Abnormal Silicon Etching Behaviors in Nanometer-Sized Channels.

Modern semiconductor fabrication is challenged by difficulties in overcoming physical and chemical constraints. A major challenge is the wet etching of dummy gate silicon, which involves the removal of materials inside confined spaces of a few nanometers. These chemical processes are significantly different in the nanoscale and bulk. Previously, electrical double-layer formation, bubble entrapment, poor wettability, and insoluble intermediate precipitation have been proposed. However, the exact suppression mechanisms remain unclear due to the lack of direct observation methods. Herein, we investigate limiting factors for the etching kinetics of silicon with tetramethylammonium hydroxide at the nanoscale by using liquid-phase transmission electron microscopy, three-dimensional electron tomography, and first-principles calculations. We reveal suppressed chemical reactions, unstripping phenomena, and stochastic etching behaviors that have never been observed on a macroscopic scale. We expect that solutions can be suggested from this comprehensive insight into the scale-dependent limiting factors of fabrication.

Diffusion calculations on reconstructed bentonite microstructures with anion exclusion effects.

Due to their prevalence in the lithosphere and their high capability of sorbing pollutants, smectite clays play a foreground role in environmental pollution studies, waste management, and soil science. In complementarity with existing approaches at the molecular or macroscopic scales, real microstructures have been employed to investigate ionic transport by diffusion through montmorillonite and water-saturated Wyoming bentonite at intermediate scales ranging between the nanometer and the micrometer. The coupled solute transport and electrostatic phenomena investigated at the nanopore scale are upscaled using the homogenization of porous media approach. Homogenization computations rely on a hierarchical description of bentonite that acknowledges the existence of pores networks at different scales. At the scale of montmorillonite layers, digitized TEM images have been employed to simulate the diffusion of ionic solutes by considering electrostatic interactions in the vicinity of the negatively charged clay platelets' surface. Finite element microstructures are created after extraction of the contours of the layers using dedicated image processing algorithms. Local electric potential distribution, anion exclusion, and cation inclusion are displayed by ion distribution maps. The effective diffusion tensor and the transport equation obtained through volume averaging are then used to simulate diffusion at the scale of a Wyoming bentonite sample composed of clay gels of variable density, solid grains, and micropores. Qualitative comparisons were made with existing diffusion data, and a particular attention is given to the anisotropy of the diffusion tensors at both the mesoscopic and macroscopic scales.

Ion Tracks and Nanohillocks Created in Natural Zirconia Irradiated with Swift Heavy Ions.

Natural monoclinic zirconia (baddeleyite) was irradiated with 340 MeV Au ions, and the irradiation-induced nanostructures (i.e., ion tracks and nanohillocks) were observed using transmission electron microscopy. The diameter of the nanohillocks was approximately 10 nm, which was similar to the maximum molten region size calculated using the analytical thermal spike model. Ion tracks were imaged as strained regions that maintained their crystalline structure. The cross-sections of most of the ion tracks were imaged as rectangular contrasts as large as 10 nm. These results strongly indicated that the molten region was recrystallized anisotropically, reflecting the lattice structure. Furthermore, low-density track cores were formed in the center of the ion tracks. The formation of low-density track cores can be attributed to the ejection of molten matter toward the surface. A comparison of the ion tracks in the synthetic zirconia nanoparticles and those in larger natural zirconia samples showed that the interface between the strained track contrast and the matrix was less clear in the former than in the latter. These findings suggest that the recrystallization process was affected by the size of the irradiated samples.

Microstructure Evolution during High-Pressure Torsion in a 7xxx AlZnMgZr Alloy.

A homogenized, supersaturated AlZnMgZr alloy was processed via severe plastic deformation (SPD) using a high-pressure torsion (HPT) technique for different revolutions at room temperature to obtain an ultrafine-grained (UFG) microstructure. The microstructure and mechanical properties of the UFG samples were then studied using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and tensile and hardness measurements. The main purpose was to study the effect of shear strain on the evolution of the microstructure of the investigated alloy. We found a very interesting evolution of the decomposed microstructure in a wide range of shear strains imposed by HPT. While the global properties, such as the average grain size (~200 nm) and hardness (~2200 MPa) appeared unchanged, the local microstructure was continuously transformed. After 1 turn of HPT, the decomposed UFG structure contained relatively large precipitates inside grains. In the sample processed by five turns in HPT, the segregation of Zn atoms into grain boundaries (GBs) was also observed. After 10 turns, more Zn atoms were segregated into GBs and only smaller-sized precipitates were observed inside grains. The intensive solute segregations into GBs may significantly affect the ductility of the material, leading to its ultralow-temperature superplasticity. Our findings pave the way for achieving advanced microstructural and mechanical properties in nanostructured metals and alloys by engineering their precipitation and segregation by means of applying different HPT regimes.

Ingenious Architecture and Coloration Generation in Enamel of Rodent Teeth.

Teeth exemplify architectures comprising an interplay of inorganic and organic constituents, resulting in sophisticated natural composites. Rodents (Rodentia) showcase extraordinary adaptations, with their continuously growing incisors surpassing human teeth in functional and structural optimizations. In this study, employing state-of-the-art direct atomic-scale imaging and nanoscale spectroscopies, we present compelling evidence that the release of material from ameloblasts and the subsequent formation of iron-rich enamel and surface layers in the constantly growing incisors of rodents are complex orchestrated processes, intricately regulated and independent of environmental factors. The synergistic fusion of three-dimensional tomography and imaging techniques of etched rodent́s enamel unveils a direct correlation between the presence of pockets infused with ferrihydrite-like material and the acid resistant properties exhibited by the iron-rich enamel, fortifying it as an efficient protective shield. Moreover, observations using optical microscopy shed light on the role of iron-rich enamel as a microstructural element that acts as a path for color transmission, although the native color remains indistinguishable from that of regular enamel, challenging the prevailing paradigms. The redefinition of "pigmented enamel" to encompass ferrihydrite-like infusion in rodent incisors reshapes our perception of incisor microstructure and color generation. The functional significance of acid-resistant iron-rich enamel and the understanding of the underlying coloration mechanism in rodent incisors have far-reaching implications for human health, development of potentially groundbreaking dental materials, and restorative dentistry. These findings enable the creation of an entirely different class of dental biomaterials with enhanced properties, inspired by the ingenious designs found in nature.

Critical parameters to standardize the size and concentration determination of nanomaterials by nanoparticle tracking analysis.

The size and concentration are critical for the diagnostic and therapeutic applications of nanomaterials but the accurate measurement remains challenging. Nanoparticle tracking analysis (NTA) is widely used for size and concentration determination. However, highly repeatable standard operating procedures (SOPs) are absent. We adopted the "search-evaluate-test" strategy to standardize the measurement by searching the critical parameters. The particles per frame are linearly proportional to the sample concentration and the measured results are more accurate and repeatable when the concentration is 108-109 particles/ml. The optimal detection threshold is around 5. The optimal camera level is such that it allows clear observation of particles without diffractive rings and overexposure. The optimal speed is ≤ 50 in AU and âˆ¼ 10 µl/min in flow rate. We then evaluated the protocol using polydisperse polystyrene particles and we found that NTA could discriminate particles in bimodal mixtures with high size resolution but the performance on multimodal mixtures is not as good as that of resistive pulse sensing (RPS). We further analyzed the polystyrene particles, SiO2 particles, and biological samples by NTA following the SOPs. The size and concentration measured by NTA differentially varies to those determined by RPS and transmission electron microscopy.

Thermal Stability and Crystallization Processes of Pd78Au4Si18 Thin Films Visualized via In Situ TEM.

Amorphous alloys or metallic glasses (MGs) thin films have attracted extensive attention in various fields due to their unique functional properties. Here, we use in situ heating transmission electron microscopy (TEM) to investigate the thermal stability and crystallization behavior of Pd-Au-Si thin films prepared by a pulsed laser deposition (PLD) method. Upon heating treatment inside a TEM, we trace the structural changes in the Pd-Au-Si thin films through directly recording high-resolution images and diffraction patterns at different temperatures. TEM observations reveal that the Pd-Au-Si thin films started to nucleate with small crystalline embryos uniformly distributed in the glassy matrix upon approaching the glass transition temperature Tg=625K, and subsequently, the growth of crystalline nuclei into sub-10 nm Pd-Si nanocrystals commenced. Upon further increasing the temperature to 673K, the thin films transformed to micro-sized patches of stacking-faulty lamellae that further crystallized into Pd9Si2 and Pd3Si intermetallic compounds. Interestingly, with prolonged thermal heating at elevated temperatures, the Pd9Si2 transformed to Pd3Si. Simultaneously, the solute Au atoms initially dissolved in glassy alloys and eventually precipitated out of the Pd9Si2 and Pd3Si intermetallics, forming nearly spherical Au nanocrystals. Our TEM results reveal the unique thermal stability and crystallization processes of the PLD-prepared Pd-Au-Si thin films as well as demonstrate a possibility of producing a large quantity of pure nanocrystals out of amorphous solids for various applications.

The Impact of Local Strain Fields in Noncollinear Antiferromagnetic Films.

Antiferromagnets hosting structural or magnetic order that breaks time reversal symmetry are of increasing interest for "beyond von Neumann" computing applications because the topology of their band structure allows for intrinsic physical properties, exploitable in integrated memory and logic function. One such group are the noncollinear antiferromagnets. Essential for domain manipulation is the existence of small net moments found routinely when the material is synthesized in thin film form and attributed to symmetry breaking caused by spin canting, either from the Dzyaloshinskii-Moriya interaction or from strain. Although the spin arrangement of these materials makes them highly sensitive to strain, there is little understanding about the influence of local strain fields caused by lattice defects on global properties, such as magnetization and anomalous Hall effect. This premise is investigated by examining noncollinear antiferromagnetic films that are either highly lattice mismatched or closely matched to their substrate. In either case, edge dislocation networks are generated and for the former case, these extend throughout the entire film thickness, creating large local strain fields. These strain fields allow for finite intrinsic magnetization in seemingly structurally relaxed films and influence the antiferromagnetic domain state and the intrinsic anomalous Hall effect.

Toxic effects of aniline in liver, gills and kidney of freshwater fish Channa punctatus after acute exposure.

Aniline (C6H5NH2) is one of the hazardous aromatic amine where an amino group -NH2) is connected to phenyl ring (C6H5). Based on the evaluation of the 96-hour LC50 of aniline, two sublethal concentrations (4.19 mg/l and 8.39 mg/l) were selected for acute exposure tests in freshwater fish Channa punctatus. The liver, gills and kidney of fish being the principal sites of xenobiotic material accumulation, respiration, biotransformation, and excretion are the focus of the present study. Throughout the exposure time, the comet assay revealed increased tail length and tail DNA percentage indicating maximum damage to liver, gills and kidney of treated group after 96 h. After acute exposure, there was a significant (p ≤ 0.05) increase in the enzymatic activity of glutathione-S-transferase (GST) and acetylcholinesterase (AChE), whereas decline in superoxide dismutase (SOD) and catalase (CAT) activity was observed. Meanwhile, levels of malondialdehyde (MDA) increased over the exposure period for both concentrations. After 96 h of exposure, degree of tissue change (DTC) was evaluated in liver, gill and kidney of aniline exposed fish. Additionally, light microscopy revealed multiple abnormalities in liver, gills and kidney of all the treated groups. Significant changes were observed in the levels of biochemical markers viz., glucose, triglyceride, cholesterol, aspartate transaminase, alanine transaminase and urea following a 96-hour exposure to aniline. Studies using ATR-FTIR and transmission electron microscopy (TEM) revealed changes in biomolecules and structural abnormalities in several tissues of the aniline-exposed groups in comparison to the control group respectively.

In situ Formation of Platinum-Carbon Catalysts in Propane Dehydrogenation.

The catalytic production of propylene via propane dehydrogenation (PDH) is a key reaction in the chemical industry. By combining operando transmission electron microscopy with density functional theory analysis, we show that the intercalation and ordering of carbon on Pt interstitials to form Pt-C solid solutions is relevant for increasing propylene production. More specifically, we found that at the point of enhanced propylene formation, the structure of platinum nanoparticles is transformed into a transient caesium chloride-type Pt-C polymorph. At more elevated temperatures, the zincblende and rock salt polymorphs seemingly coexist. When propylene production was highest, multiple crystal structures consisting of Pt and carbon were occasionally found to coexist in one individual nanoparticle, distorting the Pt lattice. Catalyst coking was detected at all stages of the reaction, but did initially not affect all particles. These findings could lead to the development of novel synthesis strategies towards tailoring highly efficient PDH catalysts.

Ultrauniform Plating of Lithium on 10-nm-Scale Ordered Carbon Grids for Long Lifespan Lithium Metal Batteries.

Tailorable lithium (Li) nucleation and uniform early-stage plating is essential for long-lifespan Li metal batteries. Among factors influencing the early plating of Li anode, the substrate is critical, but a fine control of the substrate structure on a scale of ≈10 nm has been rarely achieved. Herein, a carbon consisting of ordered grids is prepared, as a model to investigate the effect of substrate structure on the Li nucleation. In contrast to the individual spherical Li nuclei formed on the flat graphene, an ultrauniform and nuclei-free Li plating is obtained on the ordered carbon with a grid size smaller than the thermodynamical critical radius of Li nucleation (≈26 nm). Simultaneously, an inorganic-rich solid-electrolyte-interphase is promoted by the cross-sectional carbon layers of such ordered grids which are exposed to the electrolyte. Consequently, the carbon grids with a grid size of ≈10 nm show a favorable cycling stability for more than 1100 cycles measured at 2 mA cm-2 in a half cell. With LiNi0.8Co0.1Mn0.1O2 as cathode, the assembled full cell with a cathode capacity of 3 mAh cm-2 and a negative/positive ratio of 1.67 demonstrates a stable cycling for over 130 cycles with a capacity retention of 88%.

Effect of Extended Defects on AlGaN Quantum Dots for Electron-Pumped Ultraviolet Emitters.

We study the origin of bimodal emission in AlGaN/AlN QD superlattices displaying a high internal quantum efficiency (around 50%) in the 230-300 nm spectral range. The secondary emission at longer wavelengths is linked to the presence of cone-like domains with deformed QD layers, which originate at the first AlN buffer/superlattice interface and propagate vertically. The cones originate at a 30°-faceted shallow pit in the AlN, which appears to be associated with a threading dislocation that produces strong shear strain. The cone-like structures present Ga enrichment at the boundaring facets and larger QDs within the conic domain. The bimodality of the luminescence is attributed to the differing dot size and composition within the cones and at the faceted boundaries, which is confirmed by the correlation of microscopy results and Schrödinger-Poisson calculations.

Real-time imaging reveal anisotropic dissolution behaviors of silver nanorods.

The morphology and size control of anisotropic nanocrystals are critical for tuning shape-dependent physicochemical properties. Although the anisotropic dissolution process is considered to be an effective means to precisely control the size and morphology of nanocrystals, the anisotropic dissolution mechanism remains poorly understood. Here, usingin situliquid cell transmission electron microscopy, we investigate the anisotropic etching dissolution behaviors of polyvinylpyrrolidone (PVP)-stabilized Ag nanorods in NaCl solution. Results show that etching dissolution occurs only in the longitudinal direction of the nanorod at low chloride concentration (0.2 mM), whereas at high chloride concentration (1 M), the lateral and longitudinal directions of the nanorods are dissolved. First-principles calculations demonstrate that PVP is selectively adsorbed on the {100} crystal plane of silver nanorods, making the tips of nanorods the only reaction sites in the anisotropic etching process. When the chemical potential difference of the Cl-concentration is higher than the diffusion barrier (0.196 eV) of Cl-in the PVP molecule, Cl-penetrates the PVP molecular layer of {100} facets on the side of the Ag nanorods. These findings provide an in-depth insight into the anisotropic etching mechanisms and lay foundations for the controlled preparation and rational design of nanostructures.

Structural Reversibility of Nanoscaled Sn Anodes.

Alloying-type anode materials provide high capacity for lithium-ion batteries; however, they suffer pulverization problems resulting from the volume change during cycling. Realizing the cycling reversibility of these anodes is therefore critical for sustaining their electrochemical performance. Here, we investigate the structural reversibility of Sn NPs during cycling at atomic-level resolution utilizing in situ high-resolution TEM. We observed a surprisingly near-perfect structural reversibility after a complete cycle. A three-step phase transition happens during lithiation, accompanied by the generation of a significant number of defects, grain boundaries, and up to 202% volume expansion. In subsequent delithiation, the volume, morphology, and crystallinity of the Sn NPs were restored to their initial state. Theoretical calculations show that compressive stress drives the removal of vacancies generated within the NPs during delithiation, therefore maintaining their intact morphology. This work demonstrates that removing vacancies during cycling can efficiently improve the structural reversibility of high-capacity anode materials.

Oligomerization states of the Mycobacterium tuberculosis RNA polymerase core and holoenzymes.

During the past few decades, a wealth of knowledge has been made available for the transcription machinery in bacteria from the structural, functional and mechanistic point of view. However, comparatively little is known about the homooligomerization of the multisubunit M. tuberculosis RNA polymerase (RNAP) enzyme and its functional relevance. While E. coli RNAP has been extensively studied, many aspects of RNAP of the deadly pathogenic M. tuberculosis are still unclear. We used biophysical and biochemical methods to study the oligomerization states of the core and holoenzymes of M. tuberculosis RNAP. By size exclusion chromatography and negative staining Transmission Electron Microscopy (TEM) studies and quantitative analysis of the TEM images, we demonstrate that the in vivo reconstituted RNAP core enzyme (α2ßß'ω) can also exist as dimers in vitro. Using similar methods, we also show that the holoenzyme (core + σA) does not dimerize in vitro and exist mostly as monomers. It is tempting to suggest that the oligomeric changes that we see in presence of σA factor might have functional relevance in the cellular process. Although reported previously in E. coli, to our knowledge we report here for the first time the study of oligomeric nature of M. tuberculosis RNAP in presence and absence of σA factor.

Multi-Stimuli Operando Transmission Electron Microscopy for Two-Terminal Oxide-Based Devices.

The integration of microelectromechanical systems (MEMS)-based chips for in situ transmission electron microscopy (TEM) has emerged as a highly promising technique in the study of nanoelectronic devices within their operational parameters. This innovative approach facilitates the comprehensive exploration of electrical properties resulting from the simultaneous exposure of these devices to a diverse range of stimuli. However, the control of each individual stimulus within the confined environment of an electron microscope is challenging. In this study, we present novel findings on the effect of a multi-stimuli application on the electrical performance of TEM lamella devices. To approximate the leakage current measurements of macroscale electronic devices in TEM lamellae, we have developed a postfocused ion beam (FIB) healing technique. This technique combines dedicated MEMS-based chips and in situ TEM gas cells, enabling biasing experiments under environmental conditions. Notably, our observations reveal a reoxidation process that leads to a decrease in leakage current for SrTiO3-based memristors and BaSrTiO3-based tunable capacitor devices following ion and electron bombardment in oxygen-rich environments. These findings represent a significant step toward the realization of multi-stimuli TEM experiments on metal-insulator-metal devices, offering the potential for further exploration and a deeper understanding of their intricate behavior.

Electrically Triggered Domain Wall Movement in Cu2Se Semiconductor.

The ion-conductive α-Cu2Se is found to possess antipolar dipoles, and the movement of the domain boundary under the applied voltage causes change of resistance, showing promising application in memristors. However, due to the complex ordering of Cu ions in the α-Cu2Se, there are multiple types of domain wall structure. Here, we show that two typical domain walls in α-Cu2Se can be formed, by controlling the voltage during phase transition from high-temperature cubic ß-Cu2Se to α-Cu2Se. We also show by in situ transmission electron microscopy that the formed [01̅0]/[101̅] domain wall performs a reversible movement under the applied external voltage, while the [010]/[01̅0] domain wall does not move. We further demonstrate that pinning of the [010]/[01̅0] domain wall could be due to the formed dislocations in the interface. This study shows that applying preprocess conditions is important to obtain the designed microstructure and resistive properties of α-Cu2Se.

Oligodendrocyte progenitor cells' fate after neonatal asphyxia-Puzzling implications for the development of hypoxic-ischemic encephalopathy.

Premature birth or complications during labor can cause temporary disruption of cerebral blood flow, often followed by long-term disturbances in brain development called hypoxic-ischemic (HI) encephalopathy. Diffuse damage to the white matter is the most frequently detected pathology in this condition. We hypothesized that oligodendrocyte progenitor cell (OPC) differentiation disturbed by mild neonatal asphyxia may affect the viability, maturation, and physiological functioning of oligodendrocytes. To address this issue, we studied the effect of temporal HI in the in vivo model in P7 rats with magnetic resonance imaging (MRI), microscopy techniques and biochemical analyses. Moreover, we recreated the injury in vitro performing the procedure of oxygen-glucose deprivation on rat neonatal OPCs to determine its effect on cell viability, proliferation, and differentiation. In the in vivo model, MRI evaluation revealed changes in the volume of different brain regions, as well as changes in the directional diffusivity of water in brain tissue that may suggest pathological changes to myelinated neuronal fibers. Hypomyelination was observed in the cortex, striatum, and CA3 region of the hippocampus. Severe changes to myelin ultrastructure were observed, including delamination of myelin sheets. Interestingly, shortly after the injury, an increase in oligodendrocyte proliferation was observed, followed by an overproduction of myelin proteins 4 weeks after HI. Results verified with the in vitro model indicate, that in the first days after damage, OPCs do not show reduced viability, intensively proliferate, and overexpress myelin proteins and oligodendrocyte-specific transcription factors. In conclusion, despite the increase in oligodendrocyte proliferation and myelin protein expression after HI, the production of functional myelin sheaths in brain tissue is impaired. Presented study provides a detailed description of oligodendrocyte pathophysiology developed in an effect of HI injury, resulting in an altered CNS myelination. The described models may serve as useful tools for searching and testing effective of effective myelination-supporting therapies for HI injuries.

An Examination of the Effects of Propolis and Quercetin in a Rat Model of Streptozotocin-Induced Diabetic Peripheral Neuropathy.

The purpose of this study was to reveal the combined effects of propolis (P) and quercetin (Q) against diabetic peripheral neuropathy developing with streptozotocin-induced diabetes in rats. Sixty-four adult male rats were divided into eight equal groups: control, P (100 mg/kg/day), Q (100 mg/kg/day), P + Q (100 mg/day for both), diabetes mellitus (DM) (single-dose 60 mg/kg streptozotocin), DM + P, DM + Q, and DM + P + Q. The rats were sacrificed, and blood and sciatic nerve tissues were collected. Blood glucose and malondialdehyde (MDA) levels increased, while IL-6 and total antioxidant status decreased in the DM group (p = 0.016 and p = 0.047, respectively). Ultrastructural findings showed degeneration of the axon and myelin sheath. The apoptotic index (AI %), TNF-α, and IL-1ß immunopositivity increased significantly in the DM group (p < 0.001). Morphological structures approaching those of the controls were observed in the DM + P, DM + Q, and DM + P + Q groups. Morphometric measurements increased markedly in all treatment groups (p < 0.001), while blood glucose and MDA levels, AI (%), TNF-α, and IL-1ß immunopositivity decreased. In conclusion, the combined effects of propolis and quercetin in diabetic neuropathy may provide optimal morphological protection with neuroprotective effects by reducing hyperglycemia, and these may represent a key alternative supplement in regenerative medicine.

Identification of antibiotic resistance genes in Escherichia coli from subclinical mastitis milk in dairy cows and goats, East Java Province.

Antibiotics are still used to treat mastitis in dairy cows in Indonesia. This study aimed to analyse antibiotic resistance genes in Escherichia coli (E. coli) from subclinical mastitis milk in East Java Province, Indonesia. The samples consisted of subclinical mastitis milk from cows and goats. A total of 592-quarter cow's milk and 71 goat's milk samples from both halves of the udder were collected from 67 farms in Lumajang, Banyuwangi, Malang, Sidoarjo, Jember, Pasuruan, Probolinggo, and Mojokerto. Subclinical mastitis samples were screened using the California mastitis test (CMT). E. coli was identified by phenotypic and genotypic methods. E. coli was confirmed with a primer specific to the polymerase chain reaction (PCR) technique. Gene resistance of E. coli was tested using the multiplex-PCR (mPCR) technique with primers encoding the genes temoneira enzyme (TEM), oxacillinase (OXA), sulfhydryl variable (SHV), and cefotaximase-munich IV (CTX-M IV). These genes were chosen because mastitis treatment generally uses oxacilline and ß-lactam antibiotics. All data obtained were analysed descriptively. The results show that six isolates of E. coli (46.15%) carried a single resistance gene (TEM or SHV) and two isolates (33.33%) were confirmed as multiple drug-resistant organisms (MDROs) (TEM and SHV). The resistance genes were found in samples originating from Blitar, Banyuwangi, Lumajang, and Pasuruan Regencies. This research implies that antibiotic-resistance genes found in E. coli on certain farms are dangerous and may allow gene transmission to other bacteria that make treatment for mastitis or other bacterial infections ineffective.