Publications by authors named "John Zhao"

As water treatment technology has improved, the amount of available process data has substantially increased, making real-time, data-driven fault detection a reality. One shortcoming of the fault detection literature is that methods are usually evaluated by comparing their performance on hand-picked, short-term case studies, which yields no insight into long-term performance. In this work, we first evaluate multiple statistical and machine learning approaches for detrending process data.

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Augmenting the natural melanocortin pathway in mouse eyes with uveitis or diabetes protects the retinas from degeneration. The retinal cells are protected from oxidative and apoptotic signals of death. Therefore, we investigated the effects of a therapeutic application of the melanocortin alpha-melanocyte-stimulating hormone (α-MSH) on an ischemia and reperfusion (I/R) model of retinal degenerative disease.

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The ring-opening of cyclic ethers (epoxide, oxetane, THF, and THP) by carboxylic acids was achieved by using -iodosuccinimide (NIS) or -bromosuccinimide (NBS) and triphenylphosphine under blue light. The corresponding ω-haloalkyl carboxylates were obtained under mild reaction conditions. The reaction is believed to work through a halogen bond complex between NIS (or NBS) and triphenylphosphine, which, upon irradiation with blue light, produces the key phosphine radical cation intermediate that initiates the ring-opening reactions.

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When obtaining surgical fixation of lateral malleolus fractures, a cortical lag screw is commonly used to obtain anatomic reduction. Subsequently, a neutralization plate is applied. Slight loss of fracture reduction after plate placement occasionally occurs.

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This is an exploratory study on the effect of electrolysis, delivered during the thawing stage of a cryoablation protocol, on tissue ablation. This treatment protocol, that combines freezing and electrolysis, is named "cryoelectrolysis". In cryoelectrolysis the cryoablation probe is also used as the electrolysis delivering electrode.

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A direct one-pot alkylation-aminoxidation of styrene derivatives was achieved using -generated alkyl and -oxyl radicals. The corresponding -alkylated hydroxylamine derivatives were obtained in moderate to good yields. The reaction features the generation of the alkyl radicals from phenyliodine(III) dicarboxylates an organocatalytic process, the use of phenyliodine(III) dicarboxylates as the source of the alkyl radicals and oxidants for the generation of -oxyl radicals, and the first generation of the β-enaminyl radicals a HAT process and their use as single-electron donors.

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Background: While the lateral hook test (LHT) has been widely used to arthroscopically evaluate syndesmotic instability in the coronal plane, it is unclear whether the angulation of the applied force has any impact on the degree of instability. We aimed to determine if changing the direction of the force applied while performing the LHT impacts the amount of coronal diastasis observed in subtle syndesmotic injuries.

Methods: In 10 cadaveric specimens, arthroscopic evaluation of the syndesmotic joint was performed by measuring anterior and posterior-third coronal plane diastasis in the intact state, and repeated after sequential transection of the 1) anterior inferior tibiofibular ligament (AITFL), 2) interosseous ligament (IOL), and 3) posterior inferior tibiofibular ligament (PITFL).

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The α-acyloxylcarbonyl motif can be found in many important pharmaceuticals and biologically active natural products and their derivatives. In this manuscript, the direct synthesis of α-acyloxylketones from ketones and readily available carboxylic acids was realized using a photo-assisted halogen bond-mediated organocatalytic α-acyloxylation reaction. The desired α-acyloxylation products were obtained in good to high yields.

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Background: Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. Although instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the isolated Weber B fibula fracture often requires further investigation. Prior authors have demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis, and swelling with instability.

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Background: The lateral fibular stress test (LFST), also known as the hook or Cotton test, is commonly performed to assess syndesmotic instability intraoperatively. Several studies have used 100 N as the force applied when performing the LFST to detect syndesmotic instability, though no evidence-based requisite force has been described for the test. We hypothesize that surgeons do not apply force uniformly or consistently when performing the LFST and that substantial variation exists.

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Portable fluoroscopy devices provide point-of-care imaging in emergency and out-patient clinics. In this prospective study, we compared weightbearing images of syndesmosis obtained using a novel lightweight portable battery-powered fluoroscopy device with those obtained with a conventional radiography device. Eleven healthy participants underwent bilateral 3-view weightbearing imaging of both ankles using a radiography (X-ray group) device and a portable fluoroscopy system (LPF group).

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Although surgical fixation can take many forms depending on ankle fracture morphology, the goals of open reduction internal fixation are to restore fracture alignment, re-establish ankle stability, and achieve an anatomic mortise. A subset of patients may present postoperatively with evidence of suboptimal open reduction internal fixation. Increased contact pressures across the tibiotalar joint, increased talar shift, and pathologic joint loading leading to the development of post-traumatic arthritis are common sequela of the malaligned mortise.

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Background: Minimally invasive surgery (MIS) is growing in the field of foot and ankle, and the MIS burr is an emerging tool. Although commonly used to perform osteotomies, the burr can also be used for arthrodesis joint preparation that traditionally would be performed through open incisions. To date, there is no study comparing the quality of joint preparation between using a fluoroscopy-guided MIS technique compared to traditional open techniques.

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The domino Michael/Michael reaction between ()-7-aryl-7-oxohept-5-enals and -cinnamaldehydes was investigated by using modularly designed organocatalysts (MDOs). It was found that both the enamine and iminium catalytic modes of the MDOs are switchable and can be individually switched on and off by using appropriate combinations of the precatalyst modules and the reaction conditions. When both the enamine and iminium catalysis modes of the MDOs are switched on, the desired domino reaction products can be obtained in good yields and stereoselectivities under optimized conditions.

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Substrate channeling, where an intermediate in a multistep reaction is directed toward a reaction center rather than freely diffusing, offers several advantages when employed in catalytic cascades. Here we present a fusion enzyme comprised of an alcohol and aldehyde dehydrogenase, that is computationally designed to facilitate electrostatic substrate channeling using a cationic linker bridging the two structures. Rosetta protein folding software was utilized to determine an optimal linker placement, added to the truncated termini of the proteins, which is as close as possible to the active sites of the enzymes without disrupting critical catalytic residues.

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The cinchona thiourea moiety in the self-assembled modularly designed organocatalysts (MDOs) switches off the iminium catalysis of these catalysts. In this study, it was found that the inhibited iminium catalysis could be switched on by using an appropriate weak acid and that, once the iminium catalysis was switched on, these catalysts could be applied for the highly stereoselective and diastereodivergent synthesis of 4-oxocyclohexanecarbaldehydes via a domino reaction between ketones and α,β-unsaturated aldehydes.

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A three-component reaction between γ-aryl-substituted α,β-unsaturated aldehydes and nitroalkenes was realized by using cinchona alkaloid-derived (thio)ureas and squaramides via the dienolate intermediates. This unprecedented 1,3- and 1,5-reactivity of dienolates of the γ-aryl-α,β-unsaturated aldehydes led to the formation of cyclohexenol derivatives with four contiguous stereogenic centers and a chiral substituent at C2 with good diastereoselectivities and high ee values. Such reactivities of the dienolates are totally different from those of the corresponding dienamine intermediates.

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A highly stereoselective method for the synthesis of functionalized 3-oxabicyclo[3.3.1]nonan-2-one derivatives with four contiguous stereogenic centers, including one tetrasubstituted stereogenic center, was realized through an organocatalytic domino Michael-hemiacetalization-Michael reaction of ()-3-aryl-2-nitroprop-2-enols and ()-7-aryl-7-oxohept-5-enals followed by a PCC oxidation.

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Article Synopsis
  • Scientists are trying to understand how cells divide and form different structures, but it's still a big mystery.
  • This study looked into how certain charged molecules affect the growth of synthetic structures that can act like cells and even divide.
  • They found that these structures behave in some ways similar to really strange physics laws, like a type of quantum equation, even though it's not exactly how quantum mechanics normally works.
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A highly stereoselective method for achieving the -Mannich reaction of aldehydes and ketones with ethyl (4-methoxyphenylimino)acetate was realized using the modularly designed organocatalysts (MDOs) self-assembled from cinchona alkaloid derivatives and (A)-pyrrolidien-3-carboxylic acid in the reaction media. The desired -Mannich products were obtained in good to excellent yields (up to 93%), excellent diastereoselectivities (up to 99:1 dr), and good to high enantioselectivities (up to 99% ee).

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The diastereodivergent synthesis of hexahydro-6H-benzo[c]chromen-6-one derivatives with good to high diastereoselectivities (up to 98:2 d.r.) and enantioselectivities (up to >99 % ee) has been achieved by using a domino Michael/Michael/hemiacetalization reaction between trans-2-hydroxy-β-nitrostyrenes and trans-7-oxo-5-heptenals followed by oxidation.

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Background: Opioid use is a public health crisis in the United States and an area of increased focus in orthopaedic surgery. The aim of this study is to investigate whether preoperative opioid use had any effect on patient-reported outcome measures (PROMs) before and after total hip arthroplasty (THA).

Methods: A total of 389 patients with THA with both preoperative and postoperative PROMs were reviewed: (1) 76 patients with preoperative opioid use (24%) and (2) 237 patients without preoperative opioid use (76%).

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Article Synopsis
  • The study evaluated the reliability of smartphone photography as a method for measuring finger range of motion (ROM) compared to traditional manual goniometry, specifically using patients with Dupuytren disease as subjects.
  • Fifty patients with Dupuytren contractures were analyzed, with measurements showing that smartphone photography resulted in contracture angles very close to those taken by trained professionals (mean difference of only 3.2°).
  • The results indicate that smartphone photography can provide accurate measurements of finger contractures, matching the precision of goniometers, which opens up potential for telemedicine applications in both clinical and research settings.
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