Publications by authors named "Nathaniel Ng"

Poorly cohesive carcinoma (PCC) is an uncommon neoplasm characterized by tumorous cells exhibiting a lack of adhesion. PCC has been reported rarely in the small intestine other than at the ampulla of Vater. We present a 40-year-old man with recurrent abdominal pain and small bowel obstruction.

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  • Traditional classification of animals, particularly birds, often relies on physical traits like plumage color, but this can lead to misclassification.
  • Recent studies using bioacoustic and genomic data have challenged these traditional methods, revealing errors in genus boundaries within the flycatcher subfamily Niltavinae.
  • The research demonstrates that song characteristics are crucial for accurate classification, prompting a reorganization of genera and a reconsideration of biogeographical limits based on integrative datasets rather than solely on morphology.
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Sugars are an important class of nutrients found in the flowers and fruits of angiosperms (flowering plants). Although T1R2-T1R3 has been identified as the mammalian sweet receptor, some birds rely on a repurposed T1R1-T1R3 savory receptor to sense sugars. Moreover, as the radiation of flowering plants occurred later than the last common ancestor of amniotes, sugar may not have been an important diet item for amniotes early in evolution, raising the question of whether T1R2-T1R3 is a universal sugar sensor or only a mammalian innovation.

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  • Quaternary climate changes have been a key factor in animal evolution, but their effects on biodiversity in Southeast Asia, where land bridges emerged during glaciation, aren't fully understood.* -
  • This study examines five songbird species complexes to explore how these land bridges affected genetic connectivity in Southeast Asian forests, using a combination of morphological, acoustic, and genomic analysis.* -
  • Findings indicate that species with specific forest habitat needs show significant genetic differentiation without gene flow during glacial periods, while more generalist species have maintained some connectivity, highlighting the importance of life history in population diversity.*
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Study Design: Prospective radiographic comparative study.

Purpose: To compare and understand the load-bearing properties of each functional spinal unit (FSU) using three commonly assumed, physiological, spinal postures, namely, the flexed (slump sitting), erect (standing) and extended (backward bending) postures.

Overview Of Literature: Sagittal spinal alignment is posture-dependent and influences the load-bearing properties of the spine.

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Birds are the best-known animal class, with only about five or six new species descriptions per year since 1999. Integrating genomic and phenotypic research with arduous fieldwork in remote regions, we describe five new songbird species and five new subspecies from a small area near Sulawesi, Indonesia, all collected in a single 6-week expedition. Two factors contributed to the description of this large number of species from such a small geographic area: (i) Knowledge of Quaternary Period land connections helped pinpoint isolated islands likely to harbor substantial endemism and (ii) studying accounts of historic collectors such as Alfred Wallace facilitated the identification of undercollected islands.

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  • * Its incidence is between 1.2-20.3 cases per 100,000 persons/year and it peaks in two age groups: young adults (20-30s) and older individuals (50-80s).
  • * Key risk factors include genetics, environmental influences, and gut microbiota, with definitive diagnosis relying heavily on histopathological findings showing specific changes in the colonic tissue.
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Leaf warblers (Aves; Phylloscopidae) are a diverse clade of insectivorous, canopy-dwelling songbirds widespread across the Old World. The taxonomy of Australasian leaf warblers is particularly complex, with multiple species-level divergences between island taxa in the region requiring further scrutiny. We use a combination of morphology, bioacoustics, and analysis of thousands of genome-wide markers to investigate and describe a new species of Phylloscopus leaf warbler from the island of Rote in the Lesser Sundas, Indonesia.

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The taxonomic status of the geographically isolated population of Short-toed Snake-eagle Circaetus gallicus on the Lesser Sundas (=Nusa Tenggara) has been controversial. In the past they have been regarded as either a migrant population or a recently arrived resident population. Here we obtained DNA sequences from the mitochondrial cytochrome-b gene and combined genetic data with assessments of published and novel morphological data to clarify the taxonomic status of the Lesser Sundas population of C.

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The role of Pleistocene Ice Age in tropical diversification is poorly understood, especially in archipelagos, in which glaciation-induced sea level fluctuations may lead to complicated changes in land distribution. To assess how Pleistocene land bridges may have facilitated gene flow in tropical archipelagos, we investigated patterns of diversification in the rarely-collected rusty-bellied fantail Rhipidura teysmanni (Passeriformes: Rhipiduridae) complex from Wallacea using a combination of bioacoustic traits and whole-genome sequencing methods (dd-RADSeq). We report a biogeographic leapfrog pattern in the vocalizations of these birds, and uncover deep genomic divergence among island populations despite the presence of intermittent land connections between some.

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The genus Peromyscus has been used as a model system for understanding maternal behavior because of the diversity of reproductive strategies within this genus. This review will describe the ecological factors that determine litter size and litter quality in polygynous species such as Peromyscus leucopus and Peromyscus maniculatus. We will also outline the physiological and social factors regulating maternal care in Peromyscus californicus, a monogamous and biparental species.

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  • - A retrospective study of 84 patients over 14 years examined the effects of different treatment methods for deep spine infections, comparing antibiotics alone, antibiotics plus debridement, and antibiotics plus debridement with instrumentation.
  • - The study found no significant differences in reoperation or reinfection rates among the treatment groups, indicating that adding instrumentation does not negatively impact patient outcomes.
  • - Those who received spinal instrumentation had a lower in-hospital mortality rate compared to those treated with antibiotics alone, suggesting that instrumentation may be a safe option in managing spine infections.
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Species identification has traditionally relied on morphology. However, morphological conservatism can lead to a high incidence of cryptic species, as characters other than morphological ones can be biologically important. In birds, the combined application of bioacoustic and molecular criteria has led to an avalanche of cryptic species discoveries over the last two decades in which findings of deep vocal differentiation have usually been corroborated by molecular data or vice versa.

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The newt, a urodele amphibian, is able to repeatedly regenerate its limbs throughout its lifespan, whereas other amphibians deteriorate or lose their ability to regenerate limbs after metamorphosis. It remains to be determined whether such an exceptional ability of the newt is either attributed to a strategy, which controls regeneration in larvae, or on a novel one invented by the newt after metamorphosis. Here we report that the newt switches the cellular mechanism for limb regeneration from a stem/progenitor-based mechanism (larval mode) to a dedifferentiation-based one (adult mode) as it transits beyond metamorphosis.

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  • - The introduction discusses severe liver bleeding and the typical use of perihepatic packing, which can have complications; an improved technique called BOLSA (Bag on Liver Supporting Anti-Hemorrhage) using Vicryl mesh wraps is introduced for treating such hemorrhages.
  • - A 59-year-old male patient showed ongoing liver bleeding post-biopsy, requiring multiple surgeries and transfusions, and ultimately benefited from the BOLSA technique to stop the hemorrhage effectively.
  • - The discussion highlights the disadvantages of traditional perihepatic packing, such as increased infection risk and the need for further surgeries, while BOLSA presents a simpler, self-supporting method that minimizes these issues in coagulopathic patients.
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Ventral hernia recurrence rates have improved with advancements in technique. Open and laparoscopic fascial component separation techniques improve recurrence rates by allowing a tension free closure. This study examines laparoscopic component separation (LCS) and open component separation (OCS) techniques in the repair of complex ventral hernias and compares factors affecting patient outcomes.

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Nanostructured piezoelectric and ferroelectric thin films are being increasingly used in sensing and actuating microdevices. In this work, we report the experimental discovery of localized electric field enhancement in nanocolumnar piezoelectric thin films and its significant impact on piezoresponse. The magnitude of electric field enhancement is associated with nonflat surface morphologies and is in agreement with theoretical and finite element models.

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The effects of surface morphology on polarization switching in thin ferroelectric films are investigated using a real-space, time-dependent Ginzburg-Landau model that incorporates electrostatic interactions. We consider a two-dimensional uni-axial ferroelectric film with a thickness that varies sinusoidally. Polarization switching, starting from a single domain remnant state, is simulated for several surface modulation amplitudes and wavelengths.

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The line width dependence of zero-phonon lines and phonon sidebands on temperature, bath dissipation, and electron-phonon coupling is studied for an underdamped Brownian oscillator model with an Ohmic dissipative bath. Factors determining the line widths vary from the zero-phonon lines to the phonon sidebands. The control-parameter space of line broadening has been mapped out, revealing that the line widths of the zero-phonon lines and phonon sidebands are linearly dependent on both the temperature and the Huang-Rhys factor.

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