope to provide an independent verification of junction formation. The doping process was simulated to elucidate the doping mechanisms involved in the one-step p-i-n junction formation.

Ferroelectric control of the conduction at the LaAlO₃/SrTiO₃ heterointerface

Modulation of band bending at a complex oxide heterointerface by a ferroelectric layer is demonstrated. The as-grown polarization (Pup ) leads to charge depletion and consequently low conduction. Switching the polarization direction (Pdown ) results in charge accumulation and enhances the conduction at the interface. The metal-insulator transition at a conducting polar/nonpolar oxide heterointerface can be controlled by ferroelectric doping.

Atomic-scale interfacial band mapping across vertically phased-separated polymer/fullerene hybrid solar cells

Using cross-sectional scanning tunneling microscope (XSTM) with samples cleaved in situ in an ultrahigh vacuum chamber, this study demonstrates the direct visualization of high-resolution interfacial band mapping images across the film thickness in an optimized bulk heterojunction polymer solar cell consisting of nanoscale phase segregated blends of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). We were able to achieve the direct observation of the interfacial band alignments at the donor (P3HT)-acceptor (PCBM) interfaces and at the interfaces between the photoactive P3HT:PCBM blends and the poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) anode modification layer with an atomic-scale spatial resolution. The unique advantage of using XSTM to characterize polymer/fullerene bulk heterojunction solar cells allows us to explore simultaneously the quantitative link between the vertical morphologies and their corresponding local electronic properties. This provides an atomic insight of interfacial band alignments between the two opposite electrodes, which will be crucial for improving the efficiencies of the charge generation, transport, and collection and the corresponding device performance of polymer solar cells.

Mapping band alignment across complex oxide heterointerfaces

In this study, direct observation of the evolution of electronic structures across complex oxide interfaces has been revealed in the LaAlO(3)/SrTiO(3) model system using cross-sectional scanning tunneling microscopy and spectroscopy. The conduction and valence band structures across the LaAlO(3)/SrTiO(3) interface are spatially resolved at the atomic level by measuring the local density of states. This study directly maps out the electronic reconstructions and a built-in electric field in the polar LaAlO(3) layer. Results also clearly reveal the band bending and the notched band structure in the SrTiO(3) adjacent to the interface.

Local conduction at the BiFeO(3)-CoFe(2)O(4) tubular oxide interface

In strongly correlated oxides, heterointerfaces, manipulating the interaction, frustration, and discontinuity of lattice, charge, orbital, and spin degrees of freedom, generate new possibilities for next generation devices. In this study, existing oxide heterostructures are examined and local conduction at the BiFeO(3)-CoFe(2)O(4) vertical interface is found. In such hetero-nanostructures the interface cannot only be the medium for the coupling between phases, but also a new state of the matter. This study demonstrates a novel concept on for oxide interface design and opens an alternative pathway for the exploration of diverse functionalities in complex oxide interfaces.

Value of Diffusion-Weighted Imaging in Grading Tumours Localized in the Fourth Ventricle Region by Visual and Quantitative Assessments

This study investigated visual and quantitative assessment of diffusion-weighted imaging (DWI) for grading tumours localized in the fourth ventricle region. Patients were diagnosed histopathologically and classified into two groups: those with high-grade (World Health Organization [WHO] grades III and IV) and those with low-grade tumours (benign, WHO grades I and II). DWI signal intensity was described using a five-point scale. Minimum apparent diffusion coefficient (ADC) values were obtained from areas with the lowest signal. The mean signal intensity was significantly higher in high-grade than in low-grade tumours. The mean minimum ADC value was significantly lower in high-grade than low-grade tumours. Marked hyperintensity had sensitivity, specificity, positive predictive value and negative predictive value of 89.7%, 100%, 100% and 94.2%, respectively, when used as a diagnostic tool for high-grade tumours compared with 96.6%, 97.9%, 96.6% and 97.9%, respectively, when using a minimum ADC of 0.9 × 10−3 mm2/s as a diagnostic marker. It was concluded that DWI is helpful in predicting the grades of tumours in the fourth ventricle region.

A unique magnetic resonance imaging feature of glioblastoma multiforme: the 'pseudopalisade' sign

This study was designed to investigate the unique magnetic resonance imaging (MRI) appearance of histopathologically-proven glioblastoma multiforme (GBM) with pseudopalisade necrosis and to assess its value for grading gliomas and providing a differential diagnosis. The study included 169 patients with intracranial masses who underwent surgery and had a proven histopathological diagnosis: 50 with GBM, 77 with gliomas (46 grade II and 31 grade III) and 42 with other intracranial masses (20 metastases, 14 lymphomas and eight abscesses). All patients underwent preoperative brain MRI including post-contrast T(1)-weighted imaging. The presence of the 'pseudopalisade' sign on post-contrast T(1)-weighted images was compared among the different types of brain mass. The frequency of the 'pseudopalisade' sign in GBMs (94.00%) was significantly higher than that seen in grade II and III gliomas (11.69%) and other intracranial masses (7.14%). The 'pseudopalisade' sign on post-contrast T(1)-weighted images was useful for grading gliomas and for differentiating GBM from other brain masses.

Dominant effector genetics in mammalian cells

We have expressed libraries of peptides in mammalian cells to select for trans-dominant effects on intracellular signaling systems. As an example-and to reveal pharmacologically relevant points in pathways that lead to Taxol resistance-we selected for peptide motifs that confer resistance to Taxol-induced cell death. Of several peptides selected, one, termed RGP8.5, was linked to upregulation of expression of the gene ABCB1 (also known as MDR1, for multiple drug resistance) in HeLa cells. Our data indicate that trans-dominant effector peptides can point to potential mechanisms by which signaling systems operate. Such tools may be useful in functional genomic analysis of signaling pathways in mammalian disease processes.

Rab37 is a novel mast cell specific GTPase localized to secretory granules

GTPases regulate a myriad of cellular functions including signal transduction, cytoskeletal organization and membrane trafficking. Rab GTPases act to coordinate the membrane dynamics of cells by organizing and regulating the activity of effector proteins important in vesicle trafficking. Rab37 is a novel Rab GTPase specifically expressed in the MC-9 mast cell line and bone marrow mast cells. Rab37 is 74% identical to Rab26 and 47% identical to Rab8, a GTPase important in Golgi to plasma membrane vesicle trafficking in mammalian cells. When green fluorescent protein tagged Rab37 is expressed in bone marrow mast cells, the secretory granules are labeled. These data suggest that Rab37 may play an important role in mast cell degranulation making this protein a potentially important target for therapeutic intervention in the treatment of allergy.

TNIK, a novel member of the germinal center kinase family that activates the c-Jun N-terminal kinase pathway and regulates the cytoskeleton

Germinal center kinases (GCKs) compose a subgroup of the Ste20 family of kinases. Here we describe the cloning and characterization of a novel GCK family kinase, Traf2- and Nck-interacting kinase (TNIK) that interacts with both Traf2 and Nck. TNIK encodes a polypeptide of 1360 amino acids with eight spliced isoforms. It has 90% amino acid identity to the Nck-interacting kinase in both the N-terminal kinase domain and the C-terminal germinal center kinase homology region. The homology drops to 53% in the intermediate region. TNIK specifically activates the c-Jun N-terminal kinase pathway when transfected into Phoenix-A cells (derivatives of 293 cells), similar to many GCKs. However, in contrast to other GCKs, this activation is mediated solely by the GCK homology region of TNIK. In addition, in Phoenix-A, NIH-3T3, and Hela cells, overexpression of wild type TNIK, but not the kinase mutant form of TNIK, results in the disruption of F-actin structure and the inhibition of cell spreading. Furthermore, TNIK can phosphorylate Gelsolin in vitro. This is the first time that a GCK family kinase is shown to be potentially involved in the regulation of cytoskeleton.

Identification of RIP3, a RIP-like kinase that activates apoptosis and NFkappaB

The tumor necrosis factor receptor 1 (TNFR1) and the Fas receptor recruit complexes formed by the interactions between RIP kinase, TRADD, FADD and RAIDD - adaptor proteins that contain death domains - which in turn recruit other proteins to initiate signaling [1][2][3][4][5]. To identify proteins associated with the TNF signaling pathway, we performed a yeast two-hybrid interaction screen using RIP as bait. We isolated a kinase, RIP3, which shares homology with the kinase domain of RIP and RIP2 (also known as Rick or CARDIAK). RIP3 could be co-immunoprecipitated with RIP, TRAF2 and TNFR1 in mammalian cells. The carboxy-terminal domain of RIP3, like that of RIP, could activate the transcription factor NFkappaB and induce apoptosis when expressed in mammalian cells. Interestingly, this region shares no significant sequence homology to the death domain of RIP, the caspase-recruiting domain (CARD) of RIP2 [6][7][8] or any other apoptosis-inducing domain. As with RIP and RIP2, the kinase domain of RIP3 was not required for either NFkappaB activation or apoptosis induction. Overexpression of a dominant-negative mutant of RIP3 strongly inhibited the caspase activation but not the NFkappaB activation induced by TNFalpha. Therefore, RIP3 appears to function as an intermediary in TNFalpha-induced apoptosis.

Use of PCR/DNA probes to identify circumsporozoite genotype of Plasmodium vivax in China

The paper reports the result of identifying cirumsporozoite (CS) genotype of Plasmodium vivax by using PCR/DNA probe labeled with biotin. The sensitivity of this method to detect patient blood samples was 0.2 parasite/microl and also with high specific to P. vivax. CS genes from 52 blood samples collected from patients with P. vivax in Hainan and Yunnan Provinces were amplified by PCR and 49 were positive by gel-e electrophoresis analysis, positive rate was 94%. Then the amplified CS genes further were probed with special oligoprobes (PV210 and PV247) that hybridized with the predominant CS repeat region and the variant CS repeat region. The results showed 46 (88.5%) PV210 positive and 6 (11.5%) PV247 positive; 2 hybridized with both probes. The variant genotype was present only in samples from Yunnan Province. The above results showed that the PCR/DNA probe labeled with biotin was highly sensitive and specific to P. vivax and found a CS variant genotype of P. vivax in Yunnan Province of China.

Detection of programmed cell death using fluorescence energy transfer

Fluorescence energy transfer (FRET) can be generated when green fluorescent protein (GFP) and blue fluorescent protein (BFP) are covalently linked together by a short peptide. Cleavage of this linkage by protease completely eliminates FRET effect. Caspase-3 (CPP32) is an important cellular protease activated during programmed cell death. An 18 amino acid peptide containing CPP32 recognition sequence, DEVD, was used to link GFP and BFP together. CPP32 activation can be monitored by FRET assay during the apoptosis process.

Identification of an alternative form of human lactoferrin mRNA that is expressed differentially in normal tissues and tumor-derived cell lines

Lactoferrin (LF), traditionally known as an iron-binding protein present in high concentrations in milk and various secretions, has emerged as a multifunctional protein involved in many aspects of the host defense against infection. Recently, LF has been shown to inhibit the growth of solid tumors and reduce experimental metastasis in mice, suggesting that LF also may play a role in the defense against tumorigenesis. Here we provide the sequence of the cDNA and promoter region, the chromosome assignment, and tissue expression pattern of a novel form of LF mRNA (delta LF). The sequence of delta LF mRNA is nearly identical to that of LF mRNA; however, at the 5' end, we find a novel sequence that replaces the N-terminal signal peptide sequence of LF mRNA. We map the delta LF mRNA to human chromosome 3 and find that both delta LF and LF sequences colocalize to the same cloned 90- to 150-kb genomic DNA fragment. We further show that the delta LF mRNA is the product of alternative splicing of the LF gene and likely is specified by use of an alternative promoter. Although we find delta LF mRNA at various levels in 20 of 20 adult and fetal human tissues, we do not find delta LF mRNA in any of 14 diverse tumor-derived cell lines.

Selection of hybrids by affinity capture (SHAC): a method for the generation of cDNAs enriched in sequences from a specific chromosome region

We have established a method for preparing cDNA sublibraries enriched in sequences from specific chromosome regions, called selection of hybrids by affinity capture (SHAC). This procedure can be described in two stages. In the first stage, a particular chromosome region, in this study mouse chromosome 11, was microdissected, followed by PCR amplification with a universal degenerate primer. This material is referred to as the "target" DNA. In the second stage, a mouse liver cDNA library with unique linker-adapter ends, referred to as the "source" cDNA, was hybridized to the biotin-labeled target DNA prepared during the first stage. The resulting DNA duplexes were captured by streptavidin-coated magnetic beads. The cDNAs were released from their biotin-labeled target homologs by alkaline denaturation and recovered by PCR amplification. These cDNAs were referred to as the SHACcDNAs. Specificity of the SHACcDNA to chromosome 11 was verified by FISH analysis. To examine representation of the SHACcDNA, we confirmed the presence of seven genes or single-copy DNA segments known to be localized on mouse chromosome 11, using a dot blot assay. In addition, a second round of SHAC was performed to achieve even higher specificity for the resulting chromosome 11 SHACcDNA. The SHAC technology should facilitate construction of cytogenetically defined cDNA libraries and should assist in the fields of gene discovery and genome mapping.

Cloning of a DNA probe and its application in the detection of Plasmodium falciparum. A preliminary report

The clones containing parasite DNA fragments were screened from a genomic DNA library of Plasmodium falciparum FCC1/HN isolate. A DNA probe derived from clone pBF4 consisting of 3 kilobase pairs hybridizes specifically with P. falciparum DNA but not with human DNA, P. cynomolgi DNA or P. berghei DNA. The nick translated radiolabelled probe can detect 10 pg purified P. falciparum DNA and a 0.001% parasitemia after 24 hours of film exposure. The probe reacts with all microscopically diagnosed P. falciparum samples and 3 of 41 P. vivax samples as well but not with any of 10 human DNA samples.

Multiple loop purification method for selective cultivation of Pentatrichomonas hominis

It is always troublesome having protozoan cultures contaminated with other organisms in the laboratory. The method described here produces high efficiencies of purification for fast moving flagellate protozoa. A human strain Pentatrichomonas hominis was employed in the study to examine the effects of multiple loop tubes on the purification of flagellates. Trichomonads were harvested from a trypticase yeast extract iron-serum-33 (TYI-S-33) medium, adjusted to 2 X 10(5) organisms/ml, and mixed with an equal volume of 2 X 10(6) organisms/ml of bacteria. The isolation was performed at 37 degrees C in TYI-S-33 medium containing a suitable amount of antibiotics (1000 U/ml of penicillin, 1000 micrograms/ml of streptomycin, and 4 micrograms/ml of fungizone). Four days later, 10(6) organisms/ml of protozoa, free of bacteria, were observed at the other end of the single loop and the double loop tubes. About the same amount of flagellates could be found at the other end of the triple loop tube six days after incubation. The traditional U-shaped tubes were used as controls and 10(5) cells/ml of flagellates were recovered in the presence of bacteria two days after incubation. An axenic culture of P. hominis was successfully isolated from the feces of a Formosan rock-monkey, Macaca cyclopsis, by this method. Purified trichomonads were recovered from a double loop purification tube five days after incubation.